# Alien DAC v1.1 Construction Thread



## peterpan188

Since most people are getting the PCBs in the comming week, I will just start this off.

 Does anymore have a complete BOM for USB power option, regardless from Digikey or Mouser?

 Also, for CL and CR, I assume film caps are the choice there rit?

 Thanks for Alf, for all this effort.

 Thanks,
 Peter


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## mb3k

Anyone have recommendations for DIY external PSU's for this DAC?


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## robzy

Quote:


  Originally Posted by *mb3k* 
_Anyone have recommendations for DIY external PSU's for this DAC?_

 

Im just doing a protoboard + 2 LM317s. (Esentially a TREAD).

 Rob.


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## RichA

My shopping list at Farnell, should it interest anyone. I make no promises as to whether this list is complete or not, or made of the best components available - I've gone for good specifications, good price, and a few different types of capacitor for CL/CR - Sanyo SH should sound nice from what I've read, if you don't fancy trying the tantalums or whatnot.

 Apparantly, Naim only bother with tantalums for coupling. Wonder if it's one of the reasons for their uncoloured sound?

  Code:


```
[left]QtyP/NDescPri(ea) ----------------------------------------------------------- 1x418596Soldering tip£2.31 // Probably only 1x418560Soldering tip£2.31 // applicable to 1x1182013Desolder braid£1.09 // me ;) ----------------------------------------------------------- 8x3056594Ferrite 600R£0.22 1x95277020805 2.2UF 25V£0.037 1x8812381CAPACITOR, 470UF 10V£0.26 2x7552290805 33PF 50V£0.028 1x4310007CAPACITOR, 47UF 6.3V£0.65 10x75695640805 S/TERM. 100NF 50V£0.057 *********************************************************** /////////////////////////////////////////////////////////// 2x1144596CAPACITOR, 100UF 6.3V£0.128 Out of stock. Alternative below. /////////////////////////////////////////////////////////// 2x9452354CAPACITOR, 100UF 6.3V£0.164 *********************************************************** 2x1100453TANTALUM 22UF 6.3V£0.44 // Experimentation with CL/CR 2x1166632ALUM. ELEC. 10UF 25V£0.69 // Experimentation with CL/CR 2x9189440SANYO SH, 4.7UF 25V£0.62 // Experimentation with CL/CR 2x9527710CAPACITOR 0808 1UF 16V£0.033 // Experimentation with CL/CR 2x9527699CAPACITOR 0603 1UF 6.3V£0.023 // Experimentation with CL/CR 2x9332847RESISTOR, 0805 22R£0.02 1x9332600RESISTOR, 0805 1K5£0.02 1x9332413RESISTOR, 0805 1M£0.02 1x9333070RESISTOR, 0805 330K£0.02 2x9334310RESISTOR, 0805 620R£0.02 1x971276312mhz 20ppm£1.18 1x971295012mhz 30ppm£0.72 1x10032093mm LED£0.09 1x1097897USB type B£1.12[/left]
```

I did try to get away with a cheaper USB socket, but couldn't find one with the same pin-out. Meh...

 I've got 4 boards here, and will be doubling up on many of the above values. *PRICES ARE PER INDIVIDUAL ITEM, NOT FOR THE QUANTITY REQUIRED.*

 Hope I've not missed anything 
	

	
	
		
		

		
			





.

 --Rich


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## Sinbios

Here's my BOM for Digikey, designed for direct power through USB. The price is in CDN for two DACs.

 Could everyone look through and make sure everything is in order?


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## tomb

I tried using all of the various BOM's available, but Doobooloo's spread between DigiKey and Mouser was best. However, she didn't choose to go for the Regulator at 4.8V with R31/R32. So, you may want to add those three things. Hers is here: Doobooloo's Alien DAC BOM

 Cook wrote one up for quantity X 2, which was helpful for me, but DigiKey is out of stock on some items - like the USB socket. His BOM appears to be an HTML-version of the DigiKey order printout, so it will not be as flexible: Cook's BOM

 Note that Doobooloo's USB socket has gold-plated contacts (Mouser). That may not be obvious if you try to source one somewhere else. She also included an Xtal Mylar spacer, which may or may not be important, but is a pretty cheap thing to add just in case.

 Finally, keep your eyes open on the SMD stuff. It hardly makes sense to order 2 or 3 SMD resistors when 10 are cheaper.


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## steinchen

Quote:


  Originally Posted by *RichA* 
_I've gone for good specifications, good price, and a few different types of capacitor for CL/CR - Sanyo SH should sound nice from what I've read, if you don't fancy trying the tantalums or whatnot.

 Apparantly, Naim only bother with tantalums for coupling. Wonder if it's one of the reasons for their uncoloured sound?_

 

standard tantalums are known to be bad when used in the signal path, I'd rather try a boxed polyester cap (like Wima MKS) when the cap has to fit onto the pcb or a (metallized) polypropylene film cap (like Wima MKP) when the cap can be air wired between pcb and rca jacks


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## RichA

Ah well, got enough bits to let me fiddle 
	

	
	
		
		

		
		
	


	




. I'll have one reference design, and one for tweaking 
	

	
	
		
		

		
		
	


	




.

 --Rich


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## peterpan188

I am looking over again at the Alien DAC part list page. It recommands electrolytic for CL and CR. From my understanding, is it bad to use such in a signal path directly? Isn't film types (Musicap, Wima MKP10, Cardas caps, Pany ECQ-P) better in this application?

 Thanks,
 Peter


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## tomb

After reading dsavitsk's reviews on capacitors (referenced in Alf's Parts List discussion on CL/R), it seems apparent that 47uF, 6.3V NX-HiQ Black Gates are the output caps of choice for DAC's. I have been afraid of Black Gates for obvious reasons, but the ones of this size are about $2.50 ea. That's a small price to pay to mean the difference between a juicy-sounding DAC and one that's only so-so. They will fit the board pattern perfectly, too.

 Note that Doobooloo's BOM, that I referenced in the earlier post above, also has these Black Gates listed for CL and CR.


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## Sinbios

Why 47uF? Wouldn't 4.7uF be sufficient?


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## dsavitsk

Quote:


  Originally Posted by *Sinbios* 
_Why 47uF? Wouldn't 4.7uF be sufficient?_

 

Yes.

 Also, don't ignore the Nichicon Muse ES series. They will add some warmth and bloom and are very cheap.


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## tomb

The suppliers I've checked do not have NX-HiQ in 4.7uF. You have to go with 47uF to get the NX-HiQ, and that is still within the range that Alf specifies. Further, the less quality, 4.7uF is _more_ expensive:

Kyoto-Electro

 The Nichicon Muse ES is the same way - at least at Handmade Electronics. The smallest is the 47uF. They are listed at $0.32, but Handmade has a $12.99 minimum, and a surcharge up to $25. It's hard to tell, though - they are in the process of renovating their website and things are screwed up.


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## Sinbios

The 4.7uF Elna Silmic II are available at digikey, and they fit the size requirements as well.


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## Alf

I just realised that I have never published my BOM 
	

	
	
		
		

		
		
	


	




 Here it goes.


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## MASantos

Quote:


  Originally Posted by *Alf* 
_I just realised that I have never published my BOM 
	

	
	
		
		

		
			





 Here it goes._


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## frdchang

hello,

 by inspection, my boards look like the pads are covered by the silkscreen material.

 is this normal? 
 here is a scan of the board:










 i scratched some silkscreen material off to reveal the pad underneath.

 [NEVERMIND]
 a quick 5 second test with a soldering iron answered all my questions. I never seen this pad coating before... the boards i get usually have tinned pads that are shiny.
 Look forward to building this thing after my MCATs.

 thanks,
 fred


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## cook

From Assembly page :

  Quote:


 If you use an adjustable regulator IC3, populate the C32 position on the bottom side while R31 and R32 go to the top side. 
 

There does not seem to be a place on the top for R31 (well at least to my eyes right now). Should R31 actually go on the bottom (top is where the PCM chip is right ?)


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## robzy

My digikey BOM is attached. Please double check things though 
	

	
	
		
		

		
		
	


	




 [size=xx-small](Also - would any americans/canadians that are doing a digikey order soonish please check out this thread, it would be _really_ appreciated 
	

	
	
		
		

		
		
	


	




)[/size]

 Rob.


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## Alf

Quote:


  Originally Posted by *frdchang* 
_hello,

 by inspection, my boards look like the pads are covered by the silkscreen material.

 is this normal? 

 ....................

 a quick 5 second test with a soldering iron answered all my questions. I never seen this pad coating before... the boards i get usually have tinned pads that are shiny.
 Look forward to building this thing after my MCATs.

 thanks,
 fred_

 

EuroCircuits use "immersion silver" technology. I think you have been scratching off the silver coating.


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## Alf

Quote:


  Originally Posted by *cook* 
_From Assembly page :



 There does not seem to be a place on the top for R31 (well at least to my eyes right now). Should R31 actually go on the bottom (top is where the PCM chip is right ?)_

 

Well spotted. Thanks for bringing it up. Your assumption is correct. It should say

 "If you use an adjustable regulator IC3, populate the C32 and R31 positions on the bottom side and R32 on the top side."

 I updated the web site accordingly.

  Quote:


  Originally Posted by *cook* 
_top is where the PCM chip is right?_

 

Correct


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## cook

So it works just fine 
	

	
	
		
		

		
		
	


	




 Sound is fine. I didn't have much time to compare it to my Revo 5.1 though.

 Still have to play with regulator - may have to decrease R31/R32 to let regulator kick in. Right now regulated 5V it almost same as it comes from USB.

 I checked DC offset without CL/CR and it was more than 1V. Right now I'm waiting for Blackgates and have temporary CL/CR in the DAC. I'm wondering why DC offset with CL/CR but without amp connected was still high. Now it's in mV range with amp connected and CL/CR... Haven't had time to check what if I remove CL/CR and connect amp. May be I can bypass CL/CR. If not - I'll need a lot of patience to wait when/if www.kyoto-electro.com shipment will come. It's already 2+ weeks wait 
	

	
	
		
		

		
		
	


	




 After build it needs cleaning big time. I still have a bit of rosin under the chips. No way I can clean that. Here are pics for your pleasure :


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## tomb

Gosh - I hope that's not a bad sign - I ordered BG's from kyoto-electro, too. 
	

	
	
		
		

		
		
	


	




 I have been a little concerned since I received neither order confirmation or Paypal payment confirmation from them.

 EDIT: Nice pics, BTW.


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## cook

Well something not right with my IC3 REG101UA-5. I have 5.3V from USB and 5.2V after reg. No matter how much I decrease R31/R32. Even after adding 22k parallel to the R31. Are those REG101s easily damaged ?


 Re: kyoto-electro: I've got Paypal/order confirmation on 6/23 but still no reply whether they shipped it or not...


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## MisterX

Quote:


  Originally Posted by *tomb* 
_Gosh - I hope that's not a bad sign - I ordered BG's from kyoto-electro, too. 
	

	
	
		
		

		
		
	


	




 I have been a little concerned since I received neither order confirmation or Paypal payment confirmation from them.

 EDIT: Nice pics, BTW._

 


 After three weeks and 4 emails I got sick of waiting for them to even reply to my emails and filed a claim with Paypal. 
 They did not even respond to the emails Paypal sent them about the claim and as such it didn't take Paypal very long to "settle the dispute"

 parts conneXion here you come.


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## peterpan188

IMHO, partsConnexion is the best source I would go for. It does take them 1 or 2 days to process your order, but it is because they are careful. I once ordered some PRP resistors, and it was the the .5watts that I am ordering. I put the part number as the 1watts ones, and wrote the description as .5watts. They called me a day after I sent in the order, to confirm about the order. I really like that, and they even changed my shipping method from express post (what I picked) to UPS, because they found it to be cheaper. It came in within 3 days. Very nice.

 Peter


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## Alf

Quote:


  Originally Posted by *cook* 
_Well something not right with my IC3 REG101UA-5. I have 5.3V from USB and 5.2V after reg. No matter how much I decrease R31/R32. Even after adding 22k parallel to the R31. Are those REG101s easily damaged_

 

Do you use the adjustable version of REG101 or the 5V one?


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## cook

Quote:


  Originally Posted by *Alf* 
_Do you use the adjustable version of REG101 or the 5V one?_

 

Doh! I didn't realize they are different. I'll have to order REG101UA-A one.


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## tomb

Quote:


  Originally Posted by *MisterX* 
_After three weeks and 4 emails I got sick of waiting for them to even reply to my emails and filed a claim with Paypal. 
 They did not even respond to the emails Paypal sent them about the claim and as such it didn't take Paypal very long to "settle the dispute"

 parts conneXion here you come. 
	

	
	
		
		

		
		
	


	


_

 

Drat! I was afraid of that.

 P.S. I ordered the REG101UA-5, too. Better check those BOM's on the Group Buy thread. The last 3 BOM's were meant for a regulated, USB-powered config, and everyone of them had REG101UA-5.


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## peterpan188

I am a little confused about IC3. I thought we can't really use the fixed voltage regulator, REG101UA-5, REG102UA-5, for direct USB powered option. The part list note says that, it doesn't really regulate. Instead we have to use REG101UA-A, or REG102UA-A as adjustable regulator, and regulate it down to 4.8V using R31 and R32. But at the same time, the part list tells that they are only mandatory for all configurations except Direct USB. What is right? I am planning to use the DAC always USB powered, what should I get?

 Thanks,
 Peter


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## cook

Quote:


  Originally Posted by *peterpan188* 
_I am a little confused about IC3. I thought we can't really use the fixed voltage regulator, REG101UA-5, REG102UA-5, for direct USB powered option. The part list note says that, it doesn't really regulate. Instead we have to use REG101UA-A, or REG102UA-A as adjustable regulator, and regulate it down to 4.8V using R31 and R32. But at the same time, the part list tells that they are only mandatory for all configurations except Direct USB. What is right? I am planning to use the DAC always USB powered, what should I get?_

 

I believe "direct USB" means that you take power from USB without any kind of regulation. Other option is "regulated USB" for which you will use REG101UA-A, or REG102UA-A. See top of the "Parts List" page.

 Also I didn't see anywhere explanation of REG101UA-A/REG102UA-A vs REG101UA-5/REG102UA-5. Text near Vout formula only says that REG101 has higher Vref than REG102. I ordered REG101UA-5 because it was first in the list. May be a little more details on IC3 selection for different power options will help others.


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## tomb

Quote:


  Originally Posted by *cook* 
_I believe "direct USB" means that you take power from USB without any kind of regulation. Other option is "regulated USB" for which you will use REG101UA-A, or REG102UA-A. See top of the "Parts List" page.

 Also I didn't see anywhere explanation of REG101UA-A/REG102UA-A vs REG101UA-5/REG102UA-5. Text near Vout formula only says that REG101 has higher Vref than REG102. I ordered REG101UA-5 because it was first in the list. May be a little more details on IC3 selection for different power options will help others._

 

Well, I wouldn't want to get into a discussion of semantics over the use of the word "direct". Whatever the strict definition, the BOM's referenced also included R31/R32, so the intent to regulate was implicit.

 As described in Alf's writeup, "Direct" USB _implies_ *no* regulation, but the trick is to regulate to the regulator chip's minimum voltage drop, e.g. 4.8V. The writeup then goes on to describe the calculation and selection of R31/R32 values to accomplish this. As Cook notes, however, there was never any distinction given to which regulator.

 I can see now that to those intimately familiar with selecting regulator chips, the "-5" meaning should've been obvious: it wasn't "4.8."

 Hmmm - well as Mister X noted, my Black Gate order will fall through, anyway. Are there some decent coupling caps at DigiKey I can get since I need to order new regulators?


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## peterpan188

Thanks, I would want to regulate the USB power, so I guess I will be using the REG101UA-A, and choose the right value for R31 and R32 right?

 Another question, what would be the point of using a -5 in the family for the regulator? Would it not regulate?

 Peter


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## tomb

Quote:


  Originally Posted by *peterpan188* 
_Thanks, I would want to regulate the USB power, so I guess I will be using the REG101UA-A, and choose the right value for R31 and R32 right?

 Another question, what would be the point of using a -5 in the family for the regulator? Would it not regulate?

 Peter_

 

Regulators that have numbered suffixes indicate the voltage that they will regulate to, period - given certain requirements. One of those requirements is that the regulator needs to burn up a couple of tenths of volts to operate. So, that means a fixed "-5" regulator would need perhaps 5.2 - 5.3 volts. (This is all documented exactly in the chip's literature.)

 To paraphrase slightly, the trick used by Alf is to pick an _adjustable_ regulator, and then regulate it as close as possible to the 5V, using only the minimum required by the chip, thus: 4.8V for the USB-powered DAC. Keep in mind, the out-of-the-box PC USB voltage is unregulated. So, even though the 5V is set, in truth it can vary at the whim of the PC, spike, sag, drop out, etc. Also note that 5V was considered the minimum for the primary DAC anyway.

 Hindsight is always 20-20, I guess - all this seems obvious, now.


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## n_maher

So, given all this discussion about which reg is the correct one is there some enterprising soul that could put out a correct BOM for a USB powered dac? It'd be greatly appreciated by those of us chugging through other projects but still wanting to build this DAC. 
	

	
	
		
		

		
		
	


	




 Thanks in advance.

 Nate


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## Tedro

I will make a BOM as long as someone will let me buy a PPAS board off of them and or another DAC board off of them. I have already copleted one and have ordered all the correct parts before to build the DAC in a number of different configurations.

 I am also working on a Step By Step build guide with pictures aswell, if someone can help me out with a board or two.


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## Buzzerbro

I don’t have a complete BOM for the Regulated USB Powered DAC but I think these resistors from Mouser should work in regulating the USB's 5V down to 4.8V. 

 R31 71-CRCW0805-37.4K (Mouser)
 R32 71-CRCW0805-11.5K (Mouser)
 IC3 REG102UA-A (Get from Digikey)


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## cook

Here is what I think is good Digikey BOM for USB-powered DAC with adjustable regulated power. Some items may be out of stock (USB receptacle in particular). *This BOM have enough parts for TWO boards*. For one board you may half some counts but minimum on most SMD part is 10.

  Code:


```
[left]2PCM2702E-ND IC1 2-REG101UA-3.3-NDIC2 2REG101UA-A-ND IC3 20490-1057-1-ND L11-L18 10478-1416-1-ND C1 2P12348-ND C2 10478-1310-1-ND C11 C12 20490-1673-1-ND C14-C19 C21 C31 10478-1391-1-ND C22 C32 2P11180-ND C13 4P11180-ND C23 C33 ******************************************* 4P11180-ND CL CR These will work but there are better sounding caps ******************************************* 10311-22.0CRCT-ND R11 R12 10311-1.50KCRCT-NDR13 10P1.00MCCT-ND R14 10311-330KCRCT-ND R15 R16 10311-32.4KCRCT-NDR31 10311-11.5KCRCT-NDR32 10311-604CRCT-ND RLED optional - only if you want LED 2X030-ND X1 2609-1039-ND USBreceptacle 2HM970-ND CASE In addition you will need : 3.5mm or RCA output connectors - mandatory Soldering flux - mandatory Contact cleaner or 99% alcohol - mandatory On/Off switch - optional LED - optional[/left]
```


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## Alf

I updated the support web site to avoid confusion regarding fixed and adjustable regulators. Also Direct USB has been renamed to Unregulated USB.

 Before ordering R31/R32, you should measure voltage of the USB port you intend to use. While the values specified in the part list work for most people, they might not work for you.


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## Sinbios

How is the USB 5v output related to the formula Vout = (1 + R31 / R32) * Vref?


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## doobooloo

Since the BGs I wanted were out of stock at Kyoto, I went to Sonic Craft. They were a real pleasure to deal with, and I got my shipment promptly.

www.soniccraft.com

 You have to email them with your order and they'll call you for your credit card information. Kind of old school, but it works and their service is very professional!

 I got a few other parts from there too, no problems.


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## cook

Quote:


  Originally Posted by *Sinbios* 
_How is the USB 5v output related to the formula Vout = (1 + R31 / R32) * Vref?_

 

To let regulator work properly USB 5v should be higher than Vout (by 0.4V at least if I understand reg101 spec pdf right)


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## Sinbios

0.4V? Ouch, my USB outputs about perfect 5.0V, so I need to set the regulator output to 4.6V? Won't performance suffer quite a bit at those levels?


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## cook

"Note 4:IC3" says "4.5-4.8V" so I hope it will not be that bad. Either way - if you are not happy with its perfomance - with adjustable REG you can add 9V battery, bump reg to 5.4V and enjoy that overclocked PCM2702


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## Tedro

My usb is exactly 5.0volts aswell though I am using the adjustible regulator and drops the voltage to 4.82volts. Sounds fine. I have enough parts complete a grip of boards but only 2 boards where I should have gotten more boards!! then I can do a shoot-out on what configuration is the best.


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## Alf

Quote:


  Originally Posted by *Sinbios* 
_How is the USB 5v output related to the formula Vout = (1 + R31 / R32) * Vref?_

 

You need to make sure that Vout < Vusb - Vdrop if you use USB for powering your DAC. Otherwise the regulator does not regulate.


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## tomb

Quote:


  Originally Posted by *doobooloo* 
_Since the BGs I wanted were out of stock at Kyoto, I went to Sonic Craft. They were a real pleasure to deal with, and I got my shipment promptly.

www.soniccraft.com

 You have to email them with your order and they'll call you for your credit card information. Kind of old school, but it works and their service is very professional!

 I got a few other parts from there too, no problems._

 

How in the world did you get enough response from Kyoto to even know they were out of stock? MisterX called it - no reponse, nothing, nada.

 I saw your earlier BOM with SonicCraft listed, but chose to go with Kyoto because they were web-order-capable. Live and learn, I guess.


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## Pappucho

Don't forget Percy Audio when looking for black gates. I've had nothing but good experience with them and they have a wide selection.


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## doobooloo

Quote:


  Originally Posted by *tomb* 
_How in the world did you get enough response from Kyoto to even know they were out of stock?_

 

Uh, their webpage for BGs shows them as not in stock. So I didn't order.


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## mb3k

What are your guy's soldering method of choice for IC1 (SSOP28).. flood and suck?


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## doobooloo

Quote:


  Originally Posted by *mb3k* 
_What are your guy's soldering method of choice for IC1 (SSOP28).. flood and suck?_

 

Pin by pin soldering for me...


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## DaKi][er

Quote:


  Originally Posted by *mb3k* 
_What are your guy's soldering method of choice for IC1 (SSOP28).. flood and suck?_

 

(flux) Paste and Draw (iron across the pins in one sweep)


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## MisterX

Quote:


  Originally Posted by *DaKi][er* 
_(flux) Paste and Draw (iron across the pins in one sweep)_

 


 Agreed. 
 That works much better then the flood and suck routine


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## MASantos

When I built the revision A DAC I used the flood and suck technique, but the prototype board I used "paste and draw" and that worked much better! It is faster, cleaner and the IC doesn't get as hot as when using flood and suck technique. I would recomend this technique to everyone!


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## tomb

Quote:


  Originally Posted by *doobooloo* 
_Uh, their webpage for BGs shows them as not in stock. So I didn't order. 
	

	
	
		
		

		
		
	


	


_

 

Hmm - I don't think that was there when I ordered. Regardless, MisterX is correct - lots of e-mails and no response. I'm giving them until the end of the week, then will contact Paypal to start the dispute process.

 The boards look great!


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## Buzzerbro

Regarding the *CL* and *CR* capacitor positions, what would be better, the *47uF/16vdc Nichicon Muse ES* or *47uF/25vdc Nichicon Muse KZ *? Size nor cost is an issue for me.


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## peterpan188

Quote:


  Originally Posted by *Buzzerbro* 
_Regarding the *CL* and *CR* capacitor positions, what would be better, the *47uF/16vdc Nichicon Muse ES* or *47uF/25vdc Nichicon Muse KZ *? Size nor cost is an issue for me._

 

I think KZ is Nichicon flagship. According to most others, ES is very bassy, but not as detailed. KZ is little thin in bass from my experience, but they do quite much up the Blackgates, except for the special smoothness I got from the BG.

 Regard,
 Peter


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## Whitewind

From the looks of REG101 and REG102 (adjustable) datasheets, it seems that Vref is 1.267V and 1.26V respectively. On Alf's site it is indicated as 1.26V and 1.1267V respectively.

 I'm not sure about this, but if someone could double check that would be great.

 Also just a question, would there be any problems by adding a 1.2V NIMH AA in series with the usb supplied voltage?


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## Sinbios

Whitewind: I thought about that, but I can't think of a way to make the DAC draw most of the current from the USB and only use the battery to boost voltage. 

 I've actually been puzzling over the power supply most of the afternoon. Assuming the USB gives perfect 5.0V (which mine does), going by direct USB regulated, the regulator wants input voltage = output voltage + 0.4V, which gives a maximum output voltage of 4.6V. Beyond that the ripple rejection drops off significantly, however the regulator will benefit from a voltage difference of even 1V between the input and output voltages. The DAC chip's minimum working voltage is 4.5V, and performance gradually improves as voltage increases, up to 5.4V. 

 The ideal situation for USB power would be to take the 5V from USB and step it up to 6.4V, and then regulating it to 5.4V and feeding it to the DAC. I looked up a few voltage converters today and this is certainly feasible, maybe for the next revision? 

 The alternative would be to hook up say, an NiMH AAA in series, which boosts the voltage to 6.2V, and regulating it down to 5.4V. Problem with this is the battery would only last about a week if the DAC is running 24/7. One idea was to limit the current draw from the battery somehow, but I can't figure out a way for when the battery is hooked up in series. Anyone with some insight on current limiting?

 The other idea was to build a trickle charger into the DAC and charge the battery from regulated USB - another idea for the next revision, perhaps?


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## robzy

Quote:


  Originally Posted by *MASantos* 
_When I built the revision A DAC I used the flood and suck technique, but the prototype board I used "paste and draw" and that worked much better! It is faster, cleaner and the IC doesn't get as hot as when using flood and suck technique. I would recomend this technique to everyone!_

 

What exactly is the past and draw technique?

 Rob.


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## MASantos

What do you guys think of using Elna Silmic II 47uF 6.3V? I am thinking of using these in all positions except for C2. Using these instead of panasonic FC's is only a few bucks.

 Would someone be interested in a group buy?


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## Sinbios

Quote:


  Originally Posted by *MASantos* 
_What do you guys think of using Elna Silmic II 47uF 6.3V? I am thinking of using these in all positions except for C2. Using these instead of panasonic FC's is only a few bucks.

 Would someone be interested in a group buy? 
	

	
	
		
		

		
		
	


	


_

 

I think the only position the Silmics would fit in is CL/CR...


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## MASantos

Quote:


  Originally Posted by *Sinbios* 
_I think the only position the Silmics would fit in is CL/CR..._

 

I have used them in the first prototipe board.I used panasonic FC first and then Silmic II. I gave each 20 hours playing time before listening. The bass was more controled and there was less hiss when no music was playing. The mids sounded a bit less muffled and the highs were a also less muffled. Overwall the sound improved.

 In the group buy board, they fit in every position except C2. 

 The Silmic II 47uf 6.3v has the following dimensions: 
 6.3mm diameter; 11mm length(it fits the smallest hammond case); pitch: 2,5mm, which fits to all positions

 In terms of capacitance values, 47uf is a good choice for C13,C23,C33 and CL/CR, according to the suggested values by Alf in the parts list page.

 Manuel


----------



## Alf

Quote:


  Originally Posted by *MASantos* 
_In terms of capacitance values, 47uf is a good choice for C13,C23,C33 and CL/CR, according to the suggested values by Alf in the parts list page._

 

C23, C33 positions accept capacitors up to 8mm. If you have a few extra dineros in your pocket, I would try 100uF Silmics here as the DAC may benefit from it.


----------



## Sinbios

MASantos: Ah, digikey doesn't carry a wide range for the Silmics so I didn't see the 10V. I'd certainly be interested in obtaining a few.

 Alf, any thoughts on the power supply?


----------



## Alf

Quote:


  Originally Posted by *Sinbios* 
_The ideal situation for USB power would be to take the 5V from USB and step it up to 6.4V, and then regulating it to 5.4V and feeding it to the DAC. I looked up a few voltage converters today and this is certainly feasible, maybe for the next revision?_

 

This approach has been part of the original design. After conducting some tests and doing more reading on the subject I removed the step-up section from the DAC. 

  Quote:


  Originally Posted by *Sinbios* 
_ Assuming the USB gives perfect 5.0V (which mine does), ….._

 

If you have a rock solid 5V (which you do), then you need no additional active regulation because your computer’s PSU does the job for you. Regulators are used to eliminate large swings of voltage. For everything else you should use passive filters. Have you noticed C1/C2/L11/L12? This is what they are there for. Do they do a perfect job? Unfortunately not, there is some space for improvement. If you have enough room in your enclosure, I suggest that you start with adding 5-6 boutique electrolytics (200-300uF) and a few 220nF film capacitors. Read a bit more about passive filtering and you can come up with more ideas. The board is very customizable in this respect and there is no excuse for not trying.


----------



## Tedro

With <3 from me

  Quote:


  Originally Posted by *Tedro* 
_








_


----------



## Whitewind

So Alf, would you recommend stepping up the input voltage of USB by adding a 1.2v NIMH AA battery in series?

 Thanks


----------



## robzy

Would people who have built it mind testing the "dc offset" between C18 and CR/CL? 

 If its low enough it might be best to take out CR/CL and use it as an output ground (assuming it has the current capacility).

 Rob.


----------



## doobooloo

Quote:


  Originally Posted by *MASantos* 
_I have used them in the first prototipe board.I used panasonic FC first and then Silmic II. I gave each 20 hours playing time before listening. The bass was more controled and there was less hiss when no music was playing. The mids sounded a bit less muffled and the highs were a also less muffled. Overwall the sound improved.

 In the group buy board, they fit in every position except C2. 

 The Silmic II 47uf 6.3v has the following dimensions: 
 6.3mm diameter; 11mm length(it fits the smallest hammond case); pitch: 2,5mm, which fits to all positions

 In terms of capacitance values, 47uf is a good choice for C13,C23,C33 and CL/CR, according to the suggested values by Alf in the parts list page.

 Manuel_

 

This is very interesting. I am a bit skeptical though of the effect the Silmics had in the filtering positions (everything other than CL/CR) - perhaps the BEST performance can be had by leaving the higher capacitance (and still very low ESR) FM/FCs in all positions other than CL/CR and use the Silmics only in the signal path, CL/CR.

 For me, I'm planning to use Black Gate NX Hi-Q bipolars in CL/CR as to minimize the negative effect of electrolytics in the signal path, and use Panasonic FMs in all other positions for low ESR and high capacitance for better filtering... IMO this should be quite close to ideal given the board limitations (no exotic film output caps, etc.)...

 But I'd still like your opinion on having "audio grade" low-density boutiques in the filtering positions. By any chance have you tried swapping just the CL/CRs, or even better, everything BUT the CL/CRs? This should be a very interesting experiment. 
	

	
	
		
		

		
		
	


	




 [edit] went back and read your post again, did you actually try the silmics in positions other than CL/CR with the early proto board or are your impressions only for the output signal path position?


----------



## 00940

Quote:


  Originally Posted by *Alf* 
_If you have a rock solid 5V (which you do), then you need no additional active regulation because your computer’s PSU does the job for you. Regulators are used to eliminate large swings of voltage. For everything else you should use passive filters. Have you noticed C1/C2/L11/L12? This is what they are there for. Do they do a perfect job? Unfortunately not, there is some space for improvement. If you have enough room in your enclosure, I suggest that you start with adding 5-6 boutique electrolytics (200-300uF) and a few 220nF film capacitors. Read a bit more about passive filtering and you can come up with more ideas. The board is very customizable in this respect and there is no excuse for not trying._

 

Be extremely careful adding capacitance on the USB bus without putting some resistance in serie before the caps. The USB specs don't allow much current to be drawn and at start up, too much capacitance could kill your USB bus. Of course, putting some resistance in serie is another evil...

 At lowish frequency, high quality regulators are actually very good at cleaning the incoming DC. A combination of regulation and passive filtering is best, especially when lots of capacitors aren't recommanded (as here). At higher frequencies, only passive filtering will work.


----------



## tomb

Quote:


  Originally Posted by *Doobooloo* 
_For me, I'm planning to use Black Gate NX Hi-Q bipolars in CL/CR as to minimize the negative effect of electrolytics in the signal path, and use Panasonic FMs in all other positions for low ESR and high capacitance for better filtering... IMO this should be quite close to ideal given the board limitations (no exotic film output caps, etc.)..._

 

I agree with that strategy, although I'm trying to find another source that would let me try all three that have been most mentioned for CL/CR:
Black Gate NX-HiQ
Elna Silmic
Nichicon Muse ES

 I received four boards, so if someone has a fourth suggestion for CL/CR, please let me know.


----------



## doobooloo

Quote:


  Originally Posted by *tomb* 
_I agree with that strategy, although I'm trying to find another source that would let me try all three that have been most mentioned for CL/CR:
Black Gate NX-HiQ
Elna Silmic
Nichicon Muse ES

 I received four boards, so if someone has a fourth suggestion for CL/CR, please let me know._

 

Is it most definately preferable to have bipolar electrolytics in the signal path? If regular electrolytics still "work" in this position, what is the exact reason for bipolars being useful here?

 Also, where would you get your Muse ES series caps?


----------



## tomb

If you read the hype, the "bi-polars" put less noise in the signal path. The rationale is a little ridiculous it seems to me, so I won't go there. Nevertheless, I read the reviews because like most people, I'd like something that sounds the best after all the work put into building it. There are enough warnings floating around against using regular FM's or other popular power electrolytics in CL/CR to convince me there's something to it.

 You can find a lot of this in Dsavitsk's capacitor review referenced by Alf in his Parts List page: Notes on Coupling Caps. I had found this review earlier from one of Dsavitsk's posts on the Millett's caps, so was a little familiar with it. Unfortunately, Alf's pages only references it with the simple word "here", so it's easy to miss.

 Nichicon Muse ES's can be obtained at:
 Handmade Electronics
 Michael Percy
 B&D Enterprises (they don't have the smaller ones - only the Millett's C7)

 P.S. I'm thinking of trying Michael Percy, since he has both the Black Gates and the Nichicon's (KZ's, too). MisterX mentioned Parts Connexion, but they only have the Black Gates. Since all these outfits have a minimum order, I was trying to choose one that has more than one type. Before I get into another Kyoto-Electro fiasco, has everyone had good luck ordering from Michael?


----------



## MisterX

Quote:


 has everyone had good luck ordering from Michael? 
 

I waited a week to get a reply to my last order request. 
 The reply I got said they had nuked all of the emails they had got because they had to much backlog and I should re-send my request. 
 So I sent them another request. 
 Care to guess what the reply was to that inquiry as well?
 Same thing. 
	

	
	
		
		

		
		
	


	




 I think you may get better results on the phone but I got sick of messin with them and ordered the Black Gates caps I needed from Parts Connexion. 
 They were here 4 days later.


----------



## tomb

Quote:


  Originally Posted by *MisterX* 
_I waited a week to get a reply to my last order request. 
 The reply I got said they had nuked all of the emails they had got because they had to much backlog and I should re-send my request. 
 So I sent them another request. 
 Care to guess what the reply was to that inquiry as well?
 Same thing. 
	

	
	
		
		

		
			





 I think you may get better results on the phone but I got sick of messin with them and ordered the Black Gates caps I needed from Parts Connexion. 
 They were here 4 days later. 
	

	
	
		
		

		
		
	


	


_

 

OK, seeing as how the front of their catalog says, "... we are usually unable to answer the phone ...", that tears it. Many thanks for your comments ... exactly what I needed to hear.


 P.S. Any luck with Handmade? They're the only other source I've found for the Nichicon Muse ES's.


----------



## doobooloo

Quote:


  Originally Posted by *tomb* 
_Any luck with Handmade? They're the only other source I've found for the Nichicon Muse ES's._

 

The last few times I ordered from Handmade they were very prompt with processing orders and called within a day if there were any problems. This was a few months back though, but I don't think it should be any different now.


----------



## MisterX

I have never had a single problem with Handmade but I know a couple of people that have had a problem with them (in both cases the "problem" was Handmade would not ship to an address that was not the same as the billing address).
 In fact I think there was even a tread about them once.


----------



## tomb

Many thanks - I will post my experiences after ordering.


----------



## doobooloo

Quote:


  Originally Posted by *MisterX* 
_I have never had a single problem with Handmade but I know a couple of people that have had a problem with them (in both cases the "problem" was Handmade would not ship to an address that was not the same as the billing address).
 In fact I think there was even a tread about them once._

 

But it's not exactly Handmade's fault, right? Better safe than sorry, I guess...


----------



## MisterX

Quote:


  Originally Posted by *doobooloo* 
_But it's not exactly Handmade's fault, right? Better safe than sorry, I guess..._

 

Roger that. 
 I would be the same way if I ran a web store like his.


----------



## dsavitsk

Quote:


  Originally Posted by *tomb* 
_Before I get into another Kyoto-Electro fiasco, has everyone had good luck ordering from Michael?_

 

For what it's worth, I have had very good luck Percy, Handmade, and Parts Connexion. Actually, Parts Connexion has screwed up nearly every order I have made (wrong resistor value, missing cap clamp, etc.) but they have always corrected it quickly. I can't speak to any recent problems, but with Percy I have ordered enough to build up a bit of a relationship which makes orders go very smoothly. Not the case with PCX and Handmade, which, while fine are more impersonal. Also, Parts Connexion shipping can be a beast.


----------



## Alf

Quote:


  Originally Posted by *00940* 
_Be extremely careful adding capacitance on the USB bus without putting some resistance in serie before the caps. The USB specs don't allow much current to be drawn and at start up, too much capacitance could kill your USB bus._

 

I use 3300uF capacitor in one of my test DACs. No negative effects so far.


----------



## 00940

well, everyone can play with fire and I'm doing it quite often myself 
	

	
	
		
		

		
		
	


	




 But when giving advice worth for every computer out there, I'm a bit more careful than I would be for me alone.


----------



## Alf

Quote:


  Originally Posted by *Whitewind* 
_So Alf, would you recommend stepping up the input voltage of USB by adding a 1.2v NIMH AA battery in series?

 Thanks_

 

I wonder why you would want to combine two evils: USB noise and short battery life.



 My first choice would be to have an external PS. It could be either a wall wart or batteries.

 If you cannot use external PS and you must have a USB powered DAC, then I would go for the underpowered configuration where USB is regulated down to around 4.6-4.8V.

 My last option would be to use unregulated USB. In this case you depend on the quality of your computer’s PSU. Anyway, even having a perfect PSU, you would be better off with either of the two options above.


----------



## Alf

Quote:


  Originally Posted by *00940* 
_well, everyone can play with fire and I'm doing it quite often myself 
	

	
	
		
		

		
		
	


	




 But when giving advice worth for every computer out there, I'm a bit more careful than I would be for me alone._

 

Agreed. Actually I was careful - I was recommending only half of the fire I play myself with (1500uF vs 3300uF).
	

	
	
		
		

		
		
	


	




 I believe that L11/L12 help to mitigate the problem. The computer should be more tolerant because the capacitance is not applied to USB directly.


----------



## mb3k

Quote:


  Originally Posted by *Alf* 
_I wonder why you would want to combine two evils: USB noise and short battery life.



 My first choice would be to have an external PS. It could be either a wall wart or batteries.

 If you cannot use external PS and you must have a USB powered DAC, then I would go for the underpowered configuration where USB is regulated down to around 4.6-4.8V.

 My last option would be to use unregulated USB. In this case you depend on the quality of your computer’s PSU. Anyway, even having a perfect PSU, you would be better off with either of the two options above._

 

I'm going the external PSREG from Welborne way (6.3V)... I havent' heard much about people using an external PSU.


----------



## robzy

I am going to use the onboard 101/102s except use an external wallwart instead of USB power.

 Rob.


----------



## doobooloo

I'm designing custom front panels for the DAC in a Hammond 1455C enclosure, and I'm wondering what the dimensions were for the USB Jack placement... i.e., what is the distance between the top or bottom of the board and the center of the USB jack? Also, how much of a protrusion is expected when board is flush against the panel?

 Thanks in advance!


----------



## NeilR

Quote:


  Originally Posted by *mb3k* 
_I'm going the external PSREG from Welborne way (6.3V)... I havent' heard much about people using an external PSU._

 

I'm building one with regulated USB in a 1455C801 case, and one with 6xAAA power with built in trickle charger, in a 1455J1201 powered by a 12V wart. Even when charging it will have to be powered by the batts because of the supply voltage needed for the charger. Unless I add a another reg... I'll figure it out when I get there 
	

	
	
		
		

		
		
	


	




 I'm very curious to see if there is any audible or measurable difference in the power options.


----------



## NeilR

Quote:


  Originally Posted by *robzy* 
_I am going to use the onboard 101/102s except use an external wallwart instead of USB power.

 Rob._

 

The onboard regs have a max supply voltage of 10V. If you use, say, a 9V unregulated wart, you might fry em since the wart might put out 10-12 volts or more under the light load of the DAC.

 You actually need a regulated supply just to protect the regulators, as strange as that sounds


----------



## robzy

Quote:


  Originally Posted by *NeilR* 
_The onboard regs have a max supply voltage of 10V. If you use, say, a 9V unregulated wart, you might fry em since the wart might put out 10-12 volts or more under the light load of the DAC._

 

Thanks for the headups, although i have already been contemplating this problem. Maybe just a big resistor between them would do it? Not overly elegant though. Could always build a 5v LM317 PSU and use that for the analogue side, and use a reg101 to do the 3.3v....

 *strokes chin*

 Or better yet - a diode or two before the reg101s?

 Rob.


----------



## NeilR

Quote:


  Originally Posted by *robzy* 
_Thanks for the headups, although i have already been contemplating this problem. Maybe just a big resistor between them would do it? Not overly elegant though. Could always build a 5v LM317 PSU and use that for the analogue side, and use a reg101 to do the 3.3v....

 *strokes chin*

 Or better yet - a diode or two before the reg101s?

 Rob._

 

I ordered an MC7809 regulator. That's easier to implement than an adjustable regulator. If you try to do it with diodes, you may find you need more than one or two, and you have no protection from a mild power surge, say 10V on the mains, that would put another volt or so into the circuit. For 46 cents you can be done with it and not have to think about all these things.

 You might want to go with an MC7808 to make sure a 9V supply (if that's what you are using) accounts for the drop out voltage. A decent rated 9V supply ought to put out 10V or more at the 50ma or so the DAC will be drawing. I went with the 7809 because my supply voltage will be 12+V to get the batteries charged.


----------



## Alf

What about using a 5-6V unregulated wallwart? It should give you <9V. Of course you have to test it first.


----------



## Buzzerbro

I completed my USB DAC the other day and here are a few pictures. By the way, I purchased all the caps Handmade Electronics and I had no problems at all. 

 I chose to regulate the USB power down to 4.8V and it works fine. The output is a little low but my preamp can correct that. 
 This was a really fun project and the SMD soldering was not difficult.


----------



## tomb

Whoa! Got a bit of capacitance there, don't you? 
	

	
	
		
		

		
		
	


	




 Looks good, though.


----------



## Tedro

After I completed the second DAC the exact same way I did the first one, I was going to compare and see if I could hear a difference between a fresh on and one that had been played a wile, Broken in. I plugged my first one in and it went up in smoke. The second one is fine and working but the first one I can not believe it went like that, just out of no where? Strange. Post mortem revealed nothing wrong. I wish I ordered more boards. I really need 2 more boards.


----------



## tomb

Could the LED leads have shorted out against the USB plug case? They're right next to each other, and in your photos the LED is standing straight up on its uninsulated legs. Just a guess. Sorry about your board.


----------



## Tedro

Quote:


  Originally Posted by *tomb* 
_Could the LED leads have shorted out against the USB plug case? They're right next to each other, and in your photos the LED is standing straight up on its uninsulated legs. Just a guess. Sorry about your board._

 

good guess but not the case, Im sure I know what the problem, or short was between 26 and 27 or 25 and 26 because L18 smoked. I was sad. For it to be working an hour before it smoked.


----------



## Whitewind

I just finished the Alien DAC (w/ 4uF ERO MKC coupling caps).

 In comparison to my modified AV-710 (w/ 4uF ERO MKC coupling caps), the mids are definitely better with a forward presentation. The sound is a lot more 3D and surrounding. This is definitely worth the build.

 I originally bought Silmic II 4.7uf from digikey for coupling, and after changing to MKC caps the sound changed dramatically for the better. (faster, better mids and a lot less bass bloat)

 I just have a couple of concerns. I bought the wrong type of ferrites (240-2539-1-ND), so I was wondering if I installed them correctly or not.

 (note my 330K resistors are air wired to my stereo jack)

 Thanks for your help 

 My soldering job was quite bad since I currently have a 3/16" tip on my iron


----------



## Tedro

Quote:


  Originally Posted by *tomb* 
_Could the LED leads have shorted out against the USB plug case? They're right next to each other, and in your photos the LED is standing straight up on its uninsulated legs. Just a guess. Sorry about your board._

 

Never mind, I resurrected my DAC from the dead, installed the PCM2702E resolved the issue though I am not sure why it acted up in the first place. Its good to have soo many parts left over, in my case enough to make a grip more DAC's


----------



## mb3k

Yikes, C16 looks bridged.
 For the ferrets, I would conclude that that's the only way to solder those types.


----------



## cook

Never mind. Always make sure windows volume is set to 100%


----------



## steinchen

did you set the system volume of your computer to 100% ? Usually it's set automatically to 50% when you connect the usb dac.


----------



## cook

Ok I didn't check volume *today* when I noticed low signal. But yes I did set it to 100% first time I connected the DAC to my PC. Today I connected second board (which presumably is identical for the Windows). For some strange reason as soon as I realized that windows mixer could be a problem, I connected DAC again, clicked volume icon and it was 100% already. Played some music - and this time it was as loud as my sound card or CDP. So I'm still not sure what happened, but its all good now.

 On a good note - replacing Panasonics with Blackgates really improved sound. First with Panasonics I noticed that bass is not as good and tight as on Revo 5.1. Now with BG I think DAC sound is better that Revo. Need some more listening before I can tell for sure.

 I've build two boards. Both for "regulated" USB power. One with 101A and default R31/R32. Which gives about 4.8V. Another one with spare 1.5K added to R32 - resulting in 4.4V. Just to check if 0.4V given in REG101UA spec really improves regulation. Both work fine... wish I had something to check and compare REG101UA outputs.


----------



## Whitewind

Does anyone know if recabling the USB cable will help in SQ?


----------



## robzy

Quote:


  Originally Posted by *Whitewind* 
_Does anyone know if recabling the USB cable will help in SQ?_

 

Without knowing the USB spec - i doubt it. I would imagine the digital data would be wrapped up within the USB protocol and as thus jitter and all that jazz would not be a problem.

 Rob.


----------



## MASantos

Quote:


  Originally Posted by *Whitewind* 
_Does anyone know if recabling the USB cable will help in SQ?_

 

I don't think so. It is only 1's and 0's. It is good to have a well built cable, but that applies to all cables, not just USB.

 For the interconnect from USB DAC to amplifier, I wouldn't spend more much as well, because this DAC is not really high end!


----------



## Whitewind

The Ferrites I used are spec'ed at 75ohm. The Alien specifies 600ohm ferrites. Would there be any difference in the sound quality?

 Thanks


----------



## 00940

0 and 1, maybe. But 0 and 1 at a particular timing. The clock used for the conversion process is derivated from the timing of the USB packets. 

 However, unlike for spdif, we don't quite know how the transfer and receiving interface impacts the re-created 1KHz USB clock. It makes it quite useless to play with USB cables.


----------



## MASantos

Quote:


  Originally Posted by *00940* 
_0 and 1, maybe. But 0 and 1 at a particular timing. The clock used for the conversion process is derivated from the timing of the USB packets. 

 However, unlike for spdif, we don't quite know how the transfer and receiving interface impacts the re-created 1KHz USB clock. It makes it quite useless to play with USB cables._

 


 I see your point, but do you mean that a cheap usb cable would interfere with the correct timing?


----------



## 00940

It might... or not. Really I wouldn't worry too much about it. Keep them short and that's it.


----------



## tomb

In that case, what do you recommend if your PC is remote - about 15-20 feet away - and you're running a wireless keyboard and mouse with a monitor extension? Extend the USB or extend the patch cords? USB was my first guess, now I'm not sure.


----------



## 00940

It's about as clear as black magic. USB specs say that you can't get further than 5 meters with an usb cable. You can go further with active extender. Since we want the device to receive a USB signal as good as possible, I would use a max of 5feet.


----------



## Alf

Quote:


  Originally Posted by *Whitewind* 
_The Ferrites I used are spec'ed at 75ohm. The Alien specifies 600ohm ferrites. Would there be any difference in the sound quality?_

 

I recommend installing 600R ferrites. There would be measurable difference.


----------



## Alf

Quote:


  Originally Posted by *Whitewind* 
_Does anyone know if recabling the USB cable will help in SQ?_

 

USB cable does affect sound quality. I would say it is the last 1%. Expensive super cables are not always better choice than cheaper ones. In my case, no name cable that came with my Epson printer performed better than touted Profigold.


----------



## doobooloo

Quote:


  Originally Posted by *Alf* 
_USB cable does affect sound quality. I would say it is the last 1%. Expensive super cables are not always better choice than cheaper ones. In my case, no name cable that came with my Epson printer performed better than touted Profigold._

 

This is like massive victory for the common man.


----------



## mb3k

After reading the entire thread I have a few questions for you guys.
 Between the REG101 and REG102, which one is preferred?
 As I've stated before, I'm going to be using an external regulated PSU, but I'm wondering if it's detrimental to regulate twice. 5.7V is what I'm planning to set the PSU at.


----------



## NeilR

Quote:


  Originally Posted by *mb3k* 
_After reading the entire thread I have a few questions for you guys.
 Between the REG101 and REG102, which one is preferred?
 As I've stated before, I'm going to be using an external regulated PSU, but I'm wondering if it's detrimental to regulate twice. 5.7V is what I'm planning to set the PSU at._

 


 I only know what I've read from the datasheets. REG102 handles higer current- 250ma vs 100ma for REG101, but REG101 has slightly better noise specs. My experience is limited to my REG102's- they are absolutely dead quiet - sitting in their ASD bags in a box 

 I would think there might be a marginal benefit to REG101.... Maybe someone who has actually fired both these variants up can comment.


----------



## MisterX

Ohhhhhh, Mouser now stocks Os-Cons? 

 When did that happen?


----------



## tomb

New stuff from Mouser all over tonight. Looking at my catalog, it looks like August will bring with it a new edition. So, are Oscon caps supposed to be good? Is that Mouser's answer to DigiKey's Elna's?

 On a different note, Kyoto-Electro apologized through a Paypal dispute process and refunded my money, since it turned out he was out of stock with those BG caps, anyway. I guess he's trying to do better. Meanwhile, my BG's from Parts ConX have been shipped.


----------



## Whitewind

time to make a pure silver usb cable


----------



## cmirza

The USB cable is supplying power to the amp. And I know USB 2.0 cables have a larger gague of power wiring than USB 1.0. This might be something to look into when optimizing the power section of the amp... Another is using a powered hub with a good wall wart...


----------



## raromachine

I hope it's not too dumb a question but I wondered if someone could offer me a little advice re: building on of these to feed into a Gainclone amp I'm building.

 My Gainclone is fed by a rather large 225VA 25VCT transformer, and I'd like have a source selector so I can use a pair of RCA style connectors and what I hope is a nice clean output from these little DACs.

 It will look something like this:

  Code:


```
[left] RCA -> (no preamp) -> source selector ---> 50K pot -> Gainclone | Alien DAC -----------------------/[/left]
```

Is any particular variant of the build more suited to this? If I feed the SMD vreg 35VDC is it going to die horribly (give it's small size and amount of power it would have to dissipate)?

 Thx!


----------



## steinchen

Quote:


  Originally Posted by *raromachine* 
_If I feed the SMD vreg 35VDC is it going to die horribly (give it's small size and amount of power it would have to dissipate)?_

 

definitely! REG101 respectively REG102 have a max input voltage of only 10V! (way different from LM317). Feed the DAC directly from the USB line or build a dedicated psu like a TREAD.


----------



## robzy

Quote:


  Originally Posted by *steinchen* 
_definitely! REG101 respectively REG102 have a max input voltage of only 10V! (way different from LM317). Feed the DAC directly from the USB line or build a dedicated psu like a TREAD._

 

As above. You *will* kill reg10* with more than 10v.

 Rob.


----------



## raromachine

Cool that's that part of the Q answered - I guess the other part is will the PCM chip feed the amp, or does it need a opamp/buffer?


----------



## raromachine

I'll assume it doesn't for now 
	

	
	
		
		

		
		
	


	




 My BOM for 3 DACs (comments please):

  Code:


```
[left]DACPart#QtyReqdQtyToBuyDigikeyPart#DescPrice Each US$Price Total US$ ICS IC133PCM2702E-ND IC 16-BIT STER D/A 28-SSOP $9.66 $28.98 IC233REG102UA-3.3-ND IC LDO REG 3.3V 250MA 8-SOIC $2.36 $7.08 IC333REG102UA-A-ND IC LDO REG ADJ 250MA 8-SOIC $2.36 $7.08 Ferrites L11-L182430490-1057-1-ND FERRITE CHIP 600 OHM 1500MA 1206 (higher current, same size) $0.20 $6.00 Capacitors C1310587-1442-1-ND CAP CER 4.7UF 10V X7R 0805 $0.28 $2.81 C233Nichicon MUSE FX 470UF 50V ( from http://shop.diyrealaudio.com/ in Taiwan? ) C11, C12610PCC330CGCT-ND CAP 33PF 50V CERM CHIP 0805 SMD $0.05 $0.49 C1333Nichicon MUSE FX 47UF 50V ( from http://shop.diyrealaudio.com/ in Taiwan? ) C14-C19,C21,C22,C31,C323040PCC1812CT-ND CAP .1UF 16V CERAMIC X7R 0805 $0.07 $2.96 C23,C3366Nichicon MUSE FX 100UF 50V ( from http://shop.diyrealaudio.com/ in Taiwan? ) CL, CR66Nichicon MUSE FX 4.7UF 50V ( from http://shop.diyrealaudio.com/ in Taiwan? ) Resistors R11,R12610311-22.0CRCT-ND RES 22.0 OHM 1/8W 1% 0805 SMD $0.08 $0.80 R13310P1.50KCCT-ND RES 1.50K OHM 1/8W 1% 0805 SMD $0.09 $0.91 R14310P1.00MCCT-ND RES 1.00M OHM 1/8W 1% 0805 SMD $0.09 $0.91 R15,R16610P330KACT-ND RES 330K OHM 1/8W 5% 0805 SMD $0.08 $0.77 R31310311-32.4CRCT-ND RES 32.4 OHM 1/8W 1% 0805 SMD $0.08 $0.80 R31ALT310311-34.8KCRCT-ND RES 34.8K OHM 1/8W 1% 0805 SMD $0.08 $0.80 R32310311-11.5KCRCT-ND RES 11.5K OHM 1/8W 1% 0805 SMD $0.08 $0.80 RLED310311-604CRCT-ND RES 604 OHM 1/8W 1% 0805 SMD $0.08 $0.80 Misc LED33160-1035-ND LED 3MM ALGAAS RED DIFFUSED $0.20 $0.60 USB33609-1039-ND CONN RCPT USB TYPE B R/A PCB $0.97 $2.91 PCB35AlienDAC PCB X133X030-ND CRYSTAL 12.000MHZ 32PF HC-49/UA $0.40 $1.20 Parts Total $66.70 Parts + Shipping to NZ $84.70 NZ$ Equiv (rough) + Credit Charges $139.82[/left]
```


----------



## Whitewind

can someone tell me which leads at the usb's data + and data -? Is it the one connecting the R11 or R12. Thanks


----------



## NeilR

I finished my first board and I have some issues.... first, high res images are in my gallery. Click "Original" below the image to see full 6mp images. 

 Symptoms:

 1. Absolutely no output on left channel
 2. Right channel has low, distorted volume. See scope image of sine wave. The positive peak of the sine wave is bizarely inverted, which is why I think I may need an exorcism. I've never seen a sine wave like this in a tech book. This seems to be a newer problem that just developed.

 History:

 I had a tough time with the 2702 chip and my first attempt at wipe and flood resulted in flooding most of the pins. You can see from the images that the pins are very clean now. I am getting good voltage at the 3.3v and 5v rails, the 5v rail reading 4.72, which is where I set the adjustable reg. I have tried this with USB power and powered by 6xAAA with same results. I originally got a very strong good signal on the right channel, about 3Vpp at full volume. Now I am getting only 1V pp; the top of the sine wave is always distorted, regardless of the singal level- it is not simply clipping at + .5mv.

 [Edit: I also shorted the pins of CL to eliminate a bad cap from the list of possibilities and this shorted pin arrangement is illustrated in the board bottom image. When powered by 6AAA the board draws about 38ma.]

 As I understand the chip, there are only 3 pins that are channel specific- a Vcc, ground and output signal for each channel. I have measured signals at the closest pads to the pins while the DAC is running to verify that it is not a simple solder problem. Although I did not want to risk measuring voltage and signals directly at the pins, I did take resistance measurements between the top of the pins (where they enter the chip case) and adjacent pads to verify that the paths are clean, which they are.

 Any help would be greatly appreciated. I have spent all day diagnosing this board and I am out of ideas.

 Regards,
 Neil


----------



## peterpan188

Hey guys,

 I tried soldering the 2702 chip onto the board for several days, which out much success. What exactly is the paste and wipe method? If it is the method that Alf put on the Alien DAC page, I am getting a little confused.

 I never used flux before, so I got the Kester paste flux, and used a cold iron to put the flux all over the board. I put the chip onto paste, and dip a very little solder onto the tip, and when I put the tip onto one of the pin, it does melt the flux on the board, but it doesn't seem to help the solder to get on the pin and the board. What did I do wrong here?

 What exactly is the wipe procedure? Am I supposed to solder each pin very quickly after 2 corner pins are down? How do I do that?

 Thanks for your help.

 Thanks,
 Peter


----------



## MisterX

Quote:


 What exactly is the paste and wipe method? 
 

http://www6.head-fi.org/forums/showp...76&postcount=7

 In short:
 you simply apply flux, place the part, tack down the corners, clean the tip of your iron, load up the tip of the iron with solder and then "wipe" the tip across the pins. 
 Inspect the results with magnification to ensure there are no solder bridges. 
 If the solder doesn't stick to the pads you need to clean your tip better.


  Quote:


 I never used flux before, so I got the Kester paste flux, 
 

what kind of paste flux? 
 I certainly hope you are not using acid flux cause that is not real good for the board and it would explain why it is not working. 
 If you do not know and cannot figure it out I would suggest that you buy a Kester flux pen ASAP. 
	

	
	
		
		

		
		
	


	




 link--------> http://www.hmcelectronics.com/cgi-bi...uct/4800-0039/


----------



## robzy

Crap! I just got my digikey order before, and it apears i ordered the wrong ferrites. Would FERRITE ARRAY 400MA 75 OHMS SMD work? It apears as if it can be made to fit.

 Rob.

 [edit]: And can you really hear the difference between 5v and 5.4v? We are talking <.0002 THD+N and only a tiny increase in SNR.

 Rob.


----------



## Sinbios

Quote:


  Originally Posted by *robzy* 
_Crap! I just got my digikey order before, and it apears i ordered the wrong ferrites. Would FERRITE ARRAY 400MA 75 OHMS SMD work? It apears as if it can be made to fit.

 Rob.

 [edit]: And can you really hear the difference between 5v and 5.4v? We are talking <.0002 THD+N and only a tiny increase in SNR.

 Rob._

 

Well, the specified ferrite is 600R, those are 75R... and I think as long as it's 1206 package it'll fit.

 I think from digikey, this is the best choice.


----------



## robzy

Quote:


  Originally Posted by *Alf* 
_ Quote:


  Originally Posted by *Whitewind* 
The Ferrites I used are spec'ed at 75ohm. The Alien specifies 600ohm ferrites. Would there be any difference in the sound quality?

 

I recommend installing 600R ferrites. There would be measurable difference._

 

Damn. Sounds as if im shelling out on some new ferrites.. 

 Rob.


----------



## raromachine

Quote:


  Originally Posted by *robzy* 
_Damn. Sounds as if im shelling out on some new ferrites.. 

 Rob._

 

I was looking at these:

 490-1057-1-ND (aka BLM31PG601SN1L) MuRATA FERRITE CHIP 600 OHM 1500MA 1206 $0.20

 They're higher current (1.5A instead of 200mA) but at the same size as their 200mA counterparts. Not all that cheap, but no mucking about trying to fit the wrong bits. If the 100mA ones would work then that's and alternative too they aren't 1206 sized however.

 They do stock non Murata ferrites of the right size/spec:
 240-2415-1-ND (aka HZ1206E601R-10) STEWARD FERRITE 500MA 600 OHM 1206 SMD

 I'm placing an order with Digikey for my bits either later tonight or early tomorrow - let me know if you want some, and I'm sure we can come to an agreement. Flick me a PM.

  Quote:


  Originally Posted by *Sinbios* 
_I think from digikey, this is the best choice._

 

I disagree - that's a weird array style, and they're 45c each. At least the 1.5A Murata ones above (490-1057-1-ND) are only 20c.


----------



## robzy

Quote:


  Originally Posted by *raromachine* 
_I'm placing an order with Digikey for my bits either later tonight or early tomorrow - let me know if you want some, and I'm sure we can come to an agreement. Flick me a PM._

 

Thanks but no thanks. As it turns out Farnell Australia is actually pretty damn good https://secure1.farnell.com/jsp/ende...KU=9526862&N=0 . I always thought RS Components was the bee's knees but all they have is high minimum's and out-of-stock signs 

 Rob.


----------



## Whitewind

I have also ordered the wrong ferrites from digikey (75ohm) 8-pin array. I managed to solder them on properly with a little bit of patience.

 I was wondering if it is really worth switching to the specified 600ohm ferrites. Would there be any noticeable difference in SQ?

 Also wondering if anyone is ordering from Digikey anytime soon so I could piggyback an order for the correct ferrites.

 Thanks


----------



## NeilR

I built up a 2nd board, the 1st one having ended badly.

 I fired up iTunes with an Apple Lossless source and I get good output level but a very bad noise floor, so bad that music is completely distorted with the Windows volume control at anything less than full volume. At full volume the noise is present but somewhat masked by high signal levels and is very bad on soft passages. All the basic measurements on the board look good and a signal generated by a PC based function generator scopes ok. There is no noise with no signal (iTunes in Stopped mode).

 Using RealOne player via a CD-Rom device, there is no noise or distortion and from that I assume there are no hardware issues with the Alien DAC board. Unfortunately I want to use iTunes as my primary source. Any suggestions would be appreciated.


----------



## mb3k

I suspect software conflicts between iTunes and the ASIO driver you're using.
 Try some other versions of the driver, maybe that will remedy it.


----------



## NeilR

Quote:


  Originally Posted by *mb3k* 
_I suspect software conflicts between iTunes and the ASIO driver you're using.
 Try some other versions of the driver, maybe that will remedy it._

 

I had previously downloaded and installed the asio4all V1.8 linked from the construction notes web site. I think it is more complicated than that and I am not familiar with the architecture of the asio drivers. A little primer would help. I did a web search on asio4all and itunes and the only thing I found was a suggestion that iTunes can not use that driver. Has anyone gotten this to work with iTunes and Win XP?


----------



## cetoole

Quote:


  Originally Posted by *NeilR* 
_I had previously downloaded and installed the asio4all V1.8 linked from the construction notes web site. I think it is more complicated than that and I am not familiar with the architecture of the asio drivers. A little primer would help. I did a web search on asio4all and itunes and the only thing I found was a suggestion that iTunes can not use that driver. Has anyone gotten this to work with iTunes and Win XP?_

 

Neil, check out this thread, it seems to have the information you want.


----------



## NeilR

Quote:


  Originally Posted by *cetoole* 
_Neil, check out this thread, it seems to have the information you want._

 

I downloaded Foobar V0.9.2and Asio V1.4 drivers. That combination plays properly on my Dell I8500 laptop, without excessive noise. Without the ASIO drivers I had a lower level of noise than I had with iTunes but still not acceptable. 

 There are all sorts of versioning issues with these two pieces of software and iTunes. The current Foobar supports Asio but iTunes Multi-Plugin is not compaible with the current Foobar. The previous Foobar version that is compatible with the Multi-Plugin is not Asio enabled. No version of Foobar supports Apple Lossless which makes it useless for iTunes (for me). 

 [Edit: The current Foobar version has an optional ALAC add-in that will play Apple Lossless files, but the download page has a disclaimer that it is buggy and known to cause instability. It's working for me after a half hour or so... YMMV and mine may too after a little more listening time...]

 And finally, the current version of iTunes may not be compatible with the current version of the multi-plugin. That's the story as I currently understand it... I may have gotten some of the details confused but I think anyone interested in this will get the general idea


----------



## robzy

Wow, 0805 is _really_ samll. Much tougher than i thought (moreso than the SSOP i reckon). But its all, more or less, going okay.

 Rob.


----------



## MASantos

Quote:


  Originally Posted by *robzy* 
_Wow, 0805 is really samll. Much tougher than i thought (moreso than the SSOP i reckon). But its all, more or less, going okay.

 Rob._

 


 I find it really easy! With the help of very fine tweazers and a fine tip in the iron.


----------



## robzy

Quote:


  Originally Posted by *MASantos* 
_I find it really easy! With the help of very fine tweazers and a fine tip in the iron._

 

You know, you're right. Let me rephrase - i find 0805 to be very "finicky". Although when it comes down to it - i think i prefer it over through whole. (Especially when the resistor spacing is bigger than the resistors you have and you try and get it all even).

 That being said though - i managed to lift up R11's track today somehow. Luckily enough it was salvagable.

 Rob.


----------



## NeilR

After building two of these boards, the biggest problem I had was with the 805 ceramic caps (not the resistors for some reason). I have what I think are fine tweezers but I had a great deal of trouble getting the ceramic caps to lay flat while I held them with the tweezers. Maybe I need a better set of tweezers. If anyone has specific suggestions for better tweezers, I'd like to hear it.

 Regards,
 Neil


----------



## Alf

[size=large]*Round 2 group buy is now open. *[/size]


----------



## dsavitsk

Quote:


  Originally Posted by *NeilR* 
_After building two of these boards, the biggest problem I had was with the 805 ceramic caps (not the resistors for some reason). I have what I think are fine tweezers but I had a great deal of trouble getting the ceramic caps to lay flat while I held them with the tweezers. Maybe I need a better set of tweezers. If anyone has specific suggestions for better tweezers, I'd like to hear it.

 Regards,
 Neil_

 

Rotate the caps 90 degrees -- with the side of the cap facing the board -- so you are grabbing what is usually the top and the bottom. This gives a bit more to grab on to.


----------



## NeilR

Quote:


  Originally Posted by *dsavitsk* 
_Rotate the caps 90 degrees -- with the side of the cap facing the board -- so you are grabbing what is usually the top and the bottom. This gives a bit more to grab on to._

 

And solder them into place rotated? I don't understand what you are suggesting. To be clear, I usually lay a thin coating of solder on the first pad I work. I lay the part down and apply heat. If I don't apply some downward pressure on the part, it sits on top of the solder hill. If I press down on the top of the part, it will often fly off into never-never land, never to be seen again. To prevent that, I try to grasp the part in the middle with tweezers in such a way that the part I am soldering has enough downward force. That method may not be the best way for everybody but it seems to be the lesser of many evils as I've tried a number of different strategies.


----------



## Fiola

Can someone recommand a good tweezer for smd work? preferably from digikey?
 I looked at the catalogue, and there are cheap ones thats around 3 bux to ones that costs 20 dollars. Is there a big difference? I don't mind paying more for a tweezer if it's going to make my life a lot easier 
	

	
	
		
		

		
			





.


----------



## Viverr

Wiha makes a very respectable set of tweezers. I like the fine tip, 30 degree offset ESD set they make, but they have a massive selection of tip offsets, widths, etc. You're pretty much garenteed find something you'll like. Fry's sells a few for $16, well worth the investment in my opinion.

 -V


----------



## cook

I *totally* love cross-locking (or clamp?) tweezers. It reaches anywhere on a such small board like this. It holds SMD part on the board so you have both hands free for soldering and no worries that part will move because of your hands or when solder tip touches it. Just have to plan ahead and solder center parts first.

 Mine was a part of some tool kit but looks very much like these :

http://www.hobbylinc.com/htm/tes/tes50632c.htm http://www.contenti.com/products/tweezers/470-040.html

 Make sure it has fine tip

 This one is *not good* for 0805 parts - tip is too wide http://www.contenti.com/products/tweezers/470-045.html


----------



## Samgotit

Quote:


  Originally Posted by *NeilR* 
_ I have what I think are fine tweezers but I had a great deal of trouble getting the ceramic caps to lay flat while I held them with the tweezers. Maybe I need a better set of tweezers. If anyone has specific suggestions for better tweezers, I'd like to hear it.

 Regards,
 Neil_

 

I'm really happy with the curved XYtonic 7-SA here:
http://www.assemblyoutfitters.com/xytronic/XY-7-SA.aspx

 I hold them like a pencil, which keeps my hand out of the way, and pressure is subsequently directed downward.

 As much as I like them you must be careful not to launch your components across the room with an uneven grip.


----------



## peterpan188

Hi guys,

 I have been working on my DAC, but at last I found myself missing R31, a 32.3KOhm resistor. Does anyone else happen to use the same resistor so then you can send me one, and I will pay you back with paypal.

 Please PM me if you can help.

 Thanks in advance,
 Peter


----------



## garrontmo

I just put in my order for a few of these boards. I was hoping to use one of them at work (where I don't have admin rights) on a windows machine. Will this work without admin rights, or does a driver need to be installed? I know some things work for normal users, like USB drives.

 Thanks,
 Garron


----------



## Whitewind

Hey NeilR, if you are still having problems with noise try rechecking your solder joints for your ferrites. I had the same problem with my second board, my music was totally unlistenable.

 Oh and just for all the alien builders, USB cables do really make a difference on SQ. I purchased a 2nd USB cable from a dollar store. Once I plugged it in, I could definitely tell something was different and off. There was a lot less detail and all the ranges seemed very recessed. I wouldn't say the difference was night and day, but more like a 10-20% variation.

 Right now im sticking to my original USB printer cable, until I find something better.

 GL w/ your builds and happy listening


----------



## pddjsteve

Well, I've finally got the last order of parts in, I'm hopefully going to have it together by tomorrow morning. The only thing that scares me is the dac chip, the rest of the smd I'm fine with (I had no trouble doing a PPAS a month ago).


----------



## kklee

Here's mine, paired up with a PPAS.





 The IC4 pads look messy because I had soldered on a BUF634, but then I changed my mind about how I was going to power it.

 I set it up to run off a 9V battery (not the same one as on the PPAS), but it sounded horrible. When I started scoping things, I found that the 5V line had a 140KHz sawtooth coming from somewhere. I couldn't figure out where it was coming from, so I reconfigured it to run off of USB power instead and it seems to work fine.

 Now I just have to cram it all into a Hammond 1455C1201 and I'm done!


----------



## whiz

Hi!

 I have read both threads about the alien DAC and i have
 some stupid questions just to clear things out!

 1)AV+ and G2 are for external power source? (battery PSU)
 if i don't need to connect external power source are there any 
 parts i sould left out?

 2) OL, OG, OR are the output and the ground? (just to be sure)

 3) which of the ICs are critical besides the PCM2702?
 so if for some reason i can't find it to leave it out


 recently i have finished a project with the PCM2902 but it needs
 fine tunning! 
	

	
	
		
		

		
		
	


	




 this is the link if anyone can help i'll be glad!

http://www6.head-fi.org/forums/showthread.php?t=192076


----------



## robzy

Hey guys, is the Pana FC low-impedance-enough for C13?

 Rob.


----------



## Alf

Quote:


  Originally Posted by *whiz* 
_I have read both threads about the alien DAC and i have
 some stupid questions just to clear things out!_

 

Also read Assembly Guide and Parts List pages on the support web site. Many of your questions are answered there.

  Quote:


  Originally Posted by *whiz* 
_1)AV+ and G2 are for external power source? (battery PSU)
 if i don't need to connect external power source are there any 
 parts i sould left out?_

 

If you build Unregulated USB configuration, you should not populate IC3 and IC4. Refer to Assembly guide for more details.

  Quote:


  Originally Posted by *whiz* 
_2) OL, OG, OR are the output and the ground? (just to be sure)_

 

Yes

  Quote:


  Originally Posted by *whiz* 
_3) which of the ICs are critical besides the PCM2702?
 so if for some reason i can't find it to leave it out_

 

You need IC1 and IC2 in minimal configuration. In theory if you have 3.3V power supply, you may get rid of IC2.


----------



## Alf

Quote:


  Originally Posted by *robzy* 
_Hey guys, is the Pana FC low-impedance-enough for C13?

 Rob._

 

It is. I doubt one can hear any difference with lower impedance capacitors.


----------



## robzy

Quote:


  Originally Posted by *Alf* 
_It is. I doubt one can hear any difference with lower impedance capacitors._

 

Thanks 
	

	
	
		
		

		
		
	


	




 Rob.


----------



## raromachine

Re: Those ferrite arrays people were talking about back on page 7 - would they have a parallel resistance effect if all pins are soldered in? i.e. would 4x 600R or 4x 75R give 150R and 18.75R (respectively) at 100MHZ (or whatever the spec of the ferrite is?) - or does it not work like that for ferrites?


----------



## pddjsteve

So, I got one soldered up nice, windows detects it, but I have absolutely no sound coming out. Time to read through this thread and do some troubleshooting.


----------



## robzy

Quote:


  Originally Posted by *pddjsteve* 
_So, I got one soldered up nice, windows detects it, but I have absolutely no sound coming out. Time to read through this thread and do some troubleshooting._

 

While there is no reason to suspect it over something else - check for bridges with your soldering, especially on the output resistors.

 Rob.


----------



## whiz

Thank you Alf!

 You're right i sould read your support site first...

 after reading the site, i have a problem and a question! 
 my question is why the REG101UA-33/REG102UA-33 are Mandatory!? 
	

	
	
		
		

		
			




 i understand that it regulates the voltage to 3.3V but why is that? as far as i know we need much more to operate the PCM2702 (sorry but i'm lost reading the threads and now i'm maybe asking the obvious)


 visiting mouser kai digikey for first time in my life, i got terrified!!! 
 do i need to pay 36E for tranportation costs, etc for buying things of 4-5E total price? i feel like i live in Mars and they gonna send them to me with Spacecraft! 
	

	
	
		
		

		
		
	


	




 Please answer because it is important for my decision to participate to
 the group buy...


----------



## robzy

Quote:


  Originally Posted by *raromachine* 
_Re: Those ferrite arrays people were talking about back on page 7 - would they have a parallel resistance effect if all pins are soldered in? i.e. would 4x 600R or 4x 75R give 150R and 18.75R (respectively) at 100MHZ (or whatever the spec of the ferrite is?) - or does it not work like that for ferrites?_

 

Im not totally sure, but i think that each of those solder contacts on the ferrites are connected together, not as in they are seperate ferrites. Kind of like this:

  Code:


```
[left]Pad 1 --> --| ______ |-- <-- Pad 1 Pad 2 --> --| |ferri| |-- <-- Pad 2 Pad 3 --> --|--|te |--|-- <-- Pad 3 Pad 4 --> --| |_____| |-- <-- Pad 4 Pad 5 --> --| |-- <-- Pad 5[/left]
```

whiz: The PCM2702 requries a 3.3v power supply for its "digital side" and a 5v power supply for its "analogue" side. The board comes with provisions for the use of TI's REG10* regulators, but you do not have to use them if you dont want to. Two diy-LM317 power supplies (a la TREAD) would suffice, although would require more work on your part.

 As for mouser and digikey shipping - yes, its very expensive. You have a couple of options here:

 1) Call in a favour from a fellow head-fi'er. Ask that, if you can get the money to them, if they can order your parts for you in an order they are already doing - and then forward them on to you.

 2) Find somewhere locally (or closer at least) that offers the parts you are after.

 Rob.


----------



## pddjsteve

Quote:


  Originally Posted by *robzy* 
_While there is no reason to suspect it over something else - check for bridges with your soldering, especially on the output resistors.

 Rob._

 

All my soldering looks ok, but I think I figured it out: my 3.3v pad reads right on, 3.3 exactly, but the 5v pad reads .04 
	

	
	
		
		

		
		
	


	




 Looks like I screwed something up with the adjustable regulator. I have no idea what, though. Maybe I'll swap it for the normal 5v regulator (I was going to try for usb powered but decided not to).

 Edit: Ok. reg101ua-5 is now on there. Same problem. 3.3v reading is fine, 5v reading is next to nothing. The regulator is getting REALLY hot. There don't appear to be solder bridges anywhere, looking under a large magnifier. I am puzzled and a bit annoyed.


----------



## robzy

Quote:


  Originally Posted by *pddjsteve* 
_Edit: Ok. reg101ua-5 is now on there. Same problem. 3.3v reading is fine, 5v reading is next to nothing. The regulator is getting REALLY hot. There don't appear to be solder bridges anywhere, looking under a large magnifier. I am puzzled and a bit annoyed._

 

Again, I'm hardly an expert here, but i would bet that there is either a solder bridge or the PCM2702 in stuffed (overheating? I dont know if that would cause it).

 Does your multimeter have a continuity function?

 Rob.


----------



## Tedro

Quote:


  Originally Posted by *pddjsteve* 
_All my soldering looks ok, but I think I figured it out: my 3.3v pad reads right on, 3.3 exactly, but the 5v pad reads .04 
	

	
	
		
		

		
		
	


	




 Looks like I screwed something up with the adjustable regulator. I have no idea what, though. Maybe I'll swap it for the normal 5v regulator (I was going to try for usb powered but decided not to).

 Edit: Ok. reg101ua-5 is now on there. Same problem. 3.3v reading is fine, 5v reading is next to nothing. The regulator is getting REALLY hot. There don't appear to be solder bridges anywhere, looking under a large magnifier. I am puzzled and a bit annoyed._

 


 I had this problem and it was from a bridge on the dac chip, I looked and looked but did not find anything but untill I reflowed the solder on the dac did it clear up the problem. The 3.3v rail was fine but the the 5.0v rail was shorted someware.


----------



## pddjsteve

Quote:


  Originally Posted by *robzy* 
_Again, I'm hardly an expert here, but i would bet that there is either a solder bridge or the PCM2702 in stuffed (overheating? I dont know if that would cause it).

 Does your multimeter have a continuity function?

 Rob._

 

 Quote:


  Originally Posted by *Tedro* 
_I had this problem and it was from a bridge on the dac chip, I looked and looked but did not find anything but untill I reflowed the solder on the dac did it clear up the problem. The 3.3v rail was fine but the the 5.0v rail was shorted someware._

 

Yeah, I've got a continuity check. I'd spent about a half hour to an hour trying to get the dac chip done right, I thought I had it but maybe I missed something.

 If there is a solder bridge anywhere, its there. I've checked over EVERY other component with a magnifier. But the +5 line is shorted to G _somewhere_.


----------



## Alf

Quote:


  Originally Posted by *pddjsteve* 
_If there is a solder bridge anywhere, its there. I've checked over EVERY other component with a magnifier. But the +5 line is shorted to G somewhere._

 

Hold the board against bright light while checking it with magnifier.


----------



## pddjsteve

Quote:


  Originally Posted by *Alf* 
_Hold the board against bright light while checking it with magnifier._

 

That REALLY helped. I held the thing right up to a 120 watt bulb - could see the teeniest little solder bridge. 

 It works! 
	

	
	
		
		

		
		
	


	




 Time to let it break in.


----------



## mikemacwillie

Are boards still available? Can I get a couple?


----------



## pddjsteve

Quote:


  Originally Posted by *mikemacwillie* 
_Are boards still available? Can I get a couple?_

 

Second group buy.


----------



## garrontmo

Can someone recommend a part from Digikey or Mouser for C2 that is in stock. I'm trying to place an order for parts for 2 DACs based on the BOMs I have seen, but the options suggested for C2 are unavailable.

 Thanks,
 Garron


----------



## ezkcdude

Here are some that would fit the specs:

 Panasonic ECG 470uF (P1158-ND) or NHG 1000 uF (P5521-ND)

 Nichicon PW 1000 uF (493-1747-ND) or VZ 1000 uF (493-1270-ND)

 United Chemi SMG 1000 uF (565-1024-ND)

 These are all 10V rated. I noticed that Digi-key also has some Elna caps at higher rated voltages. You may want to check those out.


----------



## Seaside

I know this has been asked more than a few times, but I gotta ask a few question regarding regulator thing again.
 Because, it is still not very clear regardless of those answers, and I need to order parts soon when I got my boards from second group buy.

 Please check and correct me if anything is wrong here.

 I will use USB as a power source.
 I know I still need IC2 any case, since it is mandatory for 3.3V digital input. 
 Questions are mostly regarding IC3.


 1. Unregulated USB.
 I do NOT need IC3, and registers arround it. I wil get 5V directly from the USB port.

 2. Regulated USB
 I will need IC3. There might be two choices, REG101UA-5 and -A?

 Option1. REG101UA-5
 I will get regulated 5V from this IC, ONLY when my USB port supplies a few mV more than 5V. 
 If my USB port works perfect, which provides 5V, the IC will not regulate since it needs a few mV more than 5V to work correctly.
 In other words, the whole thing works just like the unregulated USB option. So there's no point of choosing this option.

 Option2. REG101UA-A
 I will need to find out the right value of register R31, and R32 to get regulated voltage of approx 4.6~4.8V from the IC3. 
 The voltage out will be (1+R31/R32)*Vref, where Vref is 1.26 for REG101 and 1.267 for REG102. 
 (Alf's support site states this value as 1.1267, so is it 1.267 or 1.1267?)

 Here's some question regarding this option.

 A. Does input voltage from USB port(Vusb) has to do anything with the regulated voltage(Vout)? 

 B. If the answer above is "Yes", Am i need to aim at Vout 0.4V less than Vusb?

 C. Assume the answer above is "No. It doesn't matter as long as it is close to 5V" then, Can I choose values of R31 and R32 to make Vout approx 5.3V in order to over-drive the DAC?
 For example, R31=33K, R32=10.5K, then Vout will be approx 5.3V. Is this possible?

 Thank you very much.


----------



## NeilR

Seaside,

 If you are using USB power, you either want to use unregulated 5V or use the adjustable regulator. A regulator works by REDUCING the input voltage to a constant level. it cannot increase it and it will not do any regulating unless it drops the input voltage a certain amount, in this case at least 100mV I think (check the datasheet-I'm going by memory here) but dropping more than the minimum increases the performance of the regulator, which is why it is recommended to drop it to 4.6V to 4.8V.

 If you use the 5V regulator (or the adjustable reg set to output 5V) , you will get 5V in, about 4.9V out (because the reg will drop the voltage just like it was a diode) and the 4.9V out will be no cleaner than the 5V in from the USB port. An expensive part basically doing nothing.

 I used R31 = 31.2K and R32 = 11.5K to get 4.7V out.

 The discussion of overclocking at 5.4V assumed you had external power coming in somewhere north of 6V or so, from a Tread for instance or a simple wall wart. The external power MUST NEVER exceed 10V or the regulator will go poof.


----------



## Seaside

Thanks, You really helped me a lot. 
 It is very hard to understand all these electonic thingy for person like me, who has no backround at electronics. I can replace those bulbs tho... 

 I guess my best bet is making Vout of 4.6~4.8V using adjustable reg. Your R31,32 value looks alright to me. Do you mind if i use the same value? 
	

	
	
		
		

		
			





 Thanks again.


----------



## NeilR

Quote:


  Originally Posted by *Seaside* 
_Thanks, You really helped me a lot. 
 It is very hard to understand all these electonic thingy for person like me, who has no backround at electronics. I can replace those bulbs tho... 

 I guess my best bet is making Vout of 4.6~4.8V using adjustable reg. Your R31,32 value looks alright to me. Do you mind if i use the same value? 
	

	
	
		
		

		
		
	


	




 Thanks again._

 

No, you may not use those values. I filed for a patent on those values last night. 
	

	
	
		
		

		
		
	


	




 Just kidding... those will work well, but if you have trouble sourcing the precise parts, anywhere in the 4.6-4.8V range should work just as well.

 Good luck!


----------



## whiz

why i'm confused here?! 
	

	
	
		
		

		
		
	


	




 the regulators for the specific job, do as follows

 they accept for minimum a few mV over the voltage we want
 to regulate and maximum less than 10V (if i remember correctly)
 and in that range they regulate to the specified voltage e.g. 3.3V-5V
 in any other conditions either they pass away or they don't regulate!

 the adjustable regulator, regulates according to the input voltage the input resistors specify the region in which the regulator starts to regulate! in fact they shift the working range.

 correct me if i am wrong!


 P.S i think the basic reason we use them here is for their low noice... (filtering the input voltage)


----------



## cook

Quote:


  Originally Posted by *Seaside* 
_(Alf's support site states this value as 1.1267, so is it 1.267 or 1.1267?)

 Here's some question regarding this option.

 A. Does input voltage from USB port(Vusb) has to do anything with the regulated voltage(Vout)? 

 B. If the answer above is "Yes", Am i need to aim at Vout 0.4V less than Vusb?

 C. Assume the answer above is "No. It doesn't matter as long as it is close to 5V" then, Can I choose values of R31 and R32 to make Vout approx 5.3V in order to over-drive the DAC?
 For example, R31=33K, R32=10.5K, then Vout will be approx 5.3V. Is this possible?

 Thank you very much._

 

You can confirm Vref in REG101-A datasheet Its 1.267V.

 Vout will always be less or equal Vin.
 So no - you can't overdrive with REG101-A.

 Alf said that Vin should be at least Vdrop (60-100mv) more than Vout.

 Though REG101 datasheet guarantees listed regulation accuracy only if you provide Vin = Vout + 0.4V (up to 10V) and do not draw more than 100mA (top of the pg3 in REG101UA pdf)


----------



## abcheng

I have a couple questions about the DAC

 First of all, is there anything wrong with this BOM? 

Attachment 8037

 My next question is, can this DAC power a set of earbuds / headphones fine without connecting an amp to it? 

 Would CL and CR not be necessary if the DAC was used only for headphones?


----------



## MASantos

Quote:


  Originally Posted by *abcheng* 
_I have a couple questions about the DAC

 First of all, is there anything wrong with this BOM? 

Attachment 8037

 My next question is, can this DAC power a set of earbuds / headphones fine without connecting an amp to it? 

 Would CL and CR not be necessary if the DAC was used only for headphones?_

 

I connected my prototipe board to my etymotic er4p and hd650. the sound achieved reasonable levels(not even loud) but there was no bass or impact in the music.. the highs were very detailed but overall the sound was "strange" this was some time ago and I don't remember very well. When I connected an amp(PA2V2) the sound became much better. With a PIMETA it became even better. 

 The dac isn't supposed to drive headphones. Use an amp. You can build a Cmoy cheaply but it will not use all the capabilities of the Alien DAC.


----------



## abcheng

Quote:


  Originally Posted by *MASantos* 
_I connected my prototipe board to my etymotic er4p and hd650. the sound achieved reasonable levels(not even loud) but there was no bass or impact in the music.. the highs were very detailed but overall the sound was "strange" this was some time ago and I don't remember very well. When I connected an amp(PA2V2) the sound became much better. With a PIMETA it became even better. 

 The dac isn't supposed to drive headphones. Use an amp. You can build a Cmoy cheaply but it will not use all the capabilities of the Alien DAC._

 

I have a couple CMoy amps already, but that means I would have to add a BUF634 since the CMoy has a virtual ground circuit correct? I'm trying to keep this as portable as possible since I would plan to use one of the four I'm building with my laptop, since my laptop's sound card is literally a piece of crap.


----------



## whiz

Quote:


  Originally Posted by *whiz* 
_why i'm confused here?! 
	

	
	
		
		

		
		
	


	




 the regulators for the specific job, do as follows

 they accept for minimum a few mV over the voltage we want
 to regulate and maximum less than 10V (if i remember correctly)
 and in that range they regulate to the specified voltage e.g. 3.3V-5V
 in any other conditions either they pass away or they don't regulate!

 the adjustable regulator, regulates according to the input voltage the input resistors specify the region in which the regulator starts to regulate! in fact they shift the working range.

 correct me if i am wrong!


 P.S i think the basic reason we use them here is for their low noice... (filtering the input voltage)_

 


 ??


----------



## NeilR

Quote:


  Originally Posted by *abcheng* 
_I have a couple CMoy amps already, but that means I would have to add a BUF634 since the CMoy has a virtual ground circuit correct? I'm trying to keep this as portable as possible since I would plan to use one of the four I'm building with my laptop, since my laptop's sound card is literally a piece of crap._

 

I believe IC4 (BUF634) is only required to POWER the DAC from the virtual ground rails. If you use USB power for the DAC, you can just hook DAC output pads to Cmoy input pads. If independently powered, it's no different than if you were hooking it to any other external amp via interconnects. You're just eliminating a set of jacks and interconnects.


----------



## abcheng

Quote:


  Originally Posted by *NeilR* 
_I believe IC4 (BUF634) is only required to POWER the DAC from the virual ground. If you use USB power for the DAC, you can just hook DAC output pads to Cmoy input pads. If independently powered, it's no different than if you were hooking it to any other external amp via interconnects. You're just eliminating a set of jacks and interconnects._

 


 ahhh.. ok. I guess I'll give the DAC a try with and without an amp and see how much of a difference there is. 

 As for CL/CR, it isn't necessary if an amp isn't used correct?


----------



## NeilR

Quote:


  Originally Posted by *abcheng* 
_ahhh.. ok. I guess I'll give the DAC a try with and without an amp and see how much of a difference there is. 

 As for CL/CR, it isn't necessary if an amp isn't used correct?_

 

You always need CL/CR. The audio stage is powered by the +5V from the IC3 regulator, or directly from the USB bus. The architecture of the chip is such that the audio output has a DC offset of almost exactly 1/2 of the supply, or about 2.5V. You need the output caps unless you want to power your hedaphones with 2.5V DC.


----------



## abcheng

Quote:


  Originally Posted by *NeilR* 
_You always need CL/CR. The audio stage is powered by the +5V from the IC3 regulator, or directly from the USB bus. The architecture of the chip is such that the audio output has a DC offset of almost exactly 1/2 of the supply, or about 2.5V. You need the output caps unless you want to power your hedaphones with 2.5V DC._

 


 ahh ok, I understand now. Thanks for answering my questions.


----------



## dsavitsk

Quote:


  Originally Posted by *MASantos* 
_I connected my prototipe board to my etymotic er4p and hd650. the sound achieved reasonable levels(not even loud) but there was no bass or impact in the music.. the highs were very detailed but overall the sound was "strange" this was some time ago and I don't remember very well._

 

Well, the output caps are forming a high pass filter here, and my guess is that the 3db point is up in the midrange. So, not only will there be no bass, but from the mids down the sound will be out of phase which would account for the strangeness. If you want to power your earbuds (in response to the other poster), increase the output caps to at least 100uF, and more like 470uF for low impedence phones. Obviously this is not optimal, but it will work in a pinch.

 -d


----------



## Alf

Sorry for the mess with Vref on my site. I updated the page with proper values. If you notice any typos or errors, please do bring it up.


----------



## pddjsteve

Question on a power source. I've got a 6v AC-AC wall wart sitting around the spare parts bin. I've got an onboard fixed 5v regulator on the dac. Could I just chop the tread schematic off at the LM317 and use the diode bridge and filter cap portion? From the tread part description it seems like that is responsible for the AC-DC conversion. And since I'm only regulating 6v to 5v, I don't think I need to use the lm317 to drop a half volt so there is still enough for the reg101-5 to work right.

  Quote:


 If you choose the AC-DC type of wall wart, there are a few additional advantages over the AC-AC type:

 * You can leave the diode bridge and filter cap out when building the TREAD.


----------



## robzy

That will work pddjsteve (Assuming its physically possible to do that to a TREAD board) although one thing you have to take into account is that you might actually have more than 6v after the diode bridge. You can not feed the reg101's more than 10v.

 Rob.


----------



## pddjsteve

Quote:


  Originally Posted by *robzy* 
_That will work pddjsteve (Assuming its physically possible to do that to a TREAD board) although one thing you have to take into account is that you might actually have more than 6v after the diode bridge. You can not feed the reg101's more than 10v.

 Rob._

 


 Hmm. Yeah, I'm aware of the limits of the reg101. I wasn't meaning actually chop off the tread board, it was more a figurative chop off. I was going to try to do it on some protoboard. I hadn't thought of the dc being higher after the diode bridge though. So I might be better off just going with a full tread and setting the lm317 for something like 5.5v output anyways?


----------



## Fiola

Another Alien DAC is alive!!
 First time doing smd, the PCM2702E gave me a little bit of trouble, but not too bad, took only 5min or so, after that, everything was easy.

 Went with the regulated usb option regulated to 4.81v, outputting to an a47 i just finished yesterday, sounds great! pics to follow soon.

 btw, how would one case this in the hammond case? the usb connector doesnt have anything to attach to the front panel......


----------



## MisterX

Quote:


 btw, how would one case this in the hammond case? the usb connector doesnt have anything to attach to the front panel...... 
 




 See the chunk of sheet stock with the foam stuck on it? 
	

	
	
		
		

		
			





 The foam is there so I can remove the trim bezels without having to cut a new piece of filler.


----------



## tomb

Quote:


  Originally Posted by *MisterX* 
_


 See the chunk of sheet stock with the foam stuck on it? 
	

	
	
		
		

		
		
	


	




 The foam is there so I can remove the trim bezels without having to cut a new piece of filler._

 

MisterX, could you elaborate? Maybe I'm just brain-dead tonight, but I'm having trouble visualizing this. I would've thought after cutting the USB opening, all you'd have to do is keep the DAC board from moving within the case when you plug in the USB cable.


----------



## MisterX

Quote:


  Originally Posted by *tomb* 
_I would've thought after cutting the USB opening, all you'd have to do is keep the DAC board from moving within the case when you plug in the USB cable._

 

errr.... let me rephrase. 

 That is exactly what the chunk of metal does.


----------



## NeilR

MisterX, how did you cut that nice neat square hole? I've been pondering how I'm going to take on that job.


----------



## Fiola

So..... tell me if I understood how your contraption works 
	

	
	
		
		

		
		
	


	




 the piece of metal with the foam on will go in on one of the slots in the case, and is sized so that the foam pushes against the back of the usb receptor when both side of the bezel is shut, correct?

 btw, howd you cut your square hole? dremel? looks very very clean 
	

	
	
		
		

		
		
	


	




 [Edit] gah NeilR, you beat me in asking about the square hole!


----------



## tomb

Quote:


  Originally Posted by *Fiola* 
_So..... tell me if I understood how your contraption works 
	

	
	
		
		

		
		
	


	




 the piece of metal with the foam on will go in on one of the slots in the case, and is sized so that the foam pushes against the back of the usb receptor when both side of the bezel is shut, correct?_

 

That's kind've what I was thinking, although I was a little surprised to read that the "sheet stock" is metal. Ingeneous of MisterX, perhaps, because this supports the stresses of plugging/unplugging a USB cable at the connrctor. The simplistic solution would be to put a couple of stops next to the board's edges in the case slots, but this would allow stress on the USB solder connections on the board.

  Quote:


 btw, howd you cut your square hole? dremel? looks very very clean 
	

	
	
		
		

		
		
	


	




 [Edit] gah NeilR, you beat me in asking about the square hole! 
 

 A good scroll saw with the right blade and lubricant might work well. Anything else might not give a sharp edge at the hole's corners.


----------



## MisterX

Quote:


  Originally Posted by *Fiola* 
_the piece of metal with the foam on will go in on one of the slots in the case, and is sized so that the foam pushes against the back of the usb receptor when both side of the bezel is shut, correct?
_

 


 You are almost there.....the chunk of metal fits between the slots in the case and "pushes against" the circuit board when the end plates are secured to the enclosure.

 Maybe another picture will help? 






  Quote:


 btw, howd you cut your square hole? 
 

Drill a 3/8" hole, use a 1/8" rotary file in the dremel to get the hole close and finish it with a file. 
 Piece of cake that takes a great deal of patience.


----------



## tomb

OK, I guessed wrong. Looking at your first pic, I thought perhaps the sheet stock slid in upside down in one of the top slots, so that the foam was pressed up against the back of the USB connector - then wedged against the back plate.


----------



## MisterX

Quote:


  Originally Posted by *tomb* 
_OK, I guessed wrong. Looking at your first pic, I thought perhaps the sheet stock slid in upside down in one of the top slots, so that the foam was pressed up against the back of the USB connector - then wedged against the back plate._

 


 how do figure that would work with all of those capacitors in the way?


----------



## tomb

Quote:


  Originally Posted by *MisterX* 
_how do figure that would work with all of those capacitors in the way? 
	

	
	
		
		

		
		
	


	


_

 

 Good point - it would have to be a "fitted" piece of foam, and you'd have to insert the board and the backstop at the same time, with both in their mutual final position (assuming a longer piece of sheet stock). Most likely the USB solder tabs and the Hammond slots are more than enough to keep the joints/board from flexing.

 I was just brainstorming ...


----------



## whiz

misterX your construction is perfect!!!
 that is exactly what i want to do! the same RCAs and the same box!


----------



## NeilR

Quote:


  Originally Posted by *tomb* 
_Good point - it would have to be a "fitted" piece of foam, and you'd have to insert the board and the backstop at the same time, with both in their mutual final position (assuming a longer piece of sheet stock). Most likely the USB solder tabs and the Hammond slots are more than enough to keep the joints/board from flexing.

 I was just brainstorming ..._

 

OK... here's MY take on this. I think he simply wedged the foam between the insert and the panel, putting a little pressure on the insert so it doesn't rattle and, I think, based on his rather cryptic post, giving adequate pressure with or without the plastic bezels mounted. His photo implies some other mysterious configuration but think that was just a trick 
	

	
	
		
		

		
			





 I am in the middle of building mine into the same or similar case and I was going to cut down some rat shack stripboard because I don't have any suitable scrap metal sheet laying around. I didn't think about the problem with the insert rattling, but I think I'll try wedging some foam in there, maybe glue it to the inside of the front panel to make things simpler to install and uninstall.


----------



## MisterX

I dunno which is worse... the fact that I had to click to be insulted by the resident troll or the fact that he doesn't get it.


----------



## NeilR

Quote:


  Originally Posted by *MisterX* 
_I dunno which is worse... the fact that I had to click to be insulted by the resident troll or the fact that he doesn't get it. 
	

	
	
		
		

		
		
	


	


_

 

I didn't realize we had a problem. Sorry to hear that since I don't see anything offensive in my replies here. I don't think I've ever been called a Troll; not here or any other forum that I frequent.


----------



## Macwizard

MisterX, could you please post your BOM. Thanks.


----------



## threepointone

I was just thinking, since these boards use the immersion silver plating, should it be _necessary_ to use silver-bearing solder to prevent the silver from leaching into the joint and weakening it? or is it too little to matter? I remember something about silver solder being originally developed for soldering joints containing silver


----------



## deadlierchair

Alright, time to look to the collective builders for help 
	

	
	
		
		

		
		
	


	




 Here is the story thus far: I built the DAC using IC3 to regulate but could never get anything to come through on the 5v so I figured that USB wasn't supplying enough voltage (4.82 on one PC, 4.96 on the other). In that configuration, the LED would light up and the DAC would recognize on the computer but there would be no sound output since the analog section of the chip wasn't receiving any power!

 I decided to remove IC3, C32, R31, and R32 (jumpering AV+ to 5v) to see if it would help. Since that change, the LED no longer lights up and on both the 3.3v and the 5v I am receiving 50mv and 160mv - clearly something is wrong. On top of that, the computer no longer recognizes the device (I would bet because the 3.3v is no longer getting power!)

 I have one question immediately: on the PCM2702, pins 16 and 17 show continuity. When I test one of my unpopulated boards, these pins are not connected. Could that be part of the problem? They showed continuity under my first config and now once I've removed regulation. Beyond that here are my pics, I wonder wonder wonder...


----------



## MASantos

Could you post bigger pictures? I believe you have some cold joints and some solder bridges. I would also clean the flux on the board with a toothbrush and some alcool. 

  Quote:


  Originally Posted by *deadlierchair* 
_Alright, time to look to the collective builders for help 
	

	
	
		
		

		
		
	


	




 Here is the story thus far: I built the DAC using IC3 to regulate but could never get anything to come through on the 5v so I figured that USB wasn't supplying enough voltage (4.82 on one PC, 4.96 on the other). In that configuration, the LED would light up and the DAC would recognize on the computer but there would be no sound output since the analog section of the chip wasn't receiving any power!

 I decided to remove IC3, C32, R31, and R32 (jumpering AV+ to 5v) to see if it would help. Since that change, the LED no longer lights up and on both the 3.3v and the 5v I am receiving 50mv and 160mv - clearly something is wrong. On top of that, the computer no longer recognizes the device (I would bet because the 3.3v is no longer getting power!)

 I have one question immediately: on the PCM2702, pins 16 and 17 show continuity. When I test one of my unpopulated boards, these pins are not connected. Could that be part of the problem? They showed continuity under my first config and now once I've removed regulation. Beyond that here are my pics, I wonder wonder wonder..._


----------



## MisterX

Quote:


  Originally Posted by *Macwizard* 
_MisterX, could you please post your BOM. Thanks._

 

Sorry but I don't have one


----------



## guzzler

Quote:


  Originally Posted by *deadlierchair* 
_I have one question immediately: on the PCM2702, pins 16 and 17 show continuity. When I test one of my unpopulated boards, these pins are not connected. Could that be part of the problem? They showed continuity under my first config and now once I've removed regulation. Beyond that here are my pics, I wonder wonder wonder.._

 

Yes, you've shorted the regulated 5V to ground. The 3.3V reg, 5V reg, and LED come off the same line so in your original configuration you were simply shorting the 5V regulated line so 3.3V and the LED line were unaffected. Now, you're shorting everything. Read the datasheet!


----------



## Fiola

yeh, pin 17 is 5V, pin 13 - 16 is ground.
 for a while i thought I had shorts between 13-16, used desoldering braid to make it really really clean and it was still shorted, then I read the spec sheet, doh! One of the gotchas if you didnt read the spec sheet I guess, heh


----------



## NeilR

Quote:


  Originally Posted by *deadlierchair* 
_Alright, time to look to the collective builders for help 
	

	
	
		
		

		
		
	


	




 Here is the story thus far: I built the DAC using IC3 to regulate but could never get anything to come through on the 5v so I figured that USB wasn't supplying enough voltage (4.82 on one PC, 4.96 on the other). In that configuration, the LED would light up and the DAC would recognize on the computer but there would be no sound output since the analog section of the chip wasn't receiving any power!

 I decided to remove IC3, C32, R31, and R32 (jumpering AV+ to 5v) to see if it would help. Since that change, the LED no longer lights up and on both the 3.3v and the 5v I am receiving 50mv and 160mv - clearly something is wrong. On top of that, the computer no longer recognizes the device (I would bet because the 3.3v is no longer getting power!)

 I have one question immediately: on the PCM2702, pins 16 and 17 show continuity. When I test one of my unpopulated boards, these pins are not connected. Could that be part of the problem? They showed continuity under my first config and now once I've removed regulation. Beyond that here are my pics, I wonder wonder wonder...

 [[/IMG][/URL]_

 


 Pin 16 is grounded and pin 17 carries +5V. The short across them is killing your +5V. Even if your PC delivers siginificantly less than 5V, if things were working correctly IC3 would just put out the USB voltage, less a small drop across the regulator. IOW, a slightly low USB voltage is NOT the problem. it is the short. If you can't see a short, try brushing between the pins with a toothbrush. It is possible a tiny wire strand fragment or some other metal is lodged beneath the pins.


----------



## pddjsteve

Quote:


  Originally Posted by *Fiola* 
_yeh, pin 17 is 5V, pin 13 - 16 is ground.
 for a while i thought I had shorts between 13-16, used desoldering braid to make it really really clean and it was still shorted, then I read the spec sheet, doh! One of the gotchas if you didnt read the spec sheet I guess, heh_

 

I had a similar problem, two pins on the pcm2702 chip had a very small solder bridge and that was killing my analog section. I used a ton of flux, and the wipe method described earlier in this thread. It finally took a suggestion to hold the board up with a light behind it rather than shining on it for me to be able to see the bridge under a magnifier. Once I got it cleaned up (more flux, and more wiping) it worked great.


----------



## splaz

Well got on the 2nd group buy and am sourcing parts.

 For CL/CR. Two caps that I can actually get for that are

 Nichicon FG 47uF

 or

 Elna Starget 22uF

 either of them worth considering ?


----------



## deadlierchair

Quote:


  Originally Posted by *NeilR* 
_Pin 16 is grounded and pin 17 carries +5V. The short across them is killing your +5V. Even if your PC delivers siginificantly less than 5V, if things were working correctly IC3 would just put out the USB voltage, less a small drop across the regulator. IOW, a slightly low USB voltage is NOT the problem. it is the short. If you can't see a short, try brushing between the pins with a toothbrush. It is possible a tiny wire strand fragment or some other metal is lodged beneath the pins._

 

Alright, all of that is understood. I checked those two pins to see if there were any bridges but couldn't find anything. At this point I'm wondering if there are bad connections elsewhere on the board, if I soldered on an incorrect part, or if I possibly killed the PCM2702 with all that heat. I tried to get some better pictures but only had a little bit of luck.

1.jpg
2.jpg
3.jpg
4.jpg


----------



## tomb

Quote:


  Originally Posted by *splaz* 
_Well got on the 2nd group buy and am sourcing parts.

 For CL/CR. Two caps that I can actually get for that are

 Nichicon FG 47uF

 or

 Elna Starget 22uF

 either of them worth considering ?_

 

I would refer to dsavitsk's site on capacitor reviews - it is listed in Alf's support pages with a tiny link on the word "here" when Alf is discussing capacitors.

 I don't think either of the ones you mention were discussed. Nichicon ES and Elna Silmic are the closest ones, I think.


----------



## Alf

Quote:


  Originally Posted by *deadlierchair* 
_Alright, all of that is understood. I checked those two pins to see if there were any bridges but couldn't find anything. At this point I'm wondering if there are bad connections elsewhere on the board, if I soldered on an incorrect part, or if I possibly killed the PCM2702 with all that heat. I tried to get some better pictures but only had a little bit of luck._

 

All components appear to be soldered correctly. You are most likely to have a short on 5V after IC3. It is either PCM2702 pins on the analog/right side or the SMD capacitors on the same side. I would triple check those (check under the pins too). Any other location is less likely. Anyway I suggest to clean the board and make sure that there is no traces of solder and flux anywhere on the board. 

 If all this does not help, find a thin screwdriver or a needle and clean/scratch between PCM2702 pins and tiny traces around it. If this does not help either, well, I am afraid it would be about time to start working on another board.


----------



## Alf

Quote:


  Originally Posted by *splaz* 
_Well got on the 2nd group buy and am sourcing parts.

 For CL/CR. Two caps that I can actually get for that are

 Nichicon FG 47uF

 or

 Elna Starget 22uF

 either of them worth considering ?_

 

If you cannot get hi-end electrolytics, go for larger film capacitors. Low-end electrolytics may sound nasty. You would be wasting your money and effort using those.


----------



## abcheng

I'm about to purchase all the parts for (4) Alien DACs. What would be the best quality cap for CL/CR with a reasonable price at digikey or mouser? I'm considering buying Averovox AFPS caps since they're a good price and got good ratings from http://ecp.cc/cap-notes.html.


----------



## MisterX

Quote:


  Originally Posted by *abcheng* 
_What would be the best quality cap for CL/CR with a reasonable price at digikey or mouser?_

 

Elna RFS series from Digikey
 To be more specific Part number #604-1054
 problem is they are a little to big around to fit flat on the board.


----------



## abcheng

Quote:


  Originally Posted by *MisterX* 
_Elna RFS series from Digikey
 To be more specific Part number #604-1054
 problem is they are a little to big around to fit flat on the board._

 

Thanks for the response 
	

	
	
		
		

		
			





. I'll definitely give those a try.


----------



## NeilR

If you want to try the Silmic II's (RFS) part 604-1052-ND fits perfectly into CL/CR, but is only 22uF.


----------



## Fiola

I said pics would follow "soon", I guess i procrastinated a bit, so here it is finally.














 The RCA jacks will be replaced by something nicer when I get around to case it up 
	

	
	
		
		

		
		
	


	




, probably, hah.

 Not bad for 1st time smd eh? The white stuff is residue from cleaning with 99% isopropynol, any way to clean it properly? I was under the impression 99% would be pure enough not to leave residue, or is that residue flux that was dissolved by the alcohol but not cleaned off the board completely?


----------



## MisterX

Quote:


  Originally Posted by *Fiola* 
_Not bad for 1st time smd eh?_

 

Not bad at all. 
	

	
	
		
		

		
		
	


	







  Quote:


 or is that residue flux that was dissolved by the alcohol but not cleaned off the board completely? 
 

Yup... that residue is the flux. 
 If you are using just alcohol and an old tooth brush you will have to clean it a couple of times to get that all off.


----------



## robzy

Hey guys, all crystals require the leads to be soldered (duh ), i know that. But what about the outer casing and the pads?

 Rob.


----------



## MisterX

where are you planning on soldering the case and or pads to? 
	

	
	
		
		

		
		
	


	




 And while I am at it... 

 Why do you think you sometimes see the can (or case as you call it) soldered to board?


----------



## robzy

Okay, sorry, may i rephrase my question?

 The PCB has pads around where the can (now that i know thats the word 
	

	
	
		
		

		
		
	


	




) should be. On some PCB's ive seen it soldered. What is its purpose?

 Rob.


----------



## MisterX

They do that for vibration and shock control.
 Tall parts don't always play nice when shipped half way around the world and that is one solution you commonly see companies use to ensure they do. 
 Ever wonder why you see glue all over large capacitors in retail gear?
 Same thing.


----------



## robzy

Ohh... interesting, i didnt know that. I take it the reason that there are pads for crystals but not other tall/er parts is because they have metal cans and thus it makes sense?

 [edit]: Also, is the improvement in overvolting the PCM2702 to 5.4v going to be noticable? Or better yet - to what extent do you think it might be noticable?

 I see that the SNR raises a few dB, nothing to be writting home about. The THD, however, goes from .002 to .0015.... whats a .0005 difference like? (Jees, when you write it like that it doesnt seem like much)

 Rob.


----------



## dsavitsk

Quote:


  Originally Posted by *MisterX* 
_They do that for vibration and shock control.
 Tall parts don't always play nice when shipped half way around the world and that is one solution you commonly see companies use to ensure they do. 
 Ever wonder why you see glue all over large capacitors in retail gear?
 Same thing. 
	

	
	
		
		

		
		
	


	


_

 

It also can dampen a circuit and improve sonic performance in some cases. This is especially noticable on speaker crossovers -- coat them in epoxy (or even better, take them out of the speakers and put them in thier own little boxes) and you will notice that the sound gets better. There are even some film caps that you can hook to a multimeter and watch the capacitance change as you squeeze them. This also happens as the air pressure in the speaker changes altering the crossover's filter points.


----------



## raromachine

Hi all,

 I've built up my first (of 5) of these, and whilst it appears to work fine I get a lot of very audible noise - which almost sounds kinda looped?

 The variant I've built is fed by a 9v battery and feeds the PCM chip 3.3v and 5.6v ( stuffed up my order of smt resistors and omited the K on the end of one of the values ) so had to use the next closest match I had.

 I've used the 1A variety of the 1206 SMT Murata ferrite, but had to sub-out the 600R for the red LED for about 60R.

 Other than that I'm using all std R values, and std C values for the smt capacitors. The electrolytics I'm using are: 470uf x1, 100uf x2, 47uf x1 and CR and CL are 10uf - all Nichicon FX.

 The Crystal is this guy:
 Digi-Key Part NumberX983-ND
 Manufacturer Part NumberECS-120-32-1X
 DescriptionCRYSTAL 12.000MHZ 32PF HC-49/UA

 Help?


----------



## robzy

raro, the _max_ voltage for the analogue side is 5.5v. I dont know if thats whats causing you problems, but i'd definetly fix it up nonetheless.

 Rob.


----------



## splaz

Quote:


 If you cannot get hi-end electrolytics, go for larger film capacitors. Low-end electrolytics may sound nasty. You would be wasting your money and effort using those. 
 

Well I was asking if they were high end enough, judging by your response they're not but from what I looked up they seemed at the very least good quality.

 Nichicon FG is 2nd to the KZ of the Muse line. One I was leaning towards as they actually fit on the board.

 Starget has been dropped from the Elna line. Used to be ROD series, OFC leads can't be that low end though. Doesn't fit that well though in the values I can get.

 Otherwise I just realised from the discussions here that the Elna RFS is at digikey so I'll get them if the FGs are that bad. They don't fit well though either...


----------



## NeilR

Quote:


  Originally Posted by *robzy* 
_raro, the max voltage for the analogue side is 5.5v. I dont know if thats whats causing you problems, but i'd definetly fix it up nonetheless.

 Rob._

 

Actually the max *specified *voltage is 5.5V. The absolute max voltage is 6.5V. You could interpret that as 5.6V probably won't damage the chip (it's a long way from 6.5V) but it isn't recommended for peak performance. It would be interesting to see if that alone fixes the problem.


----------



## splaz

okay noob question.

 Alf's site states something about using a slightly higher voltage as the 2702 has slightly better performance at a higher voltage.

 How do you supply it with 5.4V ?

 I know you use an adjustable regulator but IIRC you should have an input voltage higher than your output voltage and the USB only supplies 5V. So you need a battery powered one to be able to do that... ?


----------



## NeilR

Quote:


  Originally Posted by *splaz* 
_okay noob question.

 Alf's site states something about using a slightly higher voltage as the 2702 has slightly better performance at a higher voltage.

 How do you supply it with 5.4V ?

 I know you use an adjustable regulator but IIRC you should have an input voltage higher than your output voltage and the USB only supplies 5V. So you need a battery powered one to be able to do that... ?_

 

Yes, you would need an external power source swuch as a battery or wall supply. There is a trade-off of "unlimited power" and convenience for performance when you use USB power, to whatever extent you can hear the difference.


----------



## raromachine

Quote:


  Originally Posted by *NeilR* 
_Actually the max *specified *voltage is 5.5V. The absolute max voltage is 6.5V. You could interpret that as 5.6V probably won't damage the chip (it's a long way from 6.5V) but it isn't recommended for peak performance. It would be interesting to see if that alone fixes the problem._

 

Thanks NeilR and Robsy - 

 The noise is aparent (and indisinguishably similar) on the 5.6v or 5v from the USB BUS. It is coming via a Belkin 7port usb2 hub, which is fed by a small 5A switcher, I'll try it from a motherboard feed. And with/without an LED attached.

 It might also be that it's something to do with the cmoy style amp connected to it - it's light again and I can go pickup a few chokes and things


----------



## raromachine

I've soldered in a 22uH choke for the USB powered one, and it works too - but still has that huge amount of hiss. This time it doesn't sound like it's looping though.

 Images below:












 My 3rd build doesn't seem to do anything - led comes one, voltages look good, but nothing on the PC showing there is a USB device. Is there a quick/simple way to check the crystal and dac are working?


----------



## raromachine

Success!

 Just re-testing my second (usb powered) build with my Pint (which I wasn't sure would work?) - and its really great, no noise, very very clear, good bass, etcetc.

 Perhaps it was my other amp?

 V1 requires another 9V battery to test - but I'm a 1x 9v battery kinda guy.

 V3 is dead dead dead, have killed the 3.3V Reg and the PCM 2702E - if anyone is ordering from Mouser/Digikey let me know as I'd like to pickup a few more bits


----------



## pddjsteve

I just made my 2nd as well. This time, I went with an adjustable regulator and USB power, to take on the go. Worked great the first try.


----------



## raromachine

Can someone explain to me how/why ASIO4ALL is better than a standard WDM driver?

 I can see that it would be great if you wanted to use an ASIO only program with your non ASIO soundcard, but other than that I fail to see the benefit - infact it looks like it adds more CPU overhead and latency to the playback of audio.

 It can't improve the quality can it? That's always as low as the weakest link - and using ASIO4ALL doesn't remove that.


----------



## robzy

ASIO prevents window's from mucking around with the audio i believe. I can definetly here a difference, sound is just a little 'cleaner' with a layer of distortion gone.

 Rob.


----------



## raromachine

Quote:


  Originally Posted by *robzy* 
_ASIO prevents window's from mucking around with the audio i believe. I can definetly here a difference, sound is just a little 'cleaner' with a layer of distortion gone._

 

AFAIK it would usually go like this (this example is what I use):

 Winamp > DirectOutput Plugin > Windows WDM Driver > Sound Hardware

 With ASIO4ALL you get:

 Winamp > ASIO Out > ASIO4ALL Wrapper > Windows WDM Driver > Sound Hardware

 I've read more and the only thing I can see is that any sampling rates less than 48khz are resampled in software (not hardware?). I guess this is advantageous, but I can't say that I know why/how it's different than on the PCM2702E in hardware.


----------



## doobooloo

Is there any way to use ASIO output from iTunes? I think there was something like, using the iTunes interface but using foobar playback?


----------



## MisterX

Quote:


 Winamp > DirectOutput Plugin > Windows WDM Driver > Sound Hardware 
 


 You are overlooking the role the dreaded Kmixer plays in all of this. 
	

	
	
		
		

		
		
	


	



 There are a few hundred threads about this here. 
 Here is one of them:

http://www6.head-fi.org/forums/showthread.php?t=77185


----------



## MisterX

Quote:


  Originally Posted by *doobooloo* 
_Is there any way to use ASIO output from iTunes? I think there was something like, using the iTunes interface but using foobar playback? 
	

	
	
		
		

		
		
	


	


_

 

There are a few hundred threads about this here. 
 Here is one of them:
http://www6.head-fi.org/forums/showthread.php?t=143270

 You know what the most ironic thing is? 
 This has already been covered once in this thread.


----------



## Calroth

Quote:


  Originally Posted by *doobooloo* 
_Is there any way to use ASIO output from iTunes? I think there was something like, using the iTunes interface but using foobar playback? 
	

	
	
		
		

		
			



_

 

You can, with a few drawbacks which you may or may not consider serious: You need an old version of foobar2000, you can't play Apple Lossless files (reliably), you can't play iTunes Music Store files.


----------



## doobooloo

Quote:


  Originally Posted by *MisterX* 
_There are a few hundred threads about this here. 
 Here is one of them:
http://www6.head-fi.org/forums/showthread.php?t=143270

 You know what the most ironic thing is? 
 This has already been covered once in this thread. 
	

	
	
		
		

		
		
	


	


_

 

Gah! Sorry!!! 
	

	
	
		
		

		
		
	


	




 And thanks for the kindness in not screaming Use the Search Button at me.


----------



## MisterX

Quote:


  Originally Posted by *doobooloo* 
_Gah! Sorry!!! 
	

	
	
		
		

		
		
	


	




 And thanks for the kindness in not screaming Use the Search Button at me._

 


 lol... I was this close ----> || 
 to doing just that but I thought better of it.


----------



## mb3k

Currently I'm parting out my BOM, does anyone have updated BOM's?


----------



## cmirza

If you aren't feeling frugal, the Propagamma USB ASIO driver is very nice for the Alien DAC, but is pretty expensive at $50. I wouldn't spring for it, but someone else on here might. 
	

	
	
		
		

		
		
	


	




http://www.usb-audio.com/

 It's a bit easier to setup than ASIO4ALL. Just install the driver and you're done. KMixer is bypassed (you can't adjust any volume controls, even master volume) and all you have to do is select the device in foobar and you're done.


----------



## Seaside

So, mb3k. Do you finished making your BOM?
 Let us know when you finished doing BOM.

 And, Any other new BOMs? Anybody?


----------



## splaz

Well I have a digikey one but I might hold off putting it up until I've placed my order.

 Don't want to seem selfish or anything but some of the parts are getting a little scarce and if a lot of people order the same parts I don't want to have half my parts missing. I already have a suspicion certain people from a certain forum have had an impact on parts quanitites...


----------



## mb3k

Quote:


  Originally Posted by *Seaside* 
_So, mb3k. Do you finished making your BOM?
 Let us know when you finished doing BOM.

 And, Any other new BOMs? Anybody?_

 

I finished my BOM yesterday, and spent a ton of money on parts (also for other projects).
 Here's what it looks like. Click the pic to download the zipped .xls file


----------



## Seaside

Thanks mb3k for showing us your nice BOM.

 It looks like you want to hook it up with your amp, put it together in a big enclosure. That surely be an interesting option. I may try myself that later.

 Question is, why do u need R31 and R32 if you choose fixed voltage regulater?


----------



## mb3k

Quote:


  Originally Posted by *Seaside* 
_Thanks mb3k for showing us your nice BOM.

 It looks like you want to hook it up with your amp, put it together in a big enclosure. That surely be an interesting option. I may try myself that later.

 Question is, why do u need R31 and R32 if you choose fixed voltage regulater?_

 

I have 4 boards, some will not all run from a dedicated PSU. I'm planning to have a USB powered one, but that will be made down the road... a long time down the road.
 My main Alien DAC will be housed with it's PSU, and the big hammond enclosure will act more for aesthetic reasons


----------



## whiz

Alf says that we can use a 20-30μH axial inductor for the av+ and 5v if we build the unregulated usb configuration...at what frequency the inductor must be? can i have more details?


----------



## raromachine

Quote:


  Originally Posted by *whiz* 
_Alf says that we can use a 20-30μH axial inductor for the av+ and 5v if we build the unregulated usb configuration...at what frequency the inductor must be? can i have more details?_

 

I can't tell you anything about freq but I used one of these and the improvement was certainly audible. 
	

	
	
		
		

		
		
	


	




http://www.jaycar.co.nz/productView....Max=&SUBCATID=


----------



## guzzler

And inductor is just an inductor, it doesn't have a rated value at a certain frequency. A ferrite does have a rated impedance at different frequencies, eg, 600R at 100MHz is a good value to look for.

 The reason an inductor is recommended on the USB line is two fold:

 1) It will filter a lot of the high frequency noise out of the USB line

 2) It will significantly reduce the instantaneous current when the device is first plugged in. There is a large change in current at this point, so the inductor chokes this.

 Theoretically underpinning this is the fundamental equation of an inductor, V=L(dI/dt), or V=L_i_. _i_ is often used in electronics as dI/dt. The voltage induced is in the opposite direction to the current flow (back EMF) and so at high frequencies (high d_i_), this appears as a large impedance.


----------



## robzy

Quote:


  Originally Posted by *guzzler* 
_Theoretically underpinning this is the fundamental equation of an inductor, V=L(dI/dt), or V=Li. i is often used in electronics as dI/dt. The voltage induced is in the opposite direction to the current flow (back EMF) and so at high frequencies (high di), this appears as a large impedance._

 

When maths and electronics meld, i love it 
	

	
	
		
		

		
		
	


	




 What is "L" for?

 (And just because it took me a second to get, dI/dt essentially means 'change in current')

 Rob.


----------



## steinchen

L is the inductance
http://en.wikipedia.org/wiki/Inductance
http://en.wikipedia.org/wiki/Inductor


----------



## guzzler

Quote:


  Originally Posted by *robzy* 
_(And just because it took me a second to get, dI/dt essentially means 'change in current')_

 

 Importantly, *rate* of change of current *with respect to time*. So, from the equation you can see that if we consider dc current to that which is not changing at all wrt time, ie, _i_=0A/s then the induced back EMF is 0V.


----------



## Sinbios

How exactly would the inductor be implemented in the DAC?


----------



## splaz

Quote:


  Originally Posted by *Sinbios* 
_How exactly would the inductor be implemented in the DAC?_

 

IIRC I've seen them put in the S1 spot on the board.

 If that's what you mean.


----------



## whiz

What do you think for these characteristics?

 Axial Lead Inductors

 inductance (μH) 27 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.1
 SRF min (Mhz) 12
 Irms (mA) 140


 inductance (μH) 22 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.0
 SRF min (Mhz) 14
 Irms (mA) 144


----------



## splaz

Okay bear with me here.

 For the crystal in this application whats the deal with the capacitance value ?

 Best to keep it as close to 30pF as possible, lower is better or maybe even higher ?


----------



## Seaside

spalz.

 I found intersting thing when I observed several BOMs posted at this thread. That is, when the impediance of crystal is 32pF the value of capacitor C1 and C2 is tend to be 33pF, and If it is 20pF value of C1 and C2 is tend to be 22pF.

 Well.. this comes from obserbation. It looks like the DAC will be working at either case without a problem. I do not know what difference the impediance of crystal makes, or what's the reason behind this. Someone more knowledgable may throw some hints for me.


----------



## splaz

You may be onto something. I looked on the net for some answers but didn't find anything specific. However I did find something about using capacitors to set something... frequency ?

 So maybe that spec on the crystal is the capacitor value you use.

 or am I completely off ?


----------



## Buzzerbro

My Alien DAC has developed a problem. It ran fine for 2 weeks then when I plugged it in one day it developed severe static in the right channel. I can still hear music but it sounds horrible. The left channel is perfect. Its not my cable or amp because they work fine in my other system. I cleaned the board with 99% alcohol again but that did not help. 

 Are there alternative Drivers for this DAC?

 Would a bad output cap cause something like this?

 The chip has separate power supplies for the Left and Right Channels. Can this be an issue?

 Here is my post with pics: http://www6.head-fi.org/forums/showp...0&postcount=95


----------



## robzy

Quote:


  Originally Posted by *splaz* 
_or am I completely off ?_

 

As far as i know you are completing on 

 The value of the two caps either side of the crystal (cant think of there names off hand) depend on what the crystal's datasheet syas.

 Rob.


----------



## whiz

Quote:


  Originally Posted by *splaz* 
_You may be onto something. I looked on the net for some answers but didn't find anything specific. However I did find something about using capacitors to set something... frequency ?

 So maybe that spec on the crystal is the capacitor value you use.

 or am I completely off ?_

 

guys the same questions i've done afew days ago on the other topic about the Alien DAC and i didn't took any answers...maybe nonone knew, maybe i posted to a wrong thread....maybe...maybe the point is that the Threads about the alien DAC are so big that makes them totaly UNREADABLE! you can't find the information your looking for...

 I believe a new thread must be created and move all the questions and problems about the alien dac there...

 my humble opinion...


----------



## robzy

Quote:


  Originally Posted by *whiz* 
_guys the same questions i've done afew days ago on the other topic about the Alien DAC and i didn't took any answers...maybe nonone knew, maybe i posted to a wrong thread....maybe...maybe the point is that the Threads about the alien DAC are so big that makes them totaly UNREADABLE! you can't find the information your looking for..._

 

Unfortunatly thats the nature of all DIY projects such as this one.

 A quick question - how are people creating holes for the USB plug? Getting FPE to do it is NOT an answer 

 Rob.


----------



## mb3k

Quote:


  Originally Posted by *robzy* 
_Unfortunatly thats the nature of all DIY projects such as this one.

 A quick question - how are people creating holes for the USB plug? Getting FPE to do it is NOT an answer 

 Rob._

 

Dremel would be the tool of choice, but I'm not entirely certain on what kind of bit to use.. super small cutting wheel?


----------



## splaz

Well that's something else buried deep within this topic.

 Heres how MisterX does it:

http://www6.head-fi.org/forums/showp...&postcount=206


----------



## whiz

What do you think for these characteristics for the AV+ 5V inductor??

 Axial Lead Inductors

 inductance (μH) 27 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.1 
 SRF min (Mhz) 12 
 Irms (mA) 140


 inductance (μH) 22 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.0 
 SRF min (Mhz) 14
 Irms (mA) 144


----------



## Alf

Quote:


  Originally Posted by *whiz* 
_What do you think for these characteristics for the AV+ 5V inductor??

 Axial Lead Inductors

 inductance (μH) 27 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.1 
 SRF min (Mhz) 12 
 Irms (mA) 140


 inductance (μH) 22 
 Q3 min 50
 Test freq. (Mhz) 2.5 
 DCR max ohm 2.0 
 SRF min (Mhz) 14
 Irms (mA) 144_

 

I doubt one could hear any difference.


----------



## whiz

You specified a limit of 20-30 and i didn't knew if i can "play" with
 bigger inductors...i thought that there can be even a small difference...

 Alf if you have spare time....me and some other guys have trouble understanding some things! please try to expain us what's going on
 with the "crystal loading capacitors" from what i know they keep the
 frequency steady... is this the reason they exist?
 I ordered some FOX crystals which they say CL=20pF i suppose i must use the nearest caps i can find (22pF) to drive them...correct? or i should use the ones you say in your site?! i have read some things about "frequency pull"
 so i guess not?


----------



## guzzler

The loading capacitors set the time required to start up the oscillator and then maintain it within it's spec. There's a ramp up time defined by Cl and the crystals specs until it becomes stable. This is important in devices where you can't gaurentee the start up response. You can slightly tweak the frequency of the x-tal using them, but not by very much. The PCM2702 defines the frequency as "12MHz +- 500ppm", and I doubt you'll ever pull it out of that range unless you use values well out of range. Just get the nearest easily available value


----------



## Seaside

Cr@p

 I found REG10*UA-A LDO is out of stock at Digikey now.
 Not able to complete my order due to that.

 Any alternative chips?

 Analong Device has LDO chip that has similar spec tho, I can not be sure it is compatible with or not. Any idea?


----------



## n_maher

Quote:


  Originally Posted by *Seaside* 
_Cr@p

 I found REG10*UA-A LDO is out of stock at Digikey now.
 Not able to complete my order due to that._

 

You sure about that? Digikey tells me that they have 300+ of the REG101UA-A in stock right now.

 Hope that helps.

 Nate


----------



## Seaside

Oops... Sorry, I must be confused of something. 
 Thanks, I ordered mine. 
	

	
	
		
		

		
			




 But it looks like REG10* chips are going short pretty fast.


----------



## splaz

Yeah well I wanted reg102ua-a but that's not been in stock at digikey for quite some time and TI has no stock either. They'll have 4000 in early october, TI that is. Digikey is estimating late october they'll have them in.

 So looks like reg101 it is.


----------



## splaz

Okay this is my last annoying Alien DAC related question. 
	

	
	
		
		

		
		
	


	




 For the LED a low current one is specified. Is it critical you use one,I can't see why, or is it just suggested ?

 From what I've gathered it shouldn't be a problem, even with the reg101, is it just that you don't want to draw too much current off the USB ?

 I'm assuming it would be fine running an LED on 20mA.


----------



## guzzler

20mA is a lot for an LED, it'll be annoyingly bright. I've got a blue one in mine down at about 1.5mA and it's plenty bright enough.


----------



## splaz

Really ?

 I thought around 15 - 20mA was typical for most LEDs.

 Wonder what I've been smoking.


----------



## n_maher

Quote:


  Originally Posted by *splaz* 
_Wonder what I've been smoking. 
	

	
	
		
		

		
		
	


	


_

 

Resistors?


----------



## mb3k

Nice one Nate,
 I have most of my LEDs running at 7mA, and they're bright enough. Check out the luminosity VS forward current plots for the LEDs you'll be using (they're usually referenced from 20mA)


----------



## mb3k

Ack,
 I just realized that I ordered the REG101UA-5 correctly, but the incorrect 3.3V regulator. I got *REG102UA-33* instead of 101.
 Does it matter if it's mismatched, or is it recommended to have the same type?
 I can easily whip up a quick order from DigiKey, but if it's not necessary then much the better.


----------



## MisterX

It seems that splaz is not the only one been smoking resistors here. 
	

	
	
		
		

		
		
	


	




  Quote:


 Does it matter if it's mismatched 
 

Not really. 


 REG101= 100mA
 REG102= 250mA


----------



## whiz

I hope my post is in the correct place... 
	

	
	
		
		

		
		
	


	




 i want to try Elna RFS (cilmic II) for my alien dac...
 47µF 6.3V Radial.

 I can't get them localy or from online store...so if someone has spare
 please find a way to comunicate with me!


----------



## mikemacwillie

digikey has 47uf 25v which there is just enough room for.


----------



## whiz

Quote:


  Originally Posted by *mikemacwillie* 
_digikey has 47uf 25v which there is just enough room for._

 

hmmmm.......as i said i can't get them online...i'm done with my orders and i can't make a new one, the cost is to big if a make a new order for a couple of caps.

 If anyone has a spare please let my know...i want to try some elna's 
	

	
	
		
		

		
			











 P.S i can pay through paypal...


----------



## robzy

Quote:


  Originally Posted by *mb3k* 
_Does it matter if it's mismatched, or is it recommended to have the same type?_

 

The reg101/reg102 is interchangable so long as the current is within spec of the respective chips. I believe the 102 has slightly less specs when it comes to noise - but i highly doubt it is anything noticable at all.

 Rob.


----------



## MASantos

Quote:


  Originally Posted by *robzy* 
_The reg101/reg102 is interchangable so long as the current is within spec of the respective chips. I believe the 102 has slightly less specs when it comes to noise - but i highly doubt it is anything noticable at all.

 Rob._

 

Thei reg101 has slightly better noise specs because it needs to handle less currrent. I also doubt that you could hear the difference but why not use it? Better specs are always better specs. And the 2702 lives very happily with the reg101!!!


----------



## robzy

True, but if one has already ordered and recieved reg102's it might not be worth doing another order just to get some reg101's. I know i wouldnt, but on the flipside - if thats what you want to do there is nothing wrong with that.

 Rob.


----------



## splaz

I personally wouldn't lose any sleep over it.

 I'm using mismatched. I wouldn't even consider doing another order for something like that, there are so many other components that could be improved that I wouldn't even consider it.

 Well anyway I swooped in and grabbed the last 1455C801 cases. So if anyone is interested I know it's a little late but I can put up a BOM for digikey for a USB powered DAC, fully occupied for that config.Without the standard case though....


----------



## mb3k

Well it turned out I placed another order with Digikey, including matching REGs now... I needed another toriodal trafo anyways.


----------



## rreynol

I don't know how you guys do it but I 'm not afraid to admit when I've been beat. I'm not quite sure where i'm going wrong but I do know I've wasted enough boards and enough PCM2702 for now. In each case, I end up with a few solder bridges that I can't get rid of. I've tried the flood & suck as well as the paste & wipe techniques using both soldering braid and a solder sucker as clean up. I always end up 1 or 2 bridges. I also have a fear that in the process of cleaning these up, I'll have burnt up the chip (which is a wonderful thing to find out AFTER you've populated the rest of the board). What do you guys do for those tough to get rid of solder bridges?

 I commend the guys who have knack for the real tight smd soldering but I think I may just have to stick with larger package sizes and buy a DAC instead.


----------



## Seaside

Well... I can not say I am expert tho... I can feel your frustration. 
 Slodering this little chip is a real pain in the rear, isn't it?

 Can I ask you what kind of soldering iron and tip you used?
 How clean is your tip?

 Because, it is very hard to solder SOP28 chip if all you got is thick or dirty tip. You should use narrower tip. Clean your tip and clean it often. Use very little solder at a time. Use flux. The flux should be enough to cover all the legs. Excessive? Maybe. But you can always clean it later.

 With a lot of flux and a little luck, you can get rid of those tiny bridges. Clean your tip the best you can, apply flux on the legs, swipping the tip over the legs approx less than 1/2 second at each leg. That will pick up solder under the leg a little by little, if your tip is clean enough. Do it again if needed. Once this is done, check if theres any bridge still there with magnifier under bright light. Then clean the flux thoroughly.

 Hope this helps.


----------



## rreynol

Quote:


  Originally Posted by *Seaside* 
_Well... I can not say I am expert tho... I can feel your frustration. 
 Slodering this little chip is a real pain in the rear, isn't it?

 Can I ask you what kind of soldering iron and tip you used?
 How clean is your tip?

 Because, it is very hard to solder SOP28 chip if all you got is thick or dirty tip. You should use narrower tip. Clean your tip and clean it often. Use very little solder at a time. Use flux. The flux should be enough to cover all the legs. Excessive? Maybe. But you can always clean it later.

 With a lot of flux and a little luck, you can get rid of those tiny bridges. Clean your tip the best you can, apply flux on the legs, swipping the tip over the legs approx less than 1/2 second at each leg. That will pick up solder under the leg a little by little, if your tip is clean enough. Do it again if needed. Once this is done, check if theres any bridge still there with magnifier under bright light. Then clean the flux thoroughly.

 Hope this helps._

 

Yeah, it is a pain. I've got 3 more untouched boards that maybe I'll revisit someday. I tried a big tip (which some said they preferred) as well as a tiny conical tip. I've got a weller soldering iron and I've used plenty of flux trying to fix it. I'm constantly cleaning the tip. Best I can guess is that somehow its not exactly straight (it was when i tacked it down). /Shrugs. At nearly 10 bucks per PCM2702 chip, it's frustrating enough to put down for a while.


----------



## dhp

Quote:


  Originally Posted by *rreynol* 
_Yeah, it is a pain. I've got 3 more untouched boards that maybe I'll revisit someday. I tried a big tip (which some said they preferred) as well as a tiny conical tip. I've got a weller soldering iron and I've used plenty of flux trying to fix it. I'm constantly cleaning the tip. Best I can guess is that somehow its not exactly straight (it was when i tacked it down). /Shrugs. At nearly 10 bucks per PCM2702 chip, it's frustrating enough to put down for a while._

 

Use braid. Try doing it all pin by pin, and then use a braid to clean it all off.


----------



## MASantos

Quote:


  Originally Posted by *rreynol* 
_Yeah, it is a pain. I've got 3 more untouched boards that maybe I'll revisit someday. I tried a big tip (which some said they preferred) as well as a tiny conical tip. I've got a weller soldering iron and I've used plenty of flux trying to fix it. I'm constantly cleaning the tip. Best I can guess is that somehow its not exactly straight (it was when i tacked it down). /Shrugs. At nearly 10 bucks per PCM2702 chip, it's frustrating enough to put down for a while._

 


 Why not ask someone to do the pcm2702 for you?


----------



## Fiola

Personally, braid is the way to go. I just started my second Alien DAC, i tried the flood and suck method, but still ended up with solder bridges, so i tried wiping it, made more bridges, then finally i just used the braid and sucked up all the bridges, then rewiped again to make them nice and shiny. Desoldering braid is definitely the way to go for SSOP28 components!


----------



## whiz

i have a problem too... 
	

	
	
		
		

		
		
	


	



 i'm going to use high quality components like os-con for the C23-C33
 and panasonic FC for the C2 and i can't find not even one brand of the capacitors specified for the output......i could use whatever i have! but i don't think it's wise...
 i either make it "cheap" or high-tech...is there anyone can suply me Cilmic II?
 or has any idea what to put for output capling?!?! 
	

	
	
		
		

		
		
	


	




 the components were real pain to collect them! from local stores/sites!!!


----------



## MASantos

Quote:


  Originally Posted by *whiz* 
_i have a problem too... 
	

	
	
		
		

		
		
	


	



 i'm going to use high quality components like os-con for the C23-C33
 and panasonic FC for the C2 and i can't find not even one brand of the capacitors specified for the output......i could use whatever i have! but i don't think it's wise...
 i either make it "cheap" or high-tech...is there anyone can suply me Cilmic II?
 or has any idea what to put for output capling?!?! 
	

	
	
		
		

		
		
	


	




 the components were real pain to collect them! from local stores/sites!!!_

 


 You could easily order everything you need from digikey! Including the outputcaps(silmicII). That is one of the good things about this dac.


----------



## whiz

@MASantos i can't buy from digikey i only need a couple of caps....


----------



## Alf

Quote:


  Originally Posted by *whiz* 
_i have a problem too... 
	

	
	
		
		

		
			




 i'm going to use high quality components like os-con for the C23-C33
 and panasonic FC for the C2 and i can't find not even one brand of the capacitors specified for the output......i could use whatever i have! but i don't think it's wise...
 i either make it "cheap" or high-tech...is there anyone can suply me Cilmic II?
 or has any idea what to put for output capling?!?! 
	

	
	
		
		

		
		
	


	




 the components were real pain to collect them! from local stores/sites!!!_

 

http://www.audio-cube.nl/elna.htm


----------



## whiz

Quote:


  Originally Posted by *Alf* 
_http://www.audio-cube.nl/elna.htm_

 

Thank you alf! 
	

	
	
		
		

		
		
	


	




 but i know this site...it's probably the only way
 to get elna capacitors without paying a fortune...but still the
 value for money of elna capacitors goes wasted because of the 9E
 for transportation cost...i only want to buy 6 capacitors and they
 only cost ~2.50E. I believe most of the online shop are effective only
 if you need to go on with a big order.

 splaz tryed to help me by puting my order in his list...but i saw his
 PM too late... 
	

	
	
		
		

		
		
	


	




 anyway...THANKS splaz!


----------



## splaz

Well like I said I don't expect someone to check in here 24/7 but you did take 3 or 4 days I think it was to get back to me and those cases weren't going to wait. :|

 Yeah well check your pms just now, I may have some extras of a different value if you're interested.


----------



## whiz

Quote:


  Originally Posted by *splaz* 
_Well like I said I don't expect someone to check in here 24/7 but you did take 3 or 4 days I think it was to get back to me and those cases weren't going to wait. :|

 Yeah well check your pms just now, I may some extras of a different value if you're interested._

 

You have PM! 
	

	
	
		
		

		
		
	


	






 (_i always wondered why we notify someone for his PM...but from my recent experience, it is very effective!_)


----------



## kennylee

Quote:


  Originally Posted by *Buzzerbro* 
_Regarding the *CL* and *CR* capacitor positions, what would be better, the *47uF/16vdc Nichicon Muse ES* or *47uF/25vdc Nichicon Muse KZ *? Size nor cost is an issue for me._

 


 Where can I get the "Nichicon Muse series Caps"? Thanks!


----------



## mikemacwillie

Quote:


  Originally Posted by *rreynol* 
_Yeah, it is a pain. I've got 3 more untouched boards that maybe I'll revisit someday. I tried a big tip (which some said they preferred) as well as a tiny conical tip. I've got a weller soldering iron and I've used plenty of flux trying to fix it. I'm constantly cleaning the tip. Best I can guess is that somehow its not exactly straight (it was when i tacked it down). /Shrugs. At nearly 10 bucks per PCM2702 chip, it's frustrating enough to put down for a while._

 

If you would like, I could solder your PCM2707 chips for you for the cost of shipping..


 Mike.


----------



## tomb

Quote:


  Originally Posted by *kennylee* 
_Where can I get the "Nichicon Muse series Caps"? Thanks!_

 

Handmade Electronics Unlike some other suppliers that may get mentioned, they are straightforward, fast, and dependable. Same for PartsConnexion if you are interested in Black Gates. I got some of both.


----------



## Seaside

I made Alien DAC yesterday. 
 Sounds great and everything is fine except one glitch.

 There's a severe distortion when directly connect earphones(Senn MX-500 and MX-510) to the dac and max up the volume. No distortion under about 75% volume, but it gets real ugly when I pump up the volume more than that. I can not hear any distortion when i hooked the dac to my amp. In short, distortion w/o amp, no distortion w/ amp. I think this might be an impediance issue, but not sure what the heck is the cause. 

 Parts I used are the same or within the range with what Alf specified at his website. 
 REG101UA-A, regulated down to 4.71V. Regulation is very stable. Pana and Elna electrolytics C2 470uf, C13,23,33 47uF, CL CR 22uF, 600ohm murata Ferrites, AVX 1uF C1, etc. Triple checked for soldering brigde and flux residue. There's no problem with them. 

 Anyone has the same problem with me? Any fix?
 Thanks.


----------



## mikemacwillie

Quote:


  Originally Posted by *Seaside* 
_I made Alien DAC yesterday. 
 Sounds great and everything is fine except one glitch.

 There's a severe distortion when directly connect earphones(Senn MX-500 and MX-510) to the dac and max up the volume. No distortion under about 75% volume, but it gets real ugly when I pump up the volume more than that. I can not hear any distortion when i hooked the dac to my amp. In short, distortion w/o amp, no distortion w/ amp. I think this might be an impediance issue, but not sure what the heck is the cause. 

 Parts I used are the same or within the range with what Alf specified at his website. 
 REG101UA-A, regulated down to 4.71V. Regulation is very stable. Pana and Elna electrolytics C2 470uf, C13,23,33 47uF, CL CR 22uF, 600ohm murata Ferrites, AVX 1uF C1, etc. Triple checked for soldering brigde and flux residue. There's no problem with them. 

 Anyone has the same problem with me? Any fix?
 Thanks._

 

The problem is that you're not supposed to use it to directly drive headphones!


----------



## doobooloo

Quote:


  Originally Posted by *mikemacwillie* 
_The problem is that you're not supposed to use it to directly drive headphones!_

 

Exactly!


----------



## robzy

Quote:


  Originally Posted by *mikemacwillie* 
_The problem is that you're not supposed to use it to directly drive headphones!_

 

As above, the DAC is _not_ made to drive headphones.

 Rob.


----------



## Seaside

Dac is not made to drive earphone... yeah... that's right.
 But that does not neccessarily means that the sound of DAC automatically will be distorted at higher volume when you plug earphones into the dac. 
 In fact I have another dac that uses PCM2704 doesn't have this kind of distortion at all, and that dac is intended to use with amps too.

 So, all of you have the same distortion experience?
 If you didn't please do so just for testing purpose and tell me what happened.
 In this way, I can figure out if my dac is normal or not.
 If all of you had the same distortion, it will be a normal characteristic of this dac. Or else, my dac has some problems to fix.


----------



## robzy

Quote:


  Originally Posted by *Seaside* 
_Dac is not made to drive earphone... yeah... that's right.
 But that does not neccessarily means that the sound of DAC automatically will be distorted at higher volume when you plug earphones into the dac._

 

You make a good point. However, it does mean that if the sound _is_ distorted the reasons should be pretty obvious.

 As you increase the volume you increase the voltage supplied, because V=IR and the resistance of your phones is pretty much fixed this means that the current would increase. The outputs of the PCM2702 are designed for low current.

 Can't hurt looking into it i guess though.

 Im not willing to try headphones with my DAC with my current knowledge though. The output stage is made to drive high impedance load and has probably been specifically designed that way.

 Rob.


----------



## tomb

Quote:


 I can not hear any distortion when i hooked the dac to my amp. In short, distortion w/o amp, no distortion w/ amp. 
 

I think it _could_ hurt to look into it. No offense, but why look for problems in an incorrect configuration when there are none without it?

 This is similar to some of the tube DIY amps lately when people take measurements without the pot in the circuit and then spend days asking what's wrong. One thing is certain: under limited power and current, a headphone will distort as the volume is turned up. That's the whole reason we build headphone amps, anyway.

 If everything sounds good with an amp, I'd chill out and enjoy my results.


----------



## whiz

I have the same problem with an other project (PCM2902)
 i don't understand it too...i thought the outpout impedance was 32Ω
 and can drive 32Ω headphones....


----------



## mikemacwillie

On page 2 of the PCM2702 datasheet, min analog output load impedance is listed at 5kohm.


----------



## abcheng

I have the same problem as well. I thought it was a bad cap or something, but since you guys have the same problems, it may just be that headphones can't be driven directly off the DAC.


----------



## whiz

something irrelevant... 
	

	
	
		
		

		
			





 Somebody told me that the analog output must be passed through "low pass filter" to farther reduce noice...is it correct? does alien dac has something like that?

 the only "filter" i know in the ouput stage that alien dac uses is the CL/CR capacitors...


----------



## mikemacwillie

Quote:


  Originally Posted by *abcheng* 
_I have the same problem as well. I thought it was a bad cap or something, but since you guys have the same problems, it may just be that headphones can't be driven directly off the DAC._

 

Theo nly 'problem' you guys are having is not understanding that it is not designed to drive headphones! 
	

	
	
		
		

		
		
	


	




 You need to use amplification. It's only a line level signal.


----------



## abcheng

Quote:


  Originally Posted by *mikemacwillie* 
_Theo nly 'problem' you guys are having is not understanding that it is not designed to drive headphones! 
	

	
	
		
		

		
		
	


	




 You need to use amplification. It's only a line level signal._

 

I realize that now. It was just that I was testing out the DAC with headphones just to see if I built the DAC properly and happened to notice that the output was distorted at higher volumes. 

 For anyone who soldered the 2702 chip the wrong way stupidly like me on one of their boards, is it possible to desolder the chip and solder it back in the correct way? If so, please enlighten me 
	

	
	
		
		

		
		
	


	




.


----------



## mikemacwillie

With the correct tools, yes. 

 Chances of the average DIYer having a hot air SMT rework station.. slim.


----------



## MASantos

Quote:


  Originally Posted by *abcheng* 
_I realize that now. It was just that I was testing out the DAC with headphones just to see if I built the DAC properly and happened to notice that the output was distorted at higher volumes. 

 For anyone who soldered the 2702 chip the wrong way stupidly like me on one of their boards, is it possible to desolder the chip and solder it back in the correct way? If so, please enlighten me 
	

	
	
		
		

		
		
	


	




._

 


 If you have a hot air gun, then you can try to melt the solder on the pins and remove the pcm2702. This will be very difficult to do, you should be very pacient and prepare yourself to ruin a board and chip.


----------



## MisterX

If ruining the board is a concern just cut the chip off.
 If salvaging the chip is the priority use the big blob of solder technique. 
	

	
	
		
		

		
		
	


	




 (fill all of the gaps between the leads on one side of the chip with solder and gently lift that side of the chip off the board, repeat for the other side... the caveat here is you will lift every pad off the board that is not connected to anything)

 Of course you could always bake it to.....


----------



## MASantos

Quote:


  Originally Posted by *MisterX* 
_If ruining the board is a concern just cut the chip off.
 If salvaging the chip is the priority use the big blob of solder technique. 
	

	
	
		
		

		
		
	


	




 (fill all of the gaps between the leads on one side of the chip with solder and gently lift that side of the chip off the board, repeat for the other side... the caveat here is you will lift every pad off the board that is not connected to anything)

 Of course you could always bake it to....._

 

Don't forget that this operation should be done fast. You can't apply too much heat to DAC chip or it will certainly get damaged. In the PCM2702 datasheet you should find the maximum solder temperature and time. Respect these values and you should be fine!


----------



## whiz

The size of the chip can help to possibly unsolder it safely...

 fill with solder both sides of the chip pull gently the chip from one side...(with tweezers or with your fingers) move the soldering iron back and forth
 until the chip starts moving from one side...after you unsolder the first side
 grab the chip with tweezers or your hand and do the same thing from the other side.

 It is possible that you can lift some pads too...or you might get burned if you use your fingers.


 In this way i have successfully removed very small chips.



 something irrelevant... 

 Somebody told me that the analog output must be passed through "low pass filter" to farther reduce noice...is it correct? does alien dac has something like that?

 the only "filter" i know in the ouput stage that alien dac uses is the CL/CR capacitors...


----------



## MASantos

Regarding the Cristal section, some questions:

 The support site says that the cristal should have a load capacitance of 30pF, but this exact value is not available. Is it better to go with 20pF or 32pF?

 The pcm2702 datasheet says that the cristal capacitors(C11,C12) value is related to the capacitance of the cristal. If I go with the 20pF one, should I change the value of those caps?

 What are the advantages of using an external clock? How much would this cost, are there available units for sale? Does anyone have any info about this?

 Manuel


----------



## MASantos

Quote:


  Originally Posted by *MisterX* 
_Ohhhhhh, Mouser now stocks Os-Cons? 

 When did that happen?_

 

MisterX, could you provide a link to these caps? They are suposed to be very good for digital decoupling right?


----------



## splaz

I asked that a few pages back, didn't get a clear cut reply as to how it all works, however robzy was of some help. 
	

	
	
		
		

		
		
	


	




 I personally went with 32pf crystal and 33pf capacitors. I think that's what some others have done.

 I believe if you chose a 20pf crystal you'd need capacitors around that value, so 18, 20 or 22pf.

 I asked someone about it, according to them at that frequency the difference between a 30pf and 32pf with the capacitors meant for 30pf would be insignificant and wouldn't alter the freqency(or pull it off or something like that), which you can only do slightly anyway. Well something to that effect. 20pf may be a different story.

 Well that's about all I can tell you.


----------



## MASantos

MixterX could you post the exact measurements of the usb connector in the front panel? 

 I want to design a FPE panel but don't want to risk ordering without being 100% sure that it will fit.


----------



## n_maher

Quote:


  Originally Posted by *MASantos* 
_MixterX could you post the exact measurements of the usb connector in the front panel?_

 

Not trying to be a pain but do you have any reason to doubt the data sheet?


----------



## MASantos

Quote:


  Originally Posted by *n_maher* 
_Not trying to be a pain but do you have any reason to doubt the data sheet?_

 

I didn't explain quite well what I need. I would like to know the position of the USB connector on the enclosure front panel. the distance from the bottom/top and left/right. They could be called the coordinates.


----------



## MisterX

Quote:


  Originally Posted by *n_maher* 
_Not trying to be a pain but do you have any reason to doubt the data sheet?_

 


 OMG!
 Are you actually suggesting that someone do something by their self for a do-it-yourself project?

 THE HORROR!


----------



## MASantos

Quote:


  Originally Posted by *MisterX* 
_OMG!
 Are you actually suggesting that someone do something by their self for a do-it-yourself project?

 THE HORROR! 
	

	
	
		
		

		
		
	


	


_

 


 I actually have done my own measurents, and am 90% sure that they're correct, HOWEVER, before spending $$$ on a pretty(read expensive) Front Panel, I wanted to have those extra 10% of confidence.

 I've asked you because I saw the pictures of your great enclosure drilling and assumed that you'd have perfect measures for this.


----------



## raromachine

Dell 700m > AlienDAC (battery powered w/ 5.6v reg) > SOHA > Sony MDR-7505






 And dang it sounds good!


----------



## Heady

Nice, raromachine. Good job.


----------



## MASantos

I have been searching for a good capacitor for the C13 position. This is the VCOM decoupling cap.

 I have been reading datasheets for 2 hours now and have discarded the panasonic FC and FM and Elna SilmicII capacitors.

 I have reduced my choice to two caps:

 1. Xicon ESRL series 47uF 50v
 Ripple current: 400mA RMS @ 105º(960mA RMS @ <50), 100Hz
 Price:0.46$(mouser)

 2. Vishay Sprague OS CON 47uF 20v
 Ripple current: 552mA RMS @ 105º (2210mA RMS @ 45º), 100Hz
 price: 2.30$(mouser)


 For comparison:

 Panasonic FC 47uF 50v. 
 Ripple current: 260mA RMS @ 105º 100Hz
 price: 0.28§(digikey)

 Elna Silmic II 47uF 10v.
 Ripple current: 85mA RMS @ 85º 120HZ


 The best choice is obviously the OS CON cap, but it is very expensive. I believe that the Xicon one is the best price/performance ratio. It cost the almost the same as the Panasonic one but has almost the doule of the ripple current. The Silmic II has very low ripple current so it doesn't seem to be appropriate at all for the C13 position.
 I hope this information is helpful.


 Any opinions, comments?


----------



## whiz

Quote:


  Originally Posted by *MASantos* 
_The best choice is obviously the OS CON cap, but it is very expensive. I believe that the Xicon one is the best price/performance ratio. It cost the almost the same as the Panasonic one but has almost the doule of the ripple current. The Silmic II has very low ripple current so it doesn't seem to be appropriate at all for the C13 position.
 I hope this information is helpful.


 Any opinions, comments?_

 

yes...if you want put informations from some os-con SA/SC to make a good comparison!


----------



## cetoole

I plan to use the 47uf 10v United Chemi-Con PSA capacitor for this position on my version of this DAC, which is pretty much the same as the Alien DAC, except for layout. It is part number APSA100ELL470MFA5G, and both Digikey and Mouser stock it, for relatively reasonable prices. It costs $0.60 from Mouser, and $0.74 from Digikey. It is a Polymer Al Electrolytic cap, rated for 105ºC, with a rated ripple currrent of 2820 mA RMS at that temperature, and extremely low ESR.


----------



## steinchen

how does higher ripple current capability lead to higher fidelity when using the cap for signal coupling instead of power rail bypassing ? The current flow is a fraction of a mA. For signal coupling caps I'd rather concentrate on impedance linearity vs frequency.


----------



## MASantos

Quote:


  Originally Posted by *cetoole* 
_I plan to use the 47uf 10v United Chemi-Con PSA capacitor for this position on my version of this DAC, which is pretty much the same as the Alien DAC, except for layout. It is part number APSA100ELL470MFA5G, and both Digikey and Mouser stock it, for relatively reasonable prices. It costs $0.60 from Mouser, and $0.74 from Digikey. It is a Polymer Al Electrolytic cap, rated for 105ºC, with a rated ripple currrent of 2820 mA RMS at that temperature, and extremely low ESR._

 


 Thanks for the info!! It does look good. It looks as good as the OS CON but with better pricing, much better pricing!


----------



## MASantos

Quote:


  Originally Posted by *steinchen* 
_how does higher ripple current capability lead to higher fidelity when using the cap for signal coupling instead of power rail bypassing ? The current flow is a fraction of a mA. For signal coupling caps I'd rather concentrate on impedance linearity vs frequency._

 

We are talking about a cap for the C13 position which is a decoupling cap for the DAC chip. For this position, the lower the ESR the better.


----------



## steinchen

oops, sry, I totally mixed that up and agree on ESR and ripple current being the key values. The pic of the SOHA build confused me somehow


----------



## guzzler

C13 is really unimportant, it simply couples in the internal "ground" to the solid ground on the board. You can use any cheap capacitor here and it won't make a blind bit of difference


----------



## MASantos

Quote:


  Originally Posted by *guzzler* 
_C13 is really unimportant, it simply couples in the internal "ground" to the solid ground on the board. You can use any cheap capacitor here and it won't make a blind bit of difference_

 


 Didn't the revision A dac use an OS CON for this? I remember having an sanyo OS CON in that board.

 Why does Alf recomend a "lowest ESR cap" for this position in the support website?


----------



## whiz

Quote:


  Originally Posted by *MASantos* 
_Didn't the revision A dac use an OS CON for this? I remember having an sanyo OS CON in that board.

 Why does Alf recomend a "lowest ESR cap" for this position in the support website?_

 

the same question i have too... 
	

	
	
		
		

		
		
	


	




 Alf recomends the lowest ESR cap for this position...which position is best for os-con?


----------



## whiz

someone kind enough to say an opinion? i don't want to waste
 an expensive component to wrong positions...


----------



## guzzler

If you've got it, just use it. All that position does, as stated, is couple the internal 1/2 supply to the real ground. You could argue that you want the lowest V=IR drop, but you can safely assume that it's steady state, so it's irrelevant.


----------



## 00940

For this position, I usually follow what's commonly asked in the datasheets or the evaluation boards and I use tantalum caps. Good quality low-esr electrolytics probably are ok too. OSCON are maybe a bit too good but if you have it, it won't hurt.


----------



## MASantos

Quote:


  Originally Posted by *cetoole* 
_I plan to use the 47uf 10v United Chemi-Con PSA capacitor for this position on my version of this DAC, which is pretty much the same as the Alien DAC, except for layout. It is part number APSA100ELL470MFA5G, and both Digikey and Mouser stock it, for relatively reasonable prices. It costs $0.60 from Mouser, and $0.74 from Digikey. It is a Polymer Al Electrolytic cap, rated for 105ºC, with a rated ripple currrent of 2820 mA RMS at that temperature, and extremely low ESR._

 


 I have decided to use this capacitor after spending some hours reading through many datasheets. It has very low ESR and only costs .60$ A panasonic is the cheapest available cap that is suitable for this position and costs about 0.28$ so it is not that much more.

 If you don't want to use this one, just get a panasonic one and it will do just fine.


----------



## whiz

Quote:


  Originally Posted by *00940* 
_OSCON are maybe a bit too good but if you have it, it won't hurt._

 

I have ordered some 47uF/6.3V os-con SA
 from what i understand it was stupid decision to get os-con...Alf recomended the lower ESR/ESL for C13 and i thought os-con is an excellent choice for C23-C33 too...

 If they aren't going to improve the total performance of the DAC i don't see any reason to waste them...

 P.S. i'm building the USB (unregulated version) and i thought os-con can balance the situation by doing a better filtering...


----------



## raromachine

Quote:


  Originally Posted by *whiz* 
_... i thought os-con is an excellent choice for C23-C33 too...

 If they aren't going to improve the total performance of the DAC i don't see any reason to waste them..._

 

If you look at the schematic you'll see that C23 sits after the 3.3v reg, and C33 after either the 5v reg or the 5v rail on from the USB feed.

 I'f I'm reading the datasheet properly then the 5v feed powers the analogue/output section of the DAC - surely you'd want to feed it as clean a signal as you could?

 Either way - I wouldn't say that OSCON are a waste, if they're good caps, they're good caps??? Perhaps build it up with cheap caps and swap to the OSCON if you're not satisfied?


----------



## rreynol

Question, With the dac hooked up to a PC and no music playing, what dc voltage should be across D+/Gnd and D-/Gnd. I get no sound out of the left channel (used temporary CL/CR caps to check). DC Offset at OutL is 0v (OutR is ~2.5v) I'm using regulated USB with a regulated voltage of 4.7V. I've measured the 3.3 and the 5.0 and get 3.3VDC and 4.7VDC for the voltage supplies. Pins VCCP, VCCL, VCC, OUTR all measure 4.7V each. VDDC and VDD both measure 3.3VDC. VBUS measure 5V.D+ with no music playing measures close to 3.0VDC and D- varies in the range of 0.05 to 0.10VDC. Should D- be bigger in magnitude than that? I've scoured for bridges and didnt find any. I gave the board a good cleaning with alcohol (didn't make a difference). Is it possible that the left channel of the chip is toasted?


----------



## whiz

can you upload a close picture of your DAC?
 check the board if you have put in wrong way some componets like
 the capacitors...check again the PCM2702 for any bridges...


----------



## rreynol

bottom:
http://www.parl.clemson.edu/~rreynol...c/AUT_5301.JPG

 top:
http://www.parl.clemson.edu/~rreynol...c/AUT_5306.JPG

http://www.parl.clemson.edu/~rreynol...c/AUT_5307.JPG

http://www.parl.clemson.edu/~rreynol...c/AUT_5308.JPG

 And I tried to hold it up to a light bulb and snap a shot but unfortunately, my camera is old.
http://www.parl.clemson.edu/~rreynol...c/AUT_5310.JPG

 I can't see any bridges on the pcm2702 using a light bulb and magnifying lense.


----------



## tomb

It does look like 5306 and 5308 show a couple of solder bridges on the chip.

 You've done a lot of great work, though - really liked that connected train photo you posted on Headwize with your DAC and SOHA.


----------



## rreynol

Quote:


  Originally Posted by *tomb* 
_It does look like 5306 and 5308 show a couple of solder bridges on the chip.

 You've done a lot of great work, though - really liked that connected train photo you posted on Headwize with your DAC and SOHA._

 

Yeah, I wish I had a better camera to get a clear shot. The continuity test on meter doesnt reveal any bridges on it and neither does visual inspection. 

 I've measured all of the following with it hooked up but with no music playing.
 VDDC -> DGNDC: 3.3VDC
 VDD -> DGND: 3.29VDC
 D+ -> Gnd: 3VDC
 D- -> Gnd: 0VDC 
 VBUS -> DGNDU: 5.07VDC
 VCCR -> AGNDR: 4.73VDC
 OUTR -> GND: 2.35VDC (ewww, dc offset. no coupling caps in right now)
 VCC -> AGND: 4.73VDC
 OUTL -> GND: 0VDC
 VCCP -> AGNDR: 4.73VDC
 VCCL -> AGNDL: 4.73VDC

 With music playing, I can measure a changing AC voltage across OUTR -> GND (as I would expect) but OUTL -> GND measures 0.17VAC and never changes.

 I'm think that I've fried the left channel on the chip because all the inputs to the chip measure what I'd think they should be, the right output is correct, and the left isn't.


----------



## whiz

Quote:


  Originally Posted by *rreynol* 
_The continuity test on meter doesnt reveal any bridges on it and neither does visual inspection._

 

you did continuity test to the pins of the IC?! my multimeter has 2.5V output for continuity tests! i don't know yours...but you could burn your chip.

 visual inspection with a magnifing glass is not always enough...if it is possible to use a eye loupe...then try it, sometimes bridges exist behind the pins and you can only see them with eye loupe if you look deep between the pins.

 i have a magnifing glass 4X from pro's kit, it is supposed to check electronics...but it is more useful to set fire to papers... 
	

	
	
		
		

		
		
	


	








 [EDIT]

 tell me something...right channel works ok?


----------



## rreynol

Maybe I am using the term wrong. What I mean is that I can set the resistance for the lowest setting (200 ohms) and it will beep it the resistance is 0 Ohms, i.e. shorted. I typically use it to test whether or not two points are electrically equivalent. I'll see if i can scrounge up a higher power magnification device to look closer. Thanks.


----------



## rreynol

Quote:


  Originally Posted by *whiz* 
_tell me something...right channel works ok?_

 

absolutely.


----------



## rreynol

Would someone with a working board mind measuring the dc voltage between VCOM and GND on the PCM2702. Thanks.


----------



## raromachine

Quote:


  Originally Posted by *rreynol* 
_Would someone with a working board mind measuring the dc voltage between VCOM and GND on the PCM2702. Thanks._

 

My $8NZ meter says 2.5v from VCOM to GND (G1). VCC is 5V to GND.


----------



## t52

just wanted to let you guys know that i finally got around to finish two of my 5 boards, one is already cased up. sorry - no digicam, no pics... probably better because my casework skills are a shame to say the least 
	

	
	
		
		

		
			




 all worked seamlessly, the other 3 are to come soon as my friends don't want to wait any longer after they heard mine


----------



## MASantos

Quote:


  Originally Posted by *t52* 
_just wanted to let you guys know that i finally got around to finish two of my 5 boards, one is already cased up. sorry - no digicam, no pics... probably better because my casework skills are a shame to say the least 
	

	
	
		
		

		
		
	


	



 all worked seamlessly, the other 3 are to come soon as my friends don't want to wait any longer after they heard mine 
	

	
	
		
		

		
		
	


	


_

 


 Ask someone a camera and take some pictures. People are always interested in seing builds. If your casing still are bad, they will improve and maybe someone will give you useful tips! Share pictures!!!


----------



## t52

Quote:


  Originally Posted by *MASantos* 
_Ask someone a camera and take some pictures. People are always interested in seing builds. If your casing still are bad, they will improve and maybe someone will give you useful tips! Share pictures!!!_

 

promise to do so


----------



## pddjsteve

Quote:


  Originally Posted by *MASantos* 
_Share pictures!!!_

 

That reminds me 
	

	
	
		
		

		
		
	


	




 The usb port area is totally crappy, but I just wanted to case it up quickly so I cut some plexi.

http://www6.head-fi.org/forums/showp...postcount=1482


----------



## MASantos

Quote:


  Originally Posted by *pddjsteve* 
_That reminds me 
	

	
	
		
		

		
		
	


	




 The usb port area is totally crappy, but I just wanted to case it up quickly so I cut some plexi.

http://www6.head-fi.org/forums/showp...postcount=1482_

 


 That's a nice panel. Front panel express also does panels in Perspex(acrilic material) You may want to check their prices for a nice custom front panel.


----------



## pddjsteve

Quote:


  Originally Posted by *MASantos* 
_That's a nice panel. Front panel express also does panels in Perspex(acrilic material) You may want to check their prices for a nice custom front panel._

 

Thanks. I made a stencil from the end panel, cut it out, then used a couple different grits of sandpaper to round the corners and smooth the edges. I was in a rush, so I just used a dremel and grinded out the usb port area. If I'd taken more time, I could probably have gotten it square. 

 Front panel express is out of my budget right now


----------



## Sando

Hi guys,

 First time SMDer here.. I've just finished building the DAC on the regulated USB configuration and it looks like I've screwed it up 
	

	
	
		
		

		
		
	


	




 On every system I try, it appears as an unknown/malfunctioning USB device... any ideas?

 Here's some pics:


----------



## MASantos

First of all, clean your board with Alcool( medical grade is just fine) and an old toothbrush. That will certainly remove the flux and give a better image. 

 Make some voltage measurents on the voltage regulators and on the pcm2702 power pins. Measure DC offset, try to find any solder bridges.

 If you can get some flux, aply it to every solder joint and reheat them. It looks like some of those joints are not very good. 


 If possible post bigger pictures, as large as you can. It is easier to check for problems that way.

  Quote:


  Originally Posted by *Sando* 
_Hi guys,

 First time SMDer here.. I've just finished building the DAC on the regulated USB configuration and it looks like I've screwed it up 
	

	
	
		
		

		
		
	


	




 On every system I try, it appears as an unknown/malfunctioning USB device... any ideas?

 Here's some pics:


 

 

_


----------



## whiz

i think your your board it's a mess...why don't you clean it?!


----------



## Seaside

Unknown/malfunctioning USB device means, your computer somehow detected the dac, but it is not working due to several reasons.

 - You probabaly have tiny solder bridges between the legs of PCM2702 chip. Your 3rd Pic shows possiblity of this situation. Check that first. 
 - One of the legs is not soldered correctly. The joint is not solid enough.
 - There's a flux residue in between legs.
 - Or you missed one or two parts.

 What MAsantos said will work. After that, you must clean flux completely. Make sure there's no flux residue especially in between those legs of 2702. Then check other parts are attached at right position. Make sure no part is missing. That will solve your problem.


----------



## whiz

I want to warn everyone who has problems with this board...

 check again and again and again your PCM2702! from every
 view! and with a good magnifing glass over 4X small bridges almost
 always do exist behind the pins and EVEN with good magnifing glass
 it's impossible to locate from standard view! look closely from the side
 of the IC

 the same thing about the rest of the components...check them all! look
 for cold joints...smds maybe have a small film of flux and they don't conduct with the pad!


 I have finished my Alien Dac and it works perfectly! it is an os-con powered DAC 
	

	
	
		
		

		
		
	


	




 maybe one day i'll upload photos!


----------



## t52

did some quick shots with my cellphone's cam, sorry for the bad quality! i'll probably get my hands on a good digicam on friday...
 here's the first board cased up in a small plastic enclosure i got from the local conrad store, there's a small psu inside, the plack thin on the front is a blue led (bright like hell, so off for the foto, probably will have to adjust rled).





 here some wood cases that are in the works for my t-amp, active xover and another alien dac.


----------



## was ist los?

Someone earlier in the thread asked whether a different value ferrite would work, but the question was never really answererd. I believe their's was a 75R rather than the specified 600R. I missed out on the group buy and am building the dac on a protoboard, but could only manage to get 832R ferrites. Anyone know if the different value ferrite would matter? Any input would be greatly appreciated.


----------



## t52

i'd say 823r (@100mhz?) sounds reasonable as well. better a higher impedance than lower...


----------



## whiz

some noob questions....(if i never ask...i'll never learn!) 
	

	
	
		
		

		
			





 i want to understand the exact function of the regulators for the
 specific project...

 1) what does "low dropout" means? (sorry i must learn... 
	

	
	
		
		

		
		
	


	




)
 2) regulators other than regulation of the voltage...do they filter??)

 once again sorry the stupid questions! i know the look like very noob for someone who has a working board like mine...


----------



## ozshadow

For solder bridges, after you clean it, using a pick or razor blade to lightly scratch between joints works wonders to get the ones that are hard to see. Be sure you clean it again after you do this and do not go digging deep.


----------



## cetoole

Thought I had posted this before, turns out headfi logged me out (again) after I hit submit, and I had already gone to a new tab and forgot about it.
  Quote:


  Originally Posted by *whiz* 
_some noob questions....(if i never ask...i'll never learn!) 
	

	
	
		
		

		
		
	


	




 i want to understand the exact function of the regulators for the
 specific project...

 1) what does "low dropout" means? (sorry i must learn... 
	

	
	
		
		

		
		
	


	




)_

 

LDO regs require much less voltage to be dropped across them in order to be able to regulate than standard regulators. The reg101 only have to drop a few hundred mV, instead of a few V for something like a LM317.
  Quote:


 2) regulators other than regulation of the voltage...do they filter??) 
 

Yup.


----------



## whiz

Thank you cetoole!!! 
	

	
	
		
		

		
		
	


	




 I was almost sure about that...but i wanted a confirmation!


----------



## ssmrsx

Hi all,

 I am just wondering has anyone compare the audio quality btw the Alien DAC and the TI development board? http://focus.ti.com/docs/toolsw/fold...m-pcm2702.html
 Which design you would suggest excluding the cost factor?


 Thx in advance!!


----------



## exphy

Is there maybe anyone who has a spare board that i could buy?


----------



## soloz2

Quote:


  Originally Posted by *exphy* 
_Is there maybe anyone who has a spare board that i could buy?_

 


 get in line buddy


----------



## whiz

heres my alien dac...

 sorry i don't have pictures of the board because i forgot to take some...and the board is glued inside the box! i can assure you it's a fine looking little board! 
	

	
	
		
		

		
		
	


	

















 [_Click on the photos to see them big_] 
	

	
	
		
		

		
		
	


	




 also sorry for the quality of the pictures!

 Alien Dac is my second DIY i hope you like it...


----------



## squalle

Just wanna say my gratitude to Alf that has designed and shipped the boards to me 
	

	
	
		
		

		
		
	


	




 after being delayed for some weeks, due to work and components lead time. yeah finally I've got my alien DAC working with no hiccup whatsoever!
 great design makes it 100% chance to get it working at first instance


----------



## n_maher

Ugh, so pissed! So I sat down this morning to begin working on my 2 DACs only to find that DigiKey shipped me the wrong parts even though the packaging is labeled correctly. Instead of the PCM2702 they sent the PCM1717 which is still a DAC but isn't going to be working in this circuit any time soon 
	

	
	
		
		

		
		
	


	




 . Looks like I'll be waiting until Monday to call Customer Service and get the part that I paid for.


----------



## MASantos

Quote:


  Originally Posted by *n_maher* 
_Ugh, so pissed! So I sat down this morning to begin working on my 2 DACs only to find that DigiKey shipped me the wrong parts even though the packaging is labeled correctly. Instead of the PCM2702 they sent the PCM1717 which is still a DAC but isn't going to be working in this circuit any time soon 
	

	
	
		
		

		
		
	


	




 . Looks like I'll be waiting until Monday to call Customer Service and get the part that I paid for._

 



 Nate, I have one extra PCM2702, just in case you need it...


----------



## ozshadow

What precautions should you take with this regarding plugging and unplugging things with the power on in this design?


----------



## MASantos

Quote:


  Originally Posted by *ozshadow* 
_What precautions should you take with this regarding plugging and unplugging things with the power on in this design?_

 


 I did all possible plugging and unplugging with this DAC and never had a problem, using USB power.


----------



## t52

here are some pictures of the second one i built, this time with a nice wood case 
	

	
	
		
		

		
		
	


	



http://t5.xlhost.de/Photos/DIY%20Projects/Alien%20DAC


----------



## Alf

Quote:


  Originally Posted by *ozshadow* 
_What precautions should you take with this regarding plugging and unplugging things with the power on in this design?_

 

This beast is quite resilient. It survived all my cruel experiments and so did my computer. Mind you, I was very resourceful in torturing it.


----------



## Alf

Quote:


  Originally Posted by *t52* 
_here are some pictures of the second one i built, this time with a nice wood case 
	

	
	
		
		

		
			




http://t5.xlhost.de/Photos/DIY%20Projects/Alien%20DAC_

 

Wow! Such a large case for such a small thingy! It looks great, though. Good job!


----------



## t52

Quote:


  Originally Posted by *Alf* 
_Wow! Such a large case for such a small thingy! It looks great, though. Good job!_

 

thanks a lot!
 i have several of these cases now and they stack up to a nice "mini component system" 
	

	
	
		
		

		
		
	


	



 pics here: http://t5.xlhost.de/Photos/DIY%20Projects/Wood%20Cases


----------



## ssmrsx

Quote:


  Originally Posted by *ssmrsx* 
_Hi all,

 I am just wondering has anyone compare the audio quality btw the Alien DAC and the TI development board? http://focus.ti.com/docs/toolsw/fold...m-pcm2702.html
 Which design you would suggest excluding the cost factor?


 Thx in advance!!_

 


 Anyone???


----------



## t52

Quote:


  Originally Posted by *ssmrsx* 
_Anyone???_

 

the ti development board doesn't even use proper voltage regulators, ferittes on the supply inputs of the chip etc., so i'd recommend the alien dac.


----------



## MASantos

Quote:


  Originally Posted by *t52* 
_thanks a lot!
 i have several of these cases now and they stack up to a nice "mini component system" 
	

	
	
		
		

		
		
	


	



 pics here: http://t5.xlhost.de/Photos/DIY%20Projects/Wood%20Cases_

 


 The case is really nice. Since you have some space available I would propose two modifications to your current config:

 1: Regulate the power supply. You can build a LM317 based PS very easily on a bread board and it will provide the DAC with much better filtered power.

 2: Try some more "exotic/boutique" capacitors and let us know the sound differences.


----------



## t52

Quote:


  Originally Posted by *MASantos* 
_The case is really nice. Since you have some space available I would propose two modifications to your current config:

 1: Regulate the power supply. You can build a LM317 based PS very easily on a bread board and it will provide the DAC with much better filtered power.

 2: Try some more "exotic/boutique" capacitors and let us know the sound differences._

 

1. the psu is regulated, i used a lm7809, after the regulator i have a 22ohms series resistor and a 2200uF low esr cap for additional filtering.
 hopefully i will have time to compare it to the "cheap" unregulated version soon.

 2. there's just so many projects on my wishlist, including some "real" speakers (with thiel coax chassis), so boutique caps are surely someting for the future... btw. hat's you're favourite "exotic" cap?


----------



## FallenAngel

Hi guys,

 After reading this tread, I've just finished putting together 2 BOMs, one for a USB powered regulated version and another for an externaly powered version.

 Could you guys take a look to make sure it's fine and that I've selected good parts. They're identical except for R32 resistor choices.

 Also, correct me if I'm wrong, but with the AlienDAC, there's still enough room to stick a small mini TREAD inside the Hammond 1455C802 with it. Of course I'll go with a small cap, no huge 1000uF/63V.

 Thanks!


----------



## MASantos

Quote:


  Originally Posted by *FallenAngel* 
_Hi guys,

 After reading this tread, I've just finished putting together 2 BOMs, one for a USB powered regulated version and another for an externaly powered version.

 Could you guys take a look to make sure it's fine and that I've selected good parts. They're identical except for R32 resistor choices.

 Also, correct me if I'm wrong, but with the AlienDAC, there's still enough room to stick a small mini TREAD inside the Hammond 1455C802 with it. Of course I'll go with a small cap, no huge 1000uF/63V.

 Thanks!_

 

I think that fitting a tread inside that case with the alien is almost impossible.


----------



## FallenAngel

I did say mini-tread, but if a full-blown tread would be "almost impossible", I think I'll be able to fit a dumb-downed version of one.

 Thanks.

 How does the BOM look? Nothing off?


----------



## pddjsteve

Quote:


  Originally Posted by *FallenAngel* 
_I did say mini-tread, but if a full-blown tread would be "almost impossible", I think I'll be able to fit a dumb-downed version of one._

 

I've been thinking about making a mini-tread too (both for my Alien DAC in a C801, and my PPAS in a J1201). For the Alien DAC the fit will definitely be harder, I've got a 6V AC wall-wart I was going to use. For the PPAS I've got a 24V wall-wart that outputs DC, so I'm leaving off the entire diode bridge and filter cap section before the regulator as per a comment in tangent's writeup.

 I notice in your breadboard tread you didn't use a heatsink for the lm317... is that because you're not regulating it down that much from the input voltage? I only need about 150mA maximum of current to run and charge the PPAS, and was going to output something like 22V from the lm3117. I haven't measured the current draw of the Alien DAC, but was going to set the output to about 6V. If I could get away with a to-92 version of the lm317, that would end up saving a lot of space. Does anyone think that would be possible? I was also thinking of mounting the to-220 underneath so it was heatsinked by the enclosure.


----------



## FallenAngel

The TO92 version, LM317L is only guaranteed for 100mA so I wouldn't try for 150mA with it.

 As for the heatsink, I've never really used it for any of my builds because I never really saw the need. The LM317 always stays cool for me. Even with my PINT (output set at 13.75V, current draw of around 55mA if charging and listening at same time) off a 24V wallwart, it doesn't heat up at all and I measured using the most sophisticated equipment known to man, the all-mighty finger touch test.


----------



## pddjsteve

Quote:


  Originally Posted by *FallenAngel* 
_The TO92 version, LM317L is only guaranteed for 100mA so I wouldn't try for 150mA with it._

 

D'oh. Reading > me. I could have sworn it said 200.

  Quote:


  Originally Posted by *FallenAngel* 
_As for the heatsink, I've never really used it for any of my builds because I never really saw the need. The LM317 always stays cool for me. Even with my PINT (output set at 13.75V, current draw of around 55mA if charging and listening at same time) off a 24V wallwart, it doesn't heat up at all and I measured using the most sophisticated equipment known to man, the all-mighty finger touch test._

 

Hmm. Then I can probably just leave it up on top.


----------



## ozshadow

Happy Birthday Alf


----------



## t52

i have a weird problem with the second board i built here. after first listening to it the left channel was dead. so i got back to the board and found that the pcm2702 leg with the left out was not connected to the pcb (no short though!). after resoldering it, it works but the output level is abt. 20% lower than the right channel. checked the connection with a dmm and it's ok now. anybody haave a clue?!


----------



## t52

some more info on my problem: the dc offset on both channels is the same within 1mV, i also checked with a dmm in the 200kohms range from output to ground (before output caps) and measured 2x ~90kohms, also identical (dac off).

 i also looked at the output with my old scope (built 1969, all tubes) which is not very precise, but both outputs show a nice sine wave form when fed with a 1khz mono sine signal... it's just that one channel's amplitude is lower.

 could it have something to do with the digital attenuator in the chip (probably being programmed to some value on one channel)? i don't even know if the attenuator can be set explicitely for one channel only. nor do i know how to set it at all, can someone shed some light on this or should i contact ti about this?

 if it's not a "software" problem, i probably have a broken chip here...


----------



## Alf

Quote:


  Originally Posted by *t52* 
_some more info on my problem: the dc offset on both channels is the same within 1mV, i also checked with a dmm in the 200kohms range from output to ground (before output caps) and measured 2x ~90kohms, also identical (dac off).

 i also looked at the output with my old scope (built 1969, all tubes) which is not very precise, but both outputs show a nice sine wave form when fed with a 1khz mono sine signal... it's just that one channel's amplitude is lower.

 could it have something to do with the digital attenuator in the chip (probably being programmed to some value on one channel)? i don't even know if the attenuator can be set explicitely for one channel only. nor do i know how to set it at all, can someone shed some light on this or should i contact ti about this?

 if it's not a "software" problem, i probably have a broken chip here..._

 


 My understanding is that the chip attenuator is controlled by the driver via USB. The volume is not hard coded in the chip. You move the volume slider in your OS/driver, the chip setting changes. I assume you have played with the slider already. What happens if you move the slider up and down? Do channels still sound different? Do you use Windows?

 If you are confident about your soldering and your software settings, then I think the broken chip is the only possibility. Contacting TI would be an interesting option too. I would like to hear what they have to say on the subject.


----------



## t52

Quote:


  Originally Posted by *Alf* 
_My understanding is that the chip attenuator is controlled by the driver via USB. The volume is not hard coded in the chip. You move the volume slider in your OS/driver, the chip setting changes. I assume you have played with the slider already. What happens if you move the slider up and down? Do channels still sound different? Do you use Windows?

 If you are confident about your soldering and your software settings, then I think the broken chip is the only possibility. Contacting TI would be an interesting option too. I would like to hear what they have to say on the subject._

 

ok, i'll try some more things tomorrow, up to now i ran this particular board with linux only. i'll try windows too... maybe the initial setting for the attenuator is different for l/r and is kept for some reason while adjusting the slider in the mixer. possibly turning down volume to 0 will fix it... this really smells like a software problem, as the sound is very good on both channels, no distortion etc... will report back!


----------



## jdimitri

Hey all, just ordered 2 boards for me to experiment with..
 I've soldered quite a bit before, mostly on guitars, but never these tiny tiny chips
 Anyone got any guides that i can look to?
 Thanks folks, looks like i'm going to come back here with problems soon enough


----------



## Alf

Quote:


  Originally Posted by *jdimitri* 
_Hey all, just ordered 2 boards for me to experiment with..
 I've soldered quite a bit before, mostly on guitars, but never these tiny tiny chips
 Anyone got any guides that i can look to?
 Thanks folks, looks like i'm going to come back here with problems soon enough 
	

	
	
		
		

		
		
	


	


_

 

http://www.myexposition.com/diy/usbdac/assembly.html


----------



## t52

just got back from experimenting with my "problem board" 
	

	
	
		
		

		
		
	


	



 seems like the chip is really broken. same symptoms under both windows and linux. i carefully checked with different mono sine waves and white noise, with white noise i also noticed the right (quieter) channel being slightly more bright - there's something really wrong here.
 of course i'm not tooooo confident with my soldering, though everything looks and measures ok. i'd be willing to ship the problem board to somebody else for doublechecking, as this really bothers me... anybody?
 will order some more pcm2702s soon as i have three boards left...


----------



## n_maher

I need some advice on checking continuity of the 2702 connections. I tried the "flood and suck" method of soldering my first one down tonight and while the results look good (no visible bridges under heavy magnification) my first test of pins one and two shows a short. 
	

	
	
		
		

		
		
	


	




 I've tried sucking, and re-sucking and nothing will keep my meter from telling there's a short. And yes, I'm quite confident that I'm holding the probes and different pins. In fact, as I started to go down the line I get continuity from pin one to a bunch of other pins. What!? Is this normal or have I already pooched my first Alien DAC before I basically got started. If so, you can expect a full kit of parts + a PCB for sale in the forums shortly. I've had way more than my fare share of troubles with SMD stuff lately and I'm nearly done for good with it.


----------



## MisterX

You are ok so far.


----------



## Yen

Quote:


  Originally Posted by *jdimitri* 
_Hey all, just ordered 2 boards for me to experiment with..
 I've soldered quite a bit before, mostly on guitars, but never these tiny tiny chips
 Anyone got any guides that i can look to?
 Thanks folks, looks like i'm going to come back here with problems soon enough 
	

	
	
		
		

		
		
	


	


_

 

Try YouTube videos, if you like visual examples.


----------



## MASantos

Quote:


  Originally Posted by *n_maher* 
_I need some advice on checking continuity of the 2702 connections. I tried the "flood and suck" method of soldering my first one down tonight and while the results look good (no visible bridges under heavy magnification) my first test of pins one and two shows a short. 
	

	
	
		
		

		
		
	


	




 I've tried sucking, and re-sucking and nothing will keep my meter from telling there's a short. And yes, I'm quite confident that I'm holding the probes and different pins. In fact, as I started to go down the line I get continuity from pin one to a bunch of other pins. What!? Is this normal or have I already pooched my first Alien DAC before I basically got started. If so, you can expect a full kit of parts + a PCB for sale in the forums shortly. I've had way more than my fare share of troubles with SMD stuff lately and I'm nearly done for good with it. 
	

	
	
		
		

		
		
	


	


_

 


 If you have some liquid flux or a flux pen, try to flux the pins and heat them all over again. This has worked very well for me many times and now I do this in every board I solder. Liquid flux is the best since it actually gets under the IC.


----------



## Sinbios

Quote:


  Originally Posted by *n_maher* 
_I need some advice on checking continuity of the 2702 connections. I tried the "flood and suck" method of soldering my first one down tonight and while the results look good (no visible bridges under heavy magnification) my first test of pins one and two shows a short. 
	

	
	
		
		

		
		
	


	




 I've tried sucking, and re-sucking and nothing will keep my meter from telling there's a short. And yes, I'm quite confident that I'm holding the probes and different pins. In fact, as I started to go down the line I get continuity from pin one to a bunch of other pins. What!? Is this normal or have I already pooched my first Alien DAC before I basically got started. If so, you can expect a full kit of parts + a PCB for sale in the forums shortly. I've had way more than my fare share of troubles with SMD stuff lately and I'm nearly done for good with it. 
	

	
	
		
		

		
		
	


	


_

 

From the datasheet it doesn't look like pin 1 should be connected to anything other than ground and pin 28... are you sure it's pin 1? Pins 13 and 14, 15 and 16 are connected. If you have an unused chip try measuring between the pins on it to see if it's meant to be shorted. If not, try adding flux to the pins and wipe the iron across. This makes any stray bits of solder melt and flow to each individual pin.


----------



## tomb

Guys,
 I thought MisterX was saying Nate was OK so far. So maybe those readings are correct?


----------



## psilosome

Quote:


  Originally Posted by *tomb* 
_Guys,
 I thought MisterX was saying Nate was OK so far. So maybe those readings are correct?_

 

A short between pins 1 and 2? Hmmm - the schematic shows pin 1 going through a cap to ground, whereas pin 2 goes through an inductor to +3.3 volts and through a cap to ground. My guess is a meter shouldn't show a short despite the common ground path via the caps, but I could be wrong.


----------



## ~n00beR

Wondering if y'all could help have read through all the thread, but as ever I'm still not 100% sure about my choice.

 As I am ordering from farnel, I am mostly going to order the same parts as Alf has suggested in his BOM.

 However for parts C2 470uF Sanyo OS-CON, and C13,C23,C33 47uF Sanyo OS-CON.

 For C13, C23, and C33 the rating is for 20V, audio wise I presume this has no detremental effects?, but better asking before I shell out on those OS-CON's.

 Cost is not too much of an issue I at least want to make 1 all out DAC.

 Also how would this compare to an all blackgate dac, as the cost is not going to be much different.

 Have not decided for CL, CR yet, I have some 50v 10uf SILMIC II's but may buy the 4.7uF HiQ blackgates.

 Thanks in advance guys


----------



## MASantos

Quote:


  Originally Posted by *~n00beR* 
_Wondering if y'all could help have read through all the thread, but as ever I'm still not 100% sure about my choice.

 As I am ordering from farnel, I am mostly going to order the same parts as Alf has suggested in his BOM.

 However for parts C2 470uF Sanyo OS-CON, and C13,C23,C33 47uF Sanyo OS-CON.

 For C13, C23, and C33 the rating is for 20V, audio wise I presume this has no detremental effects?, but better asking before I shell out on those OS-CON's.

 Cost is not too much of an issue I at least want to make 1 all out DAC.

 Also how would this compare to an all blackgate dac, as the cost is not going to be much different.

 Have not decided for CL, CR yet, I have some 50v 10uf SILMIC II's but may buy the 4.7uF HiQ blackgates.

 Thanks in advance guys 
	

	
	
		
		

		
		
	


	


_

 


 Why would you want all blackgate dac? Or OS-CON's in all those positions? There is only one place on the board where a blackgate capacitor makes sence and that is CL/CR.

 Capacitors have different functions in diferent sections of the circuit and the characteristics of blackgates don't suit the need of all the positions. The same applies to the OS-CON's. Use them only in the C13 position, it is where it makes sence. On the other positions use panasonic FM or nichicon UPW or something similar. Blackgate capacitors in those positions won't improve the performance of the DAC. 

 A good DIY build is also one where the builder can make a good balance between price and performance. 

 Sorry if I seem a bit harsh with this post, but I see many people who think that blackgates or elnas in every position will give the best performance and that is not true. And I am not speaking without knowledge, I have done some extensive listening and part selection with the Alien DAC both during the first prototiping stage and with the final boards.

 Good luck with your build.


----------



## ~n00beR

Quote:


  Originally Posted by *MASantos* 
_........

 Sorry if I seem a bit harsh with this post, but I see many people who think that blackgates or elnas in every position will give the best performance and that is not true. And I am not speaking without knowledge, I have done some extensive listening and part selection with the Alien DAC both during the first prototiping stage and with the final boards.

 Good luck with your build._

 


 No your words are not harsh at all. I have read this thread through and appreciate your comments as I see you have input alot into this thread, and others.

 Thanks again for your advice, im off to ammend my list 
	

	
	
		
		

		
		
	


	




 Ps my wallet says a big thank you too


----------



## dakotart1984

One way of soldering the Ic's I havent seen shown is the method I learned while working for panasonic. Its quite easy and is relatively quick, and looks very clean after completed. Basically you get some liquid flux, dillute it 70/30 with alcohol because initally it is entirely too sticky. Then place the component down with tweezers and put a small dab of solder on the tip of the hot iron. Place a bit of solder on one of the corners and dont be afraid to flood the pins next to it, thats the objective. Repeat the process for the adjacent corner. Then take the liquid flux and put a drop or 2 on the side you are working with. Starting at the corner with the bead of solder work your way down the legs of the chip dragging the bead of solder to the other side. If you have too much solder at the end use some desoldering braid and take a tiny bit off and go across the legs again with more flux if needed. Repeat the process for each one of the sides and use some heavy duty flux cleaner, alcohol bath, or other pcb cleaner to clean after all the components are done. Once complete I fooled a supervisor in thinking that the board was done by a machine! good luck and if this is helpful ill make a tutorial on how to do it.


----------



## MisterX

That is referred to as "the paste and wipe method" 
	

	
	
		
		

		
			





http://www6.head-fi.org/forums/showp...&postcount=132


----------



## dakotart1984

Thanks misterx, although Id say tho that liquid flux makes this MUCH easier, and cleaner to work with.


----------



## pipp

pcm chips arrived today, just awaiting bords. Man these are small, I'm so not looking forward to solder this. I'w done pcm2706 before but I'm imagening these are smaller, witch they probably arnt. Well it usualy works out


----------



## Mazuki

I got a quick question. So I bought the Hammond enclosure for the AlienDAC. The problem is the board isn't as long as the enclosure, therefore there's no way to prevent the board from sliding fom one side to the other. This is bad because the USB jack is on the board itself. 

 Is there any way to secure the board without having to drill from the bottom of the case? That would ruin the aesthetics.


----------



## tomb

Look back earlier in the thread (yep - pretty long now). MisterX had a solution where he cut out another piece of plastic to fill the rest of the slot, and a piece of foam to cushion between the boards ... or something like that. (If I got it wrong, he'll probably correct me. 
	

	
	
		
		

		
		
	


	




 )


----------



## steinchen

simply cut off a piece from a sheet of aluminum or a perfboard to fill the empty space


----------



## kklee

I used a less elegant solution, but it worked for me. I epoxied a small nut inside the case to act as a stopper to hold the PCB in pace. The trick was getting the nut to stay in the right place and keeping it there until the epoxy set.


----------



## Mazuki

Thanks for the responses guys, I got a piece of thin useless perfboard. That should do the trick.


----------



## dhp

it appears that I have a problem. Right channel outputs ~1 mV, and left channel outputs 100 mV. What could possibly cause this? Can't be the soics or the ssop can it?


----------



## pddjsteve

I used my first and only failed attempt, cut the partially populated board down to about 2/3, and put it in as a spacer


----------



## pegasus21

The BUF634U is only used for configurations where the power supply will be shared with an amplifier right? For all other configurations it's not needed?


----------



## Alf

Quote:


  Originally Posted by *pegasus21* 
_The BUF634U is only used for configurations where the power supply will be shared with an amplifier right? For all other configurations it's not needed?_

 

This is correct


----------



## n_maher

Well, looks like SMD stuff is out to get me lately. Got the DAC populated yesterday afternoon and decided to try it today. No joy. It might serve as a nice space heater but as a DAC it's no good, the chip gets seriously hot within 2 or 3 seconds of plugging it into the computer. 

 My USB is putting out a steady 5.07VDC but upon plugging in the DAC the led does not light, the 3V3 pad reads 1.07VDC and the 5V pad reads .75VDC. Any thoughts or suggestions before I throw this thing in the can? 

 I was pretty obsessive about checking for shorts on the DAC chip to the point of taking high-res macros of the chip and the only short that I could find was between pins 1 and 2 and MisterX seemed to think that was ok. And the rest of the assembly went without issue. 

 Coming soon to the for sale forums near you, a complete Alien DAC parts and PCB package 
	

	
	
		
		

		
		
	


	




...

 Nate


----------



## psilosome

I would guess you have a short between +3.3V and ground (which are connected to those two pins as I posted earlier). This should be easy enough to confirm with a meter, though probably harder to find and fix, but at least it might give you an idea of where to look. 

 I had a similar short between +5V and ground that I could never find. I put that board aside, and my second build worked right away.


----------



## blaken

is there any advantage to using BUF634U over OPA551UA? Just wondering because BUF634U costs about $3 more.


----------



## pegasus21

I did ask something related just a few posts above. So I'll ask you this. Are you even going to tap the power source for your Alien DAC from another amplifier? If you are not, you don't need the BUF634.

 BTW, I'm looking to implement an amplifier circuit after the DAC and the amp will be tapping power from the USB +5V and Gnd. I don't know if it'll work though. Does the analogue out from the PCM2702 reference from it's own analogue ground rather than the USB digital ground?


----------



## splaz

Bit of a dig but just thought I'd say, you guys were right, definitely get the flux.

 When I was shopping around to try and get some one guy, although he didn't have it, said it was great and you can pretty much 'sweat' the solder on.

 That is a pretty good description, it was a lot easier and just seemed to make a brilliant connection and faster than usual.

 Same goes for a good set of tweezers, I had been using some rather awkward cheap tweezers but they get really sore to hold for a while and I often dropped things because they didn't grip all that well. That was often a write off too, if they'd fall on the floor and bounced under the desk they could be anywhere. Picked up a nice set of tweezers and the need very little force to hold things, grip them well and are just all around nicer.

 Anyway, in summary you don't need flux or good tweezers but they make life a lot easier.


----------



## mb3k

Quote:


  Originally Posted by *splaz* 
_Bit of a dig but just thought I'd say, you guys were right, definitely get the flux.

 When I was shopping around to try and get some one guy, although he didn't have it, said it was great and you can pretty much 'sweat' the solder on.

 That is a pretty good description, it was a lot easier and just seemed to make a brilliant connection and faster than usual.

 Same goes for a good set of tweezers, I had been using some rather awkward cheap tweezers but they get really sore to hold for a while and I often dropped things because they didn't grip all that well. That was often a write off too, if they'd fall on the floor and bounced under the desk they could be anywhere. Picked up a nice set of tweezers and the need very little force to hold things, grip them well and are just all around nicer.

 Anyway, in summary you don't need flux or good tweezers but they make life a lot easier._

 

I'm debating between two types, no-clean and RMA.
 Digikey Part numbers:
 KE1803-ND
 KE1804-ND
 Any recommendations, or benefits of choosing one over the other?


----------



## splaz

Well I'm just using a syringe of the only stuff I could find, Interflux IF 8300. 

 Apaprently that doesn't require cleaning, possibly it doesn't conduct. However I still clean it off with isopropyl as it makes a bit of a mess.

 So basically if you're going to clean it off you can go with either, but I suppose if you're lazy you could go the no-clean.


----------



## pipp

Anyone tried using an external xo instead of the crystal ? Yea I know implementing this require some effort


----------



## t52

Quote:


  Originally Posted by *pipp* 
_Anyone tried using an external xo instead of the crystal ? Yea I know implementing this require some effort 
	

	
	
		
		

		
		
	


	


_

 

btw. anybody know a good and reasoanbly simple crystal oscillator circuit which drives the crystal in *series* resonance (as that mode seems to have the lowest side band noise [aka jitter])?


----------



## Calroth

So, my final shipment of Alien DAC parts arrived the other day. It was time to build.

 Before this project, I was a SMD virgin. The PCM2702 was the first SMD chip that I ever soldered. Hell of a way to start. Pasted the area with flux, clipped it down, soldered. Only made two bridges on the 5V side and the 3.3v side was perfect. Cleaned up one of the bridges with braid, the other was both to ground anyway. Soldered down the other parts, hooked up the battery (it's powered by 4 AA cells), jumpered S1 so I wouldn't have to buy another switch, and powered up.

 The 3.3v rail was wobbly and all over the place. Oops, the regulator pin going to ground wasn't tacked down properly. Reflowed it, now a rock-solid 3.3v rail. The 5v rail looked great. Another cursory check with the multimeter and everything seemed OK. Or so I thought.

 Plugged it in to the computer. Turned it on. Computer immediately shut down and would not power on again...

 This was a Calroth-special screw-up. I jumpered S1 when powering from a battery. So I was dumping 6V back into the 5V computer power rail. Needless to say, this is an utterly stupid thing to do. Don't do it. (The computer eventually came back to life after I did some Mac voodoo on it, but it was an anxious time.)

 Swore, cursed, etc. Cut the S1 jumper, went over everything with a fine-tooth comb (so to speak). Tried it out on an _expendable_ computer. Windows complained about a malfunctioning device. Went over all the solder joins again. It turns out that the bridge on PCM2702 that I thought I cleaned up wasn't. It was bridged under the pins, ugh. Used a knife and a mapping pin, scraped it out and cleaned up as best I could, and reflowed the area. No more bridge.

 However, now the 5v rail was shorted to ground. Went over the solder joins yet again. And again. A few hours later, tracked it down to another solder bridge on PCM2702 that I made cleaning up the first one. Cleaned that up. Plugged into the computer, powered on. Nothing exploded, nothing happened. Pulled out the multimeter again for another round of checks. It turns out that the 3.3v side of PCM2702, the side which I thought was soldered perfectly, wasn't actually soldered down at all. I thought it was because when testing for continuity, I was pressing down on the pins, forcing contact with the PCB...

 Reflowed that side. Cleaned up the bridge that I made doing it. Plugged into the computer. It detected! And (to cut the rest of the story short) it works. Now I am going to bed.

 I apologise to anyone who's read this far, for making you more stupid by reading this


----------



## MisterX

lol.


----------



## splaz

Calroth, knew the name was familiar. We were talking about the pimeta over at headphonic, I go by real name over there 
	

	
	
		
		

		
		
	


	




, still haven't got round to building it.

 Sounds like one of my stories, plenty of mishaps although minus the destruction. 
	

	
	
		
		

		
		
	


	




 I made a mistake on a PINT and went postal on the pot so I am putting my Alien DAC off for a bit as the anger is still brewing, in my mind i need to finish off the PINT before I start anything anyway. My SMD work was so nice on that too.....


----------



## villekille

I'd like to build Alien Dac but I missed the group order for the PCB..if someone has one for sale I'd like to buy it.


----------



## rsabo

Quote:


  Originally Posted by *villekille* /img/forum/go_quote.gif 
_I'd like to build Alien Dac but I missed the group order for the PCB..if someone has one for sale I'd like to buy it._

 

I think alf has some spares for sale, check the group buy thread.


----------



## Calroth

I have performed RightMark Audio Analyzer testing on my Alien DAC, and posted the results.

 The playback computer was a desktop PC with the following sound cards, for comparison:
a Sound Blaster Digital Music (a cheap USB sound card)
the on-board Realtek ALC850 sound card
the Alien DAC
a Chaintech AV-710, using the high-quality output
The recording computer was a MacBook Pro using its on-board SigmaTel Audio sound card. I ran the outputs from above into the MacBook Pro's line-in port without any extra load, to simulate a headphone amplifier. All playback and recording was done at 16-bit, 48kHz.

 The recording computer doesn't have the greatest sound card ever, so the numbers on the report aren't absolute. However, the devices can be compared to each other.

 If anyone has any questions about my testing method, or has their own RMAA tests, please post.

Edit: I updated the tests; see this post. The original results are still available here.


----------



## MisterX

Something is fishy with your results because I have got the following frequency responce "graph" with every Alien DAC I have tested in "loopback" mode without a dummy load.


----------



## Calroth

It could be due to my input device, which isn't ideal (alas, it's what I have).


----------



## MisterX

Yeah, it does kinda look that way.


----------



## frdchang

this usb dac sounds great.

 thanks for making this happen.


----------



## Ikarios

Yay! Got my three boards today in the mail. Now it's time to kill myself soldering.... 
	

	
	
		
		

		
		
	


	




 But anyway, as for parts selection, has anyone used Doobooloo's BOM, spread between Digikey and Mouser, successfully? I plan to basically use it for all parts except C13 (likely going to use 47uf 10v United Chemi-Con PSA capacitors) and CL/CR (I'm still undecided as to which cap I'm going to pick for CL/CLR; reading Whitewind's impressions, I'm leaning towards the 4uF ERO MKC coupling caps he mentioned, but I'm not sure what they are, exactly... can anyone provide me with a part number for either Mouser or Digikey?). I'd like to get BlackGates for CL/CR, but I'm trying to keep the cost of this thing fairly low, and I don't want to deal with any more shipping/handling costs than I already will be.


----------



## faizanbrohi

Hello , everyone , i have just joined this forum and really have found This Alien DAC Project Interesting .what i am trying to make with this is USB Wireless headphones or speakers. I have made and tested the Wireless Audio Transmitter . i built it Using BH1417 , and it works like a charm . i only need this USB Sound card to make it a USB Wireless speaker. i have ordered all the IC's from texas instruments . i just have to order some components from farnell and others i will find in my local market. THE Only Problem is the PCB. Is anyone kind enough to trace the PCB or can you tell me if the Schematic is correct by looking at the PCB . and Then i will Design My PCB Myself on a single layered board that anyone can make.


----------



## skudmunky

Quote:


  Originally Posted by *Aflac* /img/forum/go_quote.gif 
_Yay! Got my three boards today in the mail. Now it's time to kill myself soldering.... 
	

	
	
		
		

		
		
	


	




 But anyway, as for parts selection, has anyone used Doobooloo's BOM, spread between Digikey and Mouser, successfully? I plan to basically use it for all parts except C13 (likely going to use 47uf 10v United Chemi-Con PSA capacitors) and CL/CR (I'm still undecided as to which cap I'm going to pick for CL/CLR; reading Whitewind's impressions, I'm leaning towards the 4uF ERO MKC coupling caps he mentioned, but I'm not sure what they are, exactly... can anyone provide me with a part number for either Mouser or Digikey?). I'd like to get BlackGates for CL/CR, but I'm trying to keep the cost of this thing fairly low, and I don't want to deal with any more shipping/handling costs than I already will be._

 

I'm also looking around for a good BOM to use, got my boards today and want to solder over christmas break or something. Gotta get me a good magnifier, smore solder, and some finer solder tips.


----------



## gmckay

I just got my package of goodies from Mouser...$38 for parts..good deal...BUT..

 UPS ground shipping..which cost $10 USD ended up costing an additional $48 for customs brokerage (and of that amount $4.00 was duty)

 Now I've ordered from Digi-Key before and never paid customs brokerage fees...


 Is there a way you guys get your stuff shipped where you don't incur brokerage fees???


----------



## mb3k

Quote:


  Originally Posted by *gmckay* /img/forum/go_quote.gif 
_I just got my package of goodies from Mouser...$38 for parts..good deal...BUT..

 UPS ground shipping..which cost $10 USD ended up costing an additional $48 for customs brokerage (and of that amount $4.00 was duty)

 Now I've ordered from Digi-Key before and never paid customs brokerage fees...


 Is there a way you guys get your stuff shipped where you don't incur brokerage fees???_

 

Ship UPS or FedEx express, it costs about the same at around $30-$40 for the shipping but you know there will be no brokerage fees, and it arrives really quickly (ie. 2 days or less)


----------



## tomb

Frdchang - 

 Wow! What a clean job of soldering - nice work!


----------



## FallenAngel

Quote:


  Originally Posted by *mb3k* /img/forum/go_quote.gif 
_Ship UPS or FedEx express, it costs about the same at around $30-$40 for the shipping but you know there will be no brokerage fees, and it arrives really quickly (ie. 2 days or less)_

 

.... Or, DON'T order from Mouser if you're in Canada!
 Between next-day shipping from Digi-Key AND Newark you're still only looking at $18 Canadian for the both of them. I haven't found many parts I completely NEEDED from Mouser that I couldn't source elsewhere.


----------



## dhp

Quote:


  Originally Posted by *Aflac* /img/forum/go_quote.gif 
_Yay! Got my three boards today in the mail. Now it's time to kill myself soldering.... 
	

	
	
		
		

		
		
	


	




 But anyway, as for parts selection, has anyone used Doobooloo's BOM, spread between Digikey and Mouser, successfully? I plan to basically use it for all parts except C13 (likely going to use 47uf 10v United Chemi-Con PSA capacitors) and CL/CR (I'm still undecided as to which cap I'm going to pick for CL/CLR; reading Whitewind's impressions, I'm leaning towards the 4uF ERO MKC coupling caps he mentioned, but I'm not sure what they are, exactly... can anyone provide me with a part number for either Mouser or Digikey?). I'd like to get BlackGates for CL/CR, but I'm trying to keep the cost of this thing fairly low, and I don't want to deal with any more shipping/handling costs than I already will be._

 

why not just order all the parts from simply one vendor?


----------



## splaz

Heres my Digikey BOM.

 I suggest having a look through it as that is just what I chose to build mine with, well mostly. The need column is just a guide, like it says you need both cases. My thinking is if a part no.s repeated then you'd only need 1 of them.

 Stock column was way out of date so not much in there, date is just for approx. restock, you can change the currency conversion if you so wish by altering the no. found below $AU or $NZ and changing the currency type and date to match.

 edit: Just found something that needs altering with it... :\

 Will be back shortly.

 I also didn't include any sort of audio sockets as I preferred ones sourced locally to what digikey had.

 Also I give no assurances that anything on that BOM is suitable. That is merely a disclaimer so if some unsuitable part explodes and takes out your arm, dont' come to me with a law suit. 
	

	
	
		
		

		
		
	


	




 R31 and R32 are for 4.74V, which is suitable for a USB voltage of 5.04V or more. That may not be suitable for all computers, especially those under a strenous load were a voltage drop may put it below that. May be a better idea to tweak those to end up with a lower minimum input voltage.


----------



## skudmunky

I just went through and created this digi-key order, parts for 4 DACs. 
BOM image
 I'm a bit confused by the power options, I'd like to have options to wall power and USB power, how should I go about doing that, with an adjustable voltage regulator? Are the resistors I selected good for what I want? 

 I'm gunna get LEDs and Audio jacks locally, and for a case I'll just use Altoids tins

 thanks to everybody who posted BOMs, helped me find the digi-key part numbers I wanted.


----------



## Alf

Quote:


  Originally Posted by *skudmunky* /img/forum/go_quote.gif 
_I'm a bit confused by the power options, I'd like to have options to wall power and USB power, how should I go about doing that, with an adjustable voltage regulator?_

 

Nothing special. If you would like to underpower PCM2702 when used with USB, then the DAC should be underpowered in both configurations. So choose your resistors as if it is for USB only.

 Also I suggest you use an on-off-on switch to switch between USB and wall power.

  Quote:


  Originally Posted by *skudmunky* /img/forum/go_quote.gif 
_Are the resistors I selected good for what I want? _

 

They look OK to me. Use the formula on the support web site to calculate the output voltage. If you happy with the result, then go for it.


----------



## skudmunky

Quote:


  Originally Posted by *Alf* /img/forum/go_quote.gif 
_Nothing special. If you would like to underpower PCM2702 when used with USB, then the DAC should be underpowered in both configurations. So choose your resistors as if it is for USB only.

 Also I suggest you use an on-off-on switch to switch between USB and wall power.



 They look OK to me. Use the formula on the support web site to calculate the output voltage. If you happy with the result, then go for it._

 

Alright, thanks. Just gotta source out the Blackgate caps and pick up the stuff I need locally.

 Looks like it's gunna come out to about 35 per DAC for me (I'm buying parts for 4 DACs), pretty sweet.


----------



## splaz

Had a quick look over it myself skudmunky.

 Be careful about the size of that 1000uF FM cap, I chose the 680uF FC over it due to space constraints. Would have had to get a little creative to get it in the Hammond.

 I had a quick look and measure and it looks to me like it should fit in an Altoids tin, but say if you mount the board on double sided tape and take into account the board thickness it may get a little tight. Probably not an issue just thought I'd mention it so you can make sure yourself if you haven't already done so.


----------



## FallenAngel

You can use the 1000uF Panasonic FM's (and other larger ones as well), just lie it on its side, over the PCM.


----------



## Yen

Blah!

 I didnt carefully inspected and read instructions and ended up buying fixed regulators (IC2 and IC3). 

 What's the best powering option soundwise for fixed regulators? External PS/batteries? How long could I use the dac with four AAs or one 9V? And how does unregulated usb sound? How does the noise from usb affect the sound?

 Just dont want to buy adjustable cos it will consume more time and money and wont be ready b4 xmas... or should I go for adjustables?

 PS. anybody has excess SMDs or is ordering them pls pm me... I'll buy parts for 2 boards.


----------



## Ikarios

Quote:


  Originally Posted by *DieInAFire* /img/forum/go_quote.gif 
_why not just order all the parts from simply one vendor?_

 

I probably should do that, but I have this inexplicable and insatiable desire to get the best parts without spending TOO much. Also, if someone says "so and so" component is bad, I probably will not get it. I've yet to see a BOM that satisfies me completely, so I'll be taking bits and pieces from everyone, which means that all my parts will most likely not be available at one vendor.

 Although, picking the capacitors are a big pain... this one is great, but it's not available where I'm ordering... this one is available, but it sucks... this one is available, but it doesn't fit... this one is.... gah!


----------



## Yen

Well, I built a unregulated usb for the first ADac. 

 However, I have a problem: Connected the DAC to the laptop and it recognizes it as usb-speaker (so the dac-chip is ok) and everything went smooth. Installed ASIO and configured winamp and f2k to use the USB-speaker (DAC) but I get no sound!

 I have checked, double checked and triple checked all the fullsize caps' position etc. The 3,3 and 5V line is ok. Why I cant get no sound? If the computer installed the dac so my chip isnt fried, right? Or is the problem at the software I am using?

 Man, I was so happy when I connected the dac. Didnt have to fight much with the PCM-chip. All were fine until I connected to the amp, oh the disapointment..... I did test the amp with other sources and it worked fine.

 EDIT: Well, I did use the fixed IC3, because I planned to use batteries as PS. But that shouldnt affect anything, cos it just doesnt regulate usb's 4,9. Am I right? It is 4am here and my GF is forcing me to go to bed. 
	

	
	
		
		

		
		
	


	




 I'll try the battery power tomorrow, but I dont think it will fix my prob.


----------



## FallenAngel

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_Well, I built a unregulated usb for the first ADac. 

 However, I have a problem: Connected the DAC to the laptop and it recognizes it as usb-speaker (so the dac-chip is ok) and everything went smooth. Installed ASIO and configured winamp and f2k to use the USB-speaker (DAC) but I get no sound!

 I have checked, double checked and triple checked all the fullsize caps' position etc. The 3,3 and 5V line is ok. Why I cant get no sound? If the computer installed the dac so my chip isnt fried, right? Or is the problem at the software I am using?

 Man, I was so happy when I connected the dac. Didnt have to fight much with the PCM-chip. All were fine until I connected to the amp, oh the disapointment..... I did test the amp with other sources and it worked fine.

 EDIT: Well, I did use the fixed IC3, because I planned to use batteries as PS. But that shouldnt affect anything, cos it just doesnt regulate usb's 4,9. Am I right? It is 4am here and my GF is forcing me to go to bed. 
	

	
	
		
		

		
		
	


	




 I'll try the battery power tomorrow, but I dont think it will fix my prob._

 

Which version of ASIO did you use? I had no luck with ASIO4ALL V2, but version 1.8 (link in Alf's site) worked perfectly. Also, try using regular Wave-output or DirectSound.


----------



## Yen

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Which version of ASIO did you use? I had no luck with ASIO4ALL V2, but version 1.8 (link in Alf's site) worked perfectly. Also, try using regular Wave-output or DirectSound._

 

Yes, I used the v1.8 ASIO4ALL and Wave-out and Directsound. No help. There is no hum, buzz or anything. Just silence.

Here is some hi-res picture of it.

 I have checked the polarities, wirings, alignment of chips, connectivity, everything... Just cant make it sing. Bernard Fanning is waiting to be unleashed. 
	

	
	
		
		

		
		
	


	




 Hmmm, I maxed out volume in windows volume panel, winamp and used wave-output I get some sound. It does play the some, but like someone is shouting far far behing the door. Really muffled and barely identifiable as a song. Apparenly my output has problems?


----------



## Seaside

Yen, I can't see C31, R31 and 32 at your pic. 
 You got IC3 (REG10*UA) there, you will need them too.


----------



## Yen

Quote:


  Originally Posted by *Seaside* /img/forum/go_quote.gif 
_Yen, I can't see C31, R31 and 32 at your pic. 
 You got IC3 (REG10*UA) there, you will need them too._

 

 Quote:


  Originally Posted by *Support Website* 
_If you use a fixed regulator IC3, put C32 on the top side in the position that ambiguously says R32/C32. Do not populate R31 and R32._

 

Who is right? 
	

	
	
		
		

		
		
	


	




 Yes, I have missed the C31... how stupid of me. 
	

	
	
		
		

		
		
	


	




 Edit: installed the cap, but didnt affect output sound. 
	

	
	
		
		

		
		
	


	




 If I max all volume (amp, windows, winamp), I'll recognize the song, but none mids, bass and highs buzz and still really muffled.

 EDIT2: Tried battery power with 9V and test points showed correct. Problem went nowhere. Tried on my other computer. Same results.

 Debugging: So if the computer recognizes the dac and apparently songs are played, then my analog output is broken, right? After reading schematics, I see the analog sound has only CL&CR and R15&R16 on its path to the rca connectors. So these two pairs or the wire plus connectors are the source of the problem. Pls correct me if I am wrong. I have checked and rechecked these. 
	

	
	
		
		

		
		
	


	




 EDIT3: Replaced the CL & CR with some 16V 47uF Elnas and also R15&16. Didnt help. I also checked that no adjacent pins of the PCM-chip touch each other. I am getting really frustrated... 
	

	
	
		
		

		
		
	


	




 EDIT4 (and final): My post is becoming ridiculous! 
	

	
	
		
		

		
		
	


	




 Bernard Fanning is singing, so does Missy Higgins! Oh, with what amount of details and openness. In everyway beats the laptop's headphone/line output hell out of it.

 As most of the problems in this thread, there were contacts between pins. I noticed after x^n amount of rechecks with magnifying glass and the board againts light.

 So what's the lesson? Check, recheck, rerecheck and even more rererecheck the pins of the chip.


----------



## Seaside

Yen, good to hear that yours is working now.
 Pretty good little thing, isn't it?

 ***
 R31,32 is mandatory if you use *adjustable* regulator at IC3. Those two resistors will determine the output voltage level of IC3.

 If you use *fixed* regulator at IC3, you do not need R31,32 as the support website said. But then again, you do not need fixed regulater at IC3 at all, since it will not really regulate. That means there is no point of using fixed regulater at position IC3. You still can use fixed regulater there, but the thing is it will work just like unregulated configuration. You can find some info about this at this thread, just serach hard.

 What the support website, basically said is that you skip IC3, skip R31 and 32, and jump AV+ and 5V in order to use the DAC as unregulated configuration. 

 Otherwise, you put *adjustable* regulater at IC3, put R31 and 32 in order to use it as regulated configuration.


----------



## whiz

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_As most of the problems in this thread, there were contacts between pins. I noticed after x^n amount of rechecks with magnifying glass and the board againts light.

 So what's the lesson? Check, recheck, rerecheck and even more rererecheck the pins of the chip. 
	

	
	
		
		

		
		
	


	


_

 

check my post somewhere in the middle of this page... 
	

	
	
		
		

		
		
	


	




http://www6.head-fi.org/forums/showt...188717&page=20


----------



## lordvader

I just received my pcbs !

 <rant>
 OMG ! They're so tiny ! How the hell do you solder them ? I'm gonna go blind !
 </rant>


----------



## Yen

I am planning an external PS to provide 6V to be regulated down to 5,4Vs and wondering current (mAh) requirements for the wallwart. Can I go for the lowest (and cheapest) ~600mAh wallwart? Other options are 800, 1100, 1500 and 2000.


----------



## FallenAngel

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_I am planning an external PS to provide 6V to be regulated down to 5,4Vs and wondering current (mAh) requirements for the wallwart. Can I go for the lowest (and cheapest) ~600mAh wallwart? Other options are 800, 1100, 1500 and 2000._

 

I don't doubt that 600mA would be much more than enough. I'm using a 9V AC 300mA through a TREAD just fine.


----------



## splaz

Hope it doesn't mean what I think it does.

 Plugged in my Alien DAC, 4.74V and 3.3V. Everything is fine there.

 USB device is well noticed by windows, however then says it's an unknown device and it's not recognised and when I bring up properties it's complaining about no driver.

 A bridge somewhere I'm imagining ? 

 If so bleh, I spent about an hour going over the chip and was sure there was nothing wrong.


----------



## Seaside

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_Hope it doesn't mean what I think it does._

 

Well... 

 My second Alien DAC acted just like that.
 I could'nt find any bridges at all even under the bright light with magnifier.
 So I turned the light off with frustration, and you know what I found?
 A little spark between legs of 2702.
 That was not a bridge, but a little burnt flux residue sticking there. 
 I scrapped it off with sharp knife edge, clean the board once again, and it works like a charm. So check again and again that little bastid.


----------



## splaz

Hmmm... well so far bridge removal methods aren't working that great. I scraped out some small little solder blobs the I thought could have been bridges no change. I'm thinking one possibility is that a before few little strands of braid snapped off onto a pin, I thought I got rid of it all, maybe theres some hiding ?

 Well this sucks but I'll find it eventually, I hope.


----------



## FallenAngel

How do you clean the flux off the board and does it really work well? I use a very stiff toothbrush and 90% alchohol, then blow off the excess with compressed air. Work pretty well.


----------



## Calroth

For what it's worth... When I was building mine, there was a point where I would plug it in and Windows would complain of a malfunctioning device. It was a bridge on the 5V side. It may help to get a bright light and hold it behind the PCB, letting the light shine through. What I also did was get a mapping pin (one of those long thin pins with a bright ball on the non-sharp end...) and shove it under the chip pins on that side - it fits (at least on mine). That may push out any crud under the chip. Combine with scraping between the chip pins with a thin blade.

 Of course, it helps if you can figure out what's shorted - lots of staring at the schematic at this point.


----------



## splaz

Well I'm using the bright light method, I've got a 60W globe in my room that hangs down and I'm standing next to it and holding the board at all sorts of angles. Hasn't really helped much. I've scraped between all the pins with fine tweezers and a pin.

 It was getting a bit late though so I've had some sleep, hoping maybe with a different mindset I'll think of something or notice something I didn't before.

 Narrowing it down is a good idea, I've done some quick measurments. Just curious, should you measure no voltage drop accross the crystal and R14 ?

 I'm getting 500mV accross the crystal's capacitors. I think it's normal though as from a capacitor leg accross a crystal I get a voltage drop and vice versa, they're the same so they cancel out I'm imagining. I don't really know how crystals work. Just thought I'd check that as I'm sure if the crystal was not working that would screw with it.

 Anything to measure other than the 5V and 3.3V supply ?

 I know it could be anything but you know, anything else cricital to the chip that I should be measuring, outside of measurements looking for a bridge.


----------



## Calroth

If you want to look at something new, read the PCM2702 datasheet. If I recall, the 3.3v side is the USB interface and digital input side, whereas the 5v side is the analog output side. So I'd guess that you need to make sure that the 3.3v side is hooked up right, for the computer to see the DAC.


----------



## splaz

Well this to me seems like I've narrowed it down significantly, both pins 2 and 4 measure 3.3V from the pin to ground. However going from the pin to their capacitor (C14,C15), for pin 2 I'm getting 2.4V and for pin 4 0V. To me I'm certain pin 2 should be 0V also, maybe I'm wrong but it seems like the case to me. Well all my knowledge up to date says that's not right.

 edit: quick pic to show what I mean.

 Okay well I'm getting my really thin soldering iron tip and see if that if I can wipe between the pins with it.

 Okay and now I lifted pin 2 trying to scrape behind it... 
	

	
	
		
		

		
			





 Such a pain trying to repair it with everything in the way as well, yes I know I can desolder it but that is a pain and takes longer to test if methods have worked.

 Arghhhh... there is tiny little gap in the track of pin 2.... solder doesn't want to get over it. This'll be fun fun fun trying to jumper accross.

 Well I've shifted the pin forward slightly and convinced the solder to bridge the gap in doing so I also bridged pin 2 and pin 3... 
	

	
	
		
		

		
		
	


	




 I don't understand why it has no problem jumping from one pin to the next, yet a slight little gap it doesn't want to go near. Solder is evil...

 Yes! After hours trying to remove any other bridges and then trying several methods I couldn't reconnect pin 2 without bridging a heap of pins. I went to a friends house for a bit of relaxation time and asked his dad about it, he said try using a long piece of thin wire so you can manouvre it around, tin it before hand, just heat it up and connect the parts you want to and sever it after you're done. Worked like a charm. Recognised as a BB 2702. Under light there is one dubious looking bit of solder that is a hair off being a bridge, however that is right next to pin 2 and given the fragile nature of it and that it seems to work I'm leaving well enough alone.

 I replaced 2 of the electrolytics that the soldering iron touched a little just in case of any damage, doubtful but possible.

 Now I need to start think about casing it up and listening to make sure everything is in order, maybe double checking some measurements but all looks well so far.

 Funny thing is I was looking over your post Calroth and was like, urghhhh, several painstaking hours. Hope that doesn't happen to me. Looks like it did.


----------



## Andrew*Debbie

I know I'm a bit late on this.

 My BOM is based on doobooloo's with a few changes. The only significant change is C1. I'm using a Murata ERB21 part. It has a lower ESR at high frequencies so in theory it would do a better job of filtering out >100MHz noise. This BOM is for USB power, so I've spec'd the adjustable reg101. I'm going to build 1 DAC with USB power and another with external power.


 Digikey BOM to save you some typing:

http://sales.digikey.com/scripts/ru....b_glue=1013411


----------



## splaz

Okay well now I'll ask. Anyone have specs/dimensions on where to cut the USB square on the Hammond front panel ?

 If not I'm trying to make a template, not very well at the moment though, just to figure it out. If no one can tell me I might get some dimensions and put them up.


----------



## pddjsteve

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_Okay well now I'll ask. Anyone have specs/dimensions on where to cut the USB square on the Hammond front panel ?

 If not I'm trying to make a template, not very well at the moment though, just to figure it out. If no one can tell me I might get some dimensions and put them up._

 

Ick, yeah, I was going to try making something in Front Panel Express but just haven't had the time to sit down and learn it. I used a piece of acrylic for mine, but it is still rough. I never got around to making a better one. The square hole is definitely the worst part about casing this up. I almost want to look for a panel mount USB jack


----------



## FallenAngel

If you're using the plastic end panels of the hammond case, it's not too bad to drill a little hole as close to the middle of the USB connector as you can eye out, then just cut out the rest using a knife. Works for me and only takes like 10 minutes.


----------



## splaz

I had to get the aluminium one. 
	

	
	
		
		

		
		
	


	





 Btw, is 0.5mV DC offset about right ?

 That's with CL and CR installed. Seems fine to me just checking.


----------



## FallenAngel

0.5mV is pretty good. Even with an amp with very high gain, it'll still be fine.


----------



## Andrew*Debbie

What tips are people using to solder this tiny project?

 I've got a Weller WTCPT (well two actually) and a Hakko 936.


----------



## FallenAngel

Pretty much any would work, but personally, I prefer a small flat tip.


----------



## splaz

I've got 3 tips I use, although only 1 sees much use.

 I use a 0.5mm conical for the majority of surface mount.

 I occasionly use a 02.mm conical, I usually use the 0.5mm over it though as it often doesn't get good enough contact to heat up groundplanes.

 I also have an extremely fine 0.5mm bevelled long reach tip. That is mostly for really, really, really thin soldering and wiping solder from between pins etc.


----------



## GarlicKnots

Blast, blast.

 It looks like I missed c22, c32 on my digikey order. 

 I would have used these:
 AVX Ceramic X7R 100nF/50V 5%

 Does anyone have (4) spare of these?

 I'll of course pay for them + shipping + whatever handling you're into.

 Would greatly appreciate PM.

 Thanks,

 f/R

 EDIT: I think I'll be alright, C14-C19, etc. are also 100nf ceramics. Looks like I labeled them incorrectly.


----------



## splaz

These are my initial dimensions for the USB square hole.

*DO NOT USE THESE TO CUT IT OUT*

 Do not go and measure this out and cut it into the end panel, so far these are preliminary based on datasheets and actual measurements. Any measurements done by me are only within an accuracy to the neareast 1/2 mm guaranteed so this is by no means perfect, but close enough to me and I'm just going by eyesight, I'll update it when I get closer to actual. Keep in mind variations in size due to manufacturer tolerances.

 Also keep in mind it does not have to be completely perfect as once I get to the one I'll actually be cutting it will be enlarged to ensure it gets through cleanly.

 Please note this is not to scale and does not represent the actual location of the hole, merely the measurements from the outsides of the panel which so far seem fairly spot on, not perfect as said but pretty close. I haven't checked all though so I'll be doing that too.

 The method I used to calculate the base of the board using the slots of the Hammond, the board is slightly thinner so is not exactly where the top of the slot ends, however it is very close so imo it doesn't matter.

 If anyone has any inputs, corrections or can compare these to their own that would be appreciated.

 If I can work out how with my limited resources, I'm using paint, final dimensions will hopefully be to scale and in the right location.

 I'll also add in where to a drill a hole in the centre if that helps.


----------



## MisterX

FPE files for the front and back. 

 <Insert standard disclaimer here>


----------



## ~n00beR

My goodness sometimes people can be just too kind 
	

	
	
		
		

		
			





 Thanks MisterX 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_FPE files for the front and back. 

 <Insert standard disclaimer here>_


----------



## splaz

You've been holding out on us.

 Then I go to all the trouble of whipping up a 5 minute paint job. 
	

	
	
		
		

		
		
	


	




 Amazingly enough my measurements aren't half as bad as I thought. 
	

	
	
		
		

		
		
	


	




 Cheers for that.


----------



## splaz

Got it semi-cased up and to the next stage of testing.

 Wow it sounds great... except the right channel is muted. 
	

	
	
		
		

		
		
	


	




 I see no shorts at all between any pins for the right channel, I'm getting continuity on all pins for the right channel to their respective locations, checked sockets and connectors all are okay.

 Heres my measurments for the analogue side, mostly for my benefit but to also possibly shed light on this: 

 VCCP: 4.7V
 AGNDP: 0V
 VCCL: 4.7V
 AGNDL: 0V
 OUTL: 2.37V
 VCC: 4.7V
 VCOM: 2.33V
 AGND: 0V
*OUTR: >1 mV (Meter was taking a long time to drop).*
 AGNDR: 0V
 VCCR: 4.7V 



 C19: 4.7V
 L18: 4.7V


 OUTR -> CR+: Continuity
 CR- -> RCA Socket: Continuity

 Scraped all around the OUTR pin to no effect, cleaned it with flux, no change.


 To me there are 2 possibilities, OUTR is grounded and I haven't found where or OUTR is stuffed on the chip.

 Now OUTL has done it as well and I dont' recall doing anything to make that happen.


----------



## Calroth

The only thing I can think of is that side isn't soldered down right - like what I originally did. Improbable, but easy to check for: press the chip down firmly with your fingers and see if it works now. Another thing you can check for is your Windows sound settings - at best it might only be 50%, but at worst it could be muted at the source or the balance could have shifted if you accidentally hit the space bar or something (or changed the output back to your original sound card). That's all I can think of at the moment.


----------



## splaz

Been through all sorts of setting in device manager, control panel, media player settings etc.

 Everything is normal, not muted.

 Pushed it down to no effect.

 At this stage I'm thinking somehow I managed to fry both outputs... although I have no idea how.


----------



## splaz

OUTL and OUTR are not grounded which is actually not what I wanted as now I have no idea.

 Well everything is normal except the unknowns to me.

 Both data pins.
 Crystal in and out pins.
 OUTL and OUTR.

 Something of interest is with the DAC connected to USB and some cheap amped computer speakers, my mate touched the USB data pins on the connector and got a beep through the speakers.

 Basically nothing from OUTLR and OUTR. Everything I've checked seems to point to the 2702, the data input itself or I suppose there is a remote possibility of some issue with the crystal as I don't know how to check that.

 Anyone got some ideas or possibilities, maybe somethign that will prove it is/isn't the chip ?


----------



## Calroth

Maybe try plugging it in to a Mac or Linux box and see what it says. If nothing else, you get better logging - on the Mac, it's in Console.app, and on Linux, check the /var/log directories and "dmesg". Apart from that, sorry, not much I can think of.


----------



## GarlicKnots

Two questions:

 1) For the RLED it suggests 600 ohm. I only have 300 ohm resistors left.
 Can I solder these in series on the pads, i assume smd parts work like that too.

 I figure series would be like a triangle. One resistor's lead would be on one pad. Another resistor's lead would be on the other pad. And I would solder the two leads in the middle together to put them in series, like this:

 Elevation view:

 __/\__

 The horizontal (flat) lines are the pads. The diagonals would be the resistors.

 Correct?

 (I imagine putting them in parallel would be stacking two resistors on top of each other?)

 2) I don't have IC4. I want to test the alien dac with a cmoy (virtual ground), any way to do so without ic4?

 Cool.

 Thanks.


----------



## Ikarios

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_2) I don't have IC4. I want to test the alien dac with a cmoy (virtual ground), any way to do so without ic4?_

 

IC4 is only if you are sharing the power supply between the amp and the Alien. If you're going to run your alien off USB power, then you don't need IC4.


----------



## threepointone

Has anyone here actually tried to share the power between the DAC and amp? I'm getting rather confused on a couple of points. Since most amps probably don't run well off of +5V, I'm assuming that there is a supply for the amp somewhere around +9V, which is downregulated to +5V for the DAC by REG102. The amp input ground (centered at a potential of 4.5V to ground) goes right through the buffer back to DAC ground (0V). Since buffers/opamps still pass on DC (I think?) isn't that a dead short from +4.5V to ground? Or has this not been noticed because of current limiting? 
 Or more likely is there just something that I'm not understanding here?


----------



## AndrewFischer

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_Two questions:

 1) For the RLED it suggests 600 ohm. I only have 300 ohm resistors left.
 Can I solder these in series on the pads, i assume smd parts work like that too.
_

 

You could put them in series. You could also try a 300 ohm resistor. 

 Umm Typical LED drops about 1.2V 3.3-1.2v = 2.1V I=E/R or 2.1/300 or .007A

 7mA isn't much. Nearly all LEDs will be fine.

 I'd hope that IC2 has the few extra mA to spare.


----------



## GarlicKnots

Troubles.

 I seem to have a bridge between pin 27 and 28 but it isn't a bridge between the actual pins. It looks like the two pads bridged. I can't seem to get the bridges out between the pads. Tried running the tip over the two pins, tried braid, etc. 

 I decided to stick the usb plug in anyway just to ruin my life or verify that there was a bridge.

 At least that got me a new error that it doesn't look like anyone has gotten yet with the dac:

 "Power surge on USB port"

 Took the dac out quickly after that. 

 I then proceeded to to use an exacto knife to try to make the pad bridge go away, I don't think that was the best idea since I scratched into the board a bit.

 Quick q: If I wanted to temp power supply it I could use a 9v battery since it is < 10 v so the adjustable reg would work.

 I would connect the 9v leads to av+ and g2 and I would still keep s1a and s1b jumpered?

 Perhaps pictures will follow tomorrow or so. 

 f/R


----------



## splaz

9V should be fine, might be a bit unwise if there are electrolytics or tantalums that will see the 9V and are rated for 10V and the battery is brand new and somewhat over 9V or one of the 9.6V batteries etc.

 Just going by what I've heard that is good to have a bit of room to breathe with those sort of components and they don't like you pushing too close to their max voltage.

 edit: Don't jumper, that connects the 5V from the USB to the regs.


----------



## error401

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_Troubles.

 I seem to have a bridge between pin 27 and 28 but it isn't a bridge between the actual pins. It looks like the two pads bridged. I can't seem to get the bridges out between the pads. Tried running the tip over the two pins, tried braid, etc._

 

Pins 27 and 28 both connect to the ground plane. Mine bridged too, you don't need to worry about it - looking at a fresh board, the solder mask between these pins is nearly nonexistent. If you're getting that power surge message it probably points to a short between power and ground somewhere, but it's not pins 27/28.

 That said, I just finished populating my first board. It was a smashing success! After a couple hours of soldering (0805 is nasty...) it's working perfectly with no hiccups. Sounds great too, the noise floor is vanishingly low. All along I thought the noisiness of my rig was due to the cheap Kenwood receiver I'm using as a headamp right now. Not so! It was the cheap SB Live card creating it all -120dB noise floor my ass!

 Now, on to a decent amplifier...

 Curse you Head-Fi!


----------



## GarlicKnots

Interesting about 27/28, the first time I read the schematic I thought they were going to different places. I need to take a look again at it.

 Anyway, with a 9v battery depleted to ~6.5 I was only able to get these crummy readings:

 .43v @ 5v
 0 @ 3.3v

 I could have easily burnt out the 2702 chip since I thought it's heat tolerance was 10s not the rated 5s. 

 Going to try another one this weekend and see what happens. Wish me well.


----------



## error401

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_Interesting about 27/28, the first time I read the schematic I thought they were going to different places. I need to take a look again at it.

 Anyway, with a 9v battery depleted to ~6.5 I was only able to get these crummy readings:

 .43v @ 5v
 0 @ 3.3v

 I could have easily burnt out the 2702 chip since I thought it's heat tolerance was 10s not the rated 5s. 

 Going to try another one this weekend and see what happens. Wish me well._

 

Do the regs get hot at all? What is the input voltage on the 5V rail with the battery attached? Does the battery get hot? What's the load current on the battery?

 If you've got decent input voltage to the regs, but no output, you're probably shorting after the regulators. I suspect though that even a current-limited (at 1A for REG101) short would drag that poor depleted 9V way down. If they're getting hot, that'd confirm this - a short before the regs would give them very little input voltage.

 At this point I wouldn't recommend replacing the 2702 just yet. Get the power supplies working first, and if you've still got trouble, replace the 2702. And also try with a more robust power supply - but not without a current limit. A battery depleted that low can probably not source enough current to do any useful work - that may be your only problem. If you've got a bench supply, use that, otherwise 4xAA or breakout the power from a USB cable. Be careful if you use batteries, a dead short across them could be harmful to your health if left for any length of time.

 After meeting with failure on the HPDAC and building the Alien, I now wonder why most of the assembly guides for HeadFier's projects recommend soldering down the huge, expensive, sensitive chips rather than building the circuit out modularly where individual parts can be tested. I ignored the assembly guide for my Alien, building the power supply sections first and adding the DAC last as it was then easy to test that nothing was going to get fried. Soldering it all in one go and praying is a bad idea IMO, even if it avoids some awkward soldering (and on this board I didn't have any trouble at all, just don't solder the 'lytics or USB connector until the end - the power supplies don't require any of this for testing). Everyone's likely to make mistakes and they're a nightmare to troubleshoot when the entire circuit is populated - especially if there's more than one error. I would like to petition the circuit designers around here to write their assembly guides in a more modular fashion, with more thought put into testing *during* assembly where troubleshooting is much easier and the consequences less dire.


----------



## splaz

Well for me the 2702 was the only thing hard to solder and with nothing else on the board it was that much easier to solder and check for bridges, still a good idea to do it in a modular fashion I suppose.

 I did the build in the all at once and hope for the best approach and am dissapointed about it beind dead, however not the power supply that has issues but somethign to do with the 2702. So to me atleast, power supply parts are easier to solder, easier to check. 2702 is a PITA, harder to spot bridges and so far according to myself and others has caused the most problems. So I'd personally still do that first.


----------



## error401

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_Well for me the 2702 was the only thing hard to solder and with nothing else on the board it was that much easier to solder and check for bridges, still a good idea to do it in a modular fashion I suppose.

 I did the build in the all at once and hope for the best approach and am dissapointed about it beind dead, however not the power supply that has issues but somethign to do with the 2702. So to me atleast, power supply parts are easier to solder, easier to check. 2702 is a PITA, harder to spot bridges and so far according to myself and others has caused the most problems. So I'd personally still do that first._

 

Well, _something_ had to have killed the 2702 (if it's in fact dead, which I doubt, though it may be poorly soldered), and if it were a miswired power supply, I'd rather figure that out before desoldering and resoldering a SSOP-28 just to find it fried again. Maybe remove the 2702 that's there to eliminate it as a source of the short, but I wouldn't go as far as replacing it outright, at least without powering the circuit and testing what you can with it removed.

 Any chance of some high-res pics?

 Good luck 
	

	
	
		
		

		
			





.


----------



## splaz

Well I covered it earlier in this thread.

 Power supplies are fine, 4.71V and 3.3V on their outputs, every single pin has the right readings on their pins except OUTR and OUTL which I get nothing or tiny readings when I should measure around 2.5V or so DC offset, no shorts to ground on either channel. Of course data pins could be doing something, but yeah, I'm assuming the DAC stage in the chip is dead or it's not getting the right data/data is stuffed somehow.

 I'm pretty sure I've killed the chip by now anyway as I shorted VBUS to GND when trying to make sure it was right a second time, I slipped, it sparked, mate said "What, don't go blowing the fuse in my laptop". 
	

	
	
		
		

		
		
	


	




 That was several hours after it wasn't working anyway and just made me even more bummed out. I'm going to give it a whirl in Linux as per Calroths suggestion, if that doesn't work I'll go to plan b.

 edit: I do have some pics, not the best photography and they look more messy than it is IRL. 

 Getting them up now. This is the only good one, second one is more just a shot of what it looks like, cap choice and so on. Bottom is too blurry so I'll retake that and try and get the other side later as the digital camera is out and about at the moment.

 Pin 2-3, look rather messy, that's because I lifted a pad due to the misfortune of pushing on the pin in an awkard way with the iron and it bent it sideways a little, massacred the board a little. Checked with a meter for continuity from the cap and it's okay. Get 3.3V and 0V for 2 and 3 so I'm assuming it's not shorted, looks like it is there though. The bit of fluff or whatever it is on the bottom left reg was just some weird loose stuff that would have fallen on it. Doubt it was there when testing and highly doubt it would cause problems anyway as it wasn't bridging anything and power supply outputs were all a-okay.

 Oh and lastly, it is detected as a Burr Brown PCM2702(Japan) or whatever it says and USB speakers under device manager. So no problems there, yet no output!


 AlienDAC-Top-01
AlienDAC -Top-02


----------



## splaz

Well I've removed that little solder ball anyway between those traces and I'll give it a whirl later, I don't have much optimism of it suddenly working though, we'll see after work.


----------



## cgrums

Hey guys. I've been having the damndest time soldering the DAC chip down. I've tried on all 3 of the PCBs I have and not a single one came out. I think I've got the technique down but need to remove the three chips so I can try again. For some reason I don't seem to be able to remove the solder with braid very well, do you have any suggestions for getting these chips off?


----------



## FallenAngel

You definitely want to get all the solder off using the braid as it's VERY hard (nearly impossible) to get that PCM chip off the board without damaging something.


----------



## whiz

Quote:


  Originally Posted by *cgrums* /img/forum/go_quote.gif 
_do you have any suggestions for getting these chips off?_

 

put some braid in flux and then try to unsolder the chip.


----------



## Alf

Quote:


  Originally Posted by *cgrums* /img/forum/go_quote.gif 
_Hey guys. I've been having the damndest time soldering the DAC chip down. I've tried on all 3 of the PCBs I have and not a single one came out. I think I've got the technique down but need to remove the three chips so I can try again. For some reason I don't seem to be able to remove the solder with braid very well, do you have any suggestions for getting these chips off?_

 

Try this method: http://www.infidigm.net/articles/solder/#desoldering

 It worked for me


----------



## cgrums

Thanks for the help guys. Alf, that worked like a charm!


----------



## cgrums

IT WORKS!!! It only took me four attempts to solder the 2702e but it's currently making beautiful sounds through my maxed out PIMETA. This has definitely been the most challenging/rewarding project I've completed yet. I'm so stoked


----------



## villekille

Will this work? I have a PPA headphone amp, and want to install Alien DAC inside it. I already bought the ic4 buffer for aliendac but I have my doubts..my amp uses a 20V power supply, isn't this too much for the alien dac? aren't the regulators getting too hot?


----------



## steinchen

Quote:


  Originally Posted by *villekille* /img/forum/go_quote.gif 
_..my amp uses a 20V power supply, isn't this too much for the alien dac? aren't the regulators getting too hot?_

 

the reg10x regulators are rated for a maximum input voltage of 12V ! You may use a simple 7808 regulator to drop the voltage


----------



## error401

Quote:


  Originally Posted by *steinchen* /img/forum/go_quote.gif 
_the reg10x regulators are rated for a maximum input voltage of 12V ! You may use a simple 7808 regulator to drop the voltage_

 

Indeed, but I believe the REG101's only see the voltage between V+ and GND, they should be able to cope, though may get quite hot. The BUF634 can handle 36V, and it's the only part that sees the full 20V so you should be fine.

 I'm not an expert, but I'm thinking that putting a regulator on V+/V- will interfere with the virtual ground and generate an unacceptable DC offset in the range of several volts. Beware if you try it. However, I believe you could use a 5V reg to drop the voltage from the amp's + rail to GND, and use the 'external supply' option. But why when the spec'd parts will handle it fine 
	

	
	
		
		

		
			





.


----------



## picklgreen

How did you come up with the value of 4uf-47uf for CL/CR please? Oh nevermind...I used 1uf Wima MKS2 caps for CL/CR and it sounds fine! I will try the blackgates when they get here from parts connexion...whenever that will be...eh?!?


----------



## AndrewFischer

My 46 year old eyes can't see SSOP-28 at all. I soldered the PCM 2702 in as much by feel as anything else.

 After a second going over with solder wick, my PC recognized the DAC. The board still has problems that I couldn't see even with stacked reading glasses. Using the super macro mode on my Olympus found three or four solder bridges.


----------



## MASantos

That board needs some cleaning! Use alcohol(the one from the pharmacy ) and an old toothbrush and give the board a good scrub. you have lots of flux there. And if you have some solder flux, reheat the PCM pins with some flux, that should take care of those bridges. You can also reheat your other solder joints with flux.


----------



## jornterpstra

Got a question,
 I can get most of the parts easily, but i'm having a hard time finding a cap for :

 C11 Ceramic 1µF-22µF. 0805 package

 my problem is that i cant find one thats within those values (1uf-22uf) is there anything i can replace it with ?


----------



## AndrewFischer

I've read through the threads and AFIK no one tuned the input filter or ran a SPICE simulation. You can use just about any ceramic 0805 cap and the DAC will work.

 I'm using a 150pF MuRata ERB series cap for C1. Mouser Part number 81-ERB21BC1H151JDX1L

 The ERB cap might do a better job keeping HF noise out of the downstream power. I don't see why C1 needs to be >> 1µF since C2 is 680µF.


----------



## AndrewFischer

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_That board needs some cleaning!_

 

Yes it did. No point in giving it a good cleaning until after I fixed the bridges. 

 The bridges are cleaned up and the +5V short is gone, and I've got output. I'm going to solder in CL, CR and C2 and see how it sounds


----------



## MASantos

Nice to know you've worked it out. I just finished 10 Alien's! Tomorrow another 10!


----------



## picklgreen

Quote:


  Originally Posted by *jornterpstra* /img/forum/go_quote.gif 
_Got a question,
 I can get most of the parts easily, but i'm having a hard time finding a cap for :

 C11 Ceramic 1µF-22µF. 0805 package

 my problem is that i cant find one thats within those values (1uf-22uf) is there anything i can replace it with ?_

 


 Digikey 490-1691-1-ND


----------



## whiz

Yesterday my Alien DAC went Alien Dead..... 
	

	
	
		
		

		
		
	


	




 i was experimenting with something for my school project and
 accidentally i misconnected the alien dac output and i burned it!
 now the project went back...but who cares about the project??? i lost my precious dac!!!

 these days i'm going to start the "aLiEn DaC ReSuRrEcTiOn PrOcEdUrE"
 I would like we all call it that way if it is not copyrighted! 
	

	
	
		
		

		
		
	


	





 Resurrection Guide:

 If you dac is totally dead like mine and the problem is the IC do the following...take a very sharp knife (knifes with very small teeth are preferable)
 remove the crystal and the near capacitors, put the knife to the pins as close
 as you can to the plastic package of the IC and start carefully cutting the pins! after cutting the one side do the same to the other (or somehow use your soldering iron to remove the other side), after you finish put flux to the surface and gently try to remove the leftover pins from the pads and the excess solder..Hopefully all pads stay intact! i lost only one pad...pad 12 which it's not connected anywhere...

 The following photos shows my alien dac after removing the IC...





 sorry for the quality...it's from my mobile phone.
 Things are not as worse as they look like pads are very clear and and 
 you can solder the IC like before...(and maybe better)

Achtung! - Attention!





 Special care is needed when you cut the IC, because you can easily drift out pins and pads
 by cutting them careless! i'm not responsible if you try and fail with the prescribed way
 and it is preferable to try it ONLY if you think that your board is for the garbage can.



 anyway! wish me luck!


----------



## picklgreen

Wait, how did you kill your DAC's chip again? All you did was unplug it??


----------



## MisterX

Quote:


 remove the crystal and the near capacitors, put the knife to the pins as close
 as you can to the plastic package of the IC and start carefully cutting the pins! after cutting the one side do the same to the other (or somehow use your soldering iron to remove the other side), after you finish put flux to the surface and gently try to remove the leftover pins from the pads and the excess solder..Hopefully all pads stay intact! i lost only one pad...pad 12 which it's not connected anywhere... 
 

Screw that. 
 I had another forum member send a non working alien dac to debug and sure enough had soldered the IC on backwards. 
 All it took was a a big blob of solder (to heat all of the pins on one side of the chip) a little prying and another big blob of solder (on the second side) to remove the chip. 
 I did not lose a single pad. 


  Quote:


 All you did was unplug it?? 
 

Read much?


----------



## whiz

ok misterX...but still it's an option! for bigger ICs maybe..where you can't
 easily heat all the pins! think of square chips! 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *picklgreen* /img/forum/go_quote.gif 
_Wait, how did you kill your DAC's chip again? All you did was unplug it??_

 

i was playing with a board connected to the alien dac and i had forgotten that alien dac was on the usb and just burned the output..that's all! 
	

	
	
		
		

		
		
	


	




 so..we must be careful with the experiments or you're going to end up 
 like me! my school project blown away..until i fix my dac.


----------



## MisterX

The big blob method works square chips to... you just need two soldering irons and a fair of bit of manual dexterity to pull it off without burning yourself.


----------



## jornterpstra

Quote:


  Originally Posted by *picklgreen* /img/forum/go_quote.gif 
_Digikey 490-1691-1-ND_

 

Yeah i know digikey has one, probably mouser also, problem is i dont fancy paying 45$ delivery for just one part
	

	
	
		
		

		
			




 I already got my other parts ordered somewhere else (they dont have those values 
	

	
	
		
		

		
		
	


	




)


----------



## picklgreen

Where are you located? I have 8 of those left...


----------



## jornterpstra

I'm from the netherlands. 
 PM or mail me if we can work something out


----------



## whiz

my alien dac is up and running!! for once again... 
	

	
	
		
		

		
		
	


	




 how many db do you think i've lost with the absence of pin 12? 
	

	
	
		
		

		
		
	


	










 thanks goes to:

 My *1,5E* soldering iron with the Weller tip! YES! really...i have it almost a year and it works PERFECT i bought it from Super-market! the only good with it it's the electric resistor of 25W which is alive all this time! and because it is grounded so it is safe enough for sensitive components... today i bought for it a Weller tip! 
	

	
	
		
		

		
		
	


	




 with moderate use all this time i have used only 2 tips...the second one is from one more 1,5E soldering iron which i bought so i can have a spare tip!


 @masantros sorry man for not buying your soldering iron...i am a poor student, i'm trying to be as economic as i can be...


----------



## splaz

Okay well I'll probably give it one last go but I'm 99.9% sure I've killed the outputs.

 Anyone here willing to to do an IC swap for me ?

 I don't feel up to it.

 I will pay a reasonable amount and cover shipping both ways of course.

 I'll supply another 2702 or you can use your own if you want.


----------



## whiz

splaz check your mail...i don't see why you can't do it alone 
	

	
	
		
		

		
		
	


	



 misterX gave an alternative.. anyway maybe i can help you.


----------



## MASantos

NO problem! 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *whiz* /img/forum/go_quote.gif 
_
 @masantos sorry man for not buying your soldering iron...i am a poor student, i'm trying to be as economic as i can be... 
	

	
	
		
		

		
		
	


	


_


----------



## Gross

For the CL/CR caps why is this one designed to use such large values? If it is feeding an amplifier, why would these values need to be any bigger than the caps normally used for input caps? I realize the larger value, the lower the crossover point and phase distortion and whatnot, but wouldnt a 1uf WIMA be sufficent? Please let me know if I am blatenly missing something. 

 Thanks.


----------



## picklgreen

1uf is fine. Honestly I have no idea how Alf came up with the 4.7uf to 47uf values he did for the CL/CR values...


----------



## doomride

Can anyone comment on using the PCM27002 just to output I2S to something like TDA1541? Would the difference be worth it?


----------



## Gross

Quote:


  Originally Posted by *picklgreen* /img/forum/go_quote.gif 
_1uf is fine. Honestly I have no idea how Alf came up with the 4.7uf to 47uf values he did for the CL/CR values..._

 

Thought so, Thanks.


----------



## threepointone

I think they were for connecting directly to headphones--but then again, I think those values are too low for a direct connection to headphones. Probably audiophile madness, if you'd ask me. . .


----------



## Gross

Well, I put together another AlienDAC today and this time used the 1uf Polyester caps that I did not put in my M3ified PINT. There is definatly some lowend rolloff. My Alien with the 47uf SILMIC II sounds much tubbyier on the bottom. The highs sound crisper with the 1uf I have, but that is probably just because there isnt the lowend to wash it out. Or maybe it is because I used an orange LED instead of red this time...


----------



## Gross

Well, it isn't the orange LED as previously suspected in the last post 
	

	
	
		
		

		
		
	


	




 Every thing sounds peachy keen if I go directly into my pint, however with my Linkwitz Crossfeed in between the DAC and amp it sucessfully lowers the inpedance that the 'crossover' on the output sees. Since the resistance of the crossfeed is going to be somwhere in between 1k-2k, If I did my rough calculations correct, seeing a 2k load, a 1uf capacitor will form a highpass crossover at 80hz, which correspond exactly with what I am hearing. A 4.7uf should get me down to 17hz, so I guess I am off to see what polypro cap I can find in a 4.7uf value.

 Thanks all for listening to me babble, If I don't make sence, lemme know.

 peace out.

 -Gross



 It looks like Parts Express has some 6.2uf Dayton metallized polypropylene capacitors which seem to be a good compromise of physical size and price. Any thoughts good or bad? http://www.partsexpress.com/pe/pshow...Number=027-427


----------



## jornterpstra

Ok so the smd soldering didn't go as planned
	

	
	
		
		

		
		
	


	



 i need some thinner solder i think, anyway i messed up on some spots, like the spot for R32/C32 and pin 4 at the 102UA. and probably the 2702, but think i can fix those on the 2702...
 so, pin4 on 102ua and the r32/c32 are bridged as you can see in the pic i attached. Tried desolder braid, but that didnt work at all this time.
 any suggestions on how to fix this? or is the board fubar now?






 thanks.

 (have parts for 1 more luckily 
	

	
	
		
		

		
		
	


	




 )


----------



## FallenAngel

Try the flood and suck technique:

 Put a length of solder across the entire PCM chip, then (not too quickly) run a hot iron over it so it looks like a huge amount of solder covers all the pins and solder pands. Put a length of desoldering braid over the pins and heat it up just like you did with the solder, run the iron slowly from one side to the other.

 I noticed that this works quite well, and that desoldering braid works much better if there is a lot of solder there.


----------



## whiz

i burned my dac once again! 
	

	
	
		
		

		
			

















 (check page 28 on this thread)

 How did it happen? 
 I had an RCA to RCA cable...and i cutted the one end so i can have RCA to naked cables so i can connect my alien dac to an amp!
 when i disconnected the cable from the amp...the naked end bridged itself
 so i burned one of the outputs! 
	

	
	
		
		

		
		
	


	




 the chip goes very hot! but it still works...


----------



## Gross

I would also suggest removing the capacitors (or next time doing them last) as it will be much easier to get your iron in to solder the small SMD stuff.


  Quote:


  Originally Posted by *jornterpstra* /img/forum/go_quote.gif 
_Ok so the smd soldering didn't go as planned
	

	
	
		
		

		
		
	


	



 i need some thinner solder i think, anyway i messed up on some spots, like the spot for R32/C32 and pin 4 at the 102UA. and probably the 2702, but think i can fix those on the 2702...
 so, pin4 on 102ua and the r32/c32 are bridged as you can see in the pic i attached. Tried desolder braid, but that didnt work at all this time.
 any suggestions on how to fix this? or is the board fubar now?






 thanks.

 (have parts for 1 more luckily 
	

	
	
		
		

		
		
	


	




 )_


----------



## sbyers77

Quote:


  Originally Posted by *jornterpstra* /img/forum/go_quote.gif 
_Ok so the smd soldering didn't go as planned
	

	
	
		
		

		
		
	


	



 i need some thinner solder i think, anyway i messed up on some spots, like the spot for R32/C32 and pin 4 at the 102UA. and probably the 2702, but think i can fix those on the 2702...
 so, pin4 on 102ua and the r32/c32 are bridged as you can see in the pic i attached. Tried desolder braid, but that didnt work at all this time.
 any suggestions on how to fix this? or is the board fubar now?


 thanks.

 (have parts for 1 more luckily 
	

	
	
		
		

		
		
	


	




 )_

 

Whats the wattage on your iron and are you using flux? Alot of those pads look like they have a cold-solder joint going on (judging by the C2 and voltage regulator pads). Apply some flux and make sure your iron is hot enough to completely melt the solder. I see you are from the Netherlands, so double check your solder type, it might be a no-lead variety that has a higher melting temperature than conventional lead based solders.


----------



## jornterpstra

Ok, cleaned all the bridges on the pcm2702, that one is fine now as far as i could see.
 Just got that mess on the 102ua and the spot for the resistor left. both are probably connected to the copper of the pcb. 
 The leg on the 102ua thats connected to the copper is the GND leg, does that even matter ?

 as for the resistor to the copper, doubt i can fix that
	

	
	
		
		

		
		
	


	



 Maybe i'm better of removing the regulator ? and make it an usb unregulated one.


----------



## Seaside

Quote:


  Originally Posted by *jornterpstra* /img/forum/go_quote.gif 
_Ok, cleaned all the bridges on the pcm2702, that one is fine now as far as i could see.
 Just got that mess on the 102ua and the spot for the resistor left. both are probably connected to the copper of the pcb. 
 The leg on the 102ua thats connected to the copper is the GND leg, does that even matter ?

 as for the resistor to the copper, doubt i can fix that
	

	
	
		
		

		
		
	


	



 Maybe i'm better of removing the regulator ? and make it an usb unregulated one._

 

Your PCB looks alright. 
 Only thing you need to do is clean excessive solders off from it.
 Cleaning 102ua would be way easier than cleaning 2702.
 What you need is desoldering braid, follow what FallenAngel said at that chip too. It is fairly easy to clean those mess off. Double Triple check on all soldering point, makes sure you don't have any cold joint. After that, make sure you clean the PCB so that there is no flux on it.


----------



## FallenAngel

Hey guys,

 I've been using BlackGate NX HiQ series caps in all my AlienDACs and they sound great, but I'm just wandering how much better they could sound with some other film caps. Of course, within reason, for a DAC which costs about $50 to build, I don't really want to put a pair of $20 caps.

 Basically, wandering if anybody has used simple the cheap caps like MKP/MKS series caps or perhaps some boutiques like Mundorf / AuriCap / MultiCap (the cheaper PPMFX series or more expensive types). Maybe some NOS Sprague Vitamin Q?

 Also, how low can I reasonably go in terms of capacitance here? 1uF?


----------



## error401

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Hey guys,
 Basically, wandering if anybody has used simple the cheap caps like MKP/MKS series caps or perhaps some boutiques like Mundorf / AuriCap / MultiCap (the cheaper PPMFX series or more expensive types). Maybe some NOS Sprague Vitamin Q?

 Also, how low can I reasonably go in terms of capacitance here? 1uF?_

 

I'm not too sure why Alf specifies such a high capacitance here, probably because he doesn't have room on the board for decent film caps and if you're going to put in 'lytics, may as well go for the higher value. As far as I can tell there's no other reason to use quite such a high value - the DAC chip isn't powerful enough to power low impedance loads like headphones, and with high impedance loads the filter response isn't too horrible with just 1uF there (-3dB at about 16Hz with 10k load, around 3Hz with 50k load).

 You might want to go up to 4.7uF but even 1uF is probably fine for most applications. Personally I've been omitting CL/CR and R14/R15 and instead relying on the higher quality film caps in my amps. I don't have easy access to boutique electrolytics and I trust that the capacitors in the amps are better matched since the resistance component of the filter is known, rather than in a source where you need to account for all possibilities.

 I've put some Panasonic ECG 0.47uF after an AlienDAC in my latest project (not done yet, mind) and I expect it to have good bass extension, the -3dB should be around 4Hz if I remember my simulations correctly.


----------



## FallenAngel

Thanks error401

 I'll probably try a couple of 1uF Sprague Vitamin Q's there 
	

	
	
		
		

		
		
	


	




 Oh, and if you need access to boutique electrolytics, check out www.partsconnexion.com, Head-Fi sponsor located in Ontario, expedited shipping to you should be pretty cheap and their prices are great.


----------



## Gross

Well, My post just 10 above this one explains that a 1uf output cap feeding into a crossfeed does not work. I would go minimum 4.7, and if you can go larger, that is even better.


----------



## AndrewFischer

I've been listening to my just completed second Alien DAC. 

 Burn in setup is Dell Precsion 380/ iTunes 7 / Alien DAC / PPA V1 / Senn 580s with HD 650 cable.

 It sounds darn good, even with Elna RFS electrolytic caps in CR/CL. Way better than the Audigy in this computer. I'll be changing to film caps with my next parts order.
 I cooked the 2702 on the first one. I'll get around to fixing it eventually. 


 Thank you Burr-Brown Japan and [size=large]Thank you Alf.[/size]


----------



## Ikarios

I really want to get started in my AlienDAC, but there are a few questions that are stopping me from ordering.

 1) What is everyone getting for CL/CR from Mouser? The two caps that I wanted (BlackGates, Nichicon KZ) aren't available.
 2) Is there a reason everyone uses RCA jacks? I want to use this as a portable DAC, so I'm assuming a mini jack would work as well?
 3) Is there a place that has either the BlackGate and the REG101UA-A together, or the BlackGates and the Hammond 1455c Black case together? Out of curiosity... I can't seem to get a suitable single-vendor order from Digikey or Mouser.


----------



## Yen

Quote:


  Originally Posted by *Aflac* /img/forum/go_quote.gif 
_I really want to get started in my AlienDAC, but there are a few questions that are stopping me from ordering.

 1) What is everyone getting for CL/CR from Mouser? The two caps that I wanted (BlackGates, Nichicon KZ) aren't available.
 2) Is there a reason everyone uses RCA jacks? I want to use this as a portable DAC, so I'm assuming a mini jack would work as well?
 3) Is there a place that has either the BlackGate and the REG101UA-A together, or the BlackGates and the Hammond 1455c Black case together? Out of curiosity... I can't seem to get a suitable single-vendor order from Digikey or Mouser._

 

1. Digikey has Elna RFS, which is (I think) SilmicII series. Silmic II is one of the recommended by Support website, just as Blackgates and Nichicon Muse.

 2. You can use any jack you want. Mini is just as ok as rca.

 3. Digikey, with Elna SilmicII.


----------



## Jrossel

Quote:


  Originally Posted by *Gross* /img/forum/go_quote.gif 
_
 Since the resistance of the crossfeed is going to be somwhere in between 1k-2k, If I did my rough calculations correct, seeing a 2k load, a 1uf capacitor will form a highpass crossover at 80hz, which correspond exactly with what I am hearing. A 4.7uf should get me down to 17hz, so I guess I am off to see what polypro cap I can find in a 4.7uf value.
_

 

Thanks for explaining this Gross. I am trying to spec out a really nice coupling cap for a kit that I am going to provide. I figure I will have Black Gate NX for the regular kit and 4.7uF Auricaps by Audience in the high end kit. 

 JR


----------



## AndrewFischer

Quote:


  Originally Posted by *Aflac* /img/forum/go_quote.gif 
_3) Is there a place that has either the BlackGate and the REG101UA-A together, or the BlackGates and the Hammond 1455c Black case together? Out of curiosity... I can't seem to get a suitable single-vendor order from Digikey or Mouser._

 

Not that I'm aware of. If you want Black Gates you will have to get them from a specialty vendor.

 I split my order between Mouser and Digikey. If you are building at least two, you can reach the minimum order value at both vendors. I posted my BOM, with Mouser / Digikey partnumbers somewhere in this thread. Shoot me a PM if you can't find it and want a copy.

 Mouser doesn't stock the Burr-Brown chip. Digikey does. If you are going to use a single vendor, I'd try Digikey.

 I built mine with the Elna RFS caps. RFS is Silmic II. That's Elna's best audio electrolytic. Not bad sounding at all.


----------



## pddjsteve

I'm also very happy with the Elna Silmic II from digikey.


----------



## MisterX

Quote:


  Originally Posted by *pddjsteve* /img/forum/go_quote.gif 
_I'm also very happy with the Elna Silmic II from digikey._

 

Me to... in fact I preferred them over the Black Gates NX caps. 
 However the Black Gates FK series are another matter.


----------



## Whitebread

Guys, is it still possible to get boards for this DAC?


----------



## AndrewFischer

The final group buy is over. Alf said he will not be doing another. Someone here may have a spare board they are not going to use. Both of mine are built up. 

 You could have short run of boards made. I don't know if Alf will give out his gerber files for free.


----------



## Whitebread

Well, I don't need any more than one board and I figure getting one made would cost a pretty penney. I will look around here and see if anyone has a spare board, but I think going with a different DIY kit would be a better idea.


----------



## AndrewFischer

Quote:


  Originally Posted by *Whitebread* /img/forum/go_quote.gif 
_Well, I don't need any more than one board and I figure getting one made would cost a pretty penney. I will look around here and see if anyone has a spare board, but I think going with a different DIY kit would be a better idea._

 

BatchPCB charges $10 + $2.50/sq. inch. This is a tiny board. have to double check that this meets their design rules.


----------



## Whitebread

O, thats nothing, if I cna get the drawings for the PCB, then I'll just go ahead with this.


----------



## splaz

PM Alf, he seems like a nice enough guy doing all those group buys for us. 
	

	
	
		
		

		
		
	


	




 If he won't just give them out maybe ask if he'll submit them for you and you'll make it worth his while.


----------



## FallenAngel

Just a sanity check here:

 With the CL/CR values recommended so high and a little enlightenment recently, I'm thinking of putting the pair of 0.33uF Mundorf MCap ZN caps that I have lying around as the output caps of this thing. All of my home based amps are using either 50K or 100K Alps Blue pots, only a couple of portables use 10K pots so I'll use the 50K value.

 That would make the corner frequency formula at

 f = 1/(2 * π * 50000 * 0.00000033) = 9.6Hz

 If there's nothing wrong with that calculation, I'm on the way to making a new AlienDac for myself


----------



## Gross

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Just a sanity check here:

 With the CL/CR values recommended so high and a little enlightenment recently, I'm thinking of putting the pair of 0.33uF Mundorf MCap ZN caps that I have lying around as the output caps of this thing. All of my home based amps are using either 50K or 100K Alps Blue pots, only a couple of portables use 10K pots so I'll use the 50K value.

 That would make the corner frequency formula at

 f = 1/(2 * π * 50000 * 0.00000033) = 9.6Hz

 If there's nothing wrong with that calculation, I'm on the way to making a new AlienDac for myself 
	

	
	
		
		

		
		
	


	


_

 

That works with my math. Just remember that though when you use it with your portable and wonder why there is nothing below 50hz


----------



## AndrewFischer

I've had a couple of PM requests for my BOM
 It is very close to what others posted in this thread. I made a few changes.

 I used an Alternate part for C1. Its on the BOM. 


 Not on the BOM are the Elna RFS-25V220ME3 caps I used for CR and CL. Digikey part number is 604-1051. They are really not bad, but output caps are a hot topic. I'm sure many people just won't be satisfied with a nine cent part.

 C13,23,33 are are 330µF Panasonic FM. Maybe Elna RFS would sound better here. You'd have to live with 22µF though. If I was building a third DAC, I'd give them a try on the Analog side of the DAC.

 I recommend getting extras of all the 0805 parts.


----------



## splaz

Quote:


  Originally Posted by *AndrewFischer* /img/forum/go_quote.gif 
_I recommend getting extras of all the 0805 parts._

 

or don't drop them on the floor....


----------



## FallenAngel

Well, it seems those output cap values are definitely a little higher than necessary. I'm now using 0.33uF Mundorf MCap ZN's in mine and it sounds fabulous. Pics in the signature


----------



## Yen

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Well, it seems those output cap values are definitely a little higher than necessary. I'm now using 0.33uF Mundorf MCap ZN's in mine and it sounds fabulous. Pics in the signature 
	

	
	
		
		

		
		
	


	


_

 

Umm, can you compare with electrolytics?


----------



## FallenAngel

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_Umm, can you compare with electrolytics?_

 

Not really, lets just say that even though the BlackGate NX-HiQ sound nice and warm, there really is no comparison in quality. These blow them out of the water.


----------



## Ikarios

Is it possible to get film caps to fit in the 1455C case? Film caps are great and all, but I don't think it's worth making the entire DAC bigger (not to mention the added shipping+handling cost... grumble grumble)


----------



## FallenAngel

You can definitely fit *some* boutique film caps into the default 1455C802 enclosure, but with the RCA's on the back, it'll be a tight squeeze for most caps of any reasonable capacitance. I'm pretty sure you could squeeze a pair of these Mundorf MCap ZN 0.33uF, maybe even the 0.47, but not much more so you'll need a high impedance pot to not have much bass roll-off. You definitely won't have any problems fitting in smaller non-boutique caps like Wima MKP's though, that should be nice on the lower priced side.


----------



## AndrewFischer

Quote:


  Originally Posted by *Aflac* /img/forum/go_quote.gif 
_Is it possible to get film caps to fit in the 1455C case?_

 

There are many *metalized* film caps that will fit. Polypropylene and foil is going to be a lot closer.

 I've done some measuring for SBE 716P caps. If I can find some, the 100V .33µF would fit in the 1455C801 case easy.
 There are some good candidates in the 200V range too.

 But AES and Angela start at 400V. The best candiate they stock is .47µF 400V.

 That cap is 1.65"x.68"x1.07" and is not going to fit in the 1455C801.
 It should fit in the 1455C1201.


----------



## Jrossel

Quote:


  Originally Posted by *Whitebread* /img/forum/go_quote.gif 
_Guys, is it still possible to get boards for this DAC?_

 

I talked to ALf about taking over the production and distribution of the boards and we have made an agreement to keep this project going. I have a batch of PC boards on order and will also provide a kit to build the DAC as well.

 More detail coming soon.

 JR


----------



## Gross

Glad to hear. It is a fun project with excellent results.


----------



## tomb

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_I talked to ALf about taking over the production and distribution of the boards and we have made an agreement to keep this project going. I have a batch of PC boards on order and will also provide a kit to build the DAC as well.

 More detail coming soon.

 JR_

 

Wow - that's great news!


----------



## MASantos

Great news. For those who don't know, Jrossel is also selling Betta 22 and sigma22 kits. I have not bought from him, but other have and from waht I read his kits are great! I look forward for this Jrossel.

 Manuel


----------



## Yen

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_More detail coming soon.

 JR_

 

Do you sell PCBs only?


----------



## Gross

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_Great news. For those who don't know, Jrossel is also selling Betta 22 and sigma22 kits. I have not bought from him, but other have and from waht I read his kits are great! I look forward for this Jrossel.

 Manuel_

 

I didnt realize it until now, but I have his site bookmarked, $56 seems hard to beat for a SOHA.


----------



## FallenAngel

Quote:


  Originally Posted by *Gross* /img/forum/go_quote.gif 
_I didnt realize it until now, but I have his site bookmarked, $56 seems hard to beat for a SOHA._

 

Yep, does look like a pretty nice kit, could improve upon a few things (I mentioned this earlier in another thread), mainly change the voltage regs to TO220 package vs TO92, and definitely change the Opamp to an OPA2107 (very very nice) and you're good. The only other thing is, the kit doesn't include the expensive stuff like the transformer, POT, enclosure or any of the casing things.


----------



## Yen

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Yep, does look like a pretty nice kit, could improve upon a few things (I mentioned this earlier in another thread), mainly change the voltage regs to TO220 package vs TO92, and definitely change the Opamp to an OPA2107 (very very nice) and you're good. The only other thing is, the kit doesn't include the expensive stuff like the transformer, POT, enclosure or any of the casing things._

 

His new site, glassjaraudio.com, has a complete SOHA kit, with Hammond enclosure, toroid, tube, Alps RK27... everything. For 91,5 bucks!!! That's ridiculous... 

 That's Level 1 kit, so he might be making different kits with better parts for higher levels.

 I bought my parts here in Finland and it cost well over 120 euros without any decent parts nor enclosure.


----------



## tomb

Yeah, I'm beginning to think the DIY Headphone Amp community has acquired a major benefactor.
	

	
	
		
		

		
			





 I don't understand how he can do it at those prices, either. IMHO, there's nothing to criticize with JRossel's offerings. Even if you bought one of his kits, then went out and purchased some boutique parts to swap out - you'd still be way ahead.

 The only way to beat it may be to order in 4's or 8's, but that's been killing me financially, and I haven't even tried to sell anything yet.


----------



## pddjsteve

Crap. After makiing 2 perfect ones, I screwed up another one I think. I'm not getting any voltage on the 3.3V test point. 
	

	
	
		
		

		
		
	


	




 I wanted one for work.


----------



## FallenAngel

Are you getting the 5V voltage ok?
 Double check that your regulators aren't flipped, I know one of mine was and was constantly overheating.


----------



## pddjsteve

No, they're in the right position. There is another thing I need to try once I get back from work, maybe I'll have a work DAC after all (it is such a pain to bring the dac and the pimeta back and forth 
	

	
	
		
		

		
		
	


	




 )


----------



## t52

could also be a short to ground of the 3.3v rail, check your pcm2702 for solder bridges...


----------



## ko_dez

Hi people.

 I would like to improve the sound from my computer, and this looks real promising. I have a DIY class-D amplifier (using Hypex modules), and would like balanced outputs. I realize that this could probably be added using a couple of opamps on each output.

 My second choice is running with what you have here, and connect the negative signal to ground at the sound-card end. That should give me some advantage over non-balanced outputs if i understand correctly.

 The question really is, if adding balanced outputs, what would need to be done? Would it seriously impair the sound quality (using decent op-amps of course)? Would I get the same noise dampening features by just soldering - to gnd in the connector?

 My problem is that there are quite a lot of noisy stuff close to my signal cable, and using a balanced cable has really improved the noise situation.

 A last couple of question:
 Does the circuit make noise when connected/disconnected from USB/power? I am hoping to be able to keep my amp powered at all times, and I am not using a preamp eighter.
 I would believe that lowering the volume from the card would be done digitally, effectively reducing the resolution of the signal when not running at 100% (50% would be 15bit, 12.5% = 13bit and so on). Is that the case, or is it really reduced analogly? If not, I want to also add a manual level attenuator so that I can run it at 100% all the time.

 Thanks
 -Ko_deZ-


----------



## Jrossel

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Yep, does look like a pretty nice kit, could improve upon a few things (I mentioned this earlier in another thread), mainly change the voltage regs to TO220 package vs TO92, and definitely change the Opamp to an OPA2107 (very very nice) and you're good. The only other thing is, the kit doesn't include the expensive stuff like the transformer, POT, enclosure or any of the casing things._

 

Hello, I really need to read all these threads more often. I will incorporate those changes into the kit. Is the 2107 a direct drop in, or are there any changes that need to be incorporated? I originally bought parts from a much earlier BOM, so I have some parts that are from an earlier design. For instance, I have a bunch of Triad split bobbin transformers gathering dust. (-: Note to self: package up those paper weights to return to Mouser... 

 But I do offer a *complete* kit, and my kit is flexible and dynamic as I get more options added. You can check up on the kits here: http://www.geocities.com/jeffrossel/ . Also I have a standard kit listed at my website: www.glassjaraudio.com

 Contact me from one of those sites for further information. w

 I have been busy shopping for JAN NOS 5963 tubes along with some triple mica 6189 black plate tubes to offer, and will be testing them and listing them as options. I also found some side getters RCAs, so I will be able to feed people's addiction to rolling tubes. I'm starting to feel like a pusher here... 

 Talk to you later


----------



## Jrossel

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_Do you sell PCBs only?_

 

I will provide boards alone or included within the kit. The boards will probably be less costly than the last group buy (barring any large changes in the Euro to Dollar exchange rates). Hopefully the PC board fabricator will make them with the same process as the last time. They should ship in mid March. I ordered a lot of them, so we should be covered for a few months...

 JR


----------



## lordvader

Will you be offering a parts only kit also ?

 I bought pcbs a while back, but sourcing components is a pain here in Australia (I don't like the idea of paying $50 postage for a $12 part !).


----------



## splaz

$50 postage ?

 For about $250 worth of parts I paid $30 shipping.

 Although yes, if you're getting only a handful of stuff shipping can be pretty expensive.That's when you make a post here and hope someone helps you out, as you have done.


----------



## lordvader

Where did you order from ?

 I'm keeping an eye out for some PCM2702's, but both digikey and mouser are fairly expensive when it comes to shipping. They use either fedex or UPS, which aren't really useful when ordering tiny smd devices from overseas


----------



## splaz

From digikey, although yes I wouldn't order off them for only a few parts. Like I had most of the components for the PINT except a few I couldn't source here, so I tacked on those few onto my Alien DAC order.

 Like right now I need some low esr caps and so I'll add them on to the next order I make when a project comes up.


----------



## FallenAngel

Hey, just a quick question guys, what exactly is the purpose of the 2 330K resistors between the output of the output caps and ground and why was this value chosen?

 Mainly wandering because I changed the values from suggested quite a bit and was curious if these resistors should also change.

 Thanks


----------



## GarlicKnots

Darn,

 getting like .8 v @ the 3.3 and .9v at the 5 v test point and IC - 1 is gets really hot.

 Is IC 1 fried already? 

 I have these two multimeters:

dm-50

 and

sperry 10-a

 I understand that the pins are closed when the resistance is 0, and open when it is at infinity. However, which ohm level should I test the pins at?

 Thanks,


----------



## FallenAngel

Garlic, pics buddy, it'll help. Basically, is your regulator backwards?


----------



## GarlicKnots

Goodness, I suck. You rock.

 IC 1 *is* backwards.

 Is the chip dead or if I desolder/resolder do I have a chance?

 Crap almighty, I honestly went pin by pin on IC 1 laboriously but now, it seems, to no avail. 

 Jeez,

 Thanks though.


----------



## FallenAngel

No worries, I did the same thing to one of mine as well, you can desolder that thing and put it back on without problems. Just don't overheat for too long.


----------



## achina

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Hey, just a quick question guys, what exactly is the purpose of the 2 330K resistors between the output of the output caps and ground and why was this value chosen?_

 

http://www.head-fi.org/forums/showpo...&postcount=169

 I don't know how a different value would affect it though. I suspect using lower values would be worse.


----------



## Calroth

Quote:


  Originally Posted by *Calroth* /img/forum/go_quote.gif 
_I have performed RightMark Audio Analyzer testing on my Alien DAC..._

 

I re-did the tests; here are the results. The test methodology is the same as last time: took a PC and sent its on-board Realtek ALC850, Alien DAC and Chaintech AV-710 high-quality output to a MacBook Pro.

 Changes are:
input device is now an M-Audio FireWire Audiophile; much more accurate
got rid of the Sound Blaster USB
added a baseline: the FireWire Audiophile is the "loopback" device
you can now download the results file for your personal gratification! Click the "download" link
As before, any questions, post and I'll follow up. Also, other people's experiences are welcome, as there are quite a few "So, how good is the Alien DAC anyway?"-type posts.


----------



## AndrewFischer

Thanks for taking the time to redo the measurements.


----------



## GarlicKnots

Ok. Unfortunately more problems on my last build.

 I am getting 3.3 and 4.72.

 When I connect it to my computer it says something akin to "USB device not recognized...one of the usb devices has malfunctioned..etc."

 What should I look for?

 Any other readings I should take?


----------



## splaz

The USB pins on the schematic. With mine, pin ahhh... 2 or 3 I think was open. Cleaned that joint up and it was recognised.

 Then next problem was my right output was fried... 
	

	
	
		
		

		
			





 I'd check pins 2 through to 9 thoroughly, also probably 1 and 28 as I don't think it would operate correctly without a clock.


----------



## Sinbios

Gah, I still have two boards waiting to be built >_<

 Quick question, what happens if Vin is below Vout for the regulator? Does it work in pass through mode, shut down completely, or actually add noise?


----------



## Sinbios

Also, quick question: is it OK if I replace REG101 with REG103, and use a 12V PSU?


----------



## amb

Quote:


  Originally Posted by *Sinbios* /img/forum/go_quote.gif 
_Quick question, what happens if Vin is below Vout for the regulator? Does it work in pass through mode, shut down completely, or actually add noise?_

 

It would drop out of regulation and work as a "pass through", down to a certain threshold voltage, then it would probably just shut down below that.


----------



## scratch.music

I'm building the Alien DAC as part of a headphone amp that I am building for a project and can't find any place that has the adjustable voltage regulators in stock. I just recently picked up a PCB off a forum member that had an extra, looks like all the distributors are sold out. Either REG101UA or REG102UA I checked: Digikey, Mouser, Arrow, Newark and Avnet, which are all the distributors listed for Michigan (I'm an MSU student) on TI's website. My complete project needs to be done in a month, does anyone have any spare regulators, knows of a place I can order them online or any alternatives that would work?
 Also, if you have other spare parts required to build the DAC I could take them off your hands. The only part I have so far is the PCM2702 and plan on ordering the rest along with parts for my headphone amp this week. I can pay with paypal.
 Thanks,


----------



## MisterX

Quote:


 does anyone have any spare regulators, knows of a place I can order them online or any alternatives that would work? 
 

Sure. 
 Pm me your address info and I will drop one in the mail in the morning.


----------



## AngryGuy

So, I want to make one of these but it appears I'm a bit late to the party. Is anyone still selling all the parts needed for it, or a kit or something?


----------



## error401

Quote:


  Originally Posted by *AngryGuy* /img/forum/go_quote.gif 
_So, I want to make one of these but it appears I'm a bit late to the party. Is anyone still selling all the parts needed for it, or a kit or something?_

 

HeadFier jrossel has apparently gotten permission from amb to provide kits and raw PCBs for this project. We should see these kits and boards appear fairly soon, from what he's said. Maybe send him a PM and see how his progress is going?

 He has a website at http://glassjaraudio.com/ with his other kits. They're apparently well regarded.


----------



## amb

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_HeadFier jrossel has apparently gotten permission from amb to provide kits and raw PCBs for this project._

 

Not me, but it was alf. Apparently jrossel is getting pcbs manufactured so hopefully they will be available again soon.


----------



## error401

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_Not me, but it was alf. Apparently jrossel is getting pcbs manufactured so hopefully they will be available again soon._

 

Ooops! So sorry Alf, I knew it was a 3-letter name starting with a, and yours came to mind.


----------



## GarlicKnots

Well guys, my alien dac debacle continues. I need some help troubleshooting. I added some pictures.

 Here is where I am now:

 1) I get 3.3
 2) I get 4.72 (where I have the adjustable reg at)
 3) Installed ASIO driver, etc.

 When I connect the DAC to a computer I get the error:
  Quote:


 USB device not recognized

 One of the USB devices attached to this computer has malfunctioned and Windows does not recognize it...

 

I've tried this on my computer and my brother's computer with the same error.

 I have two meters, I have tested continuity with both of them and there doesn't seem to be continuity. I will admit I'm a bit unsure on how to test continuity since it seems too easy. I've checked with a 15x microscope also.

 Here are some pictures. I socketed c2 to make it easier to work on IC1.

 I believe (hope) that I'm missing something very simple. Suggestions?

 I don't take pictures well, and my camera's zoom isn't too good so I couldn't get closer pictures.


----------



## AndrewFischer

You may have some solder bridges on the dac chip. 

 Looks like pins 27 and 28 may be bridged. Maybe 25 and 24. hard to tell from the photo. You could try some flux and solderwick and try and pick up some of the extra solder.

 I'd also check all the pins are connected. I had to reflow solder on both of mine. If all else fails, remove the 2702 and try again. I used 3 chips to make two working DACs.


----------



## GarlicKnots

Quote:


 You may have some solder bridges on the dac chip.

 Looks like pins 27 and 28 may be bridged. Maybe 25 and 24. hard to tell from the photo. You could try some flux and solderwick and try and pick up some of the extra solder.

 I'd also check all the pins are connected. I had to reflow solder on both of mine. If all else fails, remove the 2702 and try again. I used 3 chips to make two working DACs. 
 

Both 27/28 are bridged. They both go to ground. I also bridged 13/14 since they go to ground. That is OK, I believe?

 If 25/24 were bridged would I still get the correct 4.7 reading @ the 5V pad?

 You are correct, some pins may not be connected. I'm going to reflow 10/11 and 1 and 15.

 Q. If I'm getting 3.3 and 4.7, should I refrain from touching 2-9 and 16-26?


----------



## AndrewFischer

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_Both 27/28 are bridged. They both go to ground. I also bridged 13/14 since they go to ground. That is OK, I believe?
_

 

nope.

http://focus.ti.com/lit/ds/symlink/pcm2702.pdf

 Pinout is on page 3

 28 goes to the crystal.
 27 is VccP

 Its hard to tell from the photos but it looks like those might be bridged. If they are you could get that error message. If you have access to an oscilloscope you can check if the crystal is oscillating. 

 25 is VccL 24 is AGNDL -- Yeah if those were bridged, you wouldn't have a working +5V supply. My bad.


----------



## splaz

Quote:


  Originally Posted by *GarlicKnots* /img/forum/go_quote.gif 
_Q. If I'm getting 3.3 and 4.7, should I refrain from touching 2-9 and 16-26?_

 


 I was getting the right voltage on the regs but it was either pin 2 or 3 that was open and I had that exact same problem as you. In fact you should get the right voltages with or without the chip installed, so just because they're right, doesn't mean they're actually connected to the chip. Unless you mean you're measuring the voltage on each pin as what it should be, in which case there shouldn't be a need to do anything to those pins.


----------



## GarlicKnots

Quote:


  Originally Posted by *AndrewFischer* /img/forum/go_quote.gif 
_nope.

http://focus.ti.com/lit/ds/symlink/pcm2702.pdf

 Pinout is on page 3

 28 goes to the crystal.
 27 is VccP

 Its hard to tell from the photos but it looks like those might be bridged. If they are you could get that error message. If you have access to an oscilloscope you can check if the crystal is oscillating. 

 25 is VccL 24 is AGNDL -- Yeah if those were bridged, you wouldn't have a working +5V supply. My bad._

 

Andrew, you're correct, my number configuration was incorrect. I thought the pin across from pin 1 was pin 15, it's pin 28.

 I'm bridging 13/14 and 15/16 by the correct pin out diagram. Those go to ground.

 I did some more resoldering, etc.

 I plugged it in and it actually recognized it at first as USB speaker, burr brown, etc.

 The 3.3 rail was correct.

 However the 5v rail was registering .1.

 I unplugged, replugged and this time it didn't recognize.

 More soldering, eh? Hopefully, I didn't burn the chip.

 f/R


----------



## SnoopyRocks

I finally got around to populating two of my boards from the 2nd group buy today after free time suddently manifest. 
	

	
	
		
		

		
			





 Both work great, though one malfunctioned due to some solder bridges on the 2702 and a mistake soldering the oscilator connections. 

 I'd like to case them up with some existing amplifiers now, but I don't have panel space to put the PCB against it. 

 Can someone please direct me to a panel mount usb jack?

 ---------
 When I was debugging the 'bad' board, windows also gave me a malfunctioning usb device error. I suggest that you measure the voltage of the two pins at closest to the crystal. They should be about 1.5V each. If they are not, the the 2702 will not function properly because its clock is malfunctioning. R14/C11/C12 on the bottom side also need to be checked. This was how I figured out what the problem was - a bad solder joint on the bottom side of the board. I hope that this helps.


----------



## dakotart1984

Snoopy: Mouser part# 568-NAUSB-B Neutrik quality there, and they also have it in silver 

 And what BOM did you go by


----------



## MisterX

Another option for USB panel mounted receptacles is l-com

http://www.l-com.com/item.aspx?id=4758

 They also sell pretty nice RCA jacks.


----------



## tomb

You guys are great. I was wondering if anyone had tried remote mounting for the USB jack. Any noise problems or lead length issues?


----------



## Jrossel

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Ooops! So sorry Alf, I knew it was a 3-letter name starting with a, and yours came to mind._

 

Yes, I had boards made with Alf's help. They are now ready along with my kit.

 BOM and email address can be seen here:

http://www.geocities.com/jeffrossel/

 I will try to get in touch with all the people who contacted me, but if I miss you please Email me.


----------



## splaz

Reading the list of parts I see at the bottom it has an option for bare boards, no price though. This a yet to be added option ?


----------



## Jrossel

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_Reading the list of parts I see at the bottom it has an option for bare boards, no price though. This a yet to be added option ?_

 

The price for bare boards is 2.00 each (close to my cost), which is less than the previous group buy due to my not having to pay VAT.

 JR


----------



## AndrewFischer

Looks like a good BOM and a great price on the boards.


----------



## threepointone

[nvm first part]

 The windows does not recognize this device errors--try checking continuity between the USB pins. One of my DACs had that shorted, and Windows couldn't ever detect it properly. I found out that the short was likely under the PCM2702 somewhere, and honestly I just gave up on that DAC. If you're lucky, your problem is somewhere obvious; otherwise, you've got quite a bit of desoldering to do =(


----------



## SnoopyRocks

Quote:


  Originally Posted by *dakotart1984* /img/forum/go_quote.gif 
_Snoopy: Mouser part# 568-NAUSB-B Neutrik quality there, and they also have it in silver 

 And what BOM did you go by_

 

On order. 
	

	
	
		
		

		
		
	


	




 I used this one (see attached). There are a few items not listed because I already had them (usb jacks & output DC blocking caps).

 ------------------------------
 I found another panel mount usb option: http://www.datapro.net/products/1591.html

 -------------------------------
 Mr X:

 Is this the high quality rca jack that you referred to?

http://www.l-com.com/item.aspx?id=1008

 As far as I can tell, it is just a single jack and they don't seem to offer different color choices (red/white/black). Is this correct or am I not looking hard enough?


----------



## MisterX

Quote:


 Is this correct or am I not looking hard enough? 
 

Correct, they only sell them individually and they only offer them with a red stripe.


----------



## splaz

^ Ouch those are expensive. I can get the same thing here for about $3AU in black or red.

http://www.altronics.com.au/index.as...=item&id=P0220


----------



## Seaside

spalz, That RCA socket surely looks nice.
 And how much is $3AU in $US?


----------



## splaz

Well normally it's about 75:100

 Current exchange is around 80:100

 Anyway, at the current exchange they're about $2.30US each, based on the actual price of $2.90AU and they look exactly the same to my eyes as what Mister X posted.

 They are pretty nice, I use them because they're the only easily sourced isolated RCA sockets I can find.


----------



## Gross

I have used these  and am happy with them.


----------



## spongezone

I just finished one of my two Alien boards, and I have to say, I had no idea what I was missing. It sounds far better than onboard.

 Unfortunately, it'll be a while until I get around to finishing the second one. I'm a few SMD components short of a complete set, and it's not worth paying $7 shipping on 5 cents of parts. 
	

	
	
		
		

		
			





 Next up is building a single enclosure for my MINT, Alien, and TREAD...


----------



## achina

Quote:


  Originally Posted by *spongezone* /img/forum/go_quote.gif 
_Unfortunately, it'll be a while until I get around to finishing the second one. I'm a few SMD components short of a complete set, and it's not worth paying $7 shipping on 5 cents of parts. 
	

	
	
		
		

		
		
	


	


_

 

What do you need?


----------



## spongezone

A couple 22 ohm resistors and a 100pF capacitor, but I'm just going to put in a Mouser order soon. I need to get stuff for a couple non-audio projects anyway.

 Any ideas on how to get ASIO working in foobar? After installing ASIO4ALL and the ASIO dll for foobar, no ASIO devices are showing up in the output section of foobar's preferences.

 Edit: Nm, figured it out.


----------



## pddjsteve

Made another

 Regulated to 5.4V, powered by 6V TREAD, Panasonic FM caps, Aerovox AFPS output caps. Needs to be cased and have switchable RCA and 1/8" jacks.

 I discovered that my bigger iron was a lot easier to do the 2702 with, it got hotter so the swipe method worked faster (and less bridges, which killed my last attempt). This is going to be for my home desk. I've got two more boards that just have the surface mount chips and nothing else, one is going to be wall powered for work and the other is going to sit around and wait for a use.


----------



## wap32

This was my first diy audio project, i needed a nice soundcard for my laptop and the Alien DAC seemed pretty cool.
 Since the group buy was over I had to make the board myself.
 Surprisingly everything went well(after one failed PCB), and the DAC sounds good. 
	

	
	
		
		

		
		
	


	




 Pics of the build here.


----------



## achina

WOW! I can't believe you managed to etch that double sided at home. That's awesome.


----------



## Calroth

Question about the virtual ground option.

 I'm hooking an Alien DAC up to a PIMETA. So I'm wiring up AV+, AV- and AG.

 AV+ and AV- is fine. But I'm confused with AG. On the PIMETA, that's connected to input ground, which is connected to the Alien DAC OG. So if I wired that, then I would be effectively connecting AG to OG (and the rest of the ground plane).

 Is that right, or am I missing something?


----------



## fordgtlover

I spent the past two days putting this DAC together. It mostly went OK, but when I plugged it into the PC I got 3.3V but no 5V.

 After a bit of work with the DMM I found that I have the following voltages on the REG101UA-A:

 Pin Voltage
 8 4.9V
 7 4.9V
 6 4.9V
 5 4.9V
 4 0.0V
 3 58.0mV
 2 33.4mV
 1 33.3mV

 I was expecting 4.75V. My PS voltage is 4.94V.

 Is my regulator broken or is there not enough voltage for it to operate?


----------



## achina

Did you install R31/R32?

 Pins 1/2 are the output pins. Pin 4 is ground. Are you numbering the pins correctly? 5-8 all on one side are tied together and connected to the input voltage.


----------



## fordgtlover

Yes I have 31.6K for R31 and 11.5K for R32 (on top of the board). According to the formula provided, these resistors in combination with the REG101 should give me an output voltage of 4.75V.

 I've double checked the pins and they're all correct according to the datasheet. Curiously though, there seems to be some discrepency between the datasheet and the schematic. The schematic seems to have the pins mirrored. 

 Data Sheet






 Schematic


----------



## splaz

That is exactly the way it should be.

 Doesn't matter if it's mirrored in the schematic as long as everything goes to the right places and it does. Schematic isn't representative of how it is connected physically so it doesn't matter, it would if that was the board layout though.


----------



## achina

Are you sure it's the adjustable version?

 Or maybe R31/R32 are swapped.

 Can you take a picture of it?


----------



## fordgtlover

Fair point, but working between the two had me scratching my head after a few more hours of troubleshooting.

 The previous post questioned whether I had the pins correct. I wrote the initial post after spending many hours staring at the schematic and the DMM. I have double - and triple - checked and I do have 4.9V on the inputs and mV on the outputs.


----------



## fordgtlover

I'll post a photo shortly, but the chip says BB REG 101UA


----------



## splaz

Have you tried it with a slightly higher input voltage ?

 IIRC, input voltage is meant to be something like 300mV higher than Vout.

 Don't quote me on that, I'd look at the datasheet.


----------



## fordgtlover

I tried it on my other computer with PS voltage of 5.14. No joy - similar voltages.

 I'm currently going back through all the joints and checking and redoing them. Nothing so far.


----------



## splaz

Checked that you have R31, R32 and C32 all in the right spots and not mixed them up ?

 Maybe it's stuffed ?


----------



## AndrewFischer

It isn't the input voltage. 


 My guess is you either have a short between +5 and ground (most likely on the 2702) or one of the parts in the regulator isn't soldered. Check for shorts then reflow the solder on the REG101.


----------



## fordgtlover

I've triple checked R31 (bottom of the board, 31.6K), R32 (top of the board, 11.5K) and C32 (bottom of the board).

 I'm thinking maybe it is stuffed
	

	
	
		
		

		
			





 But I'll stay on it for a few more days.


  Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_Checked that you have R31, R32 and C32 all in the right spots and not mixed them up ?

 Maybe it's stuffed ?_

 

I took the REG101 off the board and found the input voltages the same and nothing on the output (as expected). 

 Given that the vast majority of problems here seem to be with the 2702, I am resigned to the fact that this is the most likely cause of my problems. I will plug away for a few more days in the vain hope that I can find the problem with the 2702, but I'm losing faith... fast


----------



## Calroth

x2 on the shorted-to-ground. Check for continuity between the 5v test point and ground. One tiny bridge on the PCM2702 will do that.


----------



## ixalarx

Might some CAD files of the PCB layout be available? I've been looking all over the place for some plans to make a PCB from, but I haven't been able to find anything. If someone could link me to an EAGLE CAD file or something, I'd really appreciate it.


----------



## fordgtlover

Sorted the 5V issue - presumably a solder bridge. 

 I have spent quite a bit of going over the pins on the PCM2702 with desolder braid, which seems to have fixed the 5V but I now am getting an unrecognized device error in Windows. By all accounts this is still most likely a solder bridge on the chip... sigh... I'll continue tonight.


----------



## Calroth

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_I have spent quite a bit of going over the pins on the PCM2702 with desolder braid, which seems to have fixed the 5V but I now am getting an unrecognized device error in Windows. By all accounts this is still most likely a solder bridge on the chip... sigh... I'll continue tonight._

 

Keep at it!

 The 5V side of the chip is the "analog" side; the 3.3V side is the "digital" side. So if there's a problem with the computer recognising the chip, then I'd check the 3.3V side.


----------



## amb

Better late than never... here is mine.
 Now ready to be cased.


----------



## tomb

Good grief, Amb! It looks robotically built - no defects at all, not even a slightly turned resistor here and there.


----------



## amb

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Good grief, Amb! It looks robotically built - no defects at all, not even a slightly turned resistor here and there._

 

Thanks, yeah, I am obsessive when it comes to the little details. Btw, the soldering is all done with a lowly Weller WSC-100 station with a ST-6 tip. Proof that you don't need a mega-buck iron to do a good job. I gotta say, though, working on this board was not kind to my tired eyes, even with 3.0 diopter clip-on glasses...


----------



## AndrewFischer

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_ Btw, the soldering is all done with a lowly Weller WSC-100 station with a ST-6 tip._

 

wow -- 
 From the photo, I assumed you borrowed a pick and place machine from work.


----------



## fordgtlover

Thanks for the tip. I'll work through the 3.3V side tomorrow.

 Cheers

  Quote:


  Originally Posted by *Calroth* /img/forum/go_quote.gif 
_Keep at it!

 The 5V side of the chip is the "analog" side; the 3.3V side is the "digital" side. So if there's a problem with the computer recognising the chip, then I'd check the 3.3V side._


----------



## btrancho

I finished my Alien DAC a few days ago and after a bit a work repairing solder bridges it tested out fine (3.3V & 4.6V), was recognized by my PC and worked fine. I ran it for a few days, on and off, between my Pimeta and the PC to break it in, waiting for the case to arrive.

 Yesterday the case arrived and I disconnected it and gave the board a good cleaning with 91% alcohol and a toothbrush. This morning I cased it up and got no audio. Testing now shows I'm now getting 1.75V on the 5V test point. Looks like my cleanup has caused a problem.

 I've gone back over my PCM2702 and it looks okay (I have a serious camera with macro lenses which helps a lot). Any hints as to where I should be looking?


----------



## btrancho

I think I've got the answer to my own question. R32 got pretty badly mangled after I had to de-solder it when I realized that I had laid it down overlapping the IC3 contacts. Once re-soldered it worked okay but I think that the toothbrush may have knocked off part of the cover that had been damaged.


----------



## FallenAngel

Quote:


  Originally Posted by *btrancho* /img/forum/go_quote.gif 
_I think I've got the answer to my own question. R32 got pretty badly mangled after I had to de-solder it when I realized that I had laid it down overlapping the IC3 contacts. Once re-soldered it worked okay but I think that the toothbrush may have knocked off part of the cover that had been damaged.




_

 

Congratulations on successfully photographing what an bomb shelter looks like after a nuclear blast, it looks brutal. 
	

	
	
		
		

		
		
	


	




 Now onto your AlienDAC - R32 is supposed to be connected across pins 3 and 4 of IC3. You might have disconnected the pads from the board. Try measuring resistance from the top of the resistor connected to pin 4 to ground to make sure there is none and again from the other side of the resistor (connected to pin 3), it should be the exact value of that resistor.


----------



## btrancho

Yeah, it certainly is ugly... but I swallowed my pride in order to get this DAC going again.

 Pin 4 to ground is zero, Pin3 to ground settles at 51.3K (that _was_ an 11K for regulated 4.75v out).

 So I guess I my options are:
 1. Get another R32 and try not to butcher it
 2. Go unregulated, de-solder IC3, R32, R31 & C32

 Correct?


----------



## error401

Quote:


  Originally Posted by *btrancho* /img/forum/go_quote.gif 
_I think I've got the answer to my own question. R32 got pretty badly mangled after I had to de-solder it when I realized that I had laid it down overlapping the IC3 contacts. Once re-soldered it worked okay but I think that the toothbrush may have knocked off part of the cover that had been damaged.




_

 

If you haven't already, you probably want to replace that resistor with a new one. The resistive element in SMD metal film resistors is actually a very thin layer underneath the black insulator with the marking on it. It sits between this black enamel and the white insulation that's showing in the photo. Since the element is obviously damaged, I'd expect that the resistance has probably increased substantially. At least meter it and check...


----------



## amb

*More pics here*.


----------



## colonelkernel8

Quote:


  Originally Posted by *btrancho* /img/forum/go_quote.gif 
_I think I've got the answer to my own question. R32 got pretty badly mangled after I had to de-solder it when I realized that I had laid it down overlapping the IC3 contacts. Once re-soldered it worked okay but I think that the toothbrush may have knocked off part of the cover that had been damaged.




_

 

That is a stunningly detailed and clear photo. You must have an amazing camera and macro lens. Sorry for the off-topic.


----------



## btrancho

Wouldn't it be nicer if were of one of amb's soldering jobs? Actually, I am fairly proud of the rest of the SMD sodlering I did on the DAC, but I really mangled this resistor during the de-solder process.

 I shoot macro photos regularly. You can see them at a closeup view - my photoblog.

 Once the DAC is repaired I'll post some photos. My Hammond case is all done - just waiting for an occupant.


----------



## btrancho

My Mouser order arrived today and I replaced the damaged 11.5k with a 9.5k. Now I only get 3.96V at the 5V post and the resistor only reads 8.03k when measured from Pin 3 to ground. Something else is going on. Could the pads be disconnected? They looked okay before I soldered the new R32.


----------



## splaz

That doesn't make much sense, if the pad's weren't connected properly the resistant should be higher, not lower.

 Also if it is 8k, assuming your R31 is 31.2k output voltage should be around 6.15V which I'm not even sure the reg101 or 102 is specced for.


----------



## btrancho

One more shot at this before I scrap this attempt and go for another.

 I removed IC3, R31, R32 and C32, and jumpered AV+ to the 5v pad, making it unregulated. I quadruple checked the PCM2702 - I even removed C13 temporarily to get a better view of the 5V side and ran a resistor lead behind the pads - it looks fine even under my 3X macro lens.

 Yet when I plug it in to my PC I only get 3.66V at the 5V pad. My USB is putting out 5.08V. Any suggestions will be greatly appreciated.


----------



## error401

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_That doesn't make much sense, if the pad's weren't connected properly the resistant should be higher, not lower._

 

Under normal operation, a current flows into Iadj through R31 to set the voltage. This means that there must be a path to ground through this pin. Measuring resistance in-circuit isn't always foolproof as there can be other paths for the measurement current to take. I can't tell for sure if that's what's happening, but it's definitely plausible. Also possible of course is that the IC is fried and you're measuring some effects of its failure.

 If your voltage rails are sagging that badly when you plug it in it's almost certainly a short somewhere. This doesn't necessarily mean that two pins on the PCM2702 are shorted, but that's the most obvious conclusion to come to. I'd try to measure it out - use a DMM to test for continuity between all adjacent pins and compare to the datasheet (there are a few pins on the IC that are internally connected). It could also be away from the PCM2702, say a ferrite accidentally placed where a capacitor should be, or a short to the ground plane where the solder mask has been scraped off or something like that. That said, I had the same problem with my HPDAC build and wasn't able to track it down without first destroying the solder pads. Good luck 
	

	
	
		
		

		
		
	


	




.


----------



## btrancho

I'll check the PCM2702 continuity. Since the DAC worked well for several days prior to cleaning the board, I'm sure that there are no misplaced components. I think that there may be a short to the ground plane at the mangled R32 pad. If I eliminate the PCM2702 as a possibility, I'll probably start over from scratch. Not a big deal - I have confidence that my next attempt will be error free. My SMD soldering skills have gotten a fairly good workout.
 Thanks for the advice.


----------



## achina

Try pulling the other electrolytic capacitors. If they were stressed they could be shorting internally. Maybe they weren't sealed good and some alcohol got in there. The output capacitors probably wouldn't have any effect though, if they shorted it wouldn't affect the power supply.

http://www.elna-america.com/tech_al_reliability.php


----------



## btrancho

The PCM2702 checks out okay. I'm going to scrap this board and start over. In the time I've spent troubleshooting this one I could have completed another. I've learned a lot - now I'll apply it to a new build.

 Thanks again for everyone's assistance.


----------



## pddjsteve

Has anyone made an amp-powered alien dac yet? I'd like to put one in my work SOHA so I don't have a seperate dac and cables cluttering my desk.

  Quote:


 Amp powered. Connect the amp’s V+ to the AV+ pad, amp’s V- to the AV- pad, and amp’s ground to the AG pad. 
 

Will this work with the +-15V in the SOHA?


----------



## MASantos

No. If you read through the design and examine the regulators datasheet you'll see that they can onlly handle up to 10v. you could work something out to drop the voltage outof you soha, but I would say that the best solution is to either use a tread connected to the transformer's output or use USB power. I have tried external power and usb power and couldn't find a difference. Furthermore, I was speaking with AMB this weekend at the international meet and he told me that he could not measure a differencebetween both using his highquality measure equipment.

 IMO, go for USB powered, the simplest and cheapest solution. Use the money on some blackgate HIGH Q- Nx caps, those really make a difference.


----------



## pddjsteve

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_No. If you read through the design and examine the regulators datasheet you'll see that they can onlly handle up to 10v. you could work something out to drop the voltage outof you soha, but I would say that the best solution is to either use a tread connected to the transformer's output or use USB power. I have tried external power and usb power and couldn't find a difference. Furthermore, I was speaking with AMB this weekend at the international meet and he told me that he could not measure a differencebetween both using his highquality measure equipment.

 IMO, go for USB powered, the simplest and cheapest solution. Use the money on some blackgate HIGH Q- Nx caps, those really make a difference._

 

Yeah, that's what I was afraid of, I knew the voltage limit on the regulators from making the wall-powered one, but wasn't sure what exactly IC4 (the buffer) did to drop voltage.

 The main reason I was thinking amp-powered over usb-powered is the ports on my laptop don't always provide enough voltage for the analog side to function right.


----------



## MisterX

Quote:


 The main reason I was thinking amp-powered over usb-powered is the ports on my laptop don't always provide enough voltage for the analog side to function right. 
 

Are you really suggesting the USB ports on your laptop are not compliant with the appropriate USB specifications?


----------



## Yen

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Are you really suggesting the USB ports on your laptop are not compliant with the appropriate USB specifications? 
	

	
	
		
		

		
		
	


	


_

 

I had a unregulated usb alien with my cheapo Acer and never have a single problem. I am building a regulated one next, but I am pretty sure there will be no difference, or at least any major.

 I measured quite stable 4.9-5.0 volts with my DMM.


----------



## pddjsteve

Quote:


  Originally Posted by *Yen* /img/forum/go_quote.gif 
_I had a unregulated usb alien with my cheapo Acer and never have a single problem. I am building a regulated one next, but I am pretty sure there will be no difference, or at least any major.

 I measured quite stable 4.9-5.0 volts with my DMM._

 

 Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Are you really suggesting the USB ports on your laptop are not compliant with the appropriate USB specifications? 
	

	
	
		
		

		
		
	


	


_

 

Yeah, I should note that it is a regulated USB configuration. I think the problem is more that the voltage dips slightly enough to mess up the output of the adjustable regulator than anything else, this particular Alien DAC has worked perfectly on my laptop at home, my media pc, and most of the time on my work laptop. I know with the regulators there is some amount of voltage required over the output voltage and it might just be that it is acting screwy because of that.

 Occasionally, I'll plug it in, it detects, but audio comes out distorted for about 2 or 3 seconds before dropping out entirely. Usually it takes a couple tries to plug it in before it works fine. The problem doesn't occur with my wall-powered one.

 I should probably just try to lower the output voltage of the reguator, but I really don't want to pay shipping for 1 smd resistor


----------



## MisterX

Yeah, even first class shipping for a single resistor is kinda silly. 
 What value do you need?


----------



## agreenfield1

I just wanted to chime in with a success story here. People obviously post more regarding the problems as opposed to the successes, which sort of skews things I think! I purchased the AlienDAC kit from jrossel, and plan on integrating it with a B22. 

 First time working with SMD components. I made lots of solder bridges on the PCM2702, but they were readily fixed using some solder braid. I had access to a stereomicroscope (7X-75X mag) at work, which allowed me to identify several cold solder joints, and a bridge.


----------



## btrancho

I received my new kit from Glass Jar today. I sat down to work at 3:30 and unplugged the soldering iron at 5:30 - connected power and it tested perfectly at 4.75V and 3.3V. Once plugged in to the PC it was recognized immediately. Here's a shot of it sitting on top of my Pimeta. It sounds great.


----------



## MASantos

Quote:


  Originally Posted by *btrancho* /img/forum/go_quote.gif 
_I received my new kit from Glass Jar today. I sat down to work at 3:30 and unplugged the soldering iron at 5:30 - connected power and it tested perfectly at 4.75V and 3.3V. Once plugged in to the PC it was recognized immediately. Here's a shot of it sitting on top of my Pimeta. It sounds great.




_

 

Nice job! Was this your first SMD project?


----------



## btrancho

It's my second attempt at the Alien DAC (see my previous post(s)). Surprisingly, the PCM2702 and the ICs gave me no trouble. I messed up the first with lousy de-soldering technique.


----------



## pddjsteve

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Yeah, even first class shipping for a single resistor is kinda silly. 
 What value do you need?_

 

I'm not sure, actually, I have to double check what I actually used on it and see if I can calculate a better value. I've kind of put fixing this on the back burner, I've still got a SOHA to case up and may is pretty much completely booked for me. Heck, by the time I figure out what I need, I'll probably have jumped on another project to order parts for anyways


----------



## sygyzy

Can anyone tell me if IC2 is connected to C22 (on top)? They are so close and I bridged them but was not sure if this is an issue. It's going to be a pain to create that mm of separation.

 Thanks.


----------



## FallenAngel

Quote:


  Originally Posted by *sygyzy* /img/forum/go_quote.gif 
_Can anyone tell me if IC2 is connected to C22 (on top)? They are so close and I bridged them but was not sure if this is an issue. It's going to be a pain to create that mm of separation.

 Thanks._

 

Good idea to have the board photo handy


----------



## sygyzy

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Good idea to have the board photo handy_

 

I have to admit that I did reference that image and while I thought it looked unconnected, I can also see a line which shows it is. Maybe I am looking at the bottom trace?


----------



## Calroth

Quote:


  Originally Posted by *Calroth* /img/forum/go_quote.gif 
_Question about the virtual ground option.

 I'm hooking an Alien DAC up to a PIMETA. So I'm wiring up AV+, AV- and AG.

 AV+ and AV- is fine. But I'm confused with AG. On the PIMETA, that's connected to input ground, which is connected to the Alien DAC OG. So if I wired that, then I would be effectively connecting AG to OG (and the rest of the ground plane).

 Is that right, or am I missing something?_

 

Right, I posted that a month ago, and in the meantime have been trying to wrap my head around virtual ground theory. As a primer: I have an Alien DAC, a PIMETA, and an OPA551 to act as the IC4 virtual ground buffer between the two. It's all to run on a 12V supply, split into +6V, 0 and -6V.

 The first thing I tried was what I described above: connected the Alien DAC OG to PIMETA IG, and the Alien DAC AV+ to the same. It pulled the entire virtual ground on both sides up by 4V... so we were +6V, +4V and -6V. That ain't right, Calroth. So back to Tangent's virtual grounds page.

 So, after some critical thought, I decided that the Alien DAC's ground should be buffered and isolated from the PIMETA's, though still at the same voltage. So, disconnected the Alien DAC OG to PIMETA IG (leaving the left and right channel wires there). Now, the Alien DAC's ground is buffered. In theory, its current draw etc. shouldn't disturb either ground level. And it didn't... much. The PIMETA's ground stayed at 0V, so the OPA551 was definitely isolating the Alien DAC. However, the Alien DAC's ground was offset by +170mV. Better!... but still unacceptable.

 Scratched my head. Then did what every self-respecting DIY'er would do: I Mini³-ified it! Added a 600R ferrite on the output of the OPA551, outside the feedback loop - plenty of spares from the Alien DAC construction. I had to lift a few pins to do it. You don't want to see the board... between this and all the other things I tried, it ain't a pretty sight. But, the ground is now offset by about +19mV. Yeah, that's close enough for me! Hooked it up and got it playing music.

 So. Having read all that... any comments? Did I do something completely stupid? Next thing to try is putting some 100nF bypass caps on the OPA551 V+ and V- (also left over from the Alien DAC build). The datasheet suggests it, but I think that's just a precautionary thing. Also, I suppose I could shift the DC blocking caps from the Alien DAC to the PIMETA to wipe off that last bit of offset.


----------



## flyhyena

just took an attempt to build this dac in one afternoon with no luck. It is my first try of smd soldering , my tweezers are too stiff when I tried to grip RLED to its postion, it jumped up and pew, disappear in the air, never found it again.
	

	
	
		
		

		
			





 save for me a LED.

 When I finished soldering and plug it to computer, I spot some little sparks at around pin 24-27, not sure exact where, then I unplug it and tried to clean the bridges and plug to computer again, no sparks, and the computer did not response either. After a few second, pin 25(i thought), which is VCCL get so hot that the residue of flux start smoking, so I guess I got some where short around this pin, but will this be the reason the computer do not recognize? I read some thread say that when the computer does not recognize, it is more likely something wrong at the 3.3V side. 
 I put some pictures here and hope some one can take a close look and spot the flaws.


----------



## jasonhanjk

There is a burnt mark. Most likely you burn your trace.


----------



## Sinbios

I doubt he could have burnt through the silkscreen and destroyed a trace... rather you can notice a rather large solder blob between the bottom left pins on the 2702 chip in this picture: http://img508.imageshack.us/my.php?image=dac6rd2.jpg


----------



## amb

That solder blob might look unsightly, but the two pins are actually supposed to be connected to each other. Again, see board layout.


----------



## daveip

hope you guys can help

 put one of these together the other day and i'm just testing my voltages. 3.3V is at 3.3V but my 5V (which should be 5.4V as I chose resistor values for OC) is at -1.4V? Any ideas? I've got my c32 in place where it says c32/r32 and my r32 where it says c32 on the reverse side. i just figured these were in paralel and it doesn't matter which way around they go. yes no? =S

 cheers

 dave


----------



## splaz

^ Externally powered ?


----------



## daveip

nope ... its all sorted now ... c32 has to go on the bottom of the board and r32 on the top of the board where it says "r32 c32"


----------



## lmiller

I successfully built the Alien DAC, but I have hum that seems to be from the oscillator. Using a head phone amp connected to the DAC with the DAC only connected to a 9 volt battery and not connected to a computer, I get hum. If I remove the battery supply, the hum goes away. If I connect the DAC to the computer, it works, but the hum is still there. I originally did not use the ferrites, but added them when I heard the hum. This seems to have reduced the hum only marginally.

 Suggestions on where to begin are appreciated.


----------



## Sinbios

Finally built one of my boards, but I'm having the opposite problem of everyone else: my 5V checks out fine, but there's a short from 3.3V to ground. 

 What are the most likely culprits for this? I checked the DAC chip for bridges, and found none. IC2 is aligned correctly.


----------



## Sinbios

Oookay, I reflowed everything and the short is gone. And then L12 glowed red hot, melted part of the silkmask and desoldered itself after carbonizing everything in a 5mm radius.

 L12 is a ferrite! What caused it to do this?

 Nevermind, apparently Vbus got shorted with GND on IC1, and L12 was in the path.

 Plugged it in and works! Yay!


----------



## pkshiu

Virtual Ground / IC4

 I too am confused as to how to use IC4 to power the Alien DAC using the virtual ground from another module. OG to IG? Or ?? Cannot figure it out from the schematic.


----------



## skudmunky

Geeze, I'm still got my 5 boards sitting upstairs in my room. Gotta get around to ordering parts 
	

	
	
		
		

		
		
	


	




 will be a fun summer project.


----------



## Calroth

Quote:


  Originally Posted by *pkshiu* /img/forum/go_quote.gif 
_Virtual Ground / IC4

 I too am confused as to how to use IC4 to power the Alien DAC using the virtual ground from another module. OG to IG? Or ?? Cannot figure it out from the schematic._

 

OK, here's what I connected. If someone with more experience can explain more, please do. This is assuming that your amp's virtual ground is tied to its input ground, which is the case with most designs I've seen.

 For the power supply section:
Amp V+ to Alien DAC AV+
Amp V- (or ground) to Alien DAC AV-
Amp virtual ground to Alien DAC AG
For the signal section:
Alien DAC OL to amp IL
Alien DAC OR to amp IR
Do not connect Alien DAC OG to amp IG
Check the voltage offset that IC4 generates between AG and the ground plane, it should be minimal. You might need to do things like adding bypass capacitors or ferrites to IC4 to get the offset down.

 I also recommend testing with a 9V power supply to begin with, which will split into +4.5/0/-4.5V. So that in the worst case (virtual ground collapse), you won't exceed the 10V limit of the REG101 chips. Of course, if you have 6.3V capacitors in the power supply path (I can't remember if there are any), you might damage those. Exciting times.


----------



## tsaavik

I just ordered and built my kit from glassjaraudio.com. After much eye-straining and trial and error i got it working, sounds better then my creative EMU10k. The bass is REALLY tight, its like going from a crappy 15" sub in a sentra trunk to a nice tight 8". The highs sound the same to me, except for the fact that I'm discovering things in my music I've never heard before. Kinda like "oh wow, there is a whistle in this song!". Also Portishead is listenable without the "OMG my head is going to split" effect! The kit i ordered came with the Elna Silmic II(sp?) caps. Didn't try any others.

 Here is a little advice that i found sprinkled throughout this thread (and a little of my own.)

 1. Install the 3.3v and 5v regulators and associated resistors and caps FIRST. Then test them, make sure you get the expected voltage levels out at both test points. If you have a bridge on the ssop28 it will most likely drag one of these rails down and you won't know if its a regulator or ssop28 problem.

 2. Flood and suck worked great, BUT you seem to get alot of bridges BEHIND the pins. Put the board ontop of a BRIGHT flashlight (i found a 5led white flashlight to work best) and look at it with some sort of magnification. Your just not going to see it with the naked eye. I have a astigmatism that allows me to take off my glasses and shove things an inch from my eye and focus on them, and even then i was unable to see some bridges.
 I also found it IMPOSSIBLE to move the iron out and sucker into place. I had much better luck using the iron and sucker together, its a squeeze but can be done.

 3. The left side (usb connector side) of the ssop28 is the "digital" side, it uses the 3.3v regulator. If your 3.3v test point stops showing 3.3v this is your problem. This will also usually make your dac not show up correctly when plugged into your PC's usb port. The usb data connections are also here.

 4. The right side of the ssop28 is the "analog" side, it uses the 5v supply. If your 5v test point isn't 5v, look for bridges here. Also if you dac is SUPER quiet (you have to blast your amp and volume settings) or the output sounds like crap you prob have a bridge here also.

 5. Solder in a loop of wire to S1 so you can externally power the DAC easily (with a current limited power supply! My DAC pulls .03amps idle, when i had a bridge i had limited the power supply to .1amps which is NICE, no POOF!). Also insert loops of wire (cap cutoffs work good) for the 5v and 3v test points. Now you can power and more importantly clip your multilmeter onto these points. The USB connector itself makes a good ground point.

 I know everyone always wants a pic, but i had to almost completely disassemble my DACs right side. It was SOO pretty the first time i put it together, but alas it didn't work (5v short). I'm currently burning it in at work with my PPAv2 before i case it, here is a shot of it, its IN the final case, just needs a little rear panel work 
	

	
	
		
		

		
			





 (its rear facing in pic)


----------



## Eokboy

My local Farnell seems to have run out of REG101s. I want to build an unregulated USB version asap. Can I use any 3.3V regulator instead? Or is a substitute available?

 The most similar pinout SO-8 regulator I could find is LE33CD. I assume it'll work with a few choice pins lifted. From the datasheet, minimum output capacitance needed is 2.2uF, so the 100uF Pana FMs I bought should work better.

 Maybe I could also air-wire TO-92 LDO regulators or LM1086. I figured SO-8 LE33CD is the neatest option though. Looking for better performing ICs though, even if air-wiring is involved.


----------



## babbkutz@comcast

bump


----------



## KerryKing

Finally 
	

	
	
		
		

		
		
	


	




 After having my kit from glassjaraudio.com at home for a long time, i finally started bulding last week, and now i am listening to sweet music 
	

	
	
		
		

		
		
	


	




 Only have the enclosure to figure out first 
	

	
	
		
		

		
		
	


	




 But that will have to wait since i now have the unenclosured DAC at the office 
	

	
	
		
		

		
		
	


	




 /Erik


----------



## ruZZ.il

just picked up my package from jeff this afternoon..
 the first thing I really noticed though with the sound is the sound stage, WOW. no comparison to my ipod line out. It's like I walked out into the open, niice 
	

	
	
		
		

		
		
	


	




 really clean and as tsaavik said, the bass is nice and tight, controlled... (gee, I see myself using these words now too.. ahh, the bliss 
	

	
	
		
		

		
		
	


	




 ) it does sound slightly subdued though but I do have 22microF behind the output.. its still much tighter and I rather prefer it, I'll see how it burns in and will probably experiment a bit here someday. will get some pics up sometime too.. 
 Jeff, thank you! and thank you head-fi 
	

	
	
		
		

		
		
	


	










 (except, as you know.. my wallet hates you  )

 -ruZZ

 p.s: tsaavik, I did flood and absorb(using that braided stuff..). worked fanschmasticly. (I think I may have read this at tangents, thanks! 
	

	
	
		
		

		
		
	


	




 )


----------



## Kizza

Interesting thread


----------



## Eokboy

Managed to get REG101s and finish one board. Sounds great so far. Unregulated USB with 22uH inductor config. Will build battery/TREAD powered versions to compare.


----------



## Eokboy

I had to file the PCB to make it fit between the screw posts.










 Case: Hammond 1593K


----------



## amb

Anyone here using an Alien DAC under Linux? It works, but I get an annoying burst of static noise when changing from one song to another, or sometimes when player app is open but not playing. There is no noise during playback. This occurs with several different player software apps (xmms, amarok, xine, mplayer, softsqueeze) I tried, so it's not a problem there. This problem doesn't occur under Windows XP, so it's definitely not a problem in the Alien DAC hardware.

 I also experienced the same thing with an M-Audio Transit USB under Linux, but the motherboard audio doesn't exhibit this problem. It seems like a Linux USB sound driver issue. I have also tried this on multiple computers just to make sure it's not isolated to one machine.

 I know this is probably not the best place to seek solutions to software issues but just thought I'd ask in case someone has BTDT and perhaps found a remedy... I use my Alien DAC on my Linux box often and would really love to get rid of the noise.


----------



## tomb

Can't help you on the Linux, Amb, but I did finally build one of these things (been a little busy with Millett MAX's):










 It worked the first time out - well, once I realized I had to jumper the switch position, that is. It's a USB-powered regulated version using Nichicon Muse ES for CL/CR. The bass is really thumping - 
	

	
	
		
		

		
		
	


	




 - and the highs are much more extended and smooth than I was expecting. 

 All these months, my primary source has been an M-Audio Transit, mostly with FLAC files or CD's in the PC drive. I was very surprised to hear more detail, dynamics, smoother sound and better bass within a few hours of plugging it in. It's running circles around the Transit.

 The build went pretty well, but I was so excited at successsfully soldering in the PCM, I proceeded to solder the first regulator in backwards. A big blob of solder on both sides with a screwdriver underneath and it lifted off nicely - turned it around, soldered it back down and everything was fine. Those SMD capacitors are something else, though - can't tell whether they're flat or on their sides. Apparently, it makes no difference, though.

 Very cool project! Many thanks to Alf and I'm building more!


----------



## error401

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_Anyone here using an Alien DAC under Linux? It works, but I get an annoying burst of static noise when changing from one song to another, or sometimes when player app is open but not playing. There is no noise during playback. This occurs with several different player software apps (xmms, amarok, xine, mplayer, softsqueeze) I tried, so it's not a problem there. This problem doesn't occur under Windows XP, so it's definitely not a problem in the Alien DAC hardware.

 I also experienced the same thing with an M-Audio Transit USB under Linux, but the motherboard audio doesn't exhibit this problem. It seems like a Linux USB sound driver issue. I have also tried this on multiple computers just to make sure it's not isolated to one machine.

 I know this is probably not the best place to seek solutions to software issues but just thought I'd ask in case someone has BTDT and perhaps found a remedy... I use my Alien DAC on my Linux box often and would really love to get rid of the noise._

 

I regularly use my AlienDAC with my Linux laptop and haven't experienced any such issues. I'm running Ubuntu Gutsy on kernel 2.6.22. All the players I use are configured to use ALSA directly to the AlienDAC (hw:1,0), with Gnome configured to use the onboard audio (hw:0,0).

 In fact, the audio is smoother than on my much more powerful Windows box which seems to empty the buffer occasionally, producing annoying clicks.

 I'd suspect some kind of software issue, though it's suspicious that it's happening on all your machines. What distro and kernel are you using?


----------



## tobias_svensk

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The bass is really thumping - 
	

	
	
		
		

		
		
	


	




 - and the highs are much more extended and smooth than I was expecting. 

 All these months, my primary source has been an M-Audio Transit, mostly with FLAC files or CD's in the PC drive. I was very surprised to hear more detail, dynamics, smoother sound and better bass within a few hours of plugging it in. It's running circles around the Transit.

 Very cool project! Many thanks to Alf and I'm building more!_

 

I was also surprised with my PCM2702 DAC (Damian's / Unisonus), although my M-Audio FireWire Audiophile measures better I think I like the sound from the 2702 better (paired with my QRV04)

 /Tobias


----------



## amb

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_What distro and kernel are you using?_

 

SUSE 10.0, kernel 2.6.13. All the players I use are configured to use ALSA directly.


----------



## error401

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_SUSE 10.0, kernel 2.6.13. All the players I use are configured to use ALSA directly._

 

All I can suggest is try a newer kernel, it seems the hardware itself can work properly with Linux from my experience.


----------



## tomb

OK, I'm on a roll now. Now that I'm over my fear of that SO-28 chip, these things are fairly straightforward (relatively speaking). I threw another one together today. This one is identical except it uses the 47uF Black Gate NX-HiQ's. You guys are right, I'm afraid: the BG's are noticeably better, right off the bat. If they're supposed to get better from here, that's really saying something. Bass is not as powerful as with the ES's, but the resolution, dynamics and high end detail is superlative. Of course, the bass is supposed to get better with time, anyway.

 I have a couple of 0.22uF Sonicaps as Dsavitsk recommends on the ES's - and will give them a try if I can figure out how to bend the leads to solder to the existing pads. 
	

	
	
		
		

		
		
	


	




 According to his reviews, that should increase the resolution with the high-end details on the ES's.

 Regardless, both of these handily beat every other source in my house:






 EDIT: Further listening confirms these differences. I think I still prefer the ES's - their bass is super-powerful and extends much lower than the BG's without any hint of roll off. The BG's are still smoother resolving top end details. I suppose this could change as time goes on ...


----------



## Dark_Shadow

Can someone have a look of my compiled BOM? I taked multiple BOM from here some some change suggested by the forum user.

  Code:


```
[left]Index Quantity Part Number Description Customer Reference 1 20 240-2539-1-ND FERRITE ARRAY 400MA 75 OHMS SMD L11-L18 2 20 490-1673-1-ND CAP CER .1UF 25V 10% X7R 0805 C14-C19, C21, C22, C31, C32 3 10 311-22.0CRCT-ND RES 22.0 OHM 1/8W 1% 0805 SMD R11-R12 4 10 311-1.50KCRCT-ND RES 1.50K OHM 1/8W 1% 0805 SMD R13 5 10 478-1310-1-ND CAP CERM 33PF 5% 50V NP0 0805 C11-C12 6 10 478-1416-1-ND CAP CERM 4.7UF 10% 6.3V X5R 0805 C1 7 2 604-1058-ND CAP 470UF 25V ELECT AUDIO RAD C2 8 4 604-1054-ND CAP 47UF 25V ELECT AUDIO RAD C13-CL-CR 9 4 604-1055-ND CAP 100UF 25V ELECT AUDIO RAD C23-C33 10 10 P1.00MCCT-ND RES 1.00M OHM 1/8W 1% 0805 SMD R14 11 10 311-330KCRCT-ND RES 330K OHM 1/8W 1% 0805 SMD R15-R16 12 10 311-32.4CRCT-ND RES 32.4 OHM 1/8W 1% 0805 SMD R31 13 10 311-11.5KCRCT-ND RES 11.5K OHM 1/8W 1% 0805 SMD R32 14 10 311-604CRCT-ND RES 604 OHM 1/8W 1% 0805 SMD RLED 15 2 X030-ND CRYSTAL 12.000MHZ 32PF HC-49/UA X1 16 2 160-1035-ND LED 3MM ALGAAS RED DIFFUSED Led 17 2 609-1039-ND CONN RCPT USB TYPE B R/A PCB USB 18 2 REG102UA-3.3-ND IC LDO REG 3.3V 250MA 8-SOICIC2 19 2 REG102UA-5-NDIC LDO REG 5V 250MA 8-SOICIC3 20 1 REG102UA-A-NDIC LDO REG ADJ 250MA 8-SOICIC4[/left]
```

Thanks in advance,

 Dark Shadow


----------



## tomb

(Note that I did not check for minimum ordering numbers.)

 1. 240-2539-1-ND is a FERRITE ARRAY, that means a bunch of ferrite parts in a single case - not what you need. 

 Use 490-1057-1-ND instead. You need *8*, not 20.

 2. 490-1673-1-ND - you need *10*, not 20

 I can't tell exactly what you're doing with the electrolytics, because some of these are combined Alien DAC part numbers, apparently, but:

 7. 604-1058-ND - this should be the main power cap. A 1000uF will easily fit here, 680uF or 560uF are still good. 470uF is a minimum choice, so I would make it bigger - use P12354-ND instead. This is a 1000uF, 10V Panasonic FM cap It is only $0.50, and is just a couple of milimeters taller than the USB socket. You only need *1*.

 Your number 604-1058-ND appears to be an ELNA RFS. As noted above, there are better choices for the power cap, C2 - IMHO. This is a good choice for C13, however, which should have the low ESR. However, you might accomplish as much with a normal cap by upsizing. You can actually fit as much as 330uF, 6.3V - which is what I selected: P12918-ND. You only need *1*. I can't take the additional time to research the actual ESR, but the point is it might be better to upsize a good quality power cap than by going boutique, IMHO.

 8. 604-1054-ND is an ELNA RFS. For CL/CR, this is a great choice. However, you only need *2*.

 9. 604-1055-ND is also an ELNA RFS. For C23/C33 they may be overkill. These are the regulator "power" caps. A standard FM or FC might be a better choice, and you can upsize them to the same 330uF, 6.3 listed above. I kept them at 47uF on mine and have no issues. Your choice. You only need *2*.

 10. This should be R14. Not sure why you switched from Yageo on this one. It is 311-1.00MCRCT-ND You need *1*.

 12. This was supposed to be R31 at 31.2*K*. However, it looks like you searched since that exact value was not available, but you dropped the "K". Yageo has a 31.6K, which is the closest. Try 311-31.6KCRCT-ND, instead. You need *1*.

 13. This is R32, you need *1* (I am not checking for minimum ordering qty's, obviously). This resistor and R31 above are used to set the voltage at ~4.7V for the USB-powered, regulated version of the Alien DAC. Only REG101UA-A or REG102UA-A is needed if you are using these values for R31 and R32. REG101/102UA-5 is _*not*_ needed.

 14. This is RLED, you need *1*.

 17. 151-1081-ND may be a better choice. It has gold-plated contacts and is still only $1.02.

 18. Despite the items below, REG101UA-3.3 or REG102UA-3.3 is mandatory for every option of the Alien DAC. You must use this chip no matter what. Your selection is fine.

 19 and 20. This may indicate some confusion. You only need one - either the REG101/2UA-5 or the REG101/2UA-A. Both are used to regulate the ~5V portions of the DAC. "...UA-5" is set at 5V, period. However, since it has to burn some fractional volts to regulate, you must have a power supply greater than 5V. "...UA-A" is the adjustable version and you have selected the proper values for R31 and R32 above to make your DAC regulated-USB-powered.

 So, you only need REG101UA-A (or REG102UA-A). REG101UA-5 or REG102UA-5 is _not needed_.


 Whew! I hope this helps.


----------



## Dark_Shadow

Thanks for the quick reply 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_
 1. 240-2539-1-ND is a FERRITE ARRAY, that means a bunch of ferrite parts in a single case - not what you need. 

 Use 490-1057-1-ND instead. You need *8*, not 20._

 

Noted, I made the change.

  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_
 I can't tell exactly what you're doing with the electrolytics, because some of these are combined Alien DAC part numbers, apparently, but:

 7. 604-1058-ND - this should be the main power cap. A 1000uF will easily fit here, 680uF or 560uF are still good. 470uF is a minimum choice, so I would make it bigger - use P12354-ND instead. This is a 1000uF, 10V Panasonic FM cap It is only $0.50, and is just a couple of milimeters taller than the USB socket. You only need *1*.

 Your number 604-1058-ND appears to be an ELNA RFS. As noted above, there are better choices for the power cap, C2 - IMHO. This is a good choice for C13, however, which should have the low ESR. However, you might accomplish as much with a normal cap by upsizing. You can actually fit as much as 330uF, 6.3V - which is what I selected: P12918-ND. You only need *1*. I can't take the additional time to research the actual ESR, but the point is it might be better to upsize a good quality power cap than by going boutique, IMHO._

 

Noted

  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_9. 604-1055-ND is also an ELNA RFS. For C23/C33 they may be overkill. These are the regulator "power" caps. A standard FM or FC might be a better choice, and you can upsize them to the same 330uF, 6.3 listed above. I kept them at 47uF on mine and have no issues. Your choice. You only need *2*._

 

This came from a suggestion from alf to try Elna instead of std caps.

  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_10. This should be R14. Not sure why you switched from Yageo on this one. It is 311-1.00MCRCT-ND You need *1*._

 

Noted

  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_12. This was supposed to be R31 at 31.2*K*. However, it looks like you searched since that exact value was not available, but you dropped the "K". Yageo has a 31.6K, which is the closest. Try 311-31.6KCRCT-ND, instead. You need *1*._

 

Correction done.

  Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_13. This is R32, you need *1* (I am not checking for minimum ordering qty's, obviously). This resistor and R31 above are used to set the voltage at ~4.7V for the USB-powered, regulated version of the Alien DAC. Only REG101UA-A or REG102UA-A is needed if you are using these values for R31 and R32. REG101/102UA-5 is *not* needed.

 19 and 20. This may indicate some confusion. You only need one - either the REG101/2UA-5 or the REG101/2UA-A. Both are used to regulate the ~5V portions of the DAC. "...UA-5" is set at 5V, period. However, since it has to burn some fractional volts to regulate, you must have a power supply greater than 5V. "...UA-A" is the adjustable version and you have selected the proper values for R31 and R32 above to make your DAC regulated-USB-powered.

 So, you only need REG101UA-A (or REG102UA-A). REG101UA-5 or REG102UA-5 is not needed._

 

I was sure that I missed to say something when I made my post yesturday night...

 I planning to do two alien dac (I already got 2 pcb). One simple powered USB one, and the other to be enclosed in a CNC machined case that will have a headphone preamp in it...Maybe a PPA v2, I'm not sure yet. so in this case I think I will need a fixed regulator right? If so, what should be the value for R31 and R32?

 Thanks again for your support

 Dark Shadow


----------



## MisterX

Skip those Yageo resistors. 
 Digi-key offers Vishay/Dale resistors which you do not have to buy in multiples of 10.


----------



## tomb

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Skip those Yageo resistors. 
 Digi-key offers Vishay/Dale resistors which you do not have to buy in multiples of 10. 
	

	
	
		
		

		
		
	


	


_

 

Yeah, mine are all V-D's as well. It looked like he was trying to stay with Yageo's for some reason, and I tailored my comments according to that theme.

 Dark_Shadow - the Elna's definitely won't hurt in those other positions, just thought you might like some other options.

 I have not studied or built the powered option. Maybe Mister X may help you with that.


----------



## dsavitsk

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_



_

 

Tom, twisting the L & R output wires together like this can lead to increased cross talk.

 Also, if you want to try an experiment, there are some 0805 "Film" caps (I think they are polyester), Digikey part #PCF1126CT-ND, that you might try bypassing the Muses with. They should fit snugly between the pins ... I haven't gotten around to trying this yet. Additionally, you could also try some silver mica 0805 caps to see how they sound.


----------



## tomb

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_Tom, twisting the L & R output wires together like this can lead to increased cross talk._

 

Is that right? I thought it was just the opposite. I've always done it - never noticed any problems.

 EDIT: Don't people braid interconnects? This serves the same purpose, doesn't it?


----------



## Dark_Shadow

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Skip those Yageo resistors. 
 Digi-key offers Vishay/Dale resistors which you do not have to buy in multiples of 10. 
	

	
	
		
		

		
		
	


	


_

 






 Cool I like vishay, we use some vishay high precision resistor for strain evaluation at work...

 Do you have any digikey part number to get me going so I can know the serie you used.

 Thanks

 Dark Shadow


----------



## user18

Has anyone put an Alien DAC in the same enclosure as a DIY amp? I'm planning to build one and put it in the same case as a CK2III (amp board, transformer, DAC would all be in one case). Would this combination lead to any noise contamination?


----------



## tomb

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_... Also, if you want to try an experiment, there are some 0805 "Film" caps (I think they are polyester), Digikey part #PCF1126CT-ND, that you might try bypassing the Muses with. They should fit snugly between the pins ... I haven't gotten around to trying this yet. Additionally, you could also try some silver mica 0805 caps to see how they sound._

 

Good thought. I already have the Sonicaps, though, will maybe try them first. As you no doubt know, the 0.22 Gen II's are not really that big - maybe like a 5W Kiwame. Still, that may not be enough considering the relative size of this thing. I'll put the ones you suggest on my next DigiKey order.

 I'm not sure the BG's will ever equal the bass of these ES's. They really thump. 
	

	
	
		
		

		
		
	


	







 Much thanks, of course, to your excellent reviews and trailblazing work in recommending these:
http://www.ecp.cc/cap-notes.html


----------



## dsavitsk

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Is that right? I thought it was just the opposite. I've always done it - never noticed any problems.

 EDIT: Don't people braid interconnects? This serves the same purpose, doesn't it?_

 

Each signal should be twisted with its own return. So, ideally you'd want two ground wires -- one with each signal wire. When people braid interconnects, like the Kimber braid, there are 2 ground wires and one signal, or two grounds and 2 signals, but the signal and return are always balanced. Here, you have two signals which can interact with each other. Now, the importance of this is probably pretty minor, but with a very high end signal it can make a difference.


----------



## dsavitsk

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Much thanks, of course, to your excellent reviews and trailblazing work in recommending these:
http://www.ecp.cc/cap-notes.html_

 

I appreciate your support on this project. I am, I think, about to embark on another round of tests. But, this time I have reason to try some of the best of the best caps, partly because I should be able to use smaller values than I have in the past. I am still trying to decide which ones to try, but I sold off my Cary cd player to fund building the best DAC I can.


----------



## tomb

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_Each signal should be twisted with its own return. So, ideally you'd want two ground wires -- one with each signal wire. When people braid interconnects, like the Kimber braid, there are 2 ground wires and one signal, or two grounds and 2 signals, but the signal and return are always balanced. Here, you have two signals which can interact with each other. Now, the importance of this is probably pretty minor, but with a very high end signal it can make a difference._

 

OK - makes sense. I always want to know if I'm doing something wrong.


----------



## tomb

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_I appreciate your support on this project. I am, I think, about to embark on another round of tests. But, this time I have reason to try some of the best of the best caps, partly because I should be able to use smaller values than I have in the past. I am still trying to decide which ones to try, but I sold off my Cary cd player to fund building the best DAC I can._

 

Can't wait to see the results of your latest work. As far as small vs. smaller, it would be nice to see some larger ones with the electrolytics. Although that could get very expensive, I suppose.


----------



## Eokboy

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_I have a couple of 0.22uF Sonicaps as Dsavitsk recommends on the ES's - and will give them a try if I can figure out how to bend the leads to solder to the existing pads. 
	

	
	
		
		

		
		
	


	




 According to his reviews, that should increase the resolution with the high-end details on the ES's.

 Regardless, both of these handily beat every other source in my house:_

 

I like FallenAngel's boutique film cap application:


----------



## TzeYang

actually, fallen angel's boutique film cap application would be so much better if he had shorten the legs.

 Sigh, parasitics inductance is bad


----------



## amb

Quote:


  Originally Posted by *TzeYang* /img/forum/go_quote.gif 
_actually, fallen angel's boutique film cap application would be so much better if he had shorten the legs.

 Sigh, parasitics inductance is bad 
	

	
	
		
		

		
		
	


	


_

 

Considering that the interconnect cable at the other end of those coupling caps are going to be much longer than the capacitor lead, it wouldn't make much difference.

 If these were power supply decoupling caps for a high speed, wideband opamp, a compensation cap or some other circuit that deals with RF, then it's a different story. It would be very important to keep the lead inductance low in those cases.


----------



## TzeYang

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_Considering that the interconnect cable at the other end of those coupling caps are going to be much longer than the capacitor lead, it wouldn't make much difference.

 If these were power supply decoupling caps for a high speed, wideband opamp, a compensation cap or some other circuit that deals with RF, then it's a different story. It would be very important to keep the lead inductance low in those cases._

 

now why didnt i thought of that 
	

	
	
		
		

		
		
	


	




 Thank you for pointing that out amb.


----------



## Dark_Shadow

It look like I don't have the right equipment to perform a good job for the soldering of the PCM2702, because I think I just scrapped one board...
	

	
	
		
		

		
		
	


	









 Anyone willing to trade 3 (or maybe 4 if the damaged board can not be saved) PCM2702 to solder the PCM for me on it or make your price... I'm more interested in the design of the case then to solder this extremely tiny SMD =)

 Thanks in advance,

 Dark Shadow


----------



## tomb

Minimalist enclosures for the Alien DAC ...








 ... using the CMoy method. There's still plenty of room for some nice bypassing film caps, too.


----------



## MASantos

Tomb,, nice work on those enclosures.

 I like that someone agrees with me about those Blackgates, they're more expensive but definitely pay out!


----------



## tomb

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_Tomb,, nice work on those enclosures.

 I like that someone agrees with me about those Blackgates, they're more expensive but definitely pay out!_

 

Thanks - but it's no comparison to the excellent casework you're offering on yours in your sponsored thread. 
	

	
	
		
		

		
		
	


	




 I agree that the BG's have more dynamics and detail - I just wish they had the bass of the ES's.


----------



## kuohsing

Dark Shadow,

 These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable.


----------



## Calroth

Quote:


  Originally Posted by *kuohsing* /img/forum/go_quote.gif 
_Dark Shadow,

 These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable._

 

Hm. The PCB does look usable, nothing that can't be cleaned up. Lots of flux and lots of desoldering braid and it should come out looking OK.

 But although the pins aren't connected to anything, I don't think they should be connected to _each other_ either. I think I noticed some weirdness with the USB not being recognised when I bridged some of those pins.


----------



## Dark_Shadow

Quote:


  Originally Posted by *kuohsing* /img/forum/go_quote.gif 
_Dark Shadow,

 These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable._

 

 Quote:


  Originally Posted by *Calroth* /img/forum/go_quote.gif 
_Hm. The PCB does look usable, nothing that can't be cleaned up. Lots of flux and lots of desoldering braid and it should come out looking OK.

 But although the pins aren't connected to anything, I don't think they should be connected to each other either. I think I noticed some weirdness with the USB not being recognised when I bridged some of those pins._

 

Thanks for hint...

 My only problem is that I do not want to scrap them trying to solder the PCM2702...I know now that I do not have the practice and equipment to solder them... Like I said in a earlier post, I'm looking for someone that have some space time to solder the PCM on my two boards with compasation. 
	

	
	
		
		

		
		
	


	




 After that, I will solder the rest and continue to work on my case design (will be CNC machined case with LCD display, preamp and maybe I will also add a Gainclone in it to use it at work.)

 Dark Shadow


----------



## FallenAngel

Hey guys,

 I've got the weirdest thing happening with one of my AlienDACs. When I plug it into my desktop PC, I get a device not working properly error and my the USB port hub (not external, just the set of USB interfaces on the motherboard) stop responding.

 The weird part is that it works perfectly on my laptop 
	

	
	
		
		

		
		
	


	




 has anybody had this kind of problems, or have any idea of what's going on?


----------



## lmiller

I had asked previously about a problem I am having but without any reply so I will try again. I built the Alien DAC and it works. However, there is a hum even with no USB connected and running on a battery. The hum seems to be around 60Hz, but also seems to go up in frequency with time. I am thinking that it has something to do with the oscillator. Rather than build a new board from scratch does anyone have suggestions as to where I should start? I did use a BOM that listed the ferrite arrays rather than the single ferrite SMD. Could that have caused the problem?


----------



## FallenAngel

Quote:


  Originally Posted by *lmiller* /img/forum/go_quote.gif 
_I had asked previously about a problem I am having but without any reply so I will try again. I built the Alien DAC and it works. However, there is a hum even with no USB connected and running on a battery. The hum seems to be around 60Hz, but also seems to go up in frequency with time. I am thinking that it has something to do with the oscillator. Rather than build a new board from scratch does anyone have suggestions as to where I should start? I did use a BOM that listed the ferrite arrays rather than the single ferrite SMD. Could that have caused the problem?_

 

Sounds strange, the oscillator is 12MHz. Which ferrites did you use?


----------



## lmiller

I'm not sure if this is the exact part number but it is similar to Digikey 240-2539-1-ND. In thinking back (I built the board in March), I'm not sure the ferrites could have anything to do with the problem since initially I did not install the ferrites, but simply wired across the pads for the ferrites. If I do hook the DAC to my computer, it plays music without a problem, but I get the hum/buzz along with the music. And I get the hum powering the DAC with a battery and nothing connected except the outputs to a headphone amp. Of course when the battery is removed, the hum goes away. It sounds like 60 Hz, but could be higher and the frequency seems to go up slightly over time. Something is oscillating, but I don't know where to look.


----------



## tomb

No offense, but it sounds like you should've installed the ferrites.


----------



## lmiller

I did install the ferrites, but the hum was there before and after installing the ferrites. Because they were the arrays, I was not sure how to install them. Once I figured that out I went back and put them in. They are now all in the circuit, but I still have the hum.


----------



## tomb

Quote:


  Originally Posted by *lmiller* /img/forum/go_quote.gif 
_I did install the ferrites, but the hum was there before and after installing the ferrites. Because they were the arrays, I was not sure how to install them. Once I figured that out I went back and put them in. They are now all in the circuit, but I still have the hum._

 

Well, this is just a suggestion, but it may be in your regulation. What kind of regulator did you choose? If the regulator doesn't have enough voltage drop, it may not be removing power supply noise as needed. As the DAC heats up slightly under load, that noise may increase in intensity. It's possible that could be mistaken for oscillation.

 Do you have a pic? Someone might be able to spot something.


----------



## lmiller

I used the TI REG102UA-3.3 and the TI REG102UA-5. I used a 9 volt battery for power as well as a regulated power supply as well as USB bus power. I wouldn't think the 9 volt battery would have much noise at least not in the 60Hz range. I would also think with 9 volts there would be sufficient voltage drop to get proper regulation.

 I'll try taking a picture tonight. The soldering is not pretty, but since it works I think most everything is OK. My initial thought is that I have the wrong value resistor or capacitor in some location. Although I am pretty methodical.


----------



## xmokshax

hi everyone,

 i'm thinking of buying an Alien DAC 1.1 kit from www.glassjaraudio.com (this is the only place PCBs are available at this point, right?), but before i do, i just want to check and see if there are any common parts substitutions that people do to improve the SQ over the stock parts offered in the kit. any suggestions?


----------



## lmiller

I found my problem. I used the fixed regulators which do not require R32, which is also marked C32. I populated that C32 as well as the C32 on the back of the board resulting in double the capacitance. As soon as I removed the second C32, the hum went away. It was in the process of photographing the board that I saw the mistake.

 Thanks to everyone that helped. Now to install in my system and see if it an imporvement over my Creative Extigy.


----------



## FallenAngel

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Hey guys,

 I've got the weirdest thing happening with one of my AlienDACs. When I plug it into my desktop PC, I get a device not working properly error and my the USB port hub (not external, just the set of USB interfaces on the motherboard) stop responding.

 The weird part is that it works perfectly on my laptop 
	

	
	
		
		

		
			





 has anybody had this kind of problems, or have any idea of what's going on?_

 

Any ideas on what could be happening, it's definitely something weird. The AlienDAC is externally powered, so I know it's not a power draw issue, and I know the regulators work perfectly.


----------



## ruZZ.il

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_hi everyone,

 i'm thinking of buying an Alien DAC 1.1 kit from www.glassjaraudio.com (this is the only place PCBs are available at this point, right?), but before i do, i just want to check and see if there are any common parts substitutions that people do to improve the SQ over the stock parts offered in the kit. any suggestions?_

 

take a look at MASantos' build of the Alien DAC, that he offers fully built, here. He's using BlackGate ouput caps which could be quiet an upgrade from the kit, for instance. There has also been some chat, i think on this thread, about the caps. I built the kit from jeff and I really like it as is. I'll probably order another kit or 2 from him sometime and just get some other caps to play with and maybe build one with a different supply option. I also found that it works pretty well with my USB port, while some may not have enough power or too much noise.. so, an external power supply may result in better performance too..


----------



## xmokshax

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_take a look at MASantos' build of the Alien DAC, that he offers fully built, here. He's using BlackGate ouput caps which could be quiet an upgrade from the kit, for instance. There has also been some chat, i think on this thread, about the caps. I built the kit from jeff and I really like it as is. I'll probably order another kit or 2 from him sometime and just get some other caps to play with and maybe build one with a different supply option. I also found that it works pretty well with my USB port, while some may not to have enough power or too much noise.. so, an external power supply may result in better performance too.._

 

so MASantos has replaced capcitors CL and CR with the Blackgates, correct? would part #60206 here be appropriate?


----------



## ruZZ.il

tom made some with different caps. he has some comments on page 38 of this thread, posts 745, 750.. there is also a BoM there(commented on below it) with some p/n's.. there are probably more cap comments scattered throughout so reading through the post is suggested specially if you plan on tweaking anything, since a lot of it has been discussed.. although, those caps at pcx (60206) look right.. but its late and I haven't looked at dimensions.. or.. anything


----------



## tomb

ruZZ.il is referring to Muse ES caps. They are among Dsavitsk's favorties and are reviewed on his "Notes on Output Coupling Caps" web page -
http://www.ecp.cc/cap-notes.html

 I used 33uF, 16V from Handmade Electronics. The 47uF's are probably better, but they were out of stock when I ordered. The have absolutely _kicker deep bass_. I also built one with Black Gates (your PCx number is corrrect), so am able to compare the two.

 Actually, after extended listening, I sort of prefer the ES's. (I'm a huge basshead at heart.) The bass is just unbelievable - deep, tight, and punchy - it's like someone attached a subwoofer to my MAX. The BG's are definitely more detailed and dynamic, but the ES's aren't bad. You can also bypass either of these caps with some nice films - probably 0.22uF Sonicap Gen II's for the ES's, or a nice pair of Vitamin Q's for the BG's. I haven't tried it yet, but my guess is that the BG's aren't going to benefit much from that, but Dsavitsk notes that the Sonicaps really open up the highs on the ES's. I'll report back when I get around to adding them.


----------



## xmokshax

excellent. thanks, tomb and ruZZ.il, for the suggestions. i think i'll pick up some of the Nichicons - i'm a bit of a basshead as well. are there any good resellers of sonicaps, or are they only available from soniccraft itself? i'm not horribly fond of any of sonicraft's payment methods.


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_excellent. thanks, tomb and ruZZ.il, for the suggestions. i think i'll pick up some of the Nichicons - i'm a bit of a basshead as well. are there any good resellers of sonicaps, or are they only available from soniccraft itself? i'm not horribly fond of any of sonicraft's payment methods._

 

Yes - the price is right for the ES's. Even the large ones are only $1-$2.

 I believe I did see the Sonicaps listed at another DIY dealer, but can't remember where. Yes, I wish Soniccraft took Paypal. Nevertheless, let me assure you that they are one of the nicest dealers in the business. I sent them an e-mail for an order, then called them to give them my credit card #. Later on, it turned out that I had made an error on one item - they actually called me at home to confirm which one I wanted! They also carry the entire line of Black Gates at cheaper prices than the other vendor most recently mentioned with that product.


----------



## dsavitsk

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_excellent. thanks, tomb and ruZZ.il, for the suggestions. i think i'll pick up some of the Nichicons - i'm a bit of a basshead as well. are there any good resellers of sonicaps, or are they only available from soniccraft itself? i'm not horribly fond of any of sonicraft's payment methods._

 

A couple of things -- Soniccraft is a top notch dealer, and I recommend them without hesitation. You can also get some Sonicaps from GR Research (http://www.gr-research.com/). I have not ordered from them, but I have interacted with the guy who runs the company online and he was very nice and super helpful. 

 Finally, Sonicaps are good caps for the money, but if you are ordering Muses from one dealer and Sonicaps from another, then the shipping is going to make up for the money saved. Handmade sells various Relcaps which are very good, though different form the Sonicaps. Percy also sells Muse caps as well as Relcaps, Auricaps, Jupiters, Dynamicaps, and a few others, and he takes PayPal.


----------



## Eokboy

Hay guys. Just wanted to ask which version of ASIO4ALL are you people using? I'm still using the recommended v1.8, and I keep getting annoying occasional clicks. 

 The latest version is v2.8 beta 2.


----------



## xmokshax

ok, i'm thinking i might still order some Muses from Handmade and try bypassing them with some Relcaps. dsavitsk, you haven't tried bypassing the Muses with any of the Relcap varieties by any chance, have you? sounds like you only tried the Sonicaps. do you know which of the MultiCap lines might be best? also, how does the ideal bypass capacitance vary with coupling capacitance, if at all? you used 4.7uF coupling caps and 0.22uF bypass caps, but i had been planning on using 47uF coupling caps.

 edit: looks as though the RTX line is the consensus favorite MultiCap... any idea whether it's worth spending nearly double the price of the PPFX?


----------



## tomb

Dsavitsk is the Master on coupling caps, but 47uF and 0.22 bypass will work great, IMHO. The characteristics don't change that much within a cap line. The 1000uF and 470uF ES's I use still have just as much bass. As a matter of fact, give the ES's time to break in, and they'll sound unbelievable on their own - no bypass needed. I haven't done mine yet and I love it - boom, boom, blam, kabloom - plus the highs still come through with great dynamics and snap. Very nice.


----------



## xmokshax

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Dsavitsk is the Master on coupling caps, but 47uF and 0.22 bypass will work great, IMHO. The characteristics don't change that much within a cap line. The 1000uF and 470uF ES's I use still have just as much bass. As a matter of fact, give the ES's time to break in, and they'll sound unbelievable on their own - no bypass needed. I haven't done mine yet and I love it - boom, boom, blam, kabloom - plus the highs still come through with great dynamics and snap. Very nice. 
	

	
	
		
		

		
		
	


	


_

 

great - you're getting me excited about this DAC with the Muses 
	

	
	
		
		

		
		
	


	




 i'll still pick up a pair of Relcaps, to reach Handmade's minimum order... i'm just wrestling with whether or not it's worth paying the extra cash for caps from their best line.


----------



## dsavitsk

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_great - you're getting me excited about this DAC with the Muses 
	

	
	
		
		

		
		
	


	




 i'll still pick up a pair of Relcaps, to reach Handmade's minimum order... i'm just wrestling with whether or not it's worth paying the extra cash for caps from their best line._

 

A word of warning on Relcaps: The Multicaps in general, and the RTX's in particular, are very neutral and very revealing caps. This is as opposed to something like a Sonicap Gen 2 or an Auricap (or a Muse or a Blackgate) which is very warm and has lots of midrange bloom. The Multicaps are probably not what you want here as they will sound recessed in the mids. I would go with the PPFA which will be much more pleasing here. Multicaps are better as power supply bypasses


----------



## xmokshax

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_A word of warning on Relcaps: The Multicaps in general, and the RTX's in particular, are very neutral and very revealing caps. This is as opposed to something like a Sonicap Gen 2 or an Auricap (or a Muse or a Blackgate) which is very warm and has lots of midrange bloom. The Multicaps are probably not what you want here as they will sound recessed in the mids. I would go with the PPFA which will be much more pleasing here. Multicaps are better as power supply bypasses_

 

@ dsavitsk: PPFAs it is. just placed an order with Handmade for those, some muses, and some cerafines... i'm now going to be waiting with bated breath for the next five days. it's times like these when i curse having moved from PA to CA 
	

	
	
		
		

		
		
	


	




 .

 @ tomb: after going back a page or two and reading your initial impressions of the Muses vs the BGs, i might still have to get my hands on some BGs and see which of the two suit my ears better. if the detail and dynamics are a whole lot better with the BGs, i just might have to sacrifice some bass. oh, one other question: what have you lined those AlienDAC penguin tins with? looks very nice.

 in any case, thanks to both of you for all the advice!


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_@ tomb: after going back a page or two and reading your initial impressions of the Muses vs the BGs, i might still have to get my hands on some BGs and see which of the two suit my ears better. if the detail and dynamics are a whole lot better with the BGs, i just might have to sacrifice some bass._

 

I'd rather have the bass, but that's me. The BG's are good enough to put life in old vinyl-to-digital rips of classic rock albums that often sound compressed compared to modern, digitally-based recordings.

  Quote:


 oh, one other question: what have you lined those AlienDAC penguin tins with? looks very nice. 
 

Plain 'ol craft foam from Walmart. It's the kind that comes in sheets about 1/16" thick and many colors. I trace the mint tin with a ball point and then cut _inside_ the lines. The standoffs are cut out with the handy-dandy hole punch again. A few strips of double-sticky Scotch tape holds it all down. 
	

	
	
		
		

		
		
	


	




  Quote:


 in any case, thanks to both of you for all the advice! 
 

You bet! I love the Alien DAC. I smell something akin to Millett snobbery lately about the Alien DAC, but that's fine with me. $30-$40 for an Alien DAC, $175 for a Millett MAX (both DIY yourself, of course!), and some good FLAC files on a PC, and you'll have music as good as what some spend $thousands for, IMHO. Some people don't know what they're missing - or maybe I don't - but I am relishing in my ignorance.


----------



## Jrossel

I now have boards with the DAC chip soldered to them. Let me know if you want one.

 JR

  Quote:


  Originally Posted by *Dark_Shadow* /img/forum/go_quote.gif 
_Thanks for hint...

 My only problem is that I do not want to scrap them trying to solder the PCM2702...I know now that I do not have the practice and equipment to solder them... Like I said in a earlier post, I'm looking for someone that have some space time to solder the PCM on my two boards with compasation. 
	

	
	
		
		

		
		
	


	




 After that, I will solder the rest and continue to work on my case design (will be CNC machined case with LCD display, preamp and maybe I will also add a Gainclone in it to use it at work.)

 Dark Shadow_


----------



## xmokshax

damnit, just a week or two after i ordered mine...

 i think i may have botched my first attempt at soldering the PCM2702. it's probably good to get the experience of soldering that chip down, but DAMN those pins are tightly spaced. it's certainly not the most friendly introduction to SMD soldering . i keep accidentally bridging adjacent pins... sometimes it's easy to just place my iron across the two pins and pull the excess solder away, but on a couple of them all the flux burned away and they now refuse to flow. i ordered some flux paste, so i think i'll wait till that comes in to try to undo the damage i've done.

 if that doesn't work, though, i MAY end up just punting and ordering a board with the chip soldered on. i don't know that i want to enter into a vicious cycle of purchasing new $10 chips until i finally manage to get it right.


----------



## Dark_Shadow

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_I now have boards with the DAC chip soldered to them. Let me know if you want one.

 JR_

 

I would love too =)

 Can I have two? How much each? to you want me to send you the two board I currently have?

 So much question, so little time


----------



## Eokboy

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_damnit, just a week or two after i ordered mine...

 i think i may have botched my first attempt at soldering the PCM2702. it's probably good to get the experience of soldering that chip down, but DAMN those pins are tightly spaced. it's certainly not the most friendly introduction to SMD soldering . i keep accidentally bridging adjacent pins... sometimes it's easy to just place my iron across the two pins and pull the excess solder away, but on a couple of them all the flux burned away and they now refuse to flow. i ordered some flux paste, so i think i'll wait till that comes in to try to undo the damage i've done.

 if that doesn't work, though, i MAY end up just punting and ordering a board with the chip soldered on. i don't know that i want to enter into a vicious cycle of purchasing new $10 chips until i finally manage to get it right. 
	

	
	
		
		

		
		
	


	


_

 

Just add more flux once they dry up. The more the better. Desoldering wick helps get the job done.


----------



## xmokshax

Quote:


  Originally Posted by *Eokboy* /img/forum/go_quote.gif 
_Just add more flux once they dry up. The more the better. Desoldering wick helps get the job done._

 

i tried to add liquid flux, but it's tough to, a) deliver to a precise location, and b) deliver more than a miniscule coating to a single joint. does flux paste work better?


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_i tried to add liquid flux, but it's tough to, a) deliver to a precise location, and b) deliver more than a miniscule coating to a single joint. does flux paste work better?_

 

The flux only activates the solder on a solder-able pad. In other words, flood the whole board with flux, apply some solder, and it will be the pads that suck up the solder, not anything inbetween.

 That said, someone else suggested a Flux Pen. I thought I'd try one and was very impressed. The flux is diluted, but the effect is one of glue when it slightly dries - it's very sticky stuff. So, when you apply it all over a part's position, you can almost use it to glue the part in place - almost. 
	

	
	
		
		

		
		
	


	




 I didn't find the flood and suck to be very fruitful. Using a de-soldering wick to clean up after a mess has already been made seems counter-intuitive to me. It also exposes the part to a lot more heat, which can't be a good thing.

 Rather, the original method referenced by Alf on his website worked best for me. Hold the soldering iron tip horizontally across the pins and work sideways while moving the tip backwards along the length of the part, applying small bits of solder along the way. Extra solder or solder between joints is minimized, but any bridging is cleaned up by pressing the tip down horizontally across the pins, and using a wiping motion away from the part in the direction of the pins. Tangent also shows this method as a last-stage cleanup in soldering SMD opamps in his videos. Of course, this is only after you've anchored the whole part by soldering the corner pin on the other side, first.


----------



## xmokshax

when i was referring to adding flux, i meant adding it to an existing joint that had gone dry and was refusing to flow. liquid flux didn't seem to be working well for me in that situation.


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_when i was referring to adding flux, i meant adding it to an existing joint that had gone dry and was refusing to flow. liquid flux didn't seem to be working well for me in that situation._

 

OK - I probably said too much as usual, but the flux pen works well for that too.


----------



## xmokshax

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_OK - I probably said too much as usual, but the flux pen works well for that too._

 

not at all, any advice is always appreciated - i was just referring to a slightly different situation than the one you were describing. 
	

	
	
		
		

		
		
	


	




 my jameco order came in, so we'll see if this solder paste does the trick. hope so!


----------



## midnite8791

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_I now have boards with the DAC chip soldered to them. Let me know if you want one.

 JR_

 

I would be interested in a couple! I shall PM you


----------



## amb

Now that I am playing around with my Alien DAC more, I am experiencing some issues that I ignored before but is probably real. Most of the time, if I hot plug the USB cable, it works fine. But sometimes doing so would result in crackly/scratchy playback when the volume level is low. And other times it would only produce a loud random digital noise during playback. In each of these cases the OS recognizes the Alien DAC PCM2702 just fine and there is no indication that anything is wrong other than the sound. The only way to clear up the problem condition seems to be to unplug the USB cable and replug it again.

 I tried a couple of different USB cables and on different computers so I could rule those out as the problem.

 My Alien DAC is USB-powered. I wonder if there is an internal power-sequencing issue during hot plug? Anyone else experience this?

 Edit: Oh, I should mention that this is on Windows XP SP2 with ASIO4ALL 1.8 installed. On Linux (Kernel 2.6.13) I also experience these problems, but the crackling noise problem can sometimes be "fixed" just by changing songs (depending on the player). The digital noise problem seems to always require a re-plug, though.


----------



## tomb

Amb,

 Except for your description of a "loud random digital noise," all of this seems fairly typical from what I've noticed. As you state, uplug it and then plug it back it in. That usually works. In my case, I typically have to readjust the PC volume level, or in a worst case, select the Alien DAC as a source again (USB Speakers). It will also "clog up" Foobar, and that may need to be killed and re-started as well.

 I would note that I've experienced these same idiosyncracies with the M-Audio Transit. It seems nothing more than a minor irritation and considering the high-level, complicated OS decisions that must take place with switching drivers, communication interface, and PC sound selection, I don't believe it rises to the level of a fault, IMHO.

 If the Alien DAC is connected on boot up, it seems to work flawlessly without exception.


----------



## rjkdivin

AMB,
 I've been playing a bit with my Alien DAC as well. I have used it on two desk tops and my laptop.....it is recognized as USB Speakers on all three and they behave similarly. I did have to adjust the computer volume up for all three, as it defaulted to 50% upon recognition. My gain 11 Pint was okay at that level, but my gain 8 Pint did not have suitable volume with adjusting the computer.

 I have had no problems with scratchy sound or random digital noise so far, either when hot-plugging or pre-plugging. I'm running XP on all of the computers, and playing back from the Alien DAC through one of my Minified Pints. It acts the same with USB power or external power. I do get a thump powering on the DAC and thump with a diminishing whizzz when powering off, but that is easily combatted by turning down/off the amp vol prior to switching the DAC on/off.

 I'm posting a couple of pics on the Post Pics thread. I copied your switch/power jack layout front and rear, but did not shorten the cases.....you must work with small layouts better than I


----------



## amb

Thanks rjkdivin. I too think that something is not quite right with my Alien DAC. Unlike tomb's experience, my M-Audio Transit almost never exhibit these issues when hot-plugged (or for that matter, the M-Audio Firewire Audiophile), so I'm inclined to think the problem is specific to my Alien DAC. I am going to try and build a second one to see if it behaves any differently.

 Btw, I re-cased my Alien DAC into a black Hammond 1455C802, not shortened, and with custom FPE panels to match my Mini³. I also eliminated the switch and the external power jack, as my previous tests showed no benefit with external power.


----------



## primer

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_I now have boards with the DAC chip soldered to them. Let me know if you want one.

 JR_

 

Do I order this at your site?


----------



## xmokshax

as mentioned above, i'm having some trouble with (predictably) soldering the PCM2702 down. i have a couple of questions regarding this process. first, some background:

 i started out by soldering one of the corner pins down to get the chip in place, then continued to try to do the pins one at a time. this worked for a few pins, but i was frequently bridging pins and having a hard time clearing them (i tried the trick of placing my iron horizontally across the pins and pulling away - it just doesn't seem to work as well on a chip with such a fine pitch). i struggled with it for quite a while yesterday, then eventually got frustrated and decided i'd try the "flood-and-suck" method. unfortunately, this isn't working at all for me - i guess i just can't get my desolder pump in there quickly enough to catch the solder while it's still molten. this leads to my questions:

 1. what's the best way of clearing a BUNCH of pins that are bridged? any tips on making the "suck" part of "flood and suck" actually work? i've been removing small amounts of solder using the above horizontal iron techique, but it's terribly slow going, and seems to stop working JUST before i've removed enough solder to clear a given bridge.

 2. how much heat can a PCM2702 take? in the process of attempting the flood-and-suck method, the chip got too hot to touch several times. with all the pins bridged, as they are with this method, the chip is basically acting as a heatsink for the giant gob of solder on the pins. should i assume that i've fried it and start anew, or do they tend to be pretty resilient? 

 3. relating to the above, are there any straightforward tests that can be done while the chip is soldered down to determine whether or not it's still in working condition?

 4. does thin-gauge solder make a difference when soldering difficult chips such as this? i'm using 0.031", and am wondering whether it's worth picking up some 0.015" for my next attempt (or if i ever manage to salvage this one).


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_as mentioned above, i'm having some trouble with (predictably) soldering the PCM2702 down. i have a couple of questions regarding this process. first, some background:

 i started out by soldering one of the corner pins down to get the chip in place, then continued to try to do the pins one at a time. this worked for a few pins, but i was frequently bridging pins and having a hard time clearing them (i tried the trick of placing my iron horizontally across the pins and pulling away - it just doesn't seem to work as well on a chip with such a fine pitch). i struggled with it for quite a while yesterday, then eventually got frustrated and decided i'd try the "flood-and-suck" method. unfortunately, this isn't working at all for me - i guess i just can't get my desolder pump in there quickly enough to catch the solder while it's still molten. this leads to my questions:

 1. what's the best way of clearing a BUNCH of pins that are bridged? any tips on making the "suck" part of "flood and suck" actually work? i've been removing small amounts of solder using the above horizontal iron techique, but it's terribly slow going, and seems to stop working JUST before i've removed enough solder to clear a given bridge.

 2. how much heat can a PCM2702 take? in the process of attempting the flood-and-suck method, the chip got too hot to touch several times. with all the pins bridged, as they are with this method, the chip is basically acting as a heatsink for the giant gob of solder on the pins. should i assume that i've fried it and start anew, or do they tend to be pretty resilient? 

 3. relating to the above, are there any straightforward tests that can be done while the chip is soldered down to determine whether or not it's still in working condition?

 4. does thin-gauge solder make a difference when soldering difficult chips such as this? i'm using 0.031", and am wondering whether it's worth picking up some 0.015" for my next attempt (or if i ever manage to salvage this one)._

 

Your experience with flood and suck sounds like mine. The key to the horizontal method is to apply the solder to the soldering iron - not to the chip/pins. Then what you're doing is actually wiping the pins with a "wet" iron. Use as little as you possibly can get away with to make the pins "shiny."

 0.031" is OK if you apply it to the iron and wipe, but it may be more difficult to control the volume of solder. I've heard that 0.015" is almost impossible to work with, breaking at the slightest provocation. 0.020" or 0.025" or something like that might be a better compromise - from what I've heard. I have one or the other of those, but can't remember which.

 As for the chip, the less heat the better. I use the Hakko 936 and make sure the temp is not set above the maximum recommended soldering temp. I don't know if that helps, but if you have a regular iron, it will continue to increase in temperature, depending on how it's used. You can refer to TI's data sheet on the PCM 2702 for recommended soldering limits:
http://www.ti.com/lit/gpn/pcm2702
 Looks like it says 260 deg. C. as the maximum soldering temp on Pg. 3. That's probably conservative and it also says 5 secs, which when you think about it, is an awfully long time to be in contact with the chip. You should solder in a "drive-by" fashion on the pins - hitting them with quick whacks - at least that's how I did it. 
	

	
	
		
		

		
		
	


	




 'Course, I've been extraordinarily lucky to have done it twice now.


----------



## holland

Wow, 260C is pretty low. I just assembled mine this weekend and used about 650F. It was my first time doing an SMT project and I lost C1 in it's packaging entirely (waiting for Jeff to get more) and had a learning experience with tweezers...spring loaded == bad. I also have to thank Jeff for helping me out and responding to my e-mails of (oops, I just lost C21, and there goes C11 too before I switched to manual tweezers).

 I did a test run and all was OK. 

 For soldering PCM2702 I found it mostly easy. Bear in mind this is this is the fourth SMT item I've ever soldered, so take it as some notes from a n00b for other n00bs. 

 The items that bothered me the most were actually the smaller SMT items like the resistors and caps. Trying to center mount them and then finding enough room to get solder onto the pads was difficult. In my earlier attempts I would move the resistor all the way over so I have more room to apply to the pad, but I got the knack of it towards the end and those are laid down a little more evenly, relative to the pads.

 Anyhow, for the PCM. I used 0.031" Radio Shack solder. I did the wipe method, but not fully. I partially flooded 1 pad, then used that to draw across the others and applied more solder to a pad and drew again. Note, it's the pad, not the pins. I never applied the solder directly to the pad or pins. Always to the soldering iron tip first then to the object. When applying solder to a pad, I put solder on the tip of my iron and touched the pad, letting fluid dynamics take it's course. 

 Sometimes it got messy from a momentary spasm or too much solder on the tip, but using a wick to clean up the excess and wiping again to reflow and clean. If some solder got behind the pins, I cleaned my tip good, then wiped the upper bends that elevate from the pads. That melts the solder and it flows down. I used paste flux liberally too, at one point, to clean I put paste all over the pads and pins and quickly wiped and then flooded with alcohol and some brushing to remove all the flux for inspection. My pad and pins are quite clean, except for the 2 pins that are bridged to ground. I may have gone overboard with the brushing as some lettering off the ICs are gone.

 I'll try to post pics some time, for evaluation.

 I hope that's helpful to you, xmokshax.


----------



## xmokshax

the above advice has definitely been helpful. unfortunately, i should have probably asked before flooding the pads entirely.... i think i now have quite a job ahead of me if i'm going to get this sucker cleaned off and all of the pins un-bridged. i'll probably take another crack at it tonight, and if that fails, i'll be sending Jeff an e-mail for a new chip and board... 

 as far as temperature goes, i started out at ~500F, then bumped it up to 600F when joints were taking a long time to melt. as i said, the chip sometimes got too hot to touch, so i'm wondering whether it's still OK, especially since i was soldering a bit above the recommended max temperature.


----------



## holland

600 should be fine as I did ~600-650 and everything works, at least from the short test I did. What you have to watch out for are the hold times. Keep it short and quick. For that, I like a hot iron. I find lower temps makes me hold longer to reflow, which doesn't work as well.

 Use a wick and clean up as much as you can on the pads, ignore the legs for the time being. Then clean the tip and wipe along the legs that raise upwards. That will help some. Keep repeating, but take breaks in between to let it cool. It's like welding a bead on a casing with parts inside, like an axle. Do it all at once and the internal components will seize.

 It wouldn't hurt to smear flux all over the legs, I believe. I didn't use liquid flux at all. I used a small screwdriver and wiped paste flux on all the pads I was working on.

 Also, if you really are having issues with heat, you may be able to put a small heatsink on the chip, and hold it in place with your finger, offset so you can work on the pins/pads on one side. Hopefully that works, I've never done it. That will help dissipate some of the heat from the chip casing.


----------



## xmokshax

i did consider heat sinking the chip, but i don't have any small sinks lying around. i'm a bit worried that i've held too long on this chip, and i wish that there were an easy way to test whether or not i've fried it, before i put a lot of time into fixing it and solder the rest of my kit's components onto this board.


----------



## error401

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_i did consider heat sinking the chip, but i don't have any small sinks lying around. i'm a bit worried that i've held too long on this chip, and i wish that there were an easy way to test whether or not i've fried it, before i put a lot of time into fixing it and solder the rest of my kit's components onto this board._

 

Anything metal can be used as a makeshift heat sink for this purpose. I often place a pair of needlenose pliers on a component or directly on the lead if possible to dissipate some heat. It makes quite a difference.


----------



## Televator

anyone having luck locating the REG101UA chips lately? Both RS-components and Farnell list 'em as "no longer available"... drats, I have a PCB laying here waiting to be built and wanted to order a couple more as well from Jrossel...


----------



## Dark_Shadow

Last quick check of the BOM before order from digikey. I think I cleaned everything that needed to be cleaned 
	

	
	
		
		

		
		
	


	




  Code:


```
[left]Customer ReferencePart NumberDescription C14-C19, C21, C22, C31, C32490-1673-1-NDCAP CER .1UF 25V 10% X7R 0805 C11-C12478-1310-1-NDCAP CERM 33PF 5% 50V NP0 0805 C1478-1416-1-NDCAP CERM 4.7UF 10% 6.3V X5R 0805 C13-CL-CR604-1054-NDCAP 47UF 25V ELECT AUDIO RAD C23-C33604-1055-NDCAP 100UF 25V ELECT AUDIO RAD X1X030-NDCRYSTAL 12.000MHZ 32PF HC-49/UA Led160-1035-NDLED 3MM ALGAAS RED DIFFUSED IC2REG102UA-3.3-NDIC LDO REG 3.3V 250MA 8-SOIC IC3REG102UA-5-NDIC LDO REG 5V 250MA 8-SOIC IC4REG102UA-A-NDIC LDO REG ADJ 250MA 8-SOIC L11-L18490-1057-1-NDFERRITE CHIP 600 OHM 1500MA 1206 C2P12354-NDCAP 1000UF 10V ELECT FM RADIAL USB151-1081-NDCONN USB JACK TYPE B HORIZON R/A R11-R12541-22.0CCT-NDRES 22.0 OHM 1/8W 1% 0805 SMD R13541-1.50KCCT-NDRES 1.50K OHM 1/8W 1% 0805 SMD R14541-1.00MCCT-NDRES 1.00M OHM 1/8W 1% 0805 SMD R15-R16541-332KCCT-NDRES 332K OHM 1/8W 1% 0805 SMD RLED541-604CCT-NDRES 604 OHM 1/8W 1% 0805 SMD[/left]
```


----------



## FallenAngel

You don't need IC4 unless you plan to power the amp via virtual ground amp (most likely you're not).

 How will you power this thing? I personally never saw a reason to use a fixed regulator because you'll have to use external power, and if you're doing that already, might as well run at 5.4V instead (hense adjustable).

 If you're powering it using USB, you're still probably better off using adjustable, just regulate it down to 4.7-4.8V. You can also leave it completely unregulated, but I personally don't know how good the performance is, I think it's pretty similar.

 Just remember, if you're going for an adjustable regulated, you'll need 2 more resistors - check out NOTES on this page.


----------



## Dark_Shadow

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_You don't need IC4 unless you plan to power the amp via virtual ground amp (most likely you're not)._

 

Noted and removed

  Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_If you're powering it using USB, you're still probably better off using adjustable, just regulate it down to 4.7-4.8V. You can also leave it completely unregulated, but I personally don't know how good the performance is, I think it's pretty similar.

 Just remember, if you're going for an adjustable regulated, you'll need 2 more resistors - check out NOTES on this page._

 

I think I gonna start the first one regulated USB so i gonna order the already calculated value for R31/R32 and will see for the AlienDAC no.2 
	

	
	
		
		

		
			





 Thanks for your support,

 Also, any comments on the quality of the component? I do not mind spending more if needed 
	

	
	
		
		

		
		
	


	




 Like I looking for No.2 to order some MUSE ES 47uf 16v to improve the sound...


----------



## FallenAngel

You're in Canada, go over to www.PartsConneXion.com and grab some BlackGate NX instead of those Elna Silmic II output caps, or better yet (and if you have room which you probably do), buy some nice film caps for that baby 
	

	
	
		
		

		
		
	


	




, just make sure to calculate how much room you have in the case before buying the caps.


----------



## tomb

The 47uF, 16V ES's are too big at 8mm diameter. The board just doesn't have room with the layout.

 One of my Aliens has the Muse ES 33uF-16V. They are the largest you can readily fit in CL/CR and they are really good. So far, I like them better than the BG's - way more bass - very, very deep, too. It's not muddied, false bass, either. It may be that my BG version is in that "fog" of mid-break-in I've read about. Yet, the ES highs are still great even with all that bass. Dsavitsk says with some Sonicap Gen II bypasses, they'll be even better. I haven't tried the bypasses yet, though.

 So, I wouldn't hesitate to go with the Muse ES 33uF/16V - good choice:

 31 cents each, but ya gotta order some more stuff to go with it for a minimum:
http://www.hndme.com/productcart/pc/...&idproduct=742


----------



## Dark_Shadow

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_
 So, I wouldn't hesitate to go with the Muse ES 33uF/16V - good choice:

 31 cents each, but ya gotta order some more stuff to go with it for a minimum:
http://www.hndme.com/productcart/pc/...&idproduct=742_

 

The only problem with handmade is that their ask for 100$ dollard minimum order to export... I can't really order for 100$ of Muse ES 
	

	
	
		
		

		
		
	


	




 and I do not really need more stuff from them....at least, not for this amount... Maybe you know a other source with a more reasonable minimum order


----------



## xmokshax

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The 47uF, 16V ES's are too big at 8mm diameter. The board just doesn't have room with the layout._

 

oh no... i ordered precisely those caps for my Alien! since i botched the PCM2702, i hadn't tried to fit any of the other parts onto the board yet. i'm sure a bit of creative lead-bending will fix the problem.


----------



## Dark_Shadow

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_You're in Canada, go over to www.PartsConneXion.com and grab some BlackGate NX instead of those Elna Silmic II output caps, or better yet (and if you have room which you probably do), buy some nice film caps for that baby 
	

	
	
		
		

		
		
	


	




, just make sure to calculate how much room you have in the case before buying the caps._

 

Any suggestion for the film cap 
	

	
	
		
		

		
		
	


	




 Because space is not a issue because I will build the case from scratch, so I'm not limited to the dimension of hammond case 
	

	
	
		
		

		
		
	


	




.


----------



## KurtW

I bought a kit from Jrossel and everything went together well. The only substitution I made was some 10uF Wima MKS film caps for the outputs which just fit on the board. I put it in a mint tin for lack of anything more suitable on hand. I am very happy with the operation and sound. I plugged it into a Mac and a Windows XP machine with no issues. Thanks Jeff for supporting this project.


----------



## tomb

Mint tin Alien DAC's are cool.


----------



## smegger

hi there i am going to buy some of these to run from my pc, and also from my mates laptop hence he would like usb powered is the chip out of stock with jeff integral to my plan of usb powered?


----------



## Televator

Quote:


  Originally Posted by *smegger* /img/forum/go_quote.gif 
_hi there i am going to buy some of these to run from my pc, and also from my mates laptop hence he would like usb powered is the chip out of stock with jeff integral to my plan of usb powered?_

 

I have just heard from Jeff the kits are in stock again (I ordered 2 right away 
	

	
	
		
		

		
		
	


	




 ) so just contact him


----------



## Eokboy

Quote:


  Originally Posted by *Televator* /img/forum/go_quote.gif 
_anyone having luck locating the REG101UA chips lately? Both RS-components and Farnell list 'em as "no longer available"... drats, I have a PCB laying here waiting to be built and wanted to order a couple more as well from Jrossel..._

 

Lol I think I bought the last REG101UA-3.3V Farnell had. No luck getting the 5V one, so I just leave it unregulated, plus inductor config.

 Farnell usually give you ETA of when 'out of stock' parts are replenished


----------



## xmokshax

so i took a second crack at soldering the PCM2702E this evening, and it was done within 15min or so EXCEPT for two pairs of bridged pins, which i can't clear for the life of me (i tried for at least an hour after finishing the rest of the chip). pins 13 and 14 are bridged, as are 15 and 16. the datasheet shows that these are "test" pins - any chance that the chip will still function despite their being bridged?


----------



## MisterX

If you check the schematic you may notice those pins are shorted together anyhow so....


----------



## xmokshax

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_If you check the schematic you may notice those pins are shorted together anyhow so...._

 

sweet! onward and upward...


----------



## xmokshax

as far as testing the DAC before plugging it in goes, is simply connecting a 9V (rechargeable putting out 9.26V) across AV+ and G2 acceptable, or does this have to be a power supply with equal +/- rails? also, after a power source is connected, are voltage measurements made between the test points and G1?

 this is a regulated USB configuration (JRossel kit)... the only thing i've changed are the output caps.


----------



## error401

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_as far as testing the DAC before plugging it in goes, is simply connecting a 9V (rechargeable putting out 9.26V) across AV+ and AG acceptable? IC3 can take up to 10V, right? also, after a power source is connected, are voltage measurements made between the test points and G1?

 this is a regulated USB configuration (JRossel kit)... the only thing i've changed are the output caps._

 

Your idea will work, if you don't have a 5V supply handy, but it's a little close to the limit for my comfort. I wouldn't suggest it, just make sure that the USB power leads are not shorted together (DMM on ohms mode) and there isn't really any way the DAC could damage your computer. Just plug it in


----------



## xmokshax

wooo! it lives! and it sounds fantastic!


----------



## civilmonkey

I just built an Alien DAC with a Jeff R kit and it sounds great! Currently I have a fixed 5 volt regulator installed and power it directly off USB (my error, I didn't read the SOIC8 chip close enough!). So I guess there is no regulation going on, but it still sounds great! Thanks to Jeff for the kit and his great service.

 1. Is anyone running their DAC like this? I.e do you think I'll notice a diffference if I swap to an adj. reg. and regulate to 4.8 volts? (I want this to be USB powered) 

 2. For another DAC I'm planning on powering with my PIMETA. If my PIMETA is 18 volts rail to rail, will I need heat sinking on the regulator? Wouldn't the SOIC8 chip have to burn off around 4 volts?

 Thanks


----------



## bhjazz

Quote:


  Originally Posted by *splaz* /img/forum/go_quote.gif 
_I replaced 2 of the electrolytics that the soldering iron touched a little just in case of any damage, doubtful but possible._

 

I've had to do that myself with certain projects. I found out (far too late) that I could wrap the caps with some tin foil before getting the iron in there. That way when my fingers flinch, the iron doesn't burn the cap-wrapping!


----------



## stevodude

crickey, 43 pages and climing 

 anyway, I bought the pcb's yonks ago, and thought I'd try to build at least 1 working aliendac ( ordering parts for 2, just in case I get it right & can build a second unit as I have plenty of pcbs 
	

	
	
		
		

		
		
	


	




 )

 anyway here's my farnel bom, check it over to see what I've done wrong.
 No CL/CR, but I have a few Muse ES 100uf 25v, can I use these?
 Regulated for 4.725v from usb power?
 I will probably use a 3.5mm stereo jack for output into a headamp (to build the soha next, but use cmoy for the moment).


----------



## MASantos

Quote:


  Originally Posted by *stevodude* /img/forum/go_quote.gif 
_crickey, 43 pages and climing 

 anyway, I bought the pcb's yonks ago, and thought I'd try to build at least 1 working aliendac ( ordering parts for 2, just in case I get it right & can build a second unit as I have plenty of pcbs 
	

	
	
		
		

		
		
	


	




 )

 anyway here's my farnel bom, check it over to see what I've done wrong.
 No CL/CR, but I have a few Muse ES 100uf 25v, can I use these?
 Regulated for 4.725v from usb power?
 I will probably use a 3.5mm stereo jack for output into a headamp (to build the soha next, but use cmoy for the moment).



_

 

Steve, I have all the necessary resistors for the Alien from my builds in spare. I won't build anymore so I don't really have any real use for them. I could send them to you if you want, so you don't have to buy 50 of each. I might have some other parts I could send you. drop me a PM if interested. 
 I'll check everything again tonight and let you know what parts I have.

 Regards

 Manuel


----------



## xmokshax

Quote:


  Originally Posted by *stevodude* /img/forum/go_quote.gif 
_crickey, 43 pages and climing 
 ...
 No CL/CR, but I have a few Muse ES 100uf 25v, can I use these?
 Regulated for 4.725v from usb power?
 ..._

 

you might be able to use them, but they're definitely too big for the board - you'll have to get pretty creative to fit them in. i have 16V 47uF Muse ESs in my Alien, and even those were a mm or two too big for the space allotted, so i had to bend the leads on one of them such that it could sit farther over on the board, i.e., not directly above its pads. this was a tight fit even with the creative lead bending, and the holes are oriented such that you won't be able to just flatten either CL or CR down on the board (there are other caps on either side of them).


----------



## xmokshax

on another note related to the Muse ESs as coupling caps, has anyone tried bypassing them with film caps? tom, have you tried those Sonicaps yet, or taken dsavitsk's suggestion and tried the 0805 SMD film caps?


----------



## tomb

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_on another note related to the Muse ESs as coupling caps, has anyone tried bypassing them with film caps? tom, have you tried those Sonicaps yet, or taken dsavitsk's suggestion and tried the 0805 SMD film caps?_

 

Nope - haven't tried them yet, but there's no reason to doubt Dsavitsk's findings. The ES caps sound pretty good by themselves. I'd rank them about 80% of the BG's overall response, with no contest in the bass. So, if the Sonicaps just open the highs up slightly, it'll be a killer combination.

 It's difficult to describe the ES highs - they don't lack in the highs, just in the resolution. The response is there, just kind of rough - perfect for a good film in bypass.


----------



## Televator

just finished my first (regulated USB) Alien DAC 
	

	
	
		
		

		
		
	


	




 it is not yet cased, but it is running nicely with my (first) Cmoy out of my 12" G4 PowerBook. My headphone out died just a couple days ago (required constant pressure to keep the right channel connected) so the DAC came just in time. It has only got a couple of hours on it, but it sounds great already.

 I ordered some kits from Jrossel, and also a PCB with the SSOP28 chip soldered in already... but I decided to give it a try myself as well (on the Board I won from Fabio 
	

	
	
		
		

		
		
	


	




 ) and it worked pretty well (first sweep left a few bridges, but they were easily cleaned up). I used the standard parts from the kit, so no experimenting with (boutique) output caps (yet)...

 I also have a fun idea for a case (based on a mints tin... can I join your team TomB?) but it won't be very easy... I'll post it in the gallery once finished


----------



## stevodude

This probably a silly question, but here goes anyway...

 If I have a computer with multiple usb ports, assuming each port can output 5v/500ma, is there a way to use a dual usb cable and generate +/-5v ie 10v@500ma to power a opa2132 headphone amp circuit?...

 Can this power section also be able to be switched to external 9-12v dc source.

 Would I need some sort of buffer at point *A, or could the aliendac drive both line out & headphone amp?

 example MS paint idea 

 Or is my idea way to complicated and morphing away from being useful...

 probably won't bother with the 'alternative power source', but utilize the dual usb power somehow, and still have headphone & line out so I can drive headphones or portable powered speakers.
 Maybe I can use the headphone out to the speakers, thereby not needing the line out?

 main thing I think would be cool is a custom connector on the morphed/aliendac so I can drive the dac from dual usb to get +/-5 at 500ma (giving me effectively 10v@250ma+ or so for headamp , instead of a dc converter from 1 usb port which will end up giving me 10v@100ma for the headphone amp...


----------



## error401

Quote:


  Originally Posted by *stevodude* /img/forum/go_quote.gif 
_This probably a silly question, but here goes anyway...

 If I have a computer with multiple usb ports, assuming each port can output 5v/500ma, is there a way to use a dual usb cable and generate +/-5v ie 10v@500ma to power a opa2132 headphone amp circuit?...

 Can this power section also be able to be switched to external 9-12v dc source.

 Would I need some sort of buffer at point *A, or could the aliendac drive both line out & headphone amp?

 example MS paint idea 

 Or is my idea way to complicated and morphing away from being useful...

 probably won't bother with the 'alternative power source', but utilize the dual usb power somehow, and still have headphone & line out so I can drive headphones or portable powered speakers.
 Maybe I can use the headphone out to the speakers, thereby not needing the line out?

 main thing I think would be cool is a custom connector on the morphed/aliendac so I can drive the dac from dual usb to get +/-5 at 500ma (giving me effectively 10v@250ma+ or so for headamp , instead of a dc converter from 1 usb port which will end up giving me 10v@100ma for the headphone amp..._

 

The problem with this idea is that internal to the computer, there is usually a single 5V supply. All the USB ports' supply lines are connected together on the motherboard, so if you connect them like you propose you're creating a short circuit


----------



## stevodude

oh...

 well there must be someway of doing it with a chip/transformer/circuit of somesorts, ie Porbably NOT like below with 2 transformers, but someway of doing it. (I just have '.' where spaces should be)

 usb1 +5v ---| |------ +5v
 .................| |
 .................| |
 .................| |
 usb1 gnd ---| |---|
 ..........................|----Gnd
 usb2 +5v ---| |---|
 .................| |
 .................| |
 .................| |
 usb2 gnd ---| |--------5v


----------



## error401

Oh yes, it can be done, but not in the way that you propose. A transformer wouldn't work because they're inductive devices and thus only work when there's a changing current - AC. You'd need a DC-DC converter of some sort (a chopper + transformer would work); these circuits are very in-demand these days in portable applications like laptops and cellphones - you'll find lots of examples at any IC manufacturer's site. It's not going to be as simple as a few pieces of wire though.

 If you're really serious about this, about the simplest I've seen is the DCP02 series from TI. The only required external components are some decoupling capacitors. I've used them in an audio application, and they're not too bad - but I would recommend post-regulation, they're pretty noisy. They don't provide much current, either and are unregulated.


----------



## dsavitsk

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_or taken dsavitsk's suggestion and tried the 0805 SMD film caps?_

 

I tried it -- bypassing some pretty large electrolytics (330uF) with the 0.1uF 0805 film caps, I didn't hear much difference. Mind you, I didn't do a close comparison, the ratio between the caps may have been too large, and the electrolytics were solid organics (os-cons) which are better at high frequencies than the Muses. So I sill think bypassing the Muses might be worth the experiment, but in my case, it didn't seem to matter.


----------



## Chrizo

I build a Alien Dac too, but I have some problems. When attaching it to my PC it says 'Unknown device (device might be broken)'. Does anyone have an idea what i might have done wrong?


----------



## xmokshax

Quote:


  Originally Posted by *Chrizo* /img/forum/go_quote.gif 
_I build a Alien Dac too, but I have some problems. When attaching it to my PC it says 'Unknown device (device might be broken)'. Does anyone have an idea what i might have done wrong?_

 

well i haven't had to do much troubleshooting on this project, and this is the most obvious thing, but the first thing you should do is re-check EVERY joint on the PCM2702. it sounds like the computer is recognizing that a chip is there, but that the chip is either, a) not connected correctly, or b) fried. 

 if you have a multimeter with fine enough probes, i recommend going over the entire chip and checking the resistance between each pad and the upper part of the corresponding pin, to ensure that you have a good joint. i also checked the resistance between adjacent pins and pads, to make sure i didn't have any hidden bridges. if you do this, note that pins 13, 14, 15 and 16 are all connected to ground, so the resistance will be roughly zero between any two of them, if they're connected properly.


----------



## xmokshax

Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_I tried it -- bypassing some pretty large electrolytics (330uF) with the 0.1uF 0805 film caps, I didn't hear much difference. Mind you, I didn't do a close comparison, the ratio between the caps may have been too large, and the electrolytics were solid organics (os-cons) which are better at high frequencies than the Muses. So I sill think bypassing the Muses might be worth the experiment, but in my case, it didn't seem to matter._

 

perhaps i'll still give those 0805 caps from Digi-Key a shot. unfortunately, i don't know that i'll ever use them again if the result isn't good, and Digi-Key makes you buy a minimum of ten 
	

	
	
		
		

		
			





. but... i guess i can forgo lunch one day and spend that $3.30 on caps instead 
	

	
	
		
		

		
		
	


	




.


----------



## bhjazz

Quote:


  Originally Posted by *Chrizo* /img/forum/go_quote.gif 
_I build a Alien Dac too, but I have some problems. When attaching it to my PC it says 'Unknown device (device might be broken)'. Does anyone have an idea what i might have done wrong?_

 

Hi Chrizo! There are many discussions about this subject within this huge thread. I would encourage you to use the search feature and search for the word unknown. I'm positive you'll find some answers. Mostly, though, you'll find that the top things to check would be:
 - is your board cleaned (flux can short some of the pins on the 2702)?
 - is there any solder between the pins of the 2702?

 As you can see, lots of items deal with the main chip on there. But there are lots of replies to those questions as well!

 Welcome to Head Fi!


----------



## ezkcdude

Quote:


  Originally Posted by *xmokshax* /img/forum/go_quote.gif 
_perhaps i'll still give those 0805 caps from Digi-Key a shot. unfortunately, i don't know that i'll ever use them again if the result isn't good, and Digi-Key makes you buy a minimum of ten 
	

	
	
		
		

		
		
	


	




. but... i guess i can forgo lunch one day and spend that $3.30 on caps instead 
	

	
	
		
		

		
		
	


	




._

 

These are such standard values for decoupling IC's, that if you do any smt PCB's in the future, you will need much more than 10. I bought 100 recently. Of course, the NP0/COG are more expensive than the X5(7)R. Still, these are generally used all over the place in electronics (not just audio).


----------



## xmokshax

Quote:


  Originally Posted by *ezkcdude* /img/forum/go_quote.gif 
_These are such standard values for decoupling IC's, that if you do any smt PCB's in the future, you will need much more than 10. I bought 100 recently. Of course, the NP0/COG are more expensive than the X5(7)R. Still, these are generally used all over the place in electronics (not just audio)._

 

good to know - i no longer feel so bad about buying 10. don't think i'll jump on board and buy 100 like you just yet, though.


----------



## mrbubbs

So I just finished botching the solder job on my 2nd alien PCB while trying to solder in the PCM chip.

 On the first board/try, I took a toothpick and individually fluxed each pad. I then tinned a corner pad with a very small amount of solder. I slid the chip into place and soldered the first pin. I was going to solder each pin.. I got up to 4 pins done and then a bridge! So I tried to add some flux and sorta move the solder away from the chip but it really wouldn't move much. I tried a solder braid but that didn't pull much solder either. I then decided to try to add more solder and make sure my tip was clean and sweep it across, but I think the solder just flowed underneath and connected where I couldn't easily reach it with the braid or just to get it to separate with heat.

 On my second board, I tried to get tricky and tin each pad with a very tiny amount of solder.. I set the chip into place and tacked the first pin. I then was pretty successful with all the pins and then on the other side, I added too much solder because some of the pins weren't setting to the pads and it went much like the first chip, only this time, the pins had kinda slid off the bump of the tinned pads and weren't lined up correctly!

 So, I'll maybe order a third PCB and if I can't get it, I'll just use Jeff Rossel's excellent pre-soldered chip option but I'm pretty stubborn about doing things myself.. since it is a DIY project!

 I was watching the very few youtube vids on SSOP28 and read some popular how-to posts on here about soldering these chips but I can't manage to get something usable (yet).


----------



## tomb

FYI - from my own experience, it seemed that to make the flood and suck work would require a too-hot iron. Like you, I found that the wick was less than optimum in pulling the solder from the pins - unless you turned the heat up and spent more time applying that heat, etc. - which can't be good for the PCM chip.

 Instead, I used the method that Alf references on his website: applying a tiny bit of solder to the tip, while working horizontally across the rows of pins and wiping constantly as you go. It's sort of an action of putting a little solder on the tip, then wiping it off in a downward and away motion parallel to the direction of the pins. If you get a bit more solder, then continue wiping until the solder cleans up. You start it out with flux everywhere - the solder will only stick to the pins and the pads. A bridge only results if you use too much solder. The wiping minimizes that potential. Better to think you haven't added enough solder than to start out cleaning up blobs in the first place.

 That seemed to work better for me, practically and psychologically. On the other hand, the flood and suck method seemed more one of "ruin it, then fix." Of course, IMHO and YMMV.


----------



## smegger

i made a bit of a hash of mine to begin with but continued to flux and wipe for about an hour till i got it done just give the chip time and dont let it get too hot.

 ill post pics once i get the mountain of flux cleaned off the board!


----------



## geofftnz

I finally found time to put mine together. Messed up the soldering of the PCM chip the first time trying to do it with my old butane iron and no flux. After that I went down to Jaycar and bought an electric iron and a flux pen. 2nd attempt was a little more successful. (Having a glass of wine also helped - my hands were too jittery from too much coffee). I painted flux over everything, pinned the opposite corners of the chip. I was worried about bridging on the bottom corner, until I realised the pins were connected anyway. I tried the method where you run the iron down the edge of the pins, but I had too much solder so it bridged the lot. I used solder braid and my (hotter) butane iron - keeping the iron on one spot in the braid and moving both quickly down the line of the pins. Not sure if that's the proper technique, but it seemed to work. By some miracle everything worked and I'm listening to it now. 

 The one thing I have noticed is that with the amp turned up, I can hear noise that is influenced by mouse movement, graphics card and disk activity. I assume it's a common thing because pretty much every work PC I've used with ****** onboard sound has had real bad noise of a similar nature. Is this RFI that's being picked up by the DAC, or something like a power supply issue? (Currently unregulated USB) I've got it sitting in an unshielded plastic case until I find it something better.

 That said, the noise floor is well below my threshold of hearing with my amp set at a reasonable volume. I'm really happy with this awesome little circuit! I'll build another when I get around to doing my headphone amp. Thanks heaps to everyone who worked on the design!


----------



## Calroth

To check if it's a power-supply issue, just grab some batteries... three fresh alkaline AA batteries should get you somewhere between 4.5 and 4.8V, enough for testing your unregulated config. Tape them together and go. (Make sure it's not above about 5.5V or you'll start frying something... Also make sure that the switch S1 on the board is OPEN, otherwise you may send the battery's juice straight back into your USB port. It doesn't like that.)


----------



## iewgnail

hi,

 i just build my alien dac.

 i got the 3v3 but on my 5v i'm getting 1.47v.

 where shld i look towards for debugging?


----------



## geofftnz

Quote:


  Originally Posted by *iewgnail* /img/forum/go_quote.gif 
_hi,

 i just build my alien dac.

 i got the 3v3 but on my 5v i'm getting 1.47v.

 where shld i look towards for debugging?_

 

If you're building the unregulated USB version, did you jumper pads AV+ to 5V? If you used an adjustable regulator, have you got the correct resistor values?


----------



## iewgnail

i'm building from a kit i got from jeff.

 so the resistor values shld be correct.

 i'm guessing since the 5v isnt there i shld be looking at the regulator IC instead. Not sure what caps and resistor shld be populated if i'm building from the kit jeff packed. it be running from usb alone


----------



## nysulli

its possible that you switched R31 and R32, as following the equation for choosing them,

 Vout = ( 1 + R31 / R32) * 1.26

 would give approximately 1.47 if you put R31 and R32 in the others position, so it could be a very minor issue, my math just so you don't have to do it for a 4.8v out

 ( 1 + 31k / 11k ) * 1.26 = 4.82

 but

 ( 1 + 11k / 31k ) * 1.26 = 1.7


----------



## tomb

Quote:


  Originally Posted by *nysulli* /img/forum/go_quote.gif 
_its possible that you switched R31 and R32, as following the equation for choosing them,

 Vout = ( 1 + R31 / R32) * 1.26

 would give approximately 1.47 if you put R31 and R32 in the others position, so it could be a very minor issue, my math just so you don't have to do it for a 4.8v out

 ( 1 + 31k / 11k ) * 1.26 = 4.82

 but

 ( 1 + 11k / 31k ) * 1.26 = 1.7_

 

Agreed - very good catch!!


----------



## iewgnail

i'm having the correct resistors.

 so i doubt its a mix up of R31 and R32.

 have posted up some pics. 

 My R32 is at btm and C32 at top. Is this the problem?


----------



## geofftnz

Quote:


  Originally Posted by *geofftnz* /img/forum/go_quote.gif 
_The one thing I have noticed is that with the amp turned up, I can hear noise that is influenced by mouse movement, graphics card and disk activity. I assume it's a common thing because pretty much every work PC I've used with ****** onboard sound has had real bad noise of a similar nature. Is this RFI that's being picked up by the DAC, or something like a power supply issue? (Currently unregulated USB) I've got it sitting in an unshielded plastic case until I find it something better._

 

After a process of elimination I found that most of the noise is coming from my LCD monitor. There's a high-pitched whine that I assume is coming from the inverter for the backlight. The noise on mouse movement seems to be from the monitor too, because that disappears if the cursor is not visible (e.g. in a fullscreen cmd shell). Time to look for a good shielded case for this project.


----------



## tomb

Quote:


  Originally Posted by *iewgnail* /img/forum/go_quote.gif 
_i'm having the correct resistors.

 so i doubt its a mix up of R31 and R32.

 have posted up some pics. 

 My R32 is at btm and C32 at top. Is this the problem?_

 

Yes, when using R31 and R32 for adjustable, regulated voltage (~4.5 - 4.8V), R31 and C32 go on the bottom. Only R32 is on top.

 Due to the pad placement in relation to the circuit, I believe that does effectively reverse the two resistors.


----------



## tsaavik

Quote:


  Originally Posted by *geofftnz* /img/forum/go_quote.gif 
_After a process of elimination I found that most of the noise is coming from my LCD monitor. There's a high-pitched whine that I assume is coming from the inverter for the backlight. The noise on mouse movement seems to be from the monitor too, because that disappears if the cursor is not visible (e.g. in a fullscreen cmd shell). Time to look for a good shielded case for this project._

 


 I had the same problem. Play with your brightness setting. Going up or down a few clicks may make the problem go away. You just have to give the coil windings in the inverter a freq that they won't resonate on.

 Good luck!


----------



## geofftnz

Quote:


  Originally Posted by *tsaavik* /img/forum/go_quote.gif 
_I had the same problem. Play with your brightness setting. Going up or down a few clicks may make the problem go away. You just have to give the coil windings in the inverter a freq that they won't resonate on.

 Good luck!_

 

Thanks for that, I'll give it a go. (It took me a few seconds to realise that "brightness" refered to the monitor, not some audiophile term 
	

	
	
		
		

		
			





 )


----------



## odoe

Thought I would share my alien dac adventure last night.
 My DAC has been built and running like a champ for a while now, I would say, 3 months, no issue, but from a kit I got from Jeff at glassjaraudio. It has since been replaced by a TC-7510, but I was getting some weird pops and clicks and after checking my MAX, I narrowed it down to the TC-7510.

 So I was going back to my Alien DAC, but figured, hey, I'm going to upgrade to some 47uf ES caps, try for a little more oomph. So I replace the caps in CL/CR and realize I had 330uf caps in there. Weird I thought, but whatever. I plug the Alien DAC in and not recognized. So I go back to the schematic and assembly guide trying to think if I fried the board while desoldering the caps.

 Now remember, the Alien DAC was my second build after a cmoy before moving on. Turns out, I didn't pay good enough attention to the board when placing my caps and put the 330uf caps in the CL/CR position and the 10uf similac caps in the C23/C33 position, basically switched them. Now the DAC had run perfectly before I put the 47uf caps in, so if anyone wants to try what I did, you should be fine, audibly, I don't know if it made a huge difference. Anyway, I got all the parts in where they should be now with my ES caps, device is now recognized and works like a charm and those ES caps definitely added some oomph to the stock build, so I'm happy. 
	

	
	
		
		

		
		
	


	




 Oh, and btw, the initial popping sound wasn't from my TC-7510 at all, but one of the wires from a DIY rca cable I made broke from ground and the pops and clicks were coming from the broken cable hitting the body of the RCA jack. 
	

	
	
		
		

		
		
	


	




 That's been fixed now too. That's what I like about the DIY, I'm always learning something.


----------



## iewgnail

Finally finish up my alien dac. After the problem with the R32 and C32 placed at wrong position, and losing R32 to the floor and waiting a week to get a spare R32.

 It's now alive and kicking but yet to be cased!
 Sounds great

 btw, how do you guys secure the panel to the case? as there's no place to mount it.


----------



## iewgnail

i'm looking at a custom panel for the 1455c series casing.

 anyone has the dimensions for the holes placement?
 or vector files etc? will be greatly appreciated!


----------



## Heady

Building my 4th AlienDAC, I ran into a problem. This is my first external powered (by a regulated wall wart - 6.5VDC). The problem is that the DAC actually worked and I was listening to it for about 5 mins when there was a loud buzz and it could not be recognised by the computer any more.

 Now the 3.3V test point reads only 1.6V although when the probes are first placed, for a split second, you can see 3.3V before it drops to 1.6V.

 I first thought it was the 3.3V regulator and changed it but it still has the same problem.

 Reading the previous posts (all 44 pages), I found most problems like this are due to short circuits. I have check all the pins of the PCN2702 for bridges and also did continuity tests with the pins. All the pins except those for ground are not shorted with its neighbour or to ground. The board has been cleaned a number of time.

 Is the PCM chip dead?

 Thanks for any help.


----------



## MisterX

Quote:


 Is the PCM chip dead? 
 

Does it get hot?


----------



## Heady

Thanks MisterX, all the voltage regulators and the PCM chips are slight warm. Not hot.


----------



## pinkfloyd4ever

anyone know what happenned to that "Big d.i.y DAC list" ? I've searched & looked back several pages and for some reason I can't find it. Anyone got a link to it? Again, why don't we sticky it?


----------



## Heady

Repost with pictures.

 Summary -
 External powered AlienDAC - not recognised by computer. 3.3V test point gives only 1.6V. No sign of short circuits on PCM chip. Worked for a few minutes before problem crops up.

 Pics of pcb -
Top
Bottom

 Any help appreciated.


----------



## Dark_Shadow

Quote:


  Originally Posted by *iewgnail* /img/forum/go_quote.gif 
_i'm looking at a custom panel for the 1455c series casing.

 anyone has the dimensions for the holes placement?
 or vector files etc? will be greatly appreciated!_

 

If you go on the hammond web site, you have Autocad DWG file that should help you...

http://www.hammondmfg.com/1455.htm


----------



## iewgnail

how do i secure the board to the 1455c series casing?

 there's plenty of space left in the casing and it slides around.


----------



## tomb

Quote:


  Originally Posted by *iewgnail* /img/forum/go_quote.gif 
_how do i secure the board to the 1455c series casing?

 there's plenty of space left in the casing and it slides around._

 

Cut some 1/16" thick card stock, plastic, whatever's handy into a shape that can slide into the remaining slot and take up the space.


----------



## MoodySteve

I've just finished soldering an Alien that I'm planning to power from my CK²-III's +15V power rail (and an LM317 circuit that reduces that to +7V). When I apply power to the V+ and G2 pads (as instructed), I do not measure the supply voltage between V+ and G2! Even if I connect a 9V battery, the voltage between those two pads is only +1.5V. The voltages at the +3.3V and +5V test points were around 0.85V. Wow, what did I screw up this time?

 I've checked for solder bridges, and found nothing on my inspection. I was careful to put the correct parts in the correct pads, and I had the PCM chip pre-soldered when I got the board. Any ideas?

 Thanks in advance!


----------



## FallenAngel

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I've just finished soldering an Alien that I'm planning to power from my CK²-III's +15V power rail (and an LM317 circuit that reduces that to +7V). When I apply power to the V+ and G2 pads (as instructed), I do not measure the supply voltage between V+ and G2! Even if I connect a 9V battery, the voltage between those two pads is only +1.5V. The voltages at the +3.3V and +5V test points were around 0.85V. Wow, what did I screw up this time?

 I've checked for solder bridges, and found nothing on my inspection. I was careful to put the correct parts in the correct pads, and I had the PCM chip pre-soldered when I got the board. Any ideas?

 Thanks in advance!_

 

If you're running from a normal 9V battery to AV+ and G2, you should definitely see the 9V between those points, no other voltage is possible. Once you have that, check the +3.3V and +5V to make sure your regulators work. Once you've got the voltages right, connect it to USB and try it out (at least get windows to recognize it and make sure you see 2.5V at each of the outputs before the caps (make sure both channels work).

 Just determine that it works by itself first, then move on to powering it from an amp.


----------



## MoodySteve

I stand by my story. 
	

	
	
		
		

		
			





 To corroborate it, when I hook up my bench supply to those two pads, it will NOT advance past 1.5V. So something is seriously wrong. I expect it's the regulator but I can't see any bridges.

 This is all in initial testing; I haven't even built the LM317 circuit yet.


----------



## iewgnail

USB and Output on the back. Led on front for the sleek look. With everything in black.


----------



## MoodySteve

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I stand by my story. 
	

	
	
		
		

		
		
	


	




 To corroborate it, when I hook up my bench supply to those two pads, it will NOT advance past 1.5V. So something is seriously wrong. I expect it's the regulator but I can't see any bridges.

 This is all in initial testing; I haven't even built the LM317 circuit yet._

 

Update: As it turns out, the power supply section works much better when the two switch contacts aren't open. 
	

	
	
		
		

		
		
	


	




 One jumper wire later and my power LED came to life. Hopefully all else will go smoothly.


----------



## tomb

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_Update: As it turns out, the power supply section works much better when the two switch contacts aren't open. 
	

	
	
		
		

		
		
	


	




 One jumper wire later and my power LED came to life. Hopefully all else will go smoothly._

 

Been there, done that. 
	

	
	
		
		

		
		
	


	







 Alf should have noted it in big letters on the support web site for us dummies, perhaps.


----------



## MH79

Ok guys, I've just ordered the kit for the AlienDac from GlassJarAudio.

 This will be my first (headphone) DIY project, so I was wondering what other parts I'll need (ie parts not in the kit).

 I'm guessing case, and connections (USB and 3.5mm jack)? Anything else worth picking up while I wait for the kit to arrive?

 Also, I'm hoping to fit this in a Penguin mint tin. Is the PCB small enough?


----------



## holland

USB comes with the kit. You may need a 3.5mm jack and maybe an LED.

 Some wire for the jacks and LED (depending on where you put it). I put my LED and 3.5mm jack in front, USB in back.

 I've seen people put it into a mint tin.


----------



## tomb

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_<snip>Also, I'm hoping to fit this in a Penguin mint tin. Is the PCB small enough?_

 

Did someone mention Penguin Mint Tins? 
	

	
	
		
		

		
		
	


	







 OK, OK, I won't repeat the pics here - Post #770 in this thread.


----------



## MH79

Awesome, I've got 100's of LED's lying around, I may go for a white one to match the colour of the tin. 
	

	
	
		
		

		
		
	


	




 Also, I can get jacks from my local electronics shop, so no problems there. 

 I assumed because the kit it so cheap (less than £20!) I'd have to buy the DAC chip separately or something like that. I really can't wait now... Hopefully the postman will come sooner rather than later.

 EDIT: Cheers for the link tomb, nice pics. I think I'll do the same or similar layout for mine. 
	

	
	
		
		

		
		
	


	




 This thread is huge, and have only read the first few pages so far... 
	

	
	
		
		

		
		
	


	




 Also, what on earth does BOM mean? Big Orange Man?


----------



## tomb

Bill Of Materials. It's sort of a common Engineering term.


----------



## MH79

Gotcha - I haven't been here that long, and am still getting to grips with some of the lingo.


----------



## raikkonen

hi guys, my alien kit is in my hands, i tought to have a pcm2702 at home...but i only have a pcm2902 and pcm2705!can i use one of these instead of the 2702?
 thanx a lot!


----------



## tomb

Quote:


  Originally Posted by *raikkonen* /img/forum/go_quote.gif 
_hi guys, my alien kit is in my hands, i tought to have a pcm2702 at home...but i only have a pcm2902 and pcm2705!can i use one of these instead of the 2702?
 thanx a lot!_

 

NO. You need to contact Jeff and get the right PCM chip ASAP.


----------



## raikkonen

s**t!ok, thanx a lot for the info!


----------



## J.D.N

Id love to build one of these, but being in my final year at uni i just don't have the time.

 Is there anyone in England/UK that has experience building these and would build me one for a small fee? 

 Ah, one important question, might seem stupid, do these work with Mac's?


----------



## MH79

Quote:


  Originally Posted by *J.D.N* /img/forum/go_quote.gif 
_Id love to build one of these, but being in my final year at uni i just don't have the time.

 Is there anyone in England/UK that has experience building these and would build me one for a small fee? 

 Ah, one important question, might seem stupid, do these work with Mac's?_

 

I'd be more than happy to build you one, but let me see how I get on with my first one once my kit arrives, as I could make a complete hash of it for all i know. 
	

	
	
		
		

		
		
	


	




 I'm sure someone more experienced than me would build you one, but I did see a thread with pre-built ones going for $110 if I remember... I'm not 100% sure if they are still avaliable.


----------



## Televator

my (mint-tinned 
	

	
	
		
		

		
		
	


	




 ) Alien DAC plays just fine with my 12" G4 PowerBook... and it sounds great


----------



## MH79

Quote:


  Originally Posted by *Televator* /img/forum/go_quote.gif 
_my (mint-tinned 
	

	
	
		
		

		
		
	


	




 ) Alien DAC plays just fine with my 12" G4 PowerBook... and it sounds great 
	

	
	
		
		

		
		
	


	


_

 

Ooo, another mint tin. 
	

	
	
		
		

		
		
	


	




 Got any pics?


----------



## J.D.N

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_Ooo, another mint tin. 
	

	
	
		
		

		
		
	


	




 Got any pics?_

 

x2 

 I was thinking of using a mint tin so it matched the Penguin. After all the umming and ahhhing im a sucker for the looks.


----------



## Televator

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_Ooo, another mint tin. 
	

	
	
		
		

		
		
	


	




 Got any pics?_

 

I still need to 'finish' it (fasten it in its case, paint the case and solder in a better 1/8" socket... got distracted by my Millet Max) but I'll post an 'almost finished' pic in a few moments


----------



## MH79

Quote:


  Originally Posted by *J.D.N* /img/forum/go_quote.gif 
_x2 

 I was thinking of using a mint tin so it matched the Penguin. After all the umming and ahhhing im a sucker for the looks._

 

Look back a page or 2, tomb has already posted pics of his AlienDac in a penguin mint tin.


----------



## J.D.N

Sweet! They will look so good together. I am still umming and ahhing a bit as to whether or not build it myself, ive built gainclone's before and the satisfaction id great. 

 One question, is it totally alright to use phono outs instead of 3.5mm and just share the ground? I have some spare canare phono's lying around and prefer the look of them to 3.5mm. 

 Cheers!


----------



## Televator

ok... so here it is.

 remember it is not finished yet. I will paint it so it matches my 12" G4 PowerBook in color (using my uncles spray-cabin, so I have to wait till it's free) and the connector has to be changed for a better one still.

 It is pictured here with my Cmoy which was meant to be my office setup... but as I've finished my Max and it sounds so good it has replaced my HeadFive in my home rig, I'll probably use the Alien DAC with the HeadFive in my office rig... so the casing might change still
















 The white bit (a restyled music note with a bite taken out) is cut out (by hand using a Dremel 
	

	
	
		
		

		
		
	


	




 ). It is covered (from the inside) with milk-white semi-opaque plastic, which I still have to cut smaller and fix for real. Together with the big white led on the inside this gives a glowing shape like the apple on macs... this was a little joke to make it match my mac a bit more


----------



## tomb

Quote:


  Originally Posted by *J.D.N* /img/forum/go_quote.gif 
_Sweet! They will look so good together. I am still umming and ahhing a bit as to whether or not build it myself, ive built gainclone's before and the satisfaction id great. 

 One question, is it totally alright to use phono outs instead of 3.5mm and just share the ground? I have some spare canare phono's lying around and prefer the look of them to 3.5mm. 

 Cheers!_

 

Yes, of course. My 3.5mm socket is commonly grounded to the mint tin by virtue of the barrel and the ring nut.


----------



## MH79

Nice pics televator, I especially like the bit you've cut out. It should look good with a white LED. You may have to use a slightly lower value resistor tho, as white LED's require a little more voltage.


----------



## gaplessophile

I'm thinking of building one of these and was just wondering, what kind of sound signature does the Alien DAC have? Is it warm and colourful, or more crisp and accurate? Thanks


----------



## tomb

Quote:


  Originally Posted by *gaplessophile* /img/forum/go_quote.gif 
_I'm thinking of building one of these and was just wondering, what kind of sound signature does the Alien DAC have? Is it warm and colourful, or more crisp and accurate? Thanks 
	

	
	
		
		

		
		
	


	


_

 

Depends on the output coupling capacitors. After listening for several months now, I agree with everyone else: the Black Gates in CL and CR are best. There are others that have some interesting effects. For instance, I really love the Nichicon Muse ES's because they can really bring on the bass and slam - even more than the Black Gates.

 However, for normal listening, the Black Gates are wonderfully musical and detailed. They have a habit of seemingly amplifying background detail so that it's pushed out farther than it might be with another source. I have stated this many times, but an Alien DAC with BG's on the output sounds _way_ better than an M-Audio Transit. Some pooh-pooh that opinion, mainly because the noise floor of the Alien is higher - it won't test as well and you will hear a bit of hiss in the darkest spots or silent parts of the music - but that's only through a very high-end amp that amplifies the smallest detail.

 So, bottom line, the sound is adjustable - ES's for slamming bass, BG's for oustanding dynamics and musical detail - those are the ones I've tried so far. There are dozens of other combinations, though.


----------



## MH79

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_So, bottom line, the sound is adjustable - ES's for slamming bass, BG's for oustanding dynamics and musical detail - those are the ones I've tried so far. There are dozens of other combinations, though.
	

	
	
		
		

		
			



_

 

Nice! I'll have to get some blackgates. 
	

	
	
		
		

		
		
	


	




 Does anyone know which coupling caps ship with the glassjaraudio kit?


----------



## tomb

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_Nice! I'll have to get some blackgates. 
	

	
	
		
		

		
		
	


	




 Does anyone know which coupling caps ship with the glassjaraudio kit?_

 

Jeff uses the Elna Silmic RFS's. Those are pretty good from what I hear and at least one notable builder prefers them (don't quote me on that, though).

 Luckily, BG's in this size range are not expensive at all. What you need is the 47uf 6.3V NX HiQ: $2.50 ea at PartsConX and Soniccraft.


----------



## MH79

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Jeff uses the Elna Silmic RFS's. Those are pretty good from what I hear and at least one notable builder prefers them (don't quote me on that, though).

 Luckily, BG's in this size range are not expensive at all. What you need is the 47uf 6.3V NX HiQ: $2.50 ea at PartsConX and Soniccraft._

 

I had a look, and they're a little more over here in the in the UK (about $8 each)... I've ordered some anyway (plus two for my iRiver), but I'll try the RFS's also as I may prefer them. 
	

	
	
		
		

		
		
	


	




 Still waiting on the kit tho, the postage is really slow in the UK right now... I wanna get soldering!


----------



## joneeboi

Quick check: Alien DAC will work with Windows Vista, correct?


----------



## kklee

Quote:


  Originally Posted by *joneeboi* /img/forum/go_quote.gif 
_Quick check: Alien DAC will work with Windows Vista, correct?_

 

It worked for me (Vista Ultimate).


----------



## GoldWarlock

I just finished my alien dac (thanks to Jeff for a kit)
 Sounds Great!

 Hey guys a question.
 I can't make it work through the Kernel Streaming in windows.
 Any ideas?


----------



## luckypictures

Where is the original thread for this?

 Can the boards still be purchased?

 I'm dyin to make this my first Audio DIY.


----------



## luckypictures

Actually, even a build thread would be nice. Am I missing it?


----------



## tomb

Quote:


  Originally Posted by *luckypictures* /img/forum/go_quote.gif 
_Actually, even a build thread would be nice. Am I missing it?_

 

This is the build thread - as in "Alien DAC v1.1 *Construction *Thread".

 Start back at Post #1 and start reading. 
	

	
	
		
		

		
		
	


	




 The documentation website was done by Alf and is still up and running (thank goodness):
http://www.myexposition.com/diy/usbdac/overview.html

 The original design thread is here (referenced on the website above):
http://www.head-fi.org/forums/showthread.php?t=139368


----------



## holland

Quote:


  Originally Posted by *luckypictures* /img/forum/go_quote.gif 
_Actually, even a build thread would be nice. Am I missing it?_

 

LOL!

  Quote:


  Originally Posted by *luckypictures* /img/forum/go_quote.gif 
_Where is the original thread for this?

 Can the boards still be purchased?

 I'm dyin to make this my first Audio DIY._

 

Are you in the USA? If so, I would order from Glass Jar Audio for a kit and a case (might have to e-mail him about it). It makes your first venture into DIY painless as you can worry on construction and less about a BOM.


----------



## smegger

jeff ships world wide too very reasonable! i have used him for 2 aliens now i am buying a max off him. Thats shipped to the uk


----------



## MH79

Glass Jar Audio also ships internationally if you ask him nicely.


----------



## MH79

smegger: How long did it take roughly to get your aliens to the UK... a week?


----------



## MoodySteve

They say nothing comes easy...

 I've installed the DAC into my amp's chassis, and it is powered by a +6V rail that is regulated from the amp's +15V rail. The power LED lights up, the computer recognizes the device, and it DOES convert digital into analog! But, like I said...

 1. If I'm not applying any power (i.e. the amp is turned off) but I plug in a USB cable, the power LED comes on. This is quite unexpected, since I wanted this to be externally powered and built it with those instructions!

 2. The volume is pitifully low...not 'gee whiz I wish this went louder' low, but the kind of low that clearly indicates a voltage problem.

 3. If I do a sharp adjustment of the volume pot, the output drops into a hum for about a second. After that, the hum goes away and is replaced by the overly low level signal.

 I'm going to set up a mini-bench near a PC and see if the Alien behaves any differently when powered from my bench supply. My first suspect is the power supply circuitry; I'm still really uncomfortable with the power LED coming on when I'm not applying any external power.

 Has anyone encountered these symptoms, and if so, what was the problem?
 Thanks again!


----------



## error401

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_They say nothing comes easy...

 I've installed the DAC into my amp's chassis, and it is powered by a +6V rail that is regulated from the amp's +15V rail. The power LED lights up, the computer recognizes the device, and it DOES convert digital into analog! But, like I said...

 1. If I'm not applying any power (i.e. the amp is turned off) but I plug in a USB cable, the power LED comes on. This is quite unexpected, since I wanted this to be externally powered and built it with those instructions!

 2. The volume is pitifully low...not 'gee whiz I wish this went louder' low, but the kind of low that clearly indicates a voltage problem.

 3. If I do a sharp adjustment of the volume pot, the output drops into a hum for about a second. After that, the hum goes away and is replaced by the overly low level signal.

 I'm going to set up a mini-bench near a PC and see if the Alien behaves any differently when powered from my bench supply. My first suspect is the power supply circuitry; I'm still really uncomfortable with the power LED coming on when I'm not applying any external power.

 Has anyone encountered these symptoms, and if so, what was the problem?
 Thanks again!
	

	
	
		
		

		
		
	


	


_

 

Do you have S1 shorted?


----------



## luckypictures

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_This is the build thread - as in "Alien DAC v1.1 *Construction *Thread".

 Start back at Post #1 and start reading. 
	

	
	
		
		

		
			





 The documentation website was done by Alf and is still up and running (thank goodness):
http://www.myexposition.com/diy/usbdac/overview.html

 The original design thread is here (referenced on the website above):
http://www.head-fi.org/forums/showthread.php?t=139368_

 


 My face isn't red, I swear.

 Okay, okay, that was my bad. My short attention span, thank you modern culture, got me as far as Alien DAC and shut off.

 And I just checked out Glass Jar Audio, so thank you to the poster who made that suggestion!


----------



## smegger

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_smegger: How long did it take roughly to get your aliens to the UK... a week?_

 

id say round that yea, i order lots from America via usps i never really have timed it but 1-2 weeks tops.


----------



## MoodySteve

Thanks for the reply, error401...I do have S1 shorted, since I do not want a separate switch for the Alien. In my usual 20/20 hindsight, I probably should have gone for USB-powered, but I couldn't resist the temptation of a slight performance increase, however inaudible.


----------



## error401

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_Thanks for the reply, error401...I do have S1 shorted, since I do not want a separate switch for the Alien. In my usual 20/20 hindsight, I probably should have gone for USB-powered, but I couldn't resist the temptation of a slight performance increase, however inaudible._

 

S1 shorts USB VBUS to the V+ rail. I believe you want this open if you're using external power.


----------



## MH79

Quote:


  Originally Posted by *smegger* /img/forum/go_quote.gif 
_id say round that yea, i order lots from America via usps i never really have timed it but 1-2 weeks tops._

 

Nice, thanks... I ordered on the 18th, so I guess it should'nt be too far off. I've even eaten a whole tin of penguin mints especially. 
	

	
	
		
		

		
		
	


	




 EDIT: Is there anyway of getting a balanced output from this circuit?


----------



## error401

Quote:


  Originally Posted by *MikeHunt79* /img/forum/go_quote.gif 
_EDIT: Is there anyway of getting a balanced output from this circuit?_

 

Aside from using a capacitor-coupled single-ended to balanced converter, no. The output from the DAC is single ended, biased to Vcc/2. You need to go to a better/different DAC chip to get balanced outputs.


----------



## Heady

Quote:


  Originally Posted by *Heady* /img/forum/go_quote.gif 
_Repost with pictures.

 Summary -
 External powered AlienDAC - not recognised by computer. 3.3V test point gives only 1.6V. No sign of short circuits on PCM chip. Worked for a few minutes before problem crops up.

 Pics of pcb -
Top
Bottom

 Any help appreciated._

 

Managed to solve this issue by re-flowing the solder on the 3.3V regulator chip leads. The ground pad is awfully difficult to heat up, the pin heats up and take the solder but the pad is not wetted by the solder but does not show as broken on a continuity check.


----------



## MH79

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Aside from using a capacitor-coupled single-ended to balanced converter, no. The output from the DAC is single ended, biased to Vcc/2. You need to go to a better/different DAC chip to get balanced outputs._

 

Ok, thanks for letting me know. Single ended will be fine for now.


----------



## geofftnz

Quote:


  Originally Posted by *smegger* /img/forum/go_quote.gif 
_id say round that yea, i order lots from America via usps i never really have timed it but 1-2 weeks tops._

 

My Alien DAC kit took 4 days to get to my letterbox in New Zealand. Postage was stupidly cheap (regular padded envelope with room to spare). I'm very happy with the results, even with the unregulated USB power supply option in an unshielded plastic case.

 I'm going to order another at some point to couple with a headphone amp in a single case.


----------



## MH79

I've normally found USB power to be pretty clean, but then I use a Tagan PSU. I'm more than happy to run unregulated, but there's no harm in going regulated if you've got the parts handy.


----------



## Televator

I had built an alien DAC, worked fine... until it seemed to short after about an hour of use.

 I inspected everything and couldn't see anything... I inspected with a jewelers binoculars under sharp light and I thought I could see a near bridge on the chip (reckoning it would short as it got a bit warmer through use)

 I tried to fix it, but destroyed the chip in the process (too much heat at one point) ... then I destroyed the board trying to desolder the chip (too much pull and lifted a couple of traces)

 I built my second alien DAC (with presoldered chip by Jeff Rossel) and it worked just fine

 ... until tonight: I replaced the 3,5mm socket and I wanted to see if it worked so I plugged it into my mac. After about half an hour, I got the same 'short' again :huh:

 I didn't change anything but the socket and it worked fine before so I was absolutely stumped... so I went over everything again and again, also checking what might have changed since last time ... and ... I was using a different USB-cable than usually. This time I was using a spare printer cable and not my usual shorter USB-cable that came with an external HD, a cable which I had found ... right after finishing the second alien. I have been using the alien for four hours straight now without changing anything but the cables again and no short, no distortion, no problem whatsoever!

 Then lightning struck: I had been using the same printer cable with the first alien as well... so I ruined a perfectly working alien (I checked and the 'near bridge' I had seen, was just the shadow of a round trace underneath the chip coupled to my eagerness to find some fault... no wonder I couldn't 'fix' it and even burned the chip while trying 
	

	
	
		
		

		
		
	


	




 )

 Lesson learned... sometimes the problem does lie with the simplest part to replace, so check that first


----------



## joneeboi

I, too, have Alien DAC woes. First, the MAX, then the Alien. Oy, va voy. The LED lights up, the test points give me the 3.3V and 4.7V I'm looking for. What more do I need to do? Admittedly the SMD soldering looks terrible, but I reflowed everything to make sure. C32 I think might be a little messed up (almost completely ripped its soldering stuff off), not to mention I lost C31 and paralleled two 47nF caps (those ARE 47nF right?). I didn't know if it was touching the ground pad so I just wired it to G2.


----------



## nysulli

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Depends on the output coupling capacitors. After listening for several months now, I agree with everyone else: the Black Gates in CL and CR are best. There are others that have some interesting effects. For instance, I really love the Nichicon Muse ES's because they can really bring on the bass and slam - even more than the Black Gates.

 However, for normal listening, the Black Gates are wonderfully musical and detailed. They have a habit of seemingly amplifying background detail so that it's pushed out farther than it might be with another source. I have stated this many times, but an Alien DAC with BG's on the output sounds way better than an M-Audio Transit. Some pooh-pooh that opinion, mainly because the noise floor of the Alien is higher - it won't test as well and you will hear a bit of hiss in the darkest spots or silent parts of the music - but that's only through a very high-end amp that amplifies the smallest detail.

 So, bottom line, the sound is adjustable - ES's for slamming bass, BG's for oustanding dynamics and musical detail - those are the ones I've tried so far. There are dozens of other combinations, though.
	

	
	
		
		

		
		
	


	


_

 

after firing my alien dac up with ES's, i can say it had tons of slam paired with my MAX

 but, i would highly suggest bypassing them with sonicaps, i used .22uf caps for the bypass and it definitely improved the high end, although the mids sound somewhat recessed compared to my modded x-fi, but only time will tell as the aliendac burns in


----------



## tomb

Quote:


  Originally Posted by *nysulli* /img/forum/go_quote.gif 
_after firing my alien dac up with ES's, i can say it had tons of slam paired with my MAX_

 

I bet!!
	

	
	
		
		

		
		
	


	







  Quote:


 but, i would highly suggest bypassing them with sonicaps, i used .22uf caps for the bypass and it definitely improved the high end, although the mids sound somewhat recessed compared to my modded x-fi, but only time will tell as the aliendac burns in 
 

Good thought - something I've always repeated should be done, but I cased mine up in those Penguin mint tins too quickly. I'm waiting to build another one before trying this.

 I'm not sure I completely agree that Dsavitsk's findings scale up, though - the Sonicaps remove a bit of that outstanding slam in the ES's on the MAX. It definitely opened up the highs and brought in the airiness and soundstage (but not in the cathode bypass position - Yuck!), so it maybe an OK tradeoff, maybe not - my opinion still runs a bit back and forth.

 It's possible that the size ratio of the ES caps with the 0.22uf Sonicaps is so much closer in the Alien that the bass isn't affected. What happens in the MAX is that the Sonicaps are so much faster that they may overwhelm the giant (by comparison) 1000uf and 470uf ES's. The smaller 33uf ES's in the Alien (the size I got to fit) may be quick enough compared to the Sonicaps that the combination works much better.


----------



## tomb

Quote:


  Originally Posted by *joneeboi* /img/forum/go_quote.gif 
_I, too, have Alien DAC woes. First, the MAX, then the Alien. Oy, va voy. The LED lights up, the test points give me the 3.3V and 4.7V I'm looking for. What more do I need to do? Admittedly the SMD soldering looks terrible, but I reflowed everything to make sure. C32 I think might be a little messed up (almost completely ripped its soldering stuff off), not to mention I lost C31 and paralleled two 47nF caps (those ARE 47nF right?). I didn't know if it was touching the ground pad so I just wired it to G2.

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6690.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6691.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6692.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6693.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6694.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6695.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6696.jpg[/IMG]

 [!IMG]http://i98.photobucket.com/albums/l246/joneeb0i/IMG_6697.jpg[/IMG]_

 

Joneeboi,

 No one else has commented yet, so I'll try. It appears that you have quite a few cold solder joints. What I mean by that is that the solder is blobbed on top of the parts instead of forming a smooth fillet between the end and the pad on the board. Because of that, I suspect that you may have quite a few parts that could have this solder forming a blob on top, but may not be making good contact on the board pads below.

 I would use a lot more flux on each joint - that helps to distribute the heat - and see if you can get that solder to flow down and across the pads. This is a diagram of what I mean:





 There are several ferrites that look as if they may not have contact with the pads - L14, L15, L16, for instance.

 It's possible that you have some shorts in some places, too - maybe those caps at C31. There may be something touching at R14, R11 and R12, just for examples.

 You should solder those tabs from the USB receptacle, too - those ground the USB case. If they are, I apologize, but it appears that they may not be.

 I don't know what else to add at this point - I'm sure you are frustrated. If none of this works (re-flowing solder yet again), you might try to get a proper replacement for that C31 cap and remove that stuff in that position.

 Just some guesses ...


----------



## Heady

Quote:


  Originally Posted by *joneeboi* /img/forum/go_quote.gif 
_I, too, have Alien DAC woes. First, the MAX, then the Alien. Oy, va voy. The LED lights up, the test points give me the 3.3V and 4.7V I'm looking for. What more do I need to do? Admittedly the SMD soldering looks terrible, but I reflowed everything to make sure. C32 I think might be a little messed up (almost completely ripped its soldering stuff off), not to mention I lost C31 and paralleled two 47nF caps (those ARE 47nF right?). I didn't know if it was touching the ground pad so I just wired it to G2._

 

Hi, I am sure no one has commented on your post because the soldering is quite obviously messy and you also did not clean up the flux left by the solder. Cleaning is quite critical for this DAC, indeed for most projects. Try cleaning with some alcohol until the board is cleared of the splashed solder and flux.

 I am sorry for being so frank but that's how my work looked too, when I first started doing DIY. So, I am sharing the lessons I learned.

 When re-flowing solder joints, I find it useful to dip the iron tip into flux paste before touching it to the solder. Of course the extra flux need to be cleaned up later.

 Regards


----------



## joneeboi

Yeah it is an atrocious job, but I've been cracking my knuckles for the past 10 years and my hands are crazy wobbly. It almost looked like I was wired on (fill in those speeding up-type drugs here) when I was soldering some of those itty-bitty resistors on. I'm just lucky I didn't lose anything other than the C31.

 As for cleaning up the flux, is it customary to clean up the board before the project is actually done? I understand flux can be generally corrosive and is pretty unsightly and ...unscently(?), but I figured why bother if it doesn't end up working? Unless you're suggesting it might work if I clean it up, then I'll jump right on it.

 Thanks for the help, guys. I will get on on that when I can.

 PS: that picture is funny to me, Tom. It doesn't make sense why it would be funny, but I like its bluntness. NO. YES. Muahaha!


----------



## tomb

Quote:


  Originally Posted by *joneeboi* /img/forum/go_quote.gif 
_Yeah it is an atrocious job, but I've been cracking my knuckles for the past 10 years and my hands are crazy wobbly. It almost looked like I was wired on (fill in those speeding up-type drugs here) when I was soldering some of those itty-bitty resistors on. I'm just lucky I didn't lose anything other than the C31.

 As for cleaning up the flux, is it customary to clean up the board before the project is actually done? I understand flux can be generally corrosive and is pretty unsightly and ...unscently(?), but I figured why bother if it doesn't end up working? Unless you're suggesting it might work if I clean it up, then I'll jump right on it.

 Thanks for the help, guys. I will get on on that when I can.

 PS: that picture is funny to me, Tom. It doesn't make sense why it would be funny, but I like its bluntness. NO. YES. Muahaha!_

 

You have to find the right time of the day. My hands shake, too, but I try to find a time of the day to set aside where I think I'm laid back enough to do some good soldering on the Alien. Most of the time, that's early in the morning on a day I don't have to go to work, but if you tied one on the night before, that might not be a good time, either. 
	

	
	
		
		

		
			








 Seriously, you are not alone in that feeling. There are many times I don't hesitate to work on a through-hole board, but wouldn't even consider messing with the Alien.

 Pick your spot in a day and time of the week, have everything laid out and organized, and then try to chill. It helps me, anyway.
	

	
	
		
		

		
		
	


	




 EDIT: Heck, you didn't have any trouble taking some of the closest macro shots I've seen of this and your MAX. Even if you had it on a tripod, you still had to concentrate and get things positioned just right. So, you've got the touch you need - you just need to learn when.


----------



## xmokshax

Quote:


  Originally Posted by *joneeboi* /img/forum/go_quote.gif 
_...

 As for cleaning up the flux, is it customary to clean up the board before the project is actually done? I understand flux can be generally corrosive and is pretty unsightly and ...unscently(?), but I figured why bother if it doesn't end up working? Unless you're suggesting it might work if I clean it up, then I'll jump right on it.

 ..._

 

indeed, cleaning up the board can produce immediate results. i've never had this happen in my limited experience, but flux CAN conduct electricity, and it's possible for such "flux bridges" to create problems. personally, i'd first heed Tom's advice and slather most or all of those globby looking joints with flux paste (this is a bit of an exaggeration - you really don't have to apply TOO much flux to get a joint to reflow well) and reflow them again so that you're more confident in the contact they're making with the pads below. reflowing in the presence of ample flux will also clear most solder bridges, if any actually exist. there's no point in cleaning before you do this, because the flux paste will melt all over the board and create a nice thick layer of goop.

 once that's done, and you're confident in all those joints, you'll probably have done MOST of the soldering you'll do on the board, so it's worth giving it a good cleaning. if you have to do further work, it will probably be isolated to specific components, and you can use an alcohol-wetted Q-tip to do some spot cleaning. if the re-flowing and cleaning works, however, you won't have to do any more tinkering - cross your fingers!


----------



## nysulli

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_I bet!!
	

	
	
		
		

		
		
	


	







 Good thought - something I've always repeated should be done, but I cased mine up in those Penguin mint tins too quickly. I'm waiting to build another one before trying this.

 I'm not sure I completely agree that Dsavitsk's findings scale up, though - the Sonicaps remove a bit of that outstanding slam in the ES's on the MAX. It definitely opened up the highs and brought in the airiness and soundstage (but not in the cathode bypass position - Yuck!), so it maybe an OK tradeoff, maybe not - my opinion still runs a bit back and forth.

 It's possible that the size ratio of the ES caps with the 0.22uf Sonicaps is so much closer in the Alien that the bass isn't affected. What happens in the MAX is that the Sonicaps are so much faster that they may overwhelm the giant (by comparison) 1000uf and 470uf ES's. The smaller 33uf ES's in the Alien (the size I got to fit) may be quick enough compared to the Sonicaps that the combination works much better._

 

trust me on this one, theres no loss in the low end with the ES's bypassed in the aliendac, how much the ratio between the 47uf and .22uf caps plays into that i'm not sure, but i would agree with you that theres something different when it comes to the tube bypass over the output bypass, but it follows dsavitsk's findings as far as i can tell.

 anyways, i'll be able to compare it to a BG capped alien in a week or so, but it'll be a little skewed as this current alien is running at 5.5v and the BG config will be running off regulated USB power


----------



## ishtob

i just finished building my first alien last night (kit from jeff), i had no experience with SMD prior to this project. Reading the SMD tutorials made me really scared 'cause the guides made it sound so hard. but the DAC worked right after i finished soldering everything. i ran it for 2 hours from my powerbok G4 12". sound great... though its a bit too crunchy for my taste.. but maybe it will smooth out after a bit more burnin.

 I'll put up some pics later 
	

	
	
		
		

		
		
	


	




.


----------



## Slaughter

Tomb or anyone else, I've read through this complete thread today since I am ready to finally build my Alien. Has anyone built the Alien without CL/CR? Wouldn't this work fine with amps like the soha and max? If so, what's the benefit in adding them, just to change the sound signature?

 Thanks


----------



## FallenAngel

Quote:


  Originally Posted by *Slaughter* /img/forum/go_quote.gif 
_Tomb or anyone else, I've read through this complete thread today since I am ready to finally build my Alien. Has anyone built the Alien without CL/CR? Wouldn't this work fine with amps like the soha and max? If so, what's the benefit in adding them, just to change the sound signature?

 Thanks_

 

These are output caps from the DAC, without them, you see about 2.5V of DC on the output of the DAC. If you don't handle this DC before you amplify it, you might damage the amp (depending on the amp - solid state amps you're looking at the opamp being damaged with this much DC, I'm not sure about tube amps), but even if you don't damage the amp, you'll fry your headphones after the DC gets amplified. This might be prevented with output caps as in the SOHA and MAX, but as far as I know, you still need to handle DC voltage before amplification.

 Basically, you need either output caps on the DAC or input caps on the Amp.


----------



## Slaughter

Thanks for the explanation, that makes sense. Making my BOM now.... I am sure Ill report back with something I screwed up


----------



## MoodySteve

I bypassed CL/CR on my Alien per the suggestion of Dougigs on the headwize forum: http://headwize.com/ubb/showpost.php...61969&fpage=39

 This mod is specifically for running the DAC into an amp that has its own method of DC protection (in the CK²III's case, the servo). Unless you're positive that your amp has a similar method of protection, I wouldn't bypass them; the negligibly small improvement in quality would not be worth the worry, in my view.


----------



## xmokshax

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I bypassed CL/CR on my Alien per the suggestion of Dougigs on the headwize forum: http://headwize.com/ubb/showpost.php...61969&fpage=39

 This mod is specifically for running the DAC into an amp that has its own method of DC protection (in the CK²III's case, the servo). Unless you're positive that your amp has a similar method of protection, I wouldn't bypass them; the negligibly small improvement in quality would not be worth the worry, in my view._

 

FWIW, you didn't "bypass" the caps, you just didn't include them... bypassing is when you parallel a larger capacitance cap with a smaller capacitance one, so that the smaller cap will pass high frequency signals that the larger cap might tend to roll off. people have certainly played with bypassing the output caps on the Alien - i know that Tom has talked about bypassing his 33uF Muse ESs with 0.22uF Sonicap Gen IIs with nice results.


----------



## MoodySteve

<Homer> 'Doh!!! </Homer>

 You're absolutely right...probably shouldn't crank out quick forum replies in the middle of preparing to leave work. In my glee I forget special EE terminology!

 I did 'bypass' them in the literal sense by not including them, but it didn't occur to me in my haste that the word 'bypass' has a special EE meaning!


----------



## geofftnz

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_You have to find the right time of the day. My hands shake, too, but I try to find a time of the day to set aside where I think I'm laid back enough to do some good soldering on the Alien. Most of the time, that's early in the morning on a day I don't have to go to work, but if you tied one on the night before, that might not be a good time, either. 
	

	
	
		
		

		
		
	


	





_

 

When I sat down to build mine, my hands were a little jittery from a couple of cups of coffee. I found a glass of wine helped heaps (not an alcoholic 
	

	
	
		
		

		
		
	


	




). I also ditched the magnifier off my "helping hands" stand because a) it was useless and b) it threw off my hand-eye coordination. 

 On the soldering front I found that my wimpy electric iron with a very fine tip wasnt pushing enough heat onto some of the joints (namely the ones connected to the ground plane) to get good flow, so for a few I used my butane iron (carefully).


----------



## Slaughter

Any idea where to get a REG101UA-A or REG102UA-A? TI, Mouser and Digikey are all out. Mouser has an expected date of Aug 2008. Any alternatives? I don't want to make this wall powered if possible.
 Thanks


----------



## smegger

hey finished my second alien a while ago for to post pics of my first one for a friend in a tin so heres my hammond, also my new rca cable!











 sorry bout the kack cam phone pics


----------



## OtterMarc

SMEGGER - there's nothing wrong with your pictures. Nice going. Sound nice? I'll be building one shortly. Jeff has sent me one in the mail.

 SLAUGHTER, wow, no REG101's. Wish I knew what to suggest. August 2008 would be fine for Aussies - it's their summer now. We've got winter projects to fiddle with!!

 I'd throw that in as a separate posting in DIY. Yes?


----------



## nysulli

well, during the 2 week down time i finished up a second alien, but i'm having some issues, namely a very low, static filled output that almost sounds like it has a compressed dynamic range due to some clipping at certain frequency ranges

 configuration is unregulated usb power, voltages stable at 4.96v and 3.29v respectively, BG NX-HiQ on the outputs, really just worried that i fried the pcm2702 chip, but i've heard of the congested output on the BG's before their broken in, but i really don't know what that sounds like

 so any help would be great


----------



## tomb

Quote:


  Originally Posted by *nysulli* /img/forum/go_quote.gif 
_well, during the 2 week down time i finished up a second alien, but i'm having some issues, namely a very low, static filled output that almost sounds like it has a compressed dynamic range due to some clipping at certain frequency ranges

 configuration is unregulated usb power, voltages stable at 4.96v and 3.29v respectively, BG NX-HiQ on the outputs, really just worried that i fried the pcm2702 chip, but i've heard of the congested output on the BG's before their broken in, but i really don't know what that sounds like

 so any help would be great_

 

Actually, the BG's I've used on the Alien sounded fantastic on first startup - output was high enough to make you turn down the volume compared to another Alien. Then they settle into a couple of weeks of bland nothingness before they come back as before.

 The "congestion" I referred to with much larger NX's on the Millett MAX is more like a lot of fuzz in between the notes of the music - like a thick soup - but no output level issues and I wouldn't call it "static." (Before break-in, of course.)

 I hope it's not true, but you may have a problem.


----------



## nysulli

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Actually, the BG's I've used on the Alien sounded fantastic on first startup - output was high enough to make you turn down the volume compared to another Alien. Then they settle into a couple of weeks of bland nothingness before they come back as before.

 The "congestion" I referred to with much larger NX's on the Millett MAX is more like a lot of fuzz in between the notes of the music - like a thick soup - but no output level issues and I wouldn't call it "static." (Before break-in, of course.)

 I hope it's not true, but you may have a problem._

 

well thankfully i've got 5 more boards, another 2702 chip, as well as half the smd parts needed to finish up another alien, now for the fun part of desoldering the other half of them


----------



## korben69

Hi all !
 I've finished my Alien DAC yesterday, and you know what it works FINE ! 
	

	
	
		
		

		
		
	


	



 Many thanks to Jeff !


----------



## lmiller

I have built my second Alien DAC. The first worked with no problem and is fantastic, but the second DAC does not work. I have used fixed regulators for both 3.3 and 5 volts. When powered by an external 8 volt supply (no jumper at S1) or when powered from the USB bus (Jumper at S1) I get 3.3 volts but the 5 volt test point shows 0.11 volts. I have replaced the 5 volt regulator with no change. I have rechecked all components related to the regulator and they all appear to be correct. When I plug the unit into my laptop, I get the sound that it sees the device and it recognizes it with the correct chip number, but I get no sound through the DAC. My suspicion is that the PCM2702 is bad. When I measure resistance from the 5 volt test point to ground I see a short. I was thinking of removing L15 - 18 and then rechecking the 5 volt test point with an external power supply. If I get 5 volts then I will assume the PCM2702 is fried on the 5 volt side.

 Any suggestions or ideas? Thanks for any help


----------



## Heady

Quote:


  Originally Posted by *lmiller* /img/forum/go_quote.gif 
_I have built my second Alien DAC. The first worked with no problem and is fantastic, but the second DAC does not work. I have used fixed regulators for both 3.3 and 5 volts. When powered by an external 8 volt supply (no jumper at S1) or when powered from the USB bus (Jumper at S1) I get 3.3 volts but the 5 volt test point shows 0.11 volts. I have replaced the 5 volt regulator with no change. I have rechecked all components related to the regulator and they all appear to be correct. When I plug the unit into my laptop, I get the sound that it sees the device and it recognizes it with the correct chip number, but I get no sound through the DAC. My suspicion is that the PCM2702 is bad. When I measure resistance from the 5 volt test point to ground I see a short. I was thinking of removing L15 - 18 and then rechecking the 5 volt test point with an external power supply. If I get 5 volts then I will assume the PCM2702 is fried on the 5 volt side.

 Any suggestions or ideas? Thanks for any help_

 

Not sure if the problem I had was same as yours. But I had a similar situation where it appeared the 5V regulator seems to be not working. Turns out, the regulator lead to ground had a cold solder joint. The Alien pcb has this quirk in that the coating on the pads seems to repel solder until it gets quite hot. With the ground leads, unfortunately, the ground plane conducts heat away too fast for the pad to really heat up.

 My regulator lead was coated with solder but there was none sticking to the pad. The joint however looks ok on visual examination.


----------



## lmiller

Quote:


  Originally Posted by *Heady* /img/forum/go_quote.gif 
_Not sure if the problem I had was same as yours. But I had a similar situation where it appeared the 5V regulator seems to be not working. Turns out, the regulator lead to ground had a cold solder joint. The Alien pcb has this quirk in that the coating on the pads seems to repel solder until it gets quite hot. With the ground leads, unfortunately, the ground plane conducts heat away too fast for the pad to really heat up.

 My regulator lead was coated with solder but there was none sticking to the pad. The joint however looks ok on visual examination._

 

Thanks for the tip I will double check to see if that is the problem. That will be easier than removing the ferrites and then possibly having to replace them.

 Lindsay


----------



## Basil101

Hi all,
 Just built my first Alien and I was wondering if anyone has a good suggestion for how to make the opening for, and secure the USB port to the plastic end cap of my Hammond 1455C802BK?
 Thanks


----------



## FallenAngel

Quote:


  Originally Posted by *Basil101* /img/forum/go_quote.gif 
_Hi all,
 Just built my first Alien and I was wondering if anyone has a good suggestion for how to make the opening for, and secure the USB port to the plastic end cap of my Hammond 1455C802BK?
 Thanks_

 

Drill, then use an exacto knife or just start with the exacto knife by cutting the rectangle over and over until you cut through. Takes about 10 minutes, but it works very well.


----------



## Basil101

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Drill, then use an exacto knife or just start with the exacto knife by cutting the rectangle over and over until you cut through. Takes about 10 minutes, but it works very well._

 

Thanks, I had some needle files to square the hole but how do you attach the USB port to the plastic end cap of the enclosure? I am afraid that using superglue or similar would deform the plastic, any tips?


----------



## FallenAngel

Quote:


  Originally Posted by *Basil101* /img/forum/go_quote.gif 
_Thanks, I had some needle files to square the hole but how do you attach the USB port to the plastic end cap of the enclosure? I am afraid that using superglue or similar would deform the plastic, any tips?_

 

Oh, simple, just use perf-board, styrofoam or basically anything that will fit the PCB slot and keep the AlienDAC PCB flush against the panel.


----------



## Basil101

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Oh, simple, just use perf-board, styrofoam or basically anything that will fit the PCB slot and keep the AlienDAC PCB flush against the panel._

 

Thanks!
 I will probably use perf-board and mount my output jacks to it.


----------



## Hubbard0

I'm getting ready to order my Alien and just had one question.

 Are you guys running headphones right off the DAC? I plan to build myself a Millet Hybrid but that will take me much longer and won't be done for another 2 months probably assuming I can even get the PCB, but the DAC will be done within a week of me receiving it. Once I get my RP-21s, can I plug them into the DAC? My other question is about running two outputs. If I put on RCAs for the Millet, can I also put on a headphone jack assuming I can plug in a headphone at all? I obviously will only have one item plugged in at a time.

 Thanks for the help, I'm a total rookie to all this.


----------



## Heady

hubbardo,
 You need to have a headphone amp after the AlienDAC to drive the headphones.


----------



## Hubbard0

Quote:


  Originally Posted by *Heady* /img/forum/go_quote.gif 
_hubbardo,
 You need to have a headphone amp after the AlienDAC to drive the headphones._

 

Ok, that shouldn't be a problem. I'll just have to build my Millet at the same time.


----------



## Solecs

Hi, just finished my AlienDAC from the Jeff Rosel kit a few weeks ago and was curious about a small upgrade. After reading through the thread it sound like there might be some other nice alternatives for the CL/CR capacitors and figured I'd give it a shot. I decided to try the Black Gate NX Hi-Q 47uF caps and ordered 4 (2 extra for the next one maybe 
	

	
	
		
		

		
			





) from parts connexion along with some other things. How big of a difference is this from the default Elna caps that came with the kit? I notice that the black gates are about 10 times bigger capacitance wise....

  Quote:


  Originally Posted by *Hubbard0* /img/forum/go_quote.gif 
_Ok, that shouldn't be a problem. I'll just have to build my Millet at the same time._

 

Actually, I've run my headphones straight from my dac before without an amp. It's probably not the best idea though since I had to turn the volume down on my comp considerably which probably ends up not giving the dac the best of signals, but it works. Depends on the sensitivity of your headphones on how much it needs to be turned down I would think, I was using KSC-75s. Also I would guess there are some load issues and some such that might affect it in terms of output current and similar characteristics. In anycase it's possible, just not recommended and probably doesn't sound as good.


----------



## Seaside

Solecs,
 How much the sound will differ from is kind of hard to say. I'd say both caps are good caps for that position and the sound difference between two caps is small and barely detectable with my ears, but others may argue differently. You may or may not detect the difference depends on your other equipments. You may able to hear the difference if you got good headphone and amp along with the DAC, otherwise you may not able to hear that.

 Hubbard0,
 Alien DAC is designed to work with amp. It requires amp to sound properly.
 You of cause can hook your headphone up with it directly since no one will prevent you from doing that. But it can not produce adequate level of sound for your headphone, and the sound will start distort when you raise volume up. That's why you need an amp for the DAC.


----------



## Solecs

Quote:


  Originally Posted by *Seaside* /img/forum/go_quote.gif 
_Solecs,
 How much the sound will differ from is kind of hard to say. I'd say both caps are good caps for that position and the sound difference between two caps is small and barely detectable with my ears, but others may argue differently. You may or may not detect the difference depends on your other equipments. You may able to hear the difference if you got good headphone and amp along with the DAC, otherwise you may not able to hear that._

 

Well, I can't say that my amp and headphones are the cream of the crop so I may not notice any difference. I guess I'll give it a try anyway though, since it doesn't hurt to try. That's what this whole DIY thing is all about I guess 
	

	
	
		
		

		
		
	


	




.


----------



## Jrossel

Hello everyone. There was a post listing an Alien DAC BOM in this thread that used V regs other than the REG101 UA-A and REG101 UA3.3 

 I can't find the post and even if I could I am not sure the link would work.

 Can someone suggest an alternative? These parts are hard to find.

 Thanks for any and all help!

 Jeff


----------



## MASantos

You can use the REG102 version which handles 250mA of current instead of the 100mA of the reg101. The specs are a little bit worse(very very little). Digikey shows the REG101-5-ND and the REG102-5-ND but none of the 3.3volt version. they have a "call" on the price. Maybe giving them a call will clear things.

 I don't under


----------



## Hubbard0

I ordered my kit today from Glass Jar Audio. It should be done in a few weeks.

 I opted out of the case since I'm also building a MH Max and I want to find something to incorporate the 2 together.


----------



## tomb

Quote:


  Originally Posted by *Hubbard0* /img/forum/go_quote.gif 
_I ordered my kit today from Glass Jar Audio. It should be done in a few weeks.

 I opted out of the case since I'm also building a MH Max and I want to find something to incorporate the 2 together._

 

The standard Hammond case for the MAX will allow enough room for an Alien DAC - minus the USB connector - if you mount the MAX board in the 3rd slot from the bottom. This means all of your MAX parts must be no taller than 1" - but that's supposed to be a regular build, anyway.

 The only issue is the USB connector. With minimum clearance from the case bottom for the Alien board, the USB connector will rise slightly above the top surface of the MAX board. This will mean that you will either have to slot the MAX board for the USB socket, or use an off-board USB socket. These can be purchased at L-Com:

USB Type B Jack, 10" Leads - ECJ504-UB

 Beware, however, they are HUGE - but still not much bigger than a couple of RCA jacks and their associated space. The people I have seen do this usually incorporate a DPDT switch and an extra pair of RCA jacks. The switch is used to switch between the DAC or the RCA jacks as input source. the secondary RCA jacks are connected to the DAC's output - allowing you to connect the DAC to something other than the amp.


----------



## FallenAngel

Another choice for panel mounting the USB socket is using Neutrik NAUSB (or NAUSB-B for black). It's available at Mouser for around $6 and looks very nice. I'm using this one for the huge amp I'm building. It just has the socket to convert USB-A to USB-B, so you'll still need another USB cable to the AlienDAC, but for modularity, it's great.


----------



## Hubbard0

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The standard Hammond case for the MAX will allow enough room for an Alien DAC - minus the USB connector - if you mount the MAX board in the 3rd slot from the bottom. This means all of your MAX parts must be no taller than 1" - but that's supposed to be a regular build, anyway.

 The only issue is the USB connector. With minimum clearance from the case bottom for the Alien board, the USB connector will rise slightly above the top surface of the MAX board. This will mean that you will either have to slot the MAX board for the USB socket, or use an off-board USB socket. These can be purchased at L-Com:

USB Type B Jack, 10" Leads - ECJ504-UB

 Beware, however, they are HUGE - but still not much bigger than a couple of RCA jacks and their associated space. The people I have seen do this usually incorporate a DPDT switch and an extra pair of RCA jacks. The switch is used to switch between the DAC or the RCA jacks as input source. the secondary RCA jacks are connected to the DAC's output - allowing you to connect the DAC to something other than the amp._

 

Here is a quick picture I made that shows what I had in my head. I would put the USB port on the back with the Amp power switch and RCA inputs for the amp. The DAC would be connected to the RCA input of the amp too, only internally. I don't if I can think of any situations where I would need another output for just the DAC so I don't think I'll go with that switch idea. My only unknown is if I would have any problems with having the DAC wired to the Amp like I do. Obviously if I was using the Amps RCA inputs, I wouldn't have the USB cable of the DAC plugged in.


----------



## Jrossel

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_You can use the REG102 version which handles 250mA of current instead of the 100mA of the reg101. The specs are a little bit worse(very very little). Digikey shows the REG101-5-ND and the REG102-5-ND but none of the 3.3volt version. they have a "call" on the price. Maybe giving them a call will clear things.

 I don't under_

 

What I truely need is a substitute for the Reg 101UA-A (or 102UA-A)
 There is a different manufacturer that would work, I had seen it here in a linked BOM. I hope I have a hard copy somewhere.

 Anyone remember who posted a non-digikey BOM?

 Thanks!


----------



## Eokboy

Quote:


 Are you guys running headphones right off the DAC? 
 

The DAC drives my HD580 decently without amping, since its a high Z headphone.


----------



## amb

Quote:


  Originally Posted by *Eokboy* /img/forum/go_quote.gif 
_The DAC drives my HD580 decently without amping, since its a high Z headphone._

 

"High" is relative. HD580 is 300 ohms, which is considered a high-impedance headphone. But the Alien's PCM2702 would _really_ strain at driving a 300 ohm load. It'd be much happier driving a load impedance that's 10x higher or more. After all, it's a line out that was intended to "see" the input of another amp stage.


----------



## bhjazz

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_What I truly need is a substitute for the Reg 101UA-A (or 102UA-A). There is a different manufacturer that would work, I had seen it here in a linked BOM. I hope I have a hard copy somewhere._

 

No kidding! Sheesh, there don't seem to be any available anywhere. If there really are substitutions, I would love to see them. 

 Are there any other options? Could I switch to battery power for these and manipulate R31/R32 so that I can get around the vacuum that is the Reg102/A problem?

 Thanks!


----------



## MisterX

http://www.micrel.com/_PDF/mic5200.pdf ?


----------



## bhjazz

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_http://www.micrel.com/_PDF/mic5200.pdf ?_

 

YESSSS!
 Very nice! I'll look into these. Thank you!


----------



## FallenAngel

You might just need to skip C22, C32 and R32 to use those MIC5200 and use the 4.8V model for the 5V, the rest looks pin compatible with the board


----------



## purplepencil

Hey all,

 Sorry if this has been answered before, but had a couple of quick questions on this. 

 1) Can this be used as a "plug-and-play" device, eg. I can plug it in to a Windows machine and it will automatically be recognised, OR do I have to use asio4all drivers?

 2) How reliable are the latest versions of the asio4all drivers? I've heard very bad things about the driver stability in the past.


 Thanks,


 Dave


----------



## FallenAngel

1) It's plug and play into any machine - Windows, Linux, Apple. ASIO4All is recommended, but no required.

 2) If you have problems with it, get v1.8 off the AlienDAC site.


  Quote:


  Originally Posted by *purplepencil* /img/forum/go_quote.gif 
_Hey all,

 Sorry if this has been answered before, but had a couple of quick questions on this. 

 1) Can this be used as a "plug-and-play" device, eg. I can plug it in to a Windows machine and it will automatically be recognised, OR do I have to use asio4all drivers?

 2) How reliable are the latest versions of the asio4all drivers? I've heard very bad things about the driver stability in the past.


 Thanks,


 Dave_


----------



## Jrossel

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_http://www.micrel.com/_PDF/mic5200.pdf ?_

 

Thanks for the substitute. I wish they also had an adjustable device.

 I am waiting until FEB for a small shipment of REG 102 UA-A. 
 TI had to mess up a good thing.

 Any other possibilities?


----------



## zx168

i just finished the kit that i got from jeff.
 everything mounted correctly with no bridging but when i plug it in to the usb port, i got unrecognized device.




 what steps needed to troubleshoot this?

 thanks


----------



## FallenAngel

Check voltages at 5V and 3.3V. How is this powered?


----------



## pinkfloyd4ever

I'm about to order a kit from Jeff, what are the pros & cons of unregulated vs fixed regulated vs adjustable regulated? I'm sure this has been discussed before somewhere but I searched and couldn't find what I was looking for.


----------



## MisterX

You're right, it has been covered before. 

Alien DAC - Parts List



  Quote:


 Any other possibilities? 
 

I have not found anything that is pin compatible. 
	

	
	
		
		

		
		
	


	




 Have you tried a parts broker? 
 Like SGI direct for instance: 
SGI - Electronic Components Parts Distributor - Call 978-922-4299

 (they have thousands of them listed as available but.....)


----------



## tomb

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_I'm about to order a kit from Jeff, what are the pros & cons of unregulated vs fixed regulated vs adjustable regulated? I'm sure this has been discussed before somewhere but I searched and couldn't find what I was looking for._

 

Regulated should be chosen in any case. I can guarantee that connecting into a powered, but unregulated USB hub results in bad effects to the sound quality.

 The real question seems to be USB-powered regulated (~4.8V with a REG101/102-A) vs. battery-powered 5V regulation (REG101/102-5). It seems that those who have tried both report no difference. So, I would opt for the REG101/102-A and use the extra resistors as described in the link that MisterX provided.


----------



## johnanderson

I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

 They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting.


----------



## FallenAngel

Quote:


  Originally Posted by *johnanderson* /img/forum/go_quote.gif 
_I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

 They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting._

 

Well, it uses a PCM2704 vs the PCM2702, so it has lower SNR and I runs a single power supply for analog and digital which might make it slightly more noisy. I can only imagine what output caps are being used in that thing and I doubt it's anything good.


----------



## xmokshax

Quote:


  Originally Posted by *johnanderson* /img/forum/go_quote.gif 
_I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

 They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting._

 

i can't answer your question specifically, because i haven't compared the two in terms of sound quality, but a couple of observations:

 1) that usb cable DAC doesn't look terribly robust - it actually looks like they just throw heat-shrink over the pcb in the middle of the cable and call it a day. sure, it's small, self-contained and convenient, but it looks like you might be able to snap it by looking at it the wrong way. maybe i'm misinterpreting the pics on the site and the middle is actually covered in some molded plastic, in which case this criticism doesn't apply.

 2) as FallenAngel points out, you have much less control (i.e., none at all) over the quality of the components that go into that DAC. sure, the chip is quite similar to the one found in the Alien, but the iPod is a perfect example of the negative effects that some crappy caps can have when placed in the signal path. if i'm not mistaken, the iPod uses an excellent Wolfson DAC, but sullies up the sound going to the headphone jack with some sub-par capacitors downstream. Jeff's kit already includes some nice, high-quality parts, but you can improve on them even more for very little added cost by throwing in, say, a pair of 47uF BG NX Hi-Q output caps. this ability to customize the Alien is a huge advantage, especially since the passive parts in the cable DAC probably aren't the best.

 3) once you get into it, SMD soldering is quite fun. the Alien is the only SMD project i've done, but i find myself wanting to buy another kit from Jeff just because i want to do some more SMD work. if you're a DIYer at heart, go ahead and give it a shot - the worst that can happen is that you lose $37, which is precisely what would happen if you accidentally snapped that flimsy-looking cable DAC. on the other hand, the best that can happen is that you get a DAC that (almost certainly) outperforms the cable by a significant margin, and you have the satisfaction of knowing that you put it together yourself.


----------



## Eokboy

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_"High" is relative. HD580 is 300 ohms, which is considered a high-impedance headphone. But the Alien's PCM2702 would really strain at driving a 300 ohm load. It'd be much happier driving a load impedance that's 10x higher or more. After all, it's a line out that was intended to "see" the input of another amp stage._

 

Yes 'high' in relation to headphones. Still it did drove my headphones quite well. A bit lack of power in the low end but I hardly notice it. 

 I prefer amping it though. We should toe the line and operate under specified conditions 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_You might just need to skip C22, C32 and R32 to use those MIC5200 and use the 4.8V model for the 5V, the rest looks pin compatible with the board 
	

	
	
		
		

		
		
	


	


_

 

And increase C21/31 to 1uF.

 MisterX: Thanks for the pin compatible suggestion. I can't find REG101s anywhere.

 I can get 3.3V MIC5200 but they're twice REG101's price. I think its cheaper to hotwire an LM317 regulator offboard but afraid I won't get the same performance.


----------



## error401

There are lots of pin-compatible options you should look at before resorting to the messy and vastly inferior LM317 to replace these regulators.

 For example, TI offers the TPS732xx series (TPS73201 adjustable, TPS73233 3.3V fixed) that's pin compatible (but requires different setting resistors for the adjustable one). It's not quite as good as REG101 (very slightly worse noise performance, significantly worse PSRR). Biggest caveat is that its absolute maximum input is 6V, so you may need a preregulator if you're not powering from USB.

 National has the LP2985 with similar specs (and allows up to 16V input), but no adjustable version (3.3V and 5V are available).

 There are more of course, but most SOT23-5 regulators use this same pinout, so browse around and look for ones with similar specs to the REG101.


----------



## MisterX

Quote:


  Originally Posted by *error401* 
_There are more of course, but most SOT23-5 regulators use this same pinout, so browse around and look for ones with similar specs to the REG101._

 


Alien DAC - Parts List

 Quoted from the site above:
  Quote:


 IC2 1 REG101UA-33 or REG102UA-33. SO8 package. Mandatory. 
 IC3 1 Fixed: REG101UA-5 or REG102UA-5. SO8 package.
 Adjustable: REG101UA-A or REG102UA-A. SO8 package. Mandatory for all configurations except Unregulated USB. Read Note 4 for more details. 
 

See a problem here?


----------



## tomb

Yep.

 The SOT23-5 version of the REG101 has the same pinouts as the SOT23-5 version of the TPS's, but that's as far as it goes. The Alien's SOIC-8 version of the REG101 bears no resemblence.


----------



## error401

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Alien DAC - Parts List

 Quoted from the site above:


 See a problem here? 
	

	
	
		
		

		
		
	


	


_

 

Funny thing is I consulted the site half a dozen times while I was poking around looking for replacements. What a brain fart 
	

	
	
		
		

		
		
	


	




.


----------



## rhester

Without reading all 100 pages (which I am trying to do), how are some of you externally powering the Alien, especially if using in a case with a headphone amp?


----------



## Hubbard0

I got mine yesterday and promptly did a terrible job on the main chip. I entirely blame my technique, so I'm picking up some flux and solder braid from Radioshack on my way home today. I ended covering all the pins with one big blob of solder, but after doing the chips with less pins I think I've found a strategy. I also need to get LEDs and a jack.


----------



## Hubbard0

Spectacular news. My Alien is now 99% functional. I stabbed in a random LED which didn't end up lighting, but I get full audio.

 After using the soldering braid on the main chip it successfully removed all the bridges and had a great connection without any touch ups. It worked right away and this was my first time doing SMD work. Now it's time to order my Millet Hybrid and put these two to work with each other.

 It's funny, I've done all this and I still don't even have any headphones, buy my RP-21s should be here tomorrow.

 Edit: I don't know if I could tell any significant differences yet between my onboard laptop soundcard and the alien, but I think that's because of the Harmon/Kardon desktop speakers aren't the best.


----------



## pinkfloyd4ever

I just finished soldering mine and am looking for a power source to test it with. Is a 9v battery too much?

 also do I measure the voltage between the 5V and 3V3 pads or from each to ground (so I guess G1 or GA) And what should they be? I'm using the adjustable regulated, USB powered version (tho it won't be powered by USB till I make sure its working right)


----------



## pinkfloyd4ever

pleeeaaaseee?!?! Anyone?? I'm dying to test this thing and (hopefully) get it up & running with my Max


----------



## FallenAngel

pinkfloyd4ever

 1) Measure 5V and 3.3V to ground.

 2) 9V is OK, but will not run for too long before the battery dies.

 Why would you want to have it powered off something instead of USB straight away?


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Why would you want to have it powered off something instead of USB straight away?_

 

that's what the website says to do and I have no idea how any of this works...I just follow the directions


----------



## pinkfloyd4ever

YYYEEEAAAAAAAHHHHHHHH 3.185v at 3V3 and 4.55v at 5V!!!
 I CAN'T BELIEVE IT..I thought i'd never get these damn tiny Ls Cs & Rs soldered w/o f'in something up
 now to see if it actually works...


----------



## pinkfloyd4ever

SUCCESSS!!!! Man, I have to say this is what I've been needing. I've always (in the past 3-4 weeks) thought it was way better than my cmoy (obviously) but was still kinda wondering what everyone was raving about, even with the tubes & BG's broken in...and it was DEFINITELY my soundcard. AHHHHHH I'm so excited
	

	
	
		
		

		
		
	


	




 Man I hate that I have to go back to homework


----------



## Hubbard0

i used mine and didn't really notice a difference. didn't use headphones but my 2.1 speaker setup.


----------



## pinkfloyd4ever

there's your problem. I've got a Millett Max that's been breaking in for about 3-4 weeks straight (24/7) and a pair of MS-1s that are way beyond broken in. If you have any amp and any decent pair of cans (including KSC75s) I'd def recommend trying them instead


----------



## tomb

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_there's your problem. I've got a Millett Max that's been breaking in for about 3-4 weeks straight (24/7) and a pair of MS-1s that are way beyond broken in. If you have any amp and any decent pair of cans (including KSC75s) I'd def recommend trying them instead_

 

IMHO, you just described one of the killer combos in inexpensive DIY headphone sound: Alien DAC -> Millett MAX -> Grados/KSC75's. It's also one of the most disdained by purists. Yes, the Alien DAC has a bit higher noise floor than many DACs, but the detail and musicality is fantastic. One might say the same for the Millett as well (disdain), at least from a testing perspective, but we keep building them for the wonderful sound anyway - almost in a cult-like fashion. As for Grados/Allesandro's/KSC75's, well at least a couple of those are often the poor man's first foray into quality headphones, again with a cult-like following.


----------



## DolbyR

Just a quick question before I start the soldering on mine.

 Do I need the Asio drivers for it to work or does wondiws have a default driver the Alien can work with...as I just found out, no external software are allowed in my work laptop


----------



## MisterX

Yes, Windoze has a built in driver for it.


----------



## DolbyR

10x MisterX, fast and helpful as always 
	

	
	
		
		

		
		
	


	



 Although I'm still wondering...as most of my music files are lossless and I'm not allowed to install any software. Is there even a point on making the DAC, if all I'll be able to use is windows media player and MP3s and WMAs? Would I possibly be better off with a HDD player with line out (i'd be running through the SOHA I'm finishing)?
 The Alien I could finish later for home use as I already got the PCB and the PCM.

 Sorry if its too OT.


----------



## tomb

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_10x MisterX, fast and helpful as always 
	

	
	
		
		

		
		
	


	



 Although I'm still wondering...as most of my music files are lossless and I'm not allowed to install any software. Is there even a point on making the DAC, if all I'll be able to use is windows media player and MP3s and WMAs? Would I possibly be better off with a HDD player with line out (i'd be running through the SOHA I'm finishing)?
 The Alien I could finish later for home use as I already got the PCB and the PCM.

 Sorry if its too OT._

 

Actually, you're the only one that can answer that - by asking your management/IT policy personnel. It's possible to have the laptop locked down enough that it won't allow you to select the Alien as the preferred sound card source (it shows up in the list as USB Speakers). Foobar makes this easy by alowing you to select the sound card source directly within the Foobar program. However, if you can't load Foobar, then you may still have an issue.

 I'd talk to them - ask them instead of us. As long as you can assure them that you won't be downloading music, that's usually enough. It's always possible that you could use CD's or an external, portable disk drive as well. Most IT people and even management are understanding about music vs. downloading every piece of software junk that comes your way from the Internet. They may also have a concern about chewing up bandwidth in the workplace. However, I've been in some pretty high-security environments and stuff like this was still allowed. You might find that they would install it for you.


----------



## DolbyR

Well, I was running Foobar...until yesterday, when our IT came for a "IT Compliance check" and uninstalled it as it's not a software that is downloadfable from our intranet software database, and therefore, they consider it high risk.
 Apart from that, the laptop is quite unlocked so selecting the source wouldn't be a problem. But not being able to play lossless kinda sucks. And I guess no decently priced portable player will compare to the SQ of the AlienDAC?


----------



## tomb

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_Well, I was running Foobar...until yesterday, when our IT came for a "IT Compliance check" and uninstalled it as it's not a software that is downloadfable from our intranet software database, and therefore, they consider it high risk.
 Apart from that, the laptop is quite unlocked so selecting the source wouldn't be a problem. But not being able to play lossless kinda sucks. And I guess no decently priced portable player will compare to the SQ of the AlienDAC?_

 

Put in an IT Help Request - tell them you can't play FLAC files on your laptop and you need them to fix it. 
	

	
	
		
		

		
		
	


	




 If they give you some grief, tell them the music helps you concentrate on your job.

 Or, perhaps you might partition them for making Foobar part of your intranet software database. I believe it's open source, something that often makes IT types feel better. Plus, it's a lot less resource intensive than Window Media Player. It's worth a shot.


----------



## error401

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Or, perhaps you might partition them for making Foobar part of your intranet software database. I believe it's open source, something that often makes IT types feel better. Plus, it's a lot less resource intensive than Window Media Player. It's worth a shot. 
	

	
	
		
		

		
		
	


	


_

 

It's not open source, unfortunately. You could always run it from a USB drive though, I did that at college and it works properly that way (configs are stored in a file etc.).


----------



## DolbyR

I was considering the Flashstick alternative also. Although they'll probably still find out, as we have realtime monitoring for all software, internet etc. It would show up as a process I guess.
 I guess for now I'll just play VBR or 320kbps MP3s or convert my FLACs to WMAL and use the crappy mediaplayer. Probably won't get much difference anyway as my headphones are not really hi-fi. I believe high bitrate MP3s through the Alien+SOHA, can't be that much worse than FLAC directly from the headphone out to the senns (thats how im running now).


----------



## J.D.N

Im gathering together the last of the bits i need to build the alien and just have a couple of questions. 

 Will an LED with these specs be ok? 

 Forward voltage max. at IF=20mA:4V
 Forward current max.:50mA
 Reverse voltage max.:5V
 Power dissipation PT:120mW
 Light output min.@ 20mA:1.9cd
 Light output typ.@ 20mA:2.3cd


 Also, which hammond case do i need? I know it is probably around here somewhere, but it seems to be eluding me!

 Cheers


----------



## DolbyR

Hammond 1455C for the case. It's on the first page of the AlienDAC website


----------



## tomb

Quote:


  Originally Posted by *nysulli* /img/forum/go_quote.gif 
_ Quote:


  Originally Posted by *TomB* 
I bet!!
	

	
	
		
		

		
		
	


	







 Good thought - something I've always repeated should be done, but I cased mine up in those Penguin mint tins too quickly. I'm waiting to build another one before trying this.

 I'm not sure I completely agree that Dsavitsk's findings scale up, though - the Sonicaps remove a bit of that outstanding slam in the ES's on the MAX. It definitely opened up the highs and brought in the airiness and soundstage (but not in the cathode bypass position - Yuck!), so it maybe an OK tradeoff, maybe not - my opinion still runs a bit back and forth.

 It's possible that the size ratio of the ES caps with the 0.22uf Sonicaps is so much closer in the Alien that the bass isn't affected. What happens in the MAX is that the Sonicaps are so much faster that they may overwhelm the giant (by comparison) 1000uf and 470uf ES's. The smaller 33uf ES's in the Alien (the size I got to fit) may be quick enough compared to the Sonicaps that the combination works much better.

 

trust me on this one, theres no loss in the low end with the ES's bypassed in the aliendac, how much the ratio between the 47uf and .22uf caps plays into that i'm not sure, but i would agree with you that theres something different when it comes to the tube bypass over the output bypass, but it follows dsavitsk's findings as far as i can tell.

 anyways, i'll be able to compare it to a BG capped alien in a week or so, but it'll be a little skewed as this current alien is running at 5.5v and the BG config will be running off regulated USB power_

 

I trust you now! 
	

	
	
		
		

		
		
	


	




 I finally got around to building some more Aliens. While at it, I decided to finally bypass my Muse ES Alien - particularly since it had become almost unused: the BG Alien DAC is so much better than the ES's alone.

 I proceeded to add the 0.22uf Sonicap GEN II's - as recommended for so long by Dsavitsk. After a short break-in, wow! It sounds better than the Black Gates. Now, that's quite a statement - but I listened to it for a long while: deep, slamming bass - but very tight; luscious mids - not recessed at all; and the big difference (over ES's alone) - sterling, extended highs with resolution.

 Not trusting myself at this apparent improvement over the Black Gates, I decided to test both of them. The ES/Sonicap GEN II's tested better! I'll post later tonight when I get back home (Superbowl was too interesting last night!). Generally speaking, the ES/Sonicaps measure noticeably better than the BG's at 1K and below. Above that - they are virtually identical. (RMAA w/M-Audio Transit - basic results compare similarly to Calroth's revised tests earlier in the thread.)


----------



## ruZZ.il

mmm juicy 
	

	
	
		
		

		
		
	


	




 I've got some 0.22 gen IIs I could pair with my ES Alien. I think the ESs alone have had some mid->high clarity lacking for me, I'll be trying this bypass out soon!


----------



## tomb

Yep - I probably did something wrong, but the results do compare well with Calroth's latest tests earlier in this thread. Also, IMHO, it's the comparison that's important, not the absolute results. 
	

	
	
		
		

		
		
	


	




RightMark Audio Analyzer test: comparison


----------



## ruZZ.il

Juicy I thought? Oh yeah! Those gen IIs have filled in a significant gap alright. When I was comparing my ES dac to my headphone out yesterday, via a mini^3, I was getting much clearer bass, well defined, but I didnt have much of an improvement from the middle up (in clarity and detail, but I still had better seperation and sound stage). It was like the bass was just drowning everything else out. The improvement now is rather significant, to say the least, and everything just shines through the bass much better, nice and defined. I'll be letting it play for a while and see how the gen IIs break in.. I'd recently built this dac board too, and was going to change the ESs out for BGs for someone. I'll have to get another board done today 
	

	
	
		
		

		
		
	


	




 In the meantime, I've still got a little harshness in the cymbals.. will be following that with these gen IIs.

 Thanks for bringing up this bypass option again and giving the incentive to try it out!







 Say, Tom, what's your audio opinion of the transit vs Alien? The measurements look in the transits favor.. but they don't always mean everything, or were you using the transits in giving it loopback favor to itself or something?


----------



## tomb

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_<snip>

 Say, Tom, what's your audio opinion of the transit vs Alien? The measurements look in the transits favor.. but they don't always mean everything, or were you using the transits in giving it loopback favor to itself or something?_

 

I'm not exactly sure what you mean there - but yes, the Transit is the loopback reference. I don't know if that means those graphs are accurate for the Transit - or any of them, for that matter. 
	

	
	
		
		

		
		
	


	




 As stated, the comparison is what's useful, I think.

 Bottom line - no, I don't like listening to the Transit as much as the Alien - no way. Personally, the Aliens sound much more detailed, albeit with some low-level hiss in the noise floor by comparison. I suppose that could mean that those harmonic distortion spikes simply give the illusion of more detail, but whatever. 
	

	
	
		
		

		
		
	


	




 The Transit is dry and lifeless by comparison - a pretty good testing vehicle, though.

 P.S. I'll try to post some pics tonight. I actually ran SPC wire leads from the GEN II's to the solder blobs for CL and CR under the board. The GEN II's are resting horizontally against the end of the Alien board. It's probably not very robust, though, so will come up with something different - I hope to try Vit Q's on the BG's next and then by themselves, too.

 EDIT: Your way looks much more stable. I bet it makes a neat package in a Hammond. There's only so much I can do in a mint tin.


----------



## ruZZ.il

Stability while flapping around outside, maybe (thanks). In a mint tin once everything is secured in place, stability is over-rated, and it looks cool anyway!. Short leads take over 
	

	
	
		
		

		
			





 I'm thinking of re-positioning the caps to be more parallel to the end of the board and much closer, if they'd fit, but they probably wont, and since it all works, I've got more stuff I'm likely to 'break' first 
	

	
	
		
		

		
		
	


	




 What vit Qs would you try? you'd need 3 0.22s to get a cut-off freq of 4~5Hz into a 50K load..


----------



## tomb

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_<snip>What vit Qs would you try? you'd need 3 0.22s to get a cut-off freq of 4~5Hz into a 50K load.._

 

I was thinking 0.22uf's to bypass with BG's, but 0.47uf's when by themselves. I've got four more going right now that I'm going to experiment with - also will try to fit them in under the board in some MAXes, if that's possible. Laying all the caps down will make it pretty flat, but by the time you count the clearance needed from the bottom of the case plus the solder blobs/leads under the board, it's less than 3/8" of inch working space. There may be a way I can mount one on the inside of the backplate - I'm not sure, yet. The L-Com panel-mounted USB jacks will help, but they're huge, too.

 We'll see ... they may end up in some more mint tins.


----------



## ruZZ.il

meanwhile, I got another A.dac running and am using some silmic IIs that jeff supplies to make sure its running nicely while I wait for some BGs. I must say, the silmic IIs are pretty decent all-rounders. A little less bass than the ES-GENII combo and a little less detail from my familiarity with BGs. Slightly less 'smooth' than both, but a fairly balanced sound.. not bad at all..
 going to compare it to my burnt in silmic II A.DAC that I haven't used for a while..


----------



## willco007

Hi All,
 I recently finished my first Alien DAC which turned out great (check the build picts thread for shots) but I'm not happy with the brightness of the LED. It's dimmer than I'd like. Is it safe to lower the resistance of RLED?

 Thanks!


----------



## error401

Quote:


  Originally Posted by *willco007* /img/forum/go_quote.gif 
_Hi All,
 I recently finished my first Alien DAC which turned out great (check the build picts thread for shots) but I'm not happy with the brightness of the LED. It's dimmer than I'd like. Is it safe to lower the resistance of RLED?

 Thanks!_

 

Yes. If you look at the schematic, the LED/RLED are connected between 3V3 and ground. RLED will drop ~1.5V with a standard red LED (1.8V), and the default 600R value will pass only 2.5mA. Most standard LEDs are rated for about 20mA, so you could decrease it to 75R.


----------



## ruZZ.il

which LED do you have?.. I guess RLED could be lowered a bit, but not by too much.. 

 check the LED spec sheet for what voltage to try obtain and at what current it it should be at, then: 
 R=(Vs-Vled)/I
 Vs=3.3 on the Alien..
 Most diodes use about 2~2.5v, so the LEDs are only drawing 2~3mA with RLED at 600R. half that would be 5mA which the reg. should still be able to handle..
 I find that with my ultra-bright LEDs I get them even too bright with RLED=600R, so you're probably better of getting the right LED and keeping the current down.

 edit: I was beat to it 
	

	
	
		
		

		
		
	


	




 and he also knows what he's talking about, so I guess the reg can easily handle a bunch more mA quiet happily.


----------



## willco007

Thanks for the prompt replies. I'll check it out.


----------



## MoodySteve

I just discovered something that other amp builders may run into in the future if they integrate an Alien and an ε12 protection circuit into the amp.

 I omitted the CL/CR coupling caps on the Alien because the amp it was hooked up to used a DC servo to nullify DC. I figured one less part in the signal path = one less opportunity for signal degradation. However, I discovered that it caused the ε12 to disengage whenever I would switch between inputs or change the volume when the Alien was selected. 

 Adding the coupling capacitors to the Alien not only fixed this problem, but also got rid of some noise I was hearing from the USB.

 Hopefully this will save some future builder the same afternoon of discovery that I just enjoyed.


----------



## ruZZ.il

I've taken in a half built alien to fix up for someone. Most of the caps and resistors were soldered on, somehow, along with the reg's. the PCMx was soldered on by Jeff, I assume, very neatly. I measured the resistors which checked out. I didn't measure any of the capacitors though I proceeded to clean things up, straighten things out and make sure everything was soldered in neatly. I built up the board with the remaining parts substituting the 1M resistor across the crystal with a through hole one I had lying around (was originaly nowhere to be found). C1 was missing but I've ommited it...
 Anyway, I fired it up and measured the voltage, which is fine. plugged it in and had snow. When the power is cycled it actually plays for a few seconds before snow blends in and takes over in a sort of intermittent way. I'm assuming its some oscillation/capacitor thing, which I'll continue to investigate. I'm not quiet sure what to measure with the caps while they're on the board but I'll probably replace a bunch of them anyway.
 I'm not sure C1 introduces such an oscillation (if thats what causes the snow) since its an 'optional' part, but I'll certainly fill that in too. I'm leaning towards something out of C11-19 being the issue but I'd appreciate any ideas and input anyone could have on the potential causes of the issue.

 Much appreciated

 -Russ.


----------



## cook

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_I built up the board with the remaining parts substituting the 1M resistor across the crystal with a through hole one I had lying around
 ....
 I'm assuming its some oscillation/capacitor thing, which I'll continue to investigate._

 

Oscillation and non-regular part by the oscillator... I'd try to get a proper 1M resistor first


----------



## ruZZ.il

didnt feel like wasting too much time, I changed out c14, c19, X1, R14 and added C1, works like a charm 
	

	
	
		
		

		
		
	


	



 the downside of the batch work, I'm not sure what the culprit is. I'll try substitute some of the parts I've used with alternatives to keep a concise spare set and check out the ones I've taken out again. at least its alive..
 Thanks for the response though! it's comforting to know its not just me behind the wheel =)


----------



## bhjazz

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_I decided to finally bypass my Muse ES Alien - particularly since it had become almost unused.

 I proceeded to add the 0.22uf Sonicap GEN II's - as recommended for so long by Dsavitsk._

 

Hi tomb, 

 Hey, just wondering which ESs you were using? Is it the 33uF or the 47uF? I'm going to be shoring up the last parts I need over the next week and wanted to try the bypass route. 

 Also - (and just to be sure): when you say bypass, you mean connect the Sonicaps in parallel to the ESs, correct? 

 Thanks!


----------



## FallenAngel

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Hi tomb, 

 Hey, just wondering which ESs you were using? Is it the 33uF or the 47uF? I'm going to be shoring up the last parts I need over the next week and wanted to try the bypass route. 

 Also - (and just to be sure): when you say bypass, you mean connect the Sonicaps in parallel to the ESs, correct? 

 Thanks!_

 

Bypassing is using the Sonicaps in parallel, should sound good 
	

	
	
		
		

		
		
	


	




 You can use either, and definitely smaller valued ES caps, anything over 4.7uF is effectively usable for any amp.


----------



## tomb

Actually, the ES's are 33uf 16V. The 47uf's at Handmade are 8mm in diameter and won't readily fit the board. 'Course, whether a cap fits the board or not doesn't stop many of us 
	

	
	
		
		

		
		
	


	




 , but I was trying to follow all the prescribed recommendations when I ordered my parts long ago. FallenAngel's response is correct, though - anything in that range would apply, and as he says, the Sonicaps are in parallel.


----------



## xnothingpoetic

I have a FallenAngel built alien dac, and I was running it with my max for around 7 days non stop and took a listen to it one day and heard distortion in the right channel. 

 I have pinned the problem to the DAC.

 But can anyone tell me on HERE where any possible problems might be causing the right channel distortion. 

 I was thinking the caps but was unable to test that theory yet and if I need to buy new parts I want to buy parts for all the possible problems.


----------



## ruZZ.il

Initially, I'd just look over the board to see if all the solder points look good, ie, they all seem soldered properly to the board, and that there are no bridges and stuff. Since it works for the most, everything is probably in the right place.. does it work after a break? 7 days isn't a nominal working time..


----------



## xnothingpoetic

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Initially, I'd just look over the board to see if all the solder points look good, ie, they all seem soldered properly to the board, and that there are no bridges and stuff. Since it works for the most, everything is probably in the right place.. does it work after a break? 7 days isn't a nominal working time.._

 

I should have noted that I bought the DAC used off of him- so he's been running it for who knows how long and when I got it, everything worked for- I don't know- a month? Then one day I just get distortion. It sounds like the signal is getting through but on a very weak connection. 

 The caps are most prone to being moved around but I guess I should be looking to make sure all connections are good. (wish I had a voltmeter).

 Do you think a bad ground from the RCA connectors could have caused distortion? I was fiddling around with those before and if the ground hoop thing wasn't making good contact with the female end, then maybe it could be the culprit... I will test that theory later today.


----------



## tomb

Quote:


  Originally Posted by *xnothingpoetic* /img/forum/go_quote.gif 
_I should have noted that I bought the DAC used off of him- so he's been running it for who knows how long and when I got it, everything worked for- I don't know- a month? Then one day I just get distortion. It sounds like the signal is getting through but on a very weak connection. 

 The caps are most prone to being moved around but I guess I should be looking to make sure all connections are good. (wish I had a voltmeter).

 Do you think a bad ground from the RCA connectors could have caused distortion? I was fiddling around with those before and if the ground hoop thing wasn't making good contact with the female end, then maybe it could be the culprit... I will test that theory later today._

 

Yep - you'll get some wild buzzing/crackling if that ground lead is only making intermittent contact. If that's not it, then check the solder connections on those output caps. If things are loose and move, the solder joint could come loose.

 Sounds like it's that ground connection, though.


----------



## fault151

hey im just wondering, how will this little dac compare to that of a beresford dac, music fidelity x-dac or the zero dac? I have just bought a second hand millet amp and im wondering if it will be of any use t me? I already have the three dacs i mentioned so am i wasting my time with the alien dac?


----------



## Pars

I'm redoing an Alien DAC for another head-fi'er and ran into a potential problem: I needed to transfer all of the components from an existing board to a new board. One of the caps (C11) came apart when I was desoldering it. This appears to be from a jrossel kit, and I had initially thought it was 33pf, but now think it is a 20pf COG ceramic, 0805 pkg. If I try to fire this thing up with this missing, I presume it should still work? Or not? I can probably grab a 0805 20pf from a lab at work, but getting a COG may be a problem...


----------



## MisterX

I would bet on it not functioning properly with that cap. 
 (without the load capacitance there is nothing there to "control" the crystal's resonant frequency)


----------



## MisterX

Quote:


 7 days isn't a nominal working time.. 
 

How do you figure that?


----------



## ruZZ.il

unscientifically
	

	
	
		
		

		
		
	


	



 I guess just not much IME, which is limited anyway.
 Ultimately, if the thing works, I guess it shouldn't have a problem working long but I suspect in such a time frame there are things that could throw it off, specially if something small is wrong.. some contact that changes with the temp. or something. Though if anything is seriously wrong, I doubt it would play for the first 7 days to begin with. Just speculating, and I'd like to eventually learn what the culprit is after all, if any.


----------



## Pars

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_I'm redoing an Alien DAC for another head-fi'er and ran into a potential problem: I needed to transfer all of the components from an existing board to a new board. One of the caps (C11) came apart when I was desoldering it. This appears to be from a jrossel kit, and I had initially thought it was 33pf, but now think it is a 20pf COG ceramic, 0805 pkg. If I try to fire this thing up with this missing, I presume it should still work? Or not? I can probably grab a 0805 20pf from a lab at work, but getting a COG may be a problem..._

 

I know, bad form to quote myself.

 It worked without the cap (at least the computer saw it as a valid USB device). Next problem: 3.3V test point was fine but 5V test point was reading about 1.5V. After going thru this thread (searches), I found one reference to the resistors (R31/R32) being reversed. Checked those, that wasn't the problem. Another reference to the ground (pin 4) on the +5V vreg not making contact... checked that with a meter to the pin of the chip and ground... that was fine. I removed both R31 and R32, made sure of their values, and reinstalled them. Same problem.

 Then, I ohmed out ground to the ground side of R32 and it was reading 40k or more. Heated this joint up alot more, and now ohming it out gave <1 ohm to ground. DAC works fine now. 

 So what the one poster was saying about the coating on the pads, particularly for ones on the ground plane, being hard to get good contact on is true. Particularly when you are using a small tip for the 0805 SMD, it is hard to heat things up enough.


----------



## rockbottom

Hi MisterX, I've heard that you're very good with DIY stuff, can you suggest a good parts list for the AlienDAC? I'll most likely be ordering through Digi-Key. Thanks!


----------



## MisterX

http://www.glassjaraudio.com/product...=4&productId=6


----------



## rockbottom

I already have PCBs though.


----------



## FallenAngel

Quote:


  Originally Posted by *rockbottom* /img/forum/go_quote.gif 
_I already have PCBs though._

 

Then just use the BOM


----------



## MisterX

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Then just use the BOM 
	

	
	
		
		

		
		
	


	


_

 

Do you remember how much does Digi-key charges to ship to Canada?


----------



## FallenAngel

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Do you remember how much does Digi-key charges to ship to Canada?_

 

Yep, it's $8 flat-rate for Purolator 2-day express, just use *Digi-Key Corporation - Canada Home Page*. Best place for parts in Canada, just avoid Mouser at all costs, shipping is expensive, slow and customs sucks!


----------



## MisterX

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Yep, it's $8 flat-rate for Purolator express, just use *Digi-Key Corporation - Canada Home Page*_

 


 Ok, so then he still has to find the regulators. 

 Do you remember (or know) how much does Jeff charges to ship to Canada?


----------



## FallenAngel

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Ok, so then he still has to find the regulators. 

 Do you remember how much does Jeff charges to ship to Canada?_

 

Good question, I can't find the email where I paid him for shipping to Canada, I think I asked for Priority and it went at around $15, but it's better to double check with him.

 Regulators are a problem, neither DigiKey nor Newark has stock. What about that regulator we mentioned some pages back? It's pin-compatible, but I don't think it's verified yet.

 EDIT: Regulator was MIC5200, to make it work you would need to skip C22, C32 and R32, use the 4.8V regulator for 5V position and increase C21/31 to 1uF. I think it's possible with those changes, but the MIC5200 is more expensive and has worse specs


----------



## Pars

On his Excel Alien DAC order form, it looks like you can 0 out the PCB... that way you could just buy all the parts from Jeff. I also noticed that Digikey didn't have the vregs when I went looking for datasheets last night.


----------



## a1rocketpilot

Well I just got my AlienDAC PCB's and am going to start gathering parts for them. A couple quick questions though about the output caps. MisterX, you had mentioned a while back that BG NX were good caps, but said that the FK's were another story. What exactly did you mean by this? Also Tom, did you ever get a chance to try out the Vitamin Q's as BG bypass?


----------



## tomb

Quote:


  Originally Posted by *a1rocketpilot* /img/forum/go_quote.gif 
_Well I just got my AlienDAC PCB's and am going to start gathering parts for them. A couple quick questions though about the output caps. MisterX, you had mentioned a while back that BG NX were good caps, but said that the FK's were another story. What exactly did you mean by this? Also Tom, did you ever get a chance to try out the Vitamin Q's as BG bypass?_

 

Nope - been experimenting with fitting an Alien into a standard-cased MAX, first. I'll get to it eventually, though. If the experience in the MAX is any indication, it will do nothing but make it sound better. 
	

	
	
		
		

		
		
	


	




 VitaminQ's are everything they're cracked up to be - just make sure they're genuine Sprague 196P or 96P series. 
	

	
	
		
		

		
		
	


	




 I did bypass the ES's with Sonicap GEN II's and that made the Alien sound much better using the ES's, but the BG's have the most "air" so to speak.

 Also, I can't speak for MisterX, but I've had others tell me that except for the NX's, all the other BG's were nothing to write home about.

 Here's some tests I ran recently using the M-Audio Transit as a loopback. Its figures are much better because it uses an opamp output, I suspect. Yet, the Alien seems to have more detail by comparison. "Flat Alien" is the one I've built to put in the standard MAX case. It's 3/8" thick at its thickest with 330uf Panasonic FM caps laid flat on the board. The power cap is 1000uf FM, but it hangs off the side. The whole assembly fits under a MAX board when using the 3rd slot from bottom in the MAX's Hammond case. It uses an L-com panel mtd USB jack (but nothing is installed yet).

 I suspect the lead lengths create just a tad more noise and/or the BG outputs are not fully broken in, yet - the peaks of the noise spikes are slightly higher than the regular BG Alien. At least by this measure, the ES/Sonicap also tests quite well, but listening with the BG's still seems slightly superior.

RightMark Audio Analyzer test: comparison


----------



## Aldyrin2

I just got my kit from Jeff, do you have to clean off the pads before soldering? What do you do this with, typically?


----------



## Animal Mother

Just wondering, how long did it take for you to get the kit? I just ordered a kit from him yesterday and I'm wondering how long shipping should take, thanks. Also, does anybody know what outputs jeffs kit comes with? Rca, mini?


----------



## Aldyrin2

I think it took me about a week. It doesn't have any jacks other than the USB jack included, so I imagine I will have to get something off Mouser. I hadn't noticed they weren't included in the BOM until you mentioned something.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_I just got my kit from Jeff, do you have to clean off the pads before soldering? What do you do this with, typically?_

 

NOOO don't do anything to the coating on the pads, its some special coating and the solder sticks to it very well


----------



## Aldyrin2

I'm trying to decide if that is sarcasm or not. 

 Just put the solder on the iron and then put the iron on the pad in order to tin it?


----------



## tomb

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_I'm trying to decide if that is sarcasm or not. 

 Just put the solder on the iron and then put the iron on the pad in order to tin it?_

 

Yes. However, I will disagree with Pinkfloyd4ever a bit: solder doesn't stick to it as well as plain plating. I think what happens is that your iron actually has to burn the coating off first. He's right about how to do it, though - don't do anything special and wait for your iron to heat it up enough for the solder to stick.

 The silver coating was on the boards in the 1st Group Buy, but not in the 2nd. The 2nd versions solder easier, IMHO. Plus, I've had some board mfrs tell me that it's easier to solder without the coating, too. Maybe it's viewed in some places as a "preservative" to keep tarnish from forming on the solder pads underneath. That's just a guess, though.

 It's no big deal in the end, just maybe takes a little longer for your iron to solder. That may be an advantage when it comes to soldering the PCM chip.


----------



## Aldyrin2

Thanks! I'm off to solder then. Let the good times roll


----------



## Aldyrin2

maybe i'm missing something here, but I'm not seeing polarity markings on some of these surface mount capacitors. However, there look like markings or holes on one pin in all the capacitor mount places. 

 Is this just a passthrough connection for something in the back, or is it a polarity marking of some kind? Tangent's tutorial said there were markings on the caps, but i'm just not seeing it.


----------



## tomb

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_maybe i'm missing something here, but I'm not seeing polarity markings on some of these surface mount capacitors. However, there look like markings or holes on one pin in all the capacitor mount places. 

 Is this just a passthrough connection for something in the back, or is it a polarity marking of some kind? Tangent's tutorial said there were markings on the caps, but i'm just not seeing it._

 

The SMD caps have no polarity. The electrolytics on the board are the same as on any other board - there's a + and Negative Ground and the caps are polarized (except for CL and CR if you bought bipolars - even then, one lead - positive - is longer than the other).

 The holes are "vias" connecting to the traces on the back.


----------



## dgbiker1

Has anyone ever built an Alien with optical inputs instead of USB? I was thinking of using Opus Toslink and SPDIF units, but spending twice as much on inputing the signal as the DAC itself seems a bit backwards


----------



## error401

Quote:


  Originally Posted by *dgbiker1* /img/forum/go_quote.gif 
_Has anyone ever built an Alien with optical inputs instead of USB?_

 

Not possible with the PCM2702 in the Alien. It's a USB-only DAC. You'd need to use the PCM290x series that has SPDIF input, but they are not pin compatible, so won't even work with the Alien PCB.

 IOW: Not possible. You'd have to design a completely new circuit & board.


----------



## dgbiker1

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Not possible with the PCM2702 in the Alien. It's a USB-only DAC. You'd need to use the PCM290x series that has SPDIF input, but they are not pin compatible, so won't even work with the Alien PCB.

 IOW: Not possible. You'd have to design a completely new circuit & board._

 

Thanks error, might be a fun project
	

	
	
		
		

		
			




 Maybe you can correct me on this, but with my Extigy it seems like the sound is much cleaner coming through optical than it is through USB... which seems odd since they're both digital signals. I think there might be a driver issue with OSX (not really supported by the Extigy) since the USB connection was cracking and popping on occasion. Theoretically should USB sound the same as optical?


----------



## Aldyrin2

I seem to have lost the R31 that Jeff included in his kit. Does anyone know the mouser part number of a replacement? There are so many different kinds with similar parameters, I figured I should ask.

 Also, if anyone has a LED suggestion, I'd be all ears.

 Thanks in advance!


----------



## tomb

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_I seem to have lost the R31 that Jeff included in his kit. Does anyone know the mouser part number of a replacement? There are so many different kinds with similar parameters, I figured I should ask.

 Also, if anyone has a LED suggestion, I'd be all ears.

 Thanks in advance!_

 

The closest at Mouser would probably be: 71-CRCW0805-31.6K. However, you need to know R32 to be sure. Refer to "Note 4" on the Alien DAC website Parts List: Alien DAC - Parts List

 If Jeff supplied an 11.5K R32, then Vout = (1+ R31/R32) * 1.26, or 4.72V with a REG101-UA. That's within the recommended regulating range of 4.5 - 4.8V.

 Any 3mm low-current LED will work with the Alien. Typically, you'd want a diffuse LED as a panel light. I think I bought a cheap 10-pack of red ones at Radio Shack for mine. 
	

	
	
		
		

		
		
	


	




 EDIT: The obvious alternative is to call Jeff and ask for the missing part.


----------



## error401

Quote:


  Originally Posted by *dgbiker1* /img/forum/go_quote.gif 
_Thanks error, might be a fun project
	

	
	
		
		

		
		
	


	



 Maybe you can correct me on this, but with my Extigy it seems like the sound is much cleaner coming through optical than it is through USB... which seems odd since they're both digital signals. I think there might be a driver issue with OSX (not really supported by the Extigy) since the USB connection was cracking and popping on occasion. Theoretically should USB sound the same as optical?_

 

You definitely shouldn't get crackling and popping over the USB interface, that's not a good sign. If that's the only difference you're experiencing, then I'd say you're right and there's a driver issue or something wrong with your Extigy.

 There are some issues regarding clock recovery with audio over USB, especially with the USB audio profile. It's possible to set up a USB audio device so that the device itself is the master and the computer sends data as requested - if that's the case, it should be superiour to SPDIF. The standard USB audio profile though requires clock recovery, and IMO the way it is set up makes that recovery more difficult than with SPDIF; if that's the case, SPDIF might sound better.

 The differences are only in clocking though, the actual data should arrive at the destination without any problem using either interface.


----------



## MisterX

Quote:


  Originally Posted by *a1rocketpilot* /img/forum/go_quote.gif 
_MisterX, you had mentioned a while back that BG NX were good caps, but said that the FK's were another story. What exactly did you mean by this?_

 

Simple....
 The FK's sound much better.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Simple....
 The FK's sound much better._

 

whaAAAA??? Seriously?


----------



## MisterX

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_whaAAAA??? Seriously?_

 







 I am not telling you what I think I read somewhere. I am telling you what I heard in a side by side listening test with my own ears.


----------



## fran

hi all,

 I'm looking for some advice here:

 I'm order order a kit from glassjar. I want to build this as best I can without being silly - so is there a single place where the best upgrades are listed? I'm wondering what are the most effective upgrades from the standard kit.

 Fran


----------



## FallenAngel

Quote:


  Originally Posted by *fran* /img/forum/go_quote.gif 
_hi all,

 I'm looking for some advice here:

 I'm order order a kit from glassjar. I want to build this as best I can without being silly - so is there a single place where the best upgrades are listed? I'm wondering what are the most effective upgrades from the standard kit.

 Fran_

 

Answered about a billion times - output caps.


----------



## Aldyrin2

So i've pretty much finished building my kit Jeff hooked me up with. While I was looking at the Assembly instructions, it says to connect a battery or external power to the DAC. 

 I built my DAC to be powered off USB, with the adjustable IC3, so I'm not really sure how (or where, or how much voltage) I should connect a battery or external power supply. 

 Any suggestions you can give would be greatly appreciated.

 In case you need to know, my R31 is "Vishay/Dale 0805 31K6 1%" and my R32 is "Vishay/Dale 0805 11K5 1% (4.75 Vout)".

 Thanks!


----------



## tomb

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_So i've pretty much finished building my kit Jeff hooked me up with. While I was looking at the Assembly instructions, it says to connect a battery or external power to the DAC. 

 I built my DAC to be powered off USB, with the adjustable IC3, so I'm not really sure how (or where, or how much voltage) I should connect a battery or external power supply. 

 Any suggestions you can give would be greatly appreciated.

 In case you need to know, my R31 is "Vishay/Dale 0805 31K6 1%" and my R32 is "Vishay/Dale 0805 11K5 1% (4.75 Vout)".

 Thanks!_

 

No, you don't need a battery. Just connect a USB cable to your PC and it should recognize it as "USB Speakers."

 However, the switch pads have to be jumpered or your DAC won't turn on when you plug it in.


----------



## Pars

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_So i've pretty much finished building my kit Jeff hooked me up with. While I was looking at the Assembly instructions, it says to connect a battery or external power to the DAC. 

 I built my DAC to be powered off USB, with the adjustable IC3, so I'm not really sure how (or where, or how much voltage) I should connect a battery or external power supply. 

 Any suggestions you can give would be greatly appreciated.

 In case you need to know, my R31 is "Vishay/Dale 0805 31K6 1%" and my R32 is "Vishay/Dale 0805 11K5 1% (4.75 Vout)".

 Thanks!_

 

That is probably just to test the 3.3V and 5V regs before you hook it up to a computer. I believe you can just use a 9V battery connected to AV+ and ground. If you don't have a DMM (meter), then don't bother as the sole purpose of doing this is to verify the reg voltages at their test points.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_That is probably just to test the 3.3V and 5V regs before you hook it up to a computer. I believe you can just use a 9V battery connected to AV+ and ground._

 

ya, that's what I did. just make sure you use a good 9V (not dead), cause I tried some 9v that I'd test first with the dmm and get 5-6 volts, (I was afraid the full 9v would be too much, which it is not) but when I connected it to the alien I didn't get the right values...till I tried a fresh 9v


----------



## fran

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Answered about a billion times - output caps._

 

Thanks - its a looooong thread to read! So there seems to be rec for either blackgates or panasonic FKs. I've emailed glass jar to see if he can supply either for extra $$ in the kit but haven't heard anything back (2 days).

 I've done a fair bit of soldering, and have done some SMT stuff, like the diamond buffers in the millet revMH etc and ounfd it easy enough. How hard is the DAC chip to solder on? 

 Fran


----------



## Aldyrin2

Well it seems like it is working. I will have plenty of time to test it out tomorrow at work. 

 I still have one question, though. I bought a hammond enclosure, and the board fits in nicely, but there is a lot of leftover space, and I'm not quite sure of the best way to secure the board so that it doesn't move back into the enclosure when I try to push the USB cable into its jack. 

 My only thought so far is to buy a cheapo protoboard and cut it to size so that it takes up the rest of the slot in the enclosure, leaving no space for the board to move. This is kind of ghetto though, so I figured there was a better way of doing it.

 Thoughts?


----------



## tomb

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_Well it seems like it is working. I will have plenty of time to test it out tomorrow at work. 

 I still have one question, though. I bought a hammond enclosure, and the board fits in nicely, but there is a lot of leftover space, and I'm not quite sure of the best way to secure the board so that it doesn't move back into the enclosure when I try to push the USB cable into its jack. 

 My only thought so far is to buy a cheapo protoboard and cut it to size so that it takes up the rest of the slot in the enclosure, leaving no space for the board to move. This is kind of ghetto though, so I figured there was a better way of doing it.

 Thoughts?_

 

On the contrary, that may be the _best_ way to do it.


----------



## Aldyrin2

Roger that!


----------



## a1rocketpilot

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Simple....
 The FK's sound much better._

 

What particular FK's did you use? And are these just on the output caps or did you use them for any of the filter cap positions as well?


----------



## error401

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_Well it seems like it is working. I will have plenty of time to test it out tomorrow at work. 

 I still have one question, though. I bought a hammond enclosure, and the board fits in nicely, but there is a lot of leftover space, and I'm not quite sure of the best way to secure the board so that it doesn't move back into the enclosure when I try to push the USB cable into its jack. 

 My only thought so far is to buy a cheapo protoboard and cut it to size so that it takes up the rest of the slot in the enclosure, leaving no space for the board to move. This is kind of ghetto though, so I figured there was a better way of doing it.

 Thoughts?_

 

I just use thick card, like the type from a cereal box. Maybe stack two sheets. Works great, and you don't need to waste perfectly good protoboard!

 Then again, I'm not too picky about enclosure interiors, as long as everything works.


----------



## ruZZ.il

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_...
 My only thought so far is to buy a cheapo protoboard and cut it to size so that it takes up the rest of the slot in the enclosure, leaving no space for the board to move. This is kind of ghetto though, so I figured there was a better way of doing it.

 Thoughts?_


----------



## Aldyrin2

lol, nice. 

 I'm here at work, and the computer is recognizing the DAC as a USB device, but isn't installing it as "USB Speakers" like my computer at home did. 

 I've tried searching around a ton to figure out a solution, but am not having any luck. Any suggestions? (I'm running XP SP2)

 I tried installing the ASIO drivers (there was no .inf file to direct the hardware wizard to for USB hardware installation), and also tried copying the usbaudio.sys file into the C:\windows\system32\drivers folder.

 Unfortunately, neither seems to have had any effect.


----------



## Aldyrin2

Well, I apparently worked my magic on the drivers, and its working now. My last step was tweaking some text in a .inf file in the system32\drivers directory.

 I've gotta say, it sounds great!

 Now I have the Alien DAC -> Millet MAX combo working at the office 
	

	
	
		
		

		
		
	


	




 Soon my ATH-W1000's should arrive, and I will really be rocking! 

 Thanks for the help, all!


----------



## Gross

Quote:


  Originally Posted by *Aldyrin2* /img/forum/go_quote.gif 
_Well it seems like it is working. I will have plenty of time to test it out tomorrow at work. 

 I still have one question, though. I bought a hammond enclosure, and the board fits in nicely, but there is a lot of leftover space, and I'm not quite sure of the best way to secure the board so that it doesn't move back into the enclosure when I try to push the USB cable into its jack. 

 My only thought so far is to buy a cheapo protoboard and cut it to size so that it takes up the rest of the slot in the enclosure, leaving no space for the board to move. This is kind of ghetto though, so I figured there was a better way of doing it.

 Thoughts?_

 

I bent up a peice of stiff wire ( similar to a coat hanger ) into a square-U shape, with one end pressing against the Alien, and the stiff legs of the wire in the channel in the hammond case. That way it left the rest of the space available for my big ol fatty caps to fit in there, which they wouldn't have with a pcb cutting the space in half. 

 On another one I cut the case down so it wasn't so long. I wrapped a peice of masking tape around it, which allowed me to draw a perfectly strait line to cut. I forget if I used a hack saw or a dremel to cut it, but I am sure have done both.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_I am not telling you what I think I read somewhere. I am telling you what I heard in a side by side listening test with my own ears. 
	

	
	
		
		

		
		
	


	


_

 

Oh I believe you, I'm just surprised cause I don't recall anyone else ever using or recommending FKs...well dammit, looks like I see another order from Sonicraft soon. What size are you using? And BTW, are you guys that I see using both at once bypassing your electrolytic output caps with film caps? Ahhhhh so many possibilities, maybe I need to get some protoboard too

 edit: can you seriously fit a lead and a wire from the off-board cap in one hole?


----------



## adamus

WHOOOP, my firstever go and smd soldering and we have success. 

 I ordered the pcm chip soldered, but it turn up not soldered (sorted with Jeff - a good chap!). So i had a crack myself, it went badly, then with the use of lot of flux and desoldering braid it came out looking good apart from one bridge. A quick look at the schmeatics and they are joined anyway.

 Sounds good, a bit grainy but its only had 30 mins on it. Certainly some good punchy bass. 

 Now i have just got to finish my soha. I have just confused myself with the transformer wiring, anyone have a soha kit and remembers the secondary wiring scheme?


----------



## DolbyR

Check here for the transformer wiring. 
mb3k.com the place to be


----------



## adamus

The Dac has about 10 hours on it now. Sound has certainly got smoother. 

 Cheers for the transformer wiring diagram.


----------



## cronic

Hello, I just finished soldering my alien that I got from Jeff with the pcm2702 already soldered. The problem I am having is that I get the following message when I try to connect the usb to the computer. Any ideas?


----------



## Pars

Quote:


  Originally Posted by *cronic* /img/forum/go_quote.gif 
_Hello, I just finished soldering my alien that I got from Jeff with the pcm2702 already soldered. The problem I am having is that I get the following message when I try to connect the usb to the computer. Any ideas?_

 

Look the board over under magnification (both sides) looking for solder bridges or no connection. Take your DMM and verify that pins are actually connected to the PCB as well.


----------



## cronic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_Look the board over under magnification (both sides) looking for solder bridges or no connection. Take your DMM and verify that pins are actually connected to the PCB as well._

 

nothing jumps out at me. I have re soldered and removed some solder, but everything looks ok.


----------



## Pars

Well, then that leaves the 2nd part... ohm it out.


----------



## cronic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_Well, then that leaves the 2nd part... ohm it out._

 

the ics solder joints check out good


----------



## Pars

What do the voltage test points look like? OK?


----------



## cronic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_What do the voltage test points look like? OK?_

 

I get this immediately upon connection to usb. No voltage. I tried taking pics of pcb, but my old camera won't take a good picture of the small board.


----------



## Pars

There is a 3.3V and a 5V test point on the board. You use your meter (DMM) to test this. If you do not have at least the 3.3V, you won't get power on the PCM2702, and it won't be recognized.

Alien DAC - Assembly

 See the Test the DAC section...


----------



## FallenAngel

Double check your regulators, I had the same thing when I accidentally switched them.


----------



## cronic

Here are some pictures. Maybe someone can spot the issue.


----------



## FallenAngel

Nice quality 3rd photo, it looks like you have a some cold joints. Get some desoldering braid in there and make them wet and shiny looking. Not positive, but it looks like one of the legs on the 5V regulator is lifted, want to resolder to make sure of that one.


----------



## tomb

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Nice quality 3rd photo, it looks like you have a some cold joints. Get some desoldering braid in there and make them wet and shiny looking. Not positive, but it looks like one of the legs on the 5V regulator is lifted, want to resolder to make sure of that one._

 

Agreed. You might check that C32 on the back side, too - it looks shoved over a bit too much on the pads - might not be making contact. C12 looks like that, too, although that one's probably not enough to cause your error message. IOW, FallenAngel's suspicion about the 5V reg seems to be a good one.

 Your PCM soldering looks pretty good.


----------



## Heady

Cronic,
 I have found pins 3 and 4 of the regulators hard to solder as they are connected to the ground and the heat gets sucked away too fast to get a good solder joint. 

 I notice some of your joints has solder whiskers which does indicate your soldering iron is not quite hot enough. This is often due to using a low watt iron.

 Hope that was helpful.


----------



## cronic

I re flowed all the joints on the pcb. I still have the same error when connected to xp pro sp2 machine and no voltage. When I hook to a vista home premium machine no errors or pop ups and no voltage. Also L12 gets very very hot when connected to computer! do the ic2 and ic3 regulators look like the are in the correct position. I also don't have outputs soldered on yet and assume that would not cause an issue? I'm confused












 I'm using this to solder


----------



## FallenAngel

OK, lets try something different - cut (or desolder) that S1 jumper, connect a 9V battery to AV+/G2 and measure voltages again. If windows is crapping out on recognition, the PCM might be blown. L12 might be getting really hot if it was having a HUGE current being sent through it, which is what windows is saying. Hmm... come to think of it, use a safe battery like NiMH/Alkaline, NOT lithium.

 Note: Also, 720F is pretty hot for SMC work, you sure you didn't cook that PCM?


----------



## cronic

I have not soldered on the pcm2702 at all, it was pre soldered. I tried a 9v as you said and i measure 0v between the 3.3 and 5v pads and g1.


----------



## FallenAngel

Quote:


  Originally Posted by *cronic* /img/forum/go_quote.gif 
_I have not soldered on the pcm2702 at all, it was pre soldered. I tried a 9v as you said and i measure 0v between the 3.3 and 5v pads and g1._

 

Whoops, sorry, keep S1 jumpered 
	

	
	
		
		

		
		
	


	




 This still doesn't explain why you get nothing out of those voltage regs though. Do they get warm at all?


----------



## cronic

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Whoops, sorry, keep S1 jumpered 
	

	
	
		
		

		
			





 This still doesn't explain why you get nothing out of those voltage regs though. Do they get warm at all?_

 

hooked to 9v alkaline with s1 jumpered i measure 0v and the only thing that gets warm is the battery.

 By the way, thanks for the help.


----------



## FallenAngel

Ok, that makes pretty much no sense, are you SURE the DMM is working properly? Measure the battery voltage 
	

	
	
		
		

		
		
	


	




 The chances that both regulators are dead are VERY slim, but even then, I'd expect them to just not regulate, not short out. Both the regulators run independent of each other, so they must both be not working properly.

 Now that I think about it, shorting a battery will make it heat up, but I don't see a short anywhere. Could one be _under_ a part?


----------



## Pars

I might start by ohming out the 3.3V and 5V pads to ground... really any voltage pad to ground and see if any of them show shorts.

 I take it you have used a meter on both the 3.3V and 5V pads to ground for voltage readings with the thing plugged into a USB cable? I had asked you earlier about that and didn't see you post what you were getting?


----------



## tomb

I agree with Pars and FallenAngel. It sounds like you've got a dead short somewhere. You might also try to see if you read zero resistance between the pads on any part. If you do, that would indicate you have a solder bridge underneath. Start with L12, for instance - if the short is there, that's where it would get hot. If you can measure zero ohms between the two pads of L12, that would be it. Remove L12 and clean up any solder bridge with heat, flux, and some braid.


----------



## cronic

Ok, I removed the voltage regulators, l12, and c22 to check for bridges. I found none. FallenAngel, yes I have checked for voltage on the 3v and 5v pad with both 9v battery and usb connections and both read 0 volts. Anything I can check while the voltage regulators are off to eliminate them as the issue? Resistance between 3.3v and g1 starts at 400k ohms and drops, the resistance between 5v and g1 starts at 49k ohms and drops. These are without the regulators, l12, and c22 attached.


----------



## Pars

Check the resistances between pins 3 and 4 of IC2 and IC3


----------



## cronic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_Check the resistances between pins 3 and 4 of IC2 and IC3_

 



 ic2 pin3 to pin4 measures 0L ohms without c22 installed (meter does not react)

 ic3 pin3 to pin4 measures 9.664k ohms with r32 installed

 between g1 and one pad for l12 i measure .15 ohms
 between g1 and the other pad for l12 i measure 8M ohms and rising


 ok, did some more probing without ic2 and ic3 installed. I measure continuity between av+ and pins 5-8 on ic2 and ic3, which is normal. However, I also read continuity between g1 and pins 5-8 on ic2 and ic3. Which means there is a short between ground and voltage somewhere on the board. Any ideas?


----------



## Pars

Quote:


  Originally Posted by *cronic* /img/forum/go_quote.gif 
_ic2 pin3 to pin4 measures 0 ohms without c22 installed_

 

That doesn't sound right... I don't have a schematic in front of me right now though. You shouldn't have a short there though, as a cap in parallel with a short is... a short. You might try running an xacto knife or whatever between those pads, and also check the schematic to see what feeds those two pins. That should be open unless there is something else connected to it.

  Quote:


  Originally Posted by *cronic* /img/forum/go_quote.gif 
_ic3 pin3 to pin4 measures 9.664k ohms with r32 installed

 between g1 and one pad for l12 i measure .15 ohms
 between g1 and the other pad for l12 i measure 8M ohms and rising


 ok, did some more probing without ic2 and ic3 installed. I measure continuity between av+ and pins 5-8 on ic2 and ic3, which is normal. However, I also read continuity between g1 and pins 5-8 on ic2 and ic3. Which means there is a short between ground and voltage somewhere on the board. Any ideas?_


----------



## cronic




----------



## cronic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_That doesn't sound right... I don't have a schematic in front of me right now though. You shouldn't have a short there though, as a cap in parallel with a short is... a short. You might try running an xacto knife or whatever between those pads, and also check the schematic to see what feeds those two pins. That should be open unless there is something else connected to it._

 

I misspoke. My meter reads 0L meaning it does not react at all when connected to pin3 and pin4 of ic2.


----------



## Pars

Quote:


  Originally Posted by *cronic* /img/forum/go_quote.gif 
_ok, did some more probing without ic2 and ic3 installed. I measure continuity between av+ and pins 5-8 on ic2 and ic3, which is normal. However, I also read continuity between g1 and pins 5-8 on ic2 and ic3. Which means there is a short between ground and voltage somewhere on the board. Any ideas?_

 

Unfortunately, this could be about anywhere... since this appears to be a short between V+ and gnd, caps like C31, C21 etc. You don't have IC4 in so that is unlikely. It is also possible that the short is in the board itself, so try to look under the soldermask if you can't find anything else wrong.


----------



## cronic

You guys ROCK! I removed c31, cleaned it up, reattached it and the regulator and bam, I got 3.3v on the 3.3v pad. I'm out of desolder braid, so I gotta run to the store and get some to re attached everything else. Cross your fingers but I think we are headed in the right direction. Thanks again guys, and I will update soon.


----------



## cronic

Its ALIVE! Thanks everyone for your fantastic help. It is working but I am noticing some static in the sound, when using the touch pad or a usb mouse.


 I got about 15 hours on the alien so far and I am impressed. I found that the static issue was only in win xp pro sp2, so I installed vista and have no issues so far..........


----------



## Kenneth S

I can only obtain REG101-3 3 Volt versions not the 3.3 V ones. Can they still be used?


----------



## splaz

Quote:


  Originally Posted by *Kenneth S* /img/forum/go_quote.gif 
_I can only obtain REG101-3 3 Volt versions not the 3.3 V ones. Can they still be used?_

 

The 2702 datasheet says the minimum digital voltage is 3v, max is 3.6v.

 So I'd say theoritically* it could possibly work, however I'd be more inclined to track down the 3.3v version... can you get a reg102-3.3 instead ?

 I'll check my parts stash... I don't think I have any laying around but you never know.


 * I'd just be concerned that the regulator might put out slightly under 3v which doesn't meet the spec or even if it does put out 3v or a little more that the 2702 might not perform as well or even be erratic at that sort of voltage.


----------



## splaz

Just had a look in my stash, nope sorry, none spare. Thought maybe they were some of the regulators but they're opa551s...


----------



## a1rocketpilot

So I'm getting my BOM together, and I was wondering if it would be possible to use a lower value for C14-C19. I was planning on using the Panasonic ECH(U)-B (Digikey #PCF1120CT-ND PPS caps from Digikey, until I found that they only have up to 39nf, instead of the 100nf that it specifies. However, considering that I am building the USB regulated version, the exact size of those caps should not be important right? My other option right now are the Cornell Dubilier .1uf acrylic stacked film caps (Mouser #598-FCA0805C104M-J2), since they seem to have much better specs with regards to capacitance change with respect to temperature and frequency than the ceramic caps I found (the best I could find for the size were X7R). Any thoughts?


----------



## error401

Quote:


  Originally Posted by *a1rocketpilot* /img/forum/go_quote.gif 
_So I'm getting my BOM together, and I was wondering if it would be possible to use a lower value for C14-C19. I was planning on using the Panasonic ECH(U)-B (Digikey #PCF1120CT-ND PPS caps from Digikey, until I found that they only have up to 39nf, instead of the 100nf that it specifies. However, considering that I am building the USB regulated version, the exact size of those caps should not be important right? My other option right now are the Cornell Dubilier .1uf acrylic stacked film caps (Mouser #598-FCA0805C104M-J2), since they seem to have much better specs with regards to capacitance change with respect to temperature and frequency than the ceramic caps I found (the best I could find for the size were X7R). Any thoughts?_

 

You really should be using ceramic caps for decoupling. Film caps generally have much higher inductance, limiting their frequency response at high frequencies. Decoupling caps are there to work at high frequencies. The nonlinearities (especially w.r.t. temperature) also don't really matter, since value is highly non-critical anyway once it's 'enough' to counteract PCB parasitics and regulator response time. I would use quality 0.1uF X7R MLCC caps on even the highest-grade project, and you'll see that every knowledgeable designer around here does the same.

 If you insist on using film caps, the generic wisdom is that any value between 0.01uF and 0.1uF is fine. Since the Panasonic datasheet is basically worthless, I can't comment either way, but those FCA caps do look pretty nice.


----------



## a1rocketpilot

Well they are stacked film, instead of being wound, so inductance shouldn't me an issue should it? As far as construction goes, it's the same as a multi-layer ceramic cap, but instead of the dielectric being ceramic, it's film. Or at least that's what the data sheets led me to believe. If they were wound, I could definitely see why ceramic would be the better choice.


----------



## TimmyMac

So... what do I do if I get nothing at 5V and 3.3V? I've measured straight from the USB cable, gets 5.10V. When I measure the pins on the USB socket they all read 0V (against ground, the outside of the USB socket or USB cable).


----------



## Pars

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_So... what do I do if I get nothing at 5V and 3.3V? I've measured straight from the USB cable, gets 5.10V._

 

Yeah, where did you measure that given the following?  Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_When I measure the pins on the USB socket they all read 0V (against ground, the outside of the USB socket or USB cable)._

 

VBUS on the schematic comes from pin 3 on the USB connector. No VBUS, no V+ and hence no 3.3V or 5V. You need to figure out why... bad solder joint? Something not where its supposed to be?


----------



## TimmyMac

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_Yeah, where did you measure that given the following? VBUS on the schematic comes from pin 3 on the USB connector. No VBUS, no V+ and hence no 3.3V or 5V. You need to figure out why... bad solder joint? Something not where its supposed to be?_

 

Measured from pin 3 on the male USB plug. I'm going to desolder the USB socket and measure the pins to see if the socket is bad. When I measure the socket pins in its current state I get 0V all around.


----------



## TimmyMac

Socket is fine. Pin 3 gives 5V when the socket is off the board, but when I reattach it I get like 150mV. Short somewhere?


----------



## Pars

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Socket is fine. Pin 3 gives 5V when the socket is off the board, but when I reattach it I get like 150mV. Short somewhere?_

 

So if you have the USB socket off the board and plugged into the device, you see 5V to ground (on socket)? But plugged into the board, it pulls it down to 150mV or so? Ohm pin 3 on the board out to ground (on the board, unpowered). You probably have a short on the board somewhere. Take a look at any bypass caps on the VBUS line that go from VBUS to ground, or any other component from VBUS to ground. Also, visually inspect the trace from pin 3 of the USB socket (VBUS) to see if you see anything like solder bridges to a nearby component, via, etc.


----------



## TimmyMac

Ok, so turns out ground to pin 3 had continuity... I desoldered all the caps and PCM2702 and now it reads 48ohm or so. Is that the correct value? I may have just not seen an unwanted bridge behind the pins, although the pins themselves looked clean.


----------



## Pars

Its pretty hard to predict what that should ohm out to, although 48 ohms is alot better than 0. Is this with everything soldered back in? If so, I'd just try it out. See if you get 5V or so for VBUS, then if so, what you get for the 3.3V and the 5V test points, etc.


----------



## pinkfloyd4ever

do you have any pics Timmy? Those would prob help


----------



## TimmyMac

Everything is soldered back on, plug it in, get 3.3V and 4.72V (as I should). Computer picks something up, says a USB device has malfunctioned and is not recognized. Is this normal? I'm going to troubleshoot more tomorrow.


----------



## Pars

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Everything is soldered back on, plug it in, get 3.3V and 4.72V (as I should). Computer picks something up, says a USB device has malfunctioned and is not recognized. Is this normal? I'm going to troubleshoot more tomorrow._

 

No, that's not normal. Look the PCM pins over closely under magnification. You also might want to ohm them out (adjacent pins to one another looking for shorts, pin on chip to board pad/trace to check that it really is making contact, etc.).


----------



## TimmyMac

Got it. When I did the SMD components on the bottom half of the board I soldered all the parts with 1 pad and then went back and did all the second pads.... forgetting to do L14. Computer recognizes it properly now that I fixed that and when I get back from my exam I'm going to hook up some RCA cords and see how it does. Thanks for your help.


----------



## pinkfloyd4ever

is it a bad idea to use _only_ a sonicap for the output, like a .47uf or so?


----------



## FallenAngel

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_is it a bad idea to use only a sonicap for the output, like a .47uf or so?_

 

Absolutely not, it's great idea, why would it be bad?

 Just make sure that you have an input impedance of 100K (50K will be OK, but not "perfect").


----------



## pinkfloyd4ever

I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap?

 I use my alien with my Millett Max...anyone know its input impedance?


----------



## FallenAngel

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap?

 I use my alien with my Millett Max...anyone know its input impedance?_

 

People use 47uF because it's the smallest BG they can find.

 This is the short version of what value output caps for what value input impedance amps:

 10K : 4.7uF
 50K : 1uF
 100K : 0.47uF

 This is a "bast case scenario" value, but you can go a bit lower and in all likelihood never hear a difference.

 I'm quite sure the Millet will be 50K, go with 1uF.

 If you want, you can bypass a 1uF Gen 1 with a 0.1uF Gen 2, should be a nice result.

 For the DAC, don't bypass BG with Sonicap, just use the Sonicap. If you're thinking of bypassing BG in the amp, that's another story, I haven't tried it.


----------



## Pars

The formula for the -3dB cutoff point on a filter (high pass in this case) is:

 f = 1 / 2 * Pi * R * C

 where C is in farads.

 So for example, your 0.47uf cap with a 100K resistor to ground would give:

 1 / 2 * 3.14159 * 100000 * 0.00000047

 or 3.39 Hz

 The filter will have some effect up to an octave or so above this.


----------



## tomb

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_I dunno, I thought it might not be enough capacitance cause it seems like everybody uses more like 47uf. I assume Gen 1 would be best? I think I'll actually go with 1.0uf since it's cheaper. Anyone ever tried bypassing BG NXs with a sonicap?

 I use my alien with my Millett Max...anyone know its input impedance?_

 

The other guys have given you good answers.

 I can't speak from personal experience, but the GEN I is supposed to be fairly neutral, while the Sonicap Platinum is supposed to stand up there with the best. I have had direct experience with the GEN II, though, and it is not up to those standards, IMHO. It works pretty good bypassing ES's in the Alien, but it's still not as good as just the BG NX's by themselves. I wouldn't waste time using a GEN II by itself or bypassing BG NX's.


----------



## FallenAngel

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The other guys have given you good answers.

 I can't speak from personal experience, but the GEN I is supposed to be fairly neutral, while the Sonicap Platinum is supposed to stand up there with the best. I have had direct experience with the GEN II, though, and it is not up to those standards, IMHO. It works pretty good bypassing ES's in the Alien, but it's still not as good as just the BG NX's by themselves. I wouldn't waste time using a GEN II by itself or bypassing BG NX's._

 

Cool, nice to know. I tried Gen1 with Gen2 bypass and Gen1 alone, I liked both quite a bit, a lot more than BG NX. I'll make sure to stay away from Gen2 alone.


----------



## bhjazz

Quote:


  Originally Posted by *MASantos* /img/forum/go_quote.gif 
_In terms of capacitance values, 47uf is a good choice for C13,C23,C33 and CL/CR, according to the suggested values by Alf in the parts list page._

 

 Quote:


  Originally Posted by *Alf* /img/forum/go_quote.gif 
_C23, C33 positions accept capacitors up to 8mm. If you have a few extra dineros in your pocket, I would try 100uF Silmics here as the DAC may benefit from it._

 

Currently Digikey is out of the Panasonic 100uF. Backordered until May 13th or something crazy like that. 

 What is the difference between using th .47 or the 100uF? Handmade has them both in the SilmicII. Should I opt for that instead. Any comparisons between the Silmic and the Panny's here (what tweakers we all are, eh?)

 Thanks!


----------



## tomb

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Currently Digikey is out of the Panasonic 100uF. Backordered until May 13th or something crazy like that. 

 What is the difference between using th .47 or the 100uF? Handmade has them both in the SilmicII. Should I opt for that instead. Any comparisons between the Silmic and the Panny's here (what tweakers we all are, eh?)

 Thanks!_

 

The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply. 
	

	
	
		
		

		
			











 Seriously, I can't really say it made much difference when tested - but I am certain it caused no problems or made the performance worse. I was trying to compensate for any issues with longer lead length while bending the leads at right angles so that the caps are horizontal and laid flat on the board. The 1000uf actually hangs horizontally off the edge of the board. It's 3/8" at it's thickest board height - an experiment to fit under a MAX board in a standard Hammond case. I'll post some pics tomorrow.

 Bottom line, I think you can greatly upsize those caps to equal the low ESR of much more esoteric caps with good effect.
	

	
	
		
		

		
		
	


	




 EDIT: It uses a panel-mounted USB jack with wire leads. Otherwise, the board-mtd USB jack results in about a 1/2" board height on its own.


----------



## error401

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply. 
	

	
	
		
		

		
		
	


	








_

 

Every motherboard I've ever used current-limits the USB power rails to a couple amps at most per pair of ports. Your supply shouldn't have trouble.


----------



## tomb

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Every motherboard I've ever used current-limits the USB power rails to a couple amps at most per pair of ports. Your supply shouldn't have trouble._

 

Duh. There were a few winkies there.


----------



## bhjazz

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_The last one I built had 300uf Panasonic FM's at C13, C22 and C33, and 1000uf at C2. It works great, but I'm worried that the current inrush will bring down my PC's power supply. 
	

	
	
		
		

		
		
	


	










 Bottom line, I think you can greatly upsize those caps to equal the low ESR of much more esoteric caps with good effect.
	

	
	
		
		

		
		
	


	


_

 

Ah, the size. Hadn't thought of that...

 Okay, then. Thanks for the info, Tom. I'll skip the Panny's and get the Silmics from Handmade. I'm happy to see that those two locations offer some options for uF.


----------



## NumpXP

i shot glassjar an email 2 days ago and still no response. anyone eager to point me a good BOM or any other kit seller?

 (prefer to use mouser or/and digikey)

 thanks in advance


----------



## bhjazz

There are four or five BOMs within this mega-thread. Yeah, I know: it's 117 pages! Just search for BOM. I seem to remember that a few of them were just for Mouser. And I know for sure that a BOM or two were split pretty evenly between Mouser/Digikey. 

 You will want to dig through the thread more, too. Since those BOMs were written, lots of experimentation has gone on with the design, and using some custom caps in CL and CR can make a big difference.


----------



## pinkfloyd4ever

I sent jeff an order form and a payment on the 17th and haven't heard anything back yet...anyone heard from him lately?


----------



## NumpXP

i've sent him like a week ago. he replied 2 days later to ask whether i need anything else.. but nothing from him after i reply.

 update: i just received an email for jeff. He's waiting for parts from mouser and delivery would be this saturday


----------



## bhjazz

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Currently Digikey is out of the Panasonic 100uF. Backordered until May 13th or something crazy like that. _

 

Simply as an FYI, I received an email for Digikey:

 "The backorder will ship automatically once it becomes available. We show
 approximately 13/May/08."


----------



## NumpXP

I got the kit from glassjar audio several days ago. After soldering everything, the the chip doesnt output right audio signal. i tried to tap directly from the chip for both left and right output. I can hear the left output but not the right one. so is this because my chip is faulty?

 thanks in advance


----------



## Pars

Quote:


  Originally Posted by *NumpXP* /img/forum/go_quote.gif 
_I got the kit from glassjar audio several days ago. After soldering everything, the the chip doesnt output right audio signal. i tried to tap directly from the chip for both left and right output. I can hear the left output but not the right one. so is this because my chip is faulty?

 thanks in advance_

 

Probably not the chip. Lets back up a second...

 This is an Alien DAC kit from Jeff at GlassJar? Did it have the PCM chip pre-soldered? Or did you solder it on?

 Its most likely a solder bridge, or something not soldered on enough (bad phrase, but whatever). These boards seem to take a bit to get somethings soldered on and making contact. A joint may look fine but isn't. If it is the right channel, take a DMM (meter) and in ohms mode, ohm the riight audio channel out from the DAC on. Make sure that you check the actual physical pin on the chip to the pad or board trace to ensure that it has continuity. There isn't alot to it--OUTL or OUTR to the coupling cap to the jack.


----------



## bhjazz

I was looking at the pdf for the PCM2702, specifically to see if there was a location to connect for a lock indicator. I know, splitting hairs since this will come from USB. Will this DAC just "work or not work"? I think we've all experienced that blast of white noise from a non-locked signal, and I'd like to save my headamp or headphones (or ears!). 

 (incidentally, I recently blew the fuse on my Classe amp by sending a non-locked blast of digital noise from my Theta preamp. Scared the crap outta me!)

 Just tossing this out for discussion...


----------



## rhester

I get the dreaded white noise from my Alien occasionally (usually after playing for a while). Any way to check and see of it is an Alien problem or a computer problem? If it is the Alien , what are some commom casues of this problem?


----------



## rhester

Also, I do get 3.3V when usb powered and 4.7V. Is the 4.7V too low?


----------



## Pars

Hard to say on the 4.7V Vcc thing. The datasheet minimum for the chip is 4.5V. The voltage of the REG101A is controlled by the ratio of R31/R32

 Vout = (1 + R31 / R32) * Vref, where Vref is 1.267 for REG101

 Stock values are supposed to be 31.2K and 11.5K... you could do something like put a 100K in parallel with R32, which would give you about 10.3K so your output voltage would be 5.1V. Soldering SMD resistors on top of one another isn't too hard to do. The 3.3V controls the digital section of the chip; I wonder if the white noise you mention is digital (lock or whatever) or analog in nature?


----------



## amb

Quote:


  Originally Posted by *rhester* /img/forum/go_quote.gif 
_I get the dreaded white noise from my Alien occasionally (usually after playing for a while). Any way to check and see of it is an Alien problem or a computer problem? If it is the Alien , what are some commom casues of this problem?_

 

This sporadically occurs for me too, although I think it happens only on WinXP, not Linux. Re-plugging the USB connector usually clears it up. I think it might be a problem in the Windows USB audio driver.

 Not everything is peachy on Linux either, though. Sometimes if I start a song using SoftSqueeze it gets all scratchy and distorted sounding, but stopping and restarting the song "fixes" it. I think this might be a SoftSqueeze issue, because it also happens with the M-Audio Transit USB sound card, but not when I use a different player software.


----------



## rhester

I wondered if it my be a Windows problem (running XP), but don't get the nosie when I go USB out to another pro usb dac. But it will usually clear up for a while if I replug or restart the music app.


----------



## bhjazz

No takers on the lock indicator? Okie dokie, then. Personally, I think it would stand out more in the specs if it really were avilable anyway. 
	

	
	
		
		

		
			





 While reading the spec for the chip, I did come across something interesting about the reset-ability of the chip. Page 9 says, "...THe PCM2702 includes an internal power-on reset circuit which automatically initializes digital logic when Vdd exceeds 2.0V typical (range 1.6V to 2.4V)." I'm wondering if this has somethign to do with the sporadic white noise and the ability to pull and replug the USB cable. If so, it makes pretty good sense, although I'm not sure why the voltage on USB would swing high like that. I mean, it's not like it's analog, right?


----------



## FallenAngel

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_No takers on the lock indicator? Okie dokie, then. Personally, I think it would stand out more in the specs if it really were avilable anyway. 
	

	
	
		
		

		
		
	


	




 While reading the spec for the chip, I did come across something interesting about the reset-ability of the chip. Page 9 says, "...THe PCM2702 includes an internal power-on reset circuit which automatically initializes digital logic when Vdd exceeds 2.0V typical (range 1.6V to 2.4V)." I'm wondering if this has somethign to do with the sporadic white noise and the ability to pull and replug the USB cable. If so, it makes pretty good sense, although I'm not sure why the voltage on USB would swing high like that. I mean, it's not like it's analog, right? 
	

	
	
		
		

		
		
	


	


_

 

Considering that there is no such thing as a "lock" in terms of the receiver chips, you don't have to worry. The chip acts as a USB host (sound card) and sends the signal to itself (only supporting 44.1kHz or 48kHz), so it never has to "lock" with another component.


----------



## bhjazz

That makes perfect sense. Cool. Thanks! I'll reserve my questions about general lock issues for another thread.


----------



## error401

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_That makes perfect sense. Cool. Thanks! I'll reserve my questions about general lock issues for another thread._

 

PCM2702 does offer two outputs that are somewhat analogous to a 'lock' indicator.

 /SSPND (pin 11) will go low when the device is successfully attached to a USB bus. This could be useful if you're self-powering the DAC. /PLYBCK (10) goes low when audio data is being played.


----------



## wiatrob

I've just put together a Glass Jar kit, USB powered . I'm only getting about 1.23vdc from the 3V3. I get a rock solid 4.7vdc on the 5V.

 Yes, it's my first surface mount with pitches like the 2702! I've checked my solder joints as well as I know how (they look good - to me - ) but is there something I'm missing? 

 Anyone know of anything specific I might check? Thanks all for any help!

 -Bill

 (I'm working on some pics of the board if it might be helpful.)


----------



## FallenAngel

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_I've just put together a Glass Jar kit, USB powered . I'm only getting about 1.23vdc from the 3V3. I get a rock solid 4.7vdc on the 5V.

 Yes, it's my first surface mount with pitches like the 2702! I've checked my solder joints as well as I know how (they look good - to me - ) but is there something I'm missing? 

 Anyone know of anything specific I might check? Thanks all for any help!

 -Bill

 (I'm working on some pics of the board if it might be helpful.)_

 

Double check the soldering on the 3.3V regulator and make sure it's oriented properly.


----------



## Pars

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_I've just put together a Glass Jar kit, USB powered . I'm only getting about 1.23vdc from the 3V3. I get a rock solid 4.7vdc on the 5V.

 Yes, it's my first surface mount with pitches like the 2702! I've checked my solder joints as well as I know how (they look good - to me - ) but is there something I'm missing? 

 Anyone know of anything specific I might check? Thanks all for any help!

 -Bill

 (I'm working on some pics of the board if it might be helpful.)_

 

http://www.head-fi.org/forums/3890511-post1059.html

 This effected the 5V instead of the 3.3V, but you need to check all the resistances around the regulator as well. And make sure they are actually grounded. These boards will allow you to do joints that look soldered OK, but aren't making good connection.


----------



## wiatrob

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_http://www.head-fi.org/forums/3890511-post1059.html

 This effected the 5V instead of the 3.3V, but you need to check all the resistances around the regulator as well. And make sure they are actually grounded. These boards will allow you to do joints that look soldered OK, but aren't making good connection._

 


 Thanks Par (and all), these are definitely avenues I'll check. I know REG101-33 is properly oriented, and I've verified all resistors are in their proper locations. 

 Off to search for that elusive cold joint!

 -Bill


----------



## wiatrob

Turns out it was a bridged C22, now getting a solid 3.29V and the computer recognizes the DAC. Thanks again.

 -Bill


----------



## DolbyR

Are there any differences between the UA, NA and GA versions of the REG101/REG102?
 I'm just compiling my BOM from Farnell and the UA's are stated as no longer stocked.

 Also, is it a problem if instead of 30pF, the crystal is 20pF, the frequency remaining the same, 12mhz?


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_Are there any differences between the UA, NA and GA versions of the REG101/REG102?
 I'm just compiling my BOM from Farnell and the UA's are stated as no longer stocked._

 

Yes, they're different packages. Unfortunately only the UA will fit the board. TI is apparently having trouble keeping up with demand on these, and none are slated to be available for some time. It's a problem at the moment for those trying to build AlienDACs.

  Quote:


 Also, is it a problem if instead of 30pF, the crystal is 20pF, the frequency remaining the same, 12mhz? 
 

The frequency must remain the same, otherwise any parallel resonant crystal should work fine, but you may need to change the load capacitors. If the crystal you buy is 20pF instead of 30pF, just change C11 and C12 to match (~20pF). It's not critical though and will probably operate fine with the 30pF caps.


----------



## DolbyR

Thanks for the fast reply Error401.
 Now...more wortless questions...
 Does anyone have any experience with Samsung caps, as I'm ordering some things from Jeff, i'm would I be better of taking what he offers for the SMD caps or would the Samnsungs (C0G and X5R, 5% and 5-10% respectively) be just as good (i can get these locally).
 For the SOHA I used UniOhms resistors but I guess for the Alien I'll really get the Vishay-Dales (unless someone tells me the difference wouldnt be really that great 
	

	
	
		
		

		
			





 )


----------



## bhjazz

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_TI is apparently having trouble keeping up with demand on these, and none are slated to be available for some time._

 

As far as I know, TI only tools up to make these once or twice a year. 

 I ordered a nice batch of parts from Handmade last night (including Muse ESs). I tried valiantly to get the whole thing coordinated through Paypal, but that got hosed up due to the address I somehow have as confirmed. Oy. I know why Handmade prefers credit cards! Ah well, I'll try again tonight. Once done, all I will need for my two Aliens will be cases. Finally!


----------



## tomb

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_As far as I know, TI only tools up to make these once or twice a year. 

 I ordered a nice batch of parts from Handmade last night (including Muse ESs). I tried valiantly to get the whole thing coordinated through Paypal, but that got hosed up due to the address I somehow have as confirmed. Oy. I know why Handmade prefers credit cards! Ah well, I'll try again tonight. Once done, all I will need for my two Aliens will be cases. Finally!_

 

Don't get me wrong - I love Handmade Electronics. They are one of our best DIY-parts vendors.

 However, when it comes to Paypal, I'm afraid they don't have a clue. They don't interface to it at all, really - expecting a customer to write down the total, then access Paypal separately and manually make a payment to Handmade's Paypal account.

 That's not exactly a programmed solution - people interface to Paypal all the time. It's less troublesome than interfacing to the Post Office, IMHO. Still, in spite of that small flaw - Handmade is the best.


----------



## MisterX

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_The frequency must remain the same, otherwise any parallel resonant crystal should work fine, but you may need to change the load capacitors. If the crystal you buy is 20pF instead of 30pF, just change C11 and C12 to match (~20pF). It's not critical though and will probably operate fine with the 30pF caps._

 

Use the following equation to calculate the load capacitance (CL) and tell me if that is correct. 






 CL1 and CL2 are the load capacitors and Cs is the circuit stray capacitance (usually 3 to 5 pF)


----------



## splaz

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Use the following equation to calculate the load capacitance (CL) and tell me if that is correct. 






 CL1 and CL2 are the load capacitors and Cs is the circuit stray capacitance (usually 3 to 5 pF)_

 

I'm not doubting you, as to be honest I have no idea, I asked a question about crystal load capacitors before and didn't get a very satisfactory answer IIRC.

 But following that equation, using the parts suggested for the Alien DAC, a crystal with CL=30pF and then C11 and C12 = 32pF. Doesn't CL actually work out to be around 20pF or so, depending on the value of Cs ?


----------



## error401

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Use the following equation to calculate the load capacitance (CL) and tell me if that is correct. 






 CL1 and CL2 are the load capacitors and Cs is the circuit stray capacitance (usually 3 to 5 pF)_

 

You're right of course. I never really thought about it, to be honest, and have always just used the quoted value directly. Thanks for the correction, I don't know why I didn't think of that myself.

 Either way, it's not too critical. A few dozen ppm error isn't going to break anything in this application. Besides, the originally specified crystal and caps aren't correct either!


----------



## MisterX

From the datasheet: 

  Quote:


 The PCM2702 requires a 12MHz (±500ppm) clock for USB
 and audio functions 
 

You're right....no point in arguing about a few measly PPM's with that kind of a tolerance.


----------



## bhjazz

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_That's not exactly a programmed solution - people interface to Paypal all the time. It's less troublesome than interfacing to the Post Office, IMHO. Still, in spite of that small flaw - Handmade is the best.
	

	
	
		
		

		
		
	


	


_

 

Agreed. And I got bit by it. Yeah, I was a little surprised at the process as well. A bit of extra work for the customer to do themselves. I think my only real gripe is that I paid with instant transfer, but when they refunded my money due to the address mixup, they do not have instant transfer, so I get to wait five business days. Odd. Ah well, I do love their selection, so I'll take another go at it next week...with my credit card!!! I want my Muse ESs!!!


----------



## rds

At Mouser it seems to say the regulators can ship in 10 days:
REG101UA-3.3
REG101UA-5

 ...the adjustable one isn't available till hell freezes over, but these will work fine afaik.
 What do you think? I was going to order some soon too.


----------



## tomb

Quote:


  Originally Posted by *rds* /img/forum/go_quote.gif 
_At Mouser it seems to say the regulators can ship in 10 days:
REG101UA-3.3
REG101UA-5

 ...the adjustable one isn't available till hell freezes over, but these will work fine afaik.
 What do you think? I was going to order some soon too._

 

Use of the REG101UA-5 means USB power is not an option.


----------



## error401

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Use of the REG101UA-5 means USB power is not an option._

 

Well, it is if you use it unregulated.


----------



## tomb

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Well, it is if you use it unregulated._

 

Which of course, sort of means a "REGulator" is pointless.


----------



## rds

so there's no solution to this usb power problem at the moment?


----------



## tomb

Jeff Rossel would be the first suggestion at Glass Jar Audio.

 Rochester Electronics (Rochester Electronics - Leaders on the Trailing Edge of Technology) apparently has thousands of the REG101UA-A. Whether that means you have to buy thousands to get one, I don't know - but it's worth a call.

 Otherwise, you may have to wait until September unless some nice Head-Fier has extras.


----------



## splaz

Quote:


  Originally Posted by *rds* /img/forum/go_quote.gif 
_so there's no solution to this usb power problem at the moment?_

 

I've had a quick look, there are a few similar chips, however pin outs aren't exactly the same.

 Didn't have a detailed look at the datasheet and indeed, not 100% sure what's desirable or if it would work.

 However, ADP3334 looks somewhat close... problems are that you'd need to do some pin lifting/jumpering or trace cutting/altering, the gnd and shutdown/enable pins are in the wrong spots for a start.

 If you get desperate maybe ?


----------



## soloz2

has anyone compared the Opus USB module v the Alien DAC?


----------



## MisterX

Quote:


  Originally Posted by *soloz2* /img/forum/go_quote.gif 
_has anyone compared the Opus USB module v the Alien DAC?_

 

Yes.


----------



## MisterX

Quote:


  Originally Posted by *rds* /img/forum/go_quote.gif 
_so there's no solution to this usb power problem at the moment?_

 

You can always just connect a jumper from the "AV+" to "5V" pad and run it without that regulator. 
 The difference is not a lot.


----------



## Eokboy

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_You can always just connect a jumper from the "AV+" to "5V" pad and run it without that regulator. 
 The difference is not a lot. 
	

	
	
		
		

		
		
	


	


_

 

I add the 22uH inductor. Don't know if there is any difference. Just put it there to make me feel better. 
	

	
	
		
		

		
		
	


	




 BTW anybody has a spare REG101UA-3.3?


----------



## MisterX

I did that with a ferrite bead once for the same reason.

 Rightmark testing suggested it was a waste of 45 cents.


----------



## bhjazz

WHO SAID FLUX PEN?????

 Brilliant! I'm working on my first pass at the PCM2702 and it's going perfectly. I covered the area with flux from the pen and using a Radio Shack 5X Magnifier (part 63-1309). I'm actually able to solder pin by pin, with no bridging. Apply a tiny dab of solder to the iron, let it sit on the joint for a second, and the solder flows into the joint. Neat! I'll throw some photos up when I can. I'm damn proud!


----------



## tomb

Yeah, one of those flux pens are so sticky it almost glues the chips down, too.


----------



## bhjazz

I'm trying to make sure there's not too much under the chip. No need to get that conductive junk under the chip where it'll never be cleanable! Yikes!

 The combination of the magnifier and a 10x jeweler's look for inspection is cool.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_No need to get that conductive junk under the chip where it'll never be cleanable! Yikes!_

 

fyi: flux isn't conductive. People often recommend cleaning it just because it looks better cleaned and supposedly it can cause stray capacitance, but I've never had any problems with projects that I haven't cleaned the flux from


----------



## tomb

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_fyi: flux isn't conductive. People often recommend cleaning it just because it looks better cleaned and supposedly it can cause stray capacitance, but I've never had any problems with projects that I haven't cleaned the flux from_

 

Besides that, you can literally immerse the whole board in alcohol before you install the electrolytics - no flux after that - even underneath.


----------



## Pars

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Jeff Rossel would be the first suggestion at Glass Jar Audio.

 Rochester Electronics (Rochester Electronics - Leaders on the Trailing Edge of Technology) apparently has thousands of the REG101UA-A. Whether that means you have to buy thousands to get one, I don't know - but it's worth a call.

 Otherwise, you may have to wait until September unless some nice Head-Fier has extras._

 

Using Octopart (?), Sierra IC seems to have some of each available:

reg101ua - Octopart


----------



## lacrossebowe8

I am planning on building an alien and I was wondering what output jacks people were using. (TRS or RCA) Also, what led do people recommend?


----------



## adamus

depends entirely on wha you want to feed and what leads you have. You wont notice much difference in sound. RCA's will porbably be more handy down the line.


----------



## DolbyR

Well, I ended up ordering the rest of all the parts from Jeff, should had done that 9 months ago when I ordered the boards, would had saved one intl shipping...

 Well, until the parts arrive, I'll have time to make a PSU/mini-tread for it (i'll be using the regulated configuration @ 5.4v), I'll be integrating this on my SOHA, so should I take the power directly from the transformer (30vct 24va), or from the 12v points in the SOHA board. 
 Also how would I regulate this? would an LM317+LM337 on a protoboard do the trick or should I add capacitors or something to them?


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_Well, I ended up ordering the rest of all the parts from Jeff, should had done that 9 months ago when I ordered the boards, would had saved one intl shipping...

 Well, until the parts arrive, I'll have time to make a PSU/mini-tread for it (i'll be using the regulated configuration @ 5.4v), I'll be integrating this on my SOHA, so should I take the power directly from the transformer (30vct 24va), or from the 12v points in the SOHA board. 
 Also how would I regulate this? would an LM317+LM337 on a protoboard do the trick or should I add capacitors or something to them?_

 

You're wanting to power your AlienDAC from the SOHA? I would just use an LM317 or LM7805 on protoboard, from the 12V supply on the SOHA, then you can skip reimplementing a rectifier and get better noise performance too. Put at least a couple uF at the input and output and you should be fine.


----------



## DolbyR

I could use this schematic probably? I would need 2 of these (1 for + and 1 for -) correct?

 According to the calculator on the same website, with R2 regulated to 910 ohms, I should get an output of around 6 volts. Or nearly 6.5v at 1Kohm.


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_





 I could use this schematic probably? I would need 2 of these (1 for + and 1 for -) correct?

 According to the calculator on the same website, with R2 regulated to 910 ohms, I should get an output of around 6 volts. Or nearly 6.5v at 1Kohm._

 

Can you clarify what you're going to be powering with this hypothetical supply? AlienDAC needs 5V and 3.3V, there is no negative supply. If you're going to the trouble of building an outboard regulator, I don't really see the point of the 5V REG101 at all.

 Set up a LM317 (or LM7805) from the +12V rail of your SOHA, and set it to output 5.0V. Run that to the AlienDAC's input and configure it for 'unregulated' operation. You'll only need the 3.3V regulator, and if you can't get one, you can always build another LM317-based one and do it outboard.


----------



## DolbyR

What I want, is to lower the power from the soha, from 12v to under 10v as the REG101s can not handle more than that..or to build a dedicated external supply for the DAC.


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_What I want, is to lower the power from the soha, from 12v to under 10v as the REG101s can not handle more than that..or to build a dedicated external supply for the DAC._

 

In that case, I would do as I suggested in the last post:

 SOHA +12V -> LM317/LM7805 5V -> AlienDAC

 Omit the 5V REG101, include the 3.3V unit. You could include the 5V regulator if you want to, and bump up the pre-regulator output to 6-7V, but I don't personally see the benefit.


----------



## DolbyR

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_In that case, I would do as I suggested in the last post:

 SOHA +12V -> LM317/LM7805 5V -> AlienDAC

 Omit the 5V REG101, include the 3.3V unit. You could include the 5V regulator if you want to, and bump up the pre-regulator output to 6-7V, but I don't personally see the benefit._

 

Thanks,
 as the parts are already on their way, and with the REG101UA-A, adjustable regulator and the corresponding resistors to get 5.4v "overclocked" configuration, I prefer using the onboard reg (i'll feel safer as I wont need to adjust the LM317 that accurately).
 What about the schematic I posted before? Is it fine for my applications. I'll be using the 317, as I already have 20 or 30 of them at home.


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_Thanks,
 as the parts are already on their way, and with the REG101UA-A, adjustable regulator and the corresponding resistors to get 5.4v "overclocked" configuration, I prefer using the onboard reg (i'll feel safer as I wont need to adjust the LM317 that accurately).
 What about the schematic I posted before? Is it fine for my applications. I'll be using the 317, as I already have 20 or 30 of them at home._

 

Sure, it'll work great. You might add an electrolytic (a couple hundred uF is more than enough) on the input, depending on the cable length from the SOHA's power supply. Since you're using the REG101s anyway it doesn't really matter, but you may want to use the 'Improved Ripple Rejection' schematic instead. It's on page 15 of the National datasheet. Basically it just adds a 10uF capacitor across R2, and will lower the output ripple. Since you're taking a regulated input and regulating it twice again (LM317 then REG101), you really don't need the extra ripple rejection. At ~65dB per stage, ripple should be down a whopping 195dB by the time it gets to the PCM2702 - which on its own has quite good ripple rejection.

 The only thing I might be concerned about is load on the little LM78L12 in the SOHA. It can only supply 100mA. The SOHA opamp shouldn't draw more than ~15mA. PCM2702 has a max of 30mA at 3.3V plus 25mA at 5V. Some quick maths and you end up with the LM317 pulling ~170mA, most of which gets burnt off as heat. You might get away with it, but really it's too much for the 78L12. You should substitute a full-size LM7812, or use your original plan and build a separate rectifier/regulator to power the DAC. Or just use USB power...


----------



## DolbyR

Great, thanks a lot.
 I guess while I'm at it, I'll upgrade the regs (maybe even to 15v regs as suggested for Jisbos - as this will probably be the next upgrade).
 The only thing that Iäm stilll confuses about is the wiring.
 On the AlienDAC webpage it says that for amp powered. Connect the amp’s V+ to the AV+ pad, amp’s V- to the AV- pad, and amp’s ground to the AG pad.
 Is this only for amps with virtual ground, AFAIK, SOHA is not a virtual ground amp and the BUF634 would not be necessary...so would the output from 317 go to AV+ and the v- from SOHA to the G2 pad?


----------



## error401

Quote:


  Originally Posted by *DolbyR* /img/forum/go_quote.gif 
_Great, thanks a lot.
 I guess while I'm at it, I'll upgrade the regs (maybe even to 15v regs as suggested for Jisbos - as this will probably be the next upgrade).
 The only thing that Iäm stilll confuses about is the wiring.
 On the AlienDAC webpage it says that for amp powered. Connect the amp’s V+ to the AV+ pad, amp’s V- to the AV- pad, and amp’s ground to the AG pad.
 Is this only for amps with virtual ground, AFAIK, SOHA is not a virtual ground amp and the BUF634 would not be necessary...so would the output from 317 go to AV+ and the v- from SOHA to the G2 pad?_

 

SOHA is not a virtual ground amp - it uses a bipolar supply and doesn't have a driven ground channel.

 The only purpose of the -ve supply in the AlienDAC is to drive the BUF634, which is only required for virtual ground amps - so you don't need it. Rig your 6V regulator and connect it to AV+. Connect the amp ground to G2. You're basically doing the 'external PS' configuration. Since your amp has a bipolar supply, you don't need to worry about the AV- and BUF634.


----------



## bhjazz

Well, the difficult parts are all soldered on, except for RLED. Just easy stuff left. All the pins on the PCM2702 really are connected in spite of that dark spot...Tool #2 for this work was a 10x jeweler's loupe!

 I am enjoying this micro-soldering very much!


----------



## MisterX

Did you use the flux pen when you soldered the caps and other parts? 
 You should not be getting those little solder peaks 
 (L15 is the worst example but a lot of the caps on the top side them have them to)


----------



## bhjazz

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Did you use the flux pen when you soldered the caps and other parts? 
 You should not be getting those little solder peaks._

 

You don't like my pastry-chef talents? 
	

	
	
		
		

		
			





 Well, it did seem to vary quite a bit (the solder peaks, not my pastry talents). Should I have used more or less of the flux pen?

 Edit: I'm thinking it should have been less. I've not had trouble with that roll of Kester solder with other projects. 

 Thanks for the feedback.


----------



## mik000000

this is probably a stupid question but here goes anyway.
 I am assembling parts to do an alien dac and have some leftover opa634u 's from another project. Can i use one instead of buf634u for ic4?


----------



## MisterX

Quote:


 Should I have used more or less of the flux pen? 
 

More. 
 And to answer the question from the original reply. 
I did.


----------



## MisterX

Quote:


  Originally Posted by *mik000000* /img/forum/go_quote.gif 
_this is probably a stupid question but here goes anyway.
 I am assembling parts to do an alien dac and have some leftover opa634u 's from another project. Can i use one instead of buf634u for ic4?_

 


 Do you even need either of them?
 (if you are not planning on powering the "DAC" from "A virtual ground amp" you don't need either of them)


----------



## mik000000

i am not actually sure. I have 2 boards and am going to make 1 as a standalone and probably incorporate the other into a millet max


----------



## Pars

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Do you even need either of them?
 (if you are not planning on powering the "DAC" from *"A virtual ground amp"* you don't need either of them)_

 

 Quote:


  Originally Posted by *mik000000* /img/forum/go_quote.gif 
_i am not actually sure. I have 2 boards and am going to make 1 as a standalone *no* and probably incorporate the other into a millet max *more no*_

 

Comments inline, but you don't need to populate ic4. Power it from the USB port.


----------



## bhjazz

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_More. 
	

	
	
		
		

		
		
	


	


_

 

Then more it'll be! Thank you. I've got three more boards to play with in the future, so I should be able to get it right by then!


----------



## bhjazz

Nice, MisterX. How very Clive Barker of you. That rocks.


----------



## bhjazz

I have a working Alien DAC! Non-boxed, spread across my work table. Currently using some substitute C13s (panasonic fc 47uF/35V) because I can't wait for the others to arrive. Sounds pretty damn good. Can't wait to get the high-buck caps on there!

 Thanks all. I appreciate your help! More soon!


----------



## CingKrab

I finished soldering and troubleshooting my Alien DAC, and the computer picks it up fine, but I'm getting ~5mV of DC offset on the right channel, and ~20mV on the left. I'm measuring OR/OR with respect to OG. This sounds high -- does anyone have tips on how to get the DC offset down? I'm using the 33uF Nichicon Muse ES caps for CL/CR from Jeff's kit.


----------



## tomb

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_I finished soldering and troubleshooting my Alien DAC, and the computer picks it up fine, but I'm getting ~5mV of DC offset on the right channel, and ~20mV on the left. I'm measuring OR/OR with respect to OG. This sounds high -- does anyone have tips on how to get the DC offset down? I'm using the 33uF Nichicon Muse ES caps for CL/CR from Jeff's kit._

 

CL and CR are DC blocking caps used on the output. Properly installed, you should not be reading anything above 1mV, and that's only the residual reading from a cheap DMM. In fact, it may be your DMM - or perhaps some issue with how CL/CR or R15/16 are soldered.


----------



## CingKrab

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_CL and CR are DC blocking caps used on the output. Properly installed, you should not be reading anything above 1mV, and that's only the residual reading from a cheap DMM. In fact, it may be your DMM - or perhaps some issue with how CL/CR or R15/16 are soldered._

 

I cleaned up those pads a little and now I'm getting ~5mV on OR/OG and ~8mV on OL/OG, so it might be my meter I guess. I'll keep an eye on the DC offset on the amp output once I finish up with that part.


----------



## tomb

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_I cleaned up those pads a little and now I'm getting ~5mV on OR/OG and ~8mV on OL/OG, so it might be my meter I guess. I'll keep an eye on the DC offset on the amp output once I finish up with that part._

 

Those are pretty trivial offset readings, anyway. I'd chill out and enjoy.


----------



## CingKrab

Hmm, I hooked everything up to my amp and while the right channel sounds fine, the left channel has no sound. It shows 0V AC on the DAC output. I also checked upstream at the PCM side of CL, and it is also 0V AC. Is there anything else I should check? I hope the PCM isn't fried...


----------



## tomb

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_Hmm, I hooked everything up to my amp and while the right channel sounds fine, the left channel has no sound. It shows 0V AC on the DAC output. I also checked upstream at the PCM side of CL, and it is also 0V AC. Is there anything else I should check? I hope the PCM isn't fried..._

 

Maybe the offset meant something. Time for pics to see if we can find anything amiss.


----------



## CingKrab

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Maybe the offset meant something. Time for pics to see if we can find anything amiss._

 

I've attached pics of the DAC. I should clean it, but I was hoping to leave that until after it worked. 

 I've reflowed pin 23 (VoutL), but no improvement. I left the solder bridge on pins 13 and 14 because they're both connected to ground anyway.


----------



## FallenAngel

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_I've attached pics of the DAC. I should clean it, but I was hoping to leave that until after it worked. 

 I've reflowed pin 23 (VoutL), but no improvement. I left the solder bridge on pins 13 and 14 because they're both connected to ground anyway.







_

 

Clean up the flux and take another photo 
	

	
	
		
		

		
			





 You also seem to have some questionable solder joints on the back.


----------



## tomb

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Clean up the flux and take another photo 
	

	
	
		
		

		
		
	


	




 You also seem to have some questionable solder joints on the back._

 

Agreed. I'm not so sure about the PCM chip and the regulators, either.

 I don't mean to give useless advice after the fact, but it helps to clean one up _before_ soldering in the electrolytics and the USB connector.


----------



## royewest

I'm using a microscope to solder the main smd chip onto the Alien DAC board. I can very clearly see each pin and its connection to the board, etc. This is the first time I've worked with such small parts.

 Most of the pins are securely soldered to the board. I can see the solder and I can use a sharp probe to push on the pin and see that it does not nudge off its pad.

 A few pins refuse to solder to their pads. I have cleaned off the board, soaked it in too much flux, then tried resoldering. The main issue is that the solder just does not seem to want to stick to the pads.

 I have ordered a few more boards and a new DAC chip -- I figure I may have ruined this pair and can start again with the AMB kit I have.

 Things I will try next time I can get back to working on it:

 * Trying a different solder. I've been working with Cardas Quad.

 * Really scrubbing the board with solvent again. I've been using Electrosolve contact cleaner (what my local shop stocks) and a tooth brush. I might soak in pure alcohol, etc.

 * I will try a much more precise application of rosin flux -- using a toothpick this time, instead of an earswab that tends to flood the whole area with flux.

 But does anyone have any other suggestions for this situation?

 Thanks,

 __Roy


----------



## adamus

the boards are a bit funny. They have a coating that seems needs a bit of burning off.


----------



## FallenAngel

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_But does anyone have any other suggestions for this situation?_

 

Yes, drop the microscope, flood the SOICs with solder and clean up with desoldering braid. Takes about 30 seconds to do the PCM, safest and easiest way I found. I don't care much for solder or chemical cleaners, but do use a toothbrush and 90%+ alcohol. Some compressed air afterwards leaves it nice and clean.


----------



## tomb

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_<snip>A few pins refuse to solder to their pads. I have cleaned off the board, soaked it in too much flux, then tried resoldering. The main issue is that the solder just does not seem to want to stick to the pads._

 

Two things cause this, but it can be a combination of both:
 1. Not enough heat in the right place.
 2. Not enough flux.

 After soldering together several of these things using a small chisel point with a Hakko 936, I've come to the conclusion that ~375 deg.C. works a lot better than something lower. Everybody has their methods, but it seems to work best for me if I do a lot of the horizontal soldering in a sweeping rolling motion away from the pins - wiping, as it were. This is detailed in Tangent's vids as a "clean-up" procedure for the final touch in soldering chips like these. Seems to work for me, too.

 Lower temperatures will simply not work with pads that are connected to the ground plane on the Alien DAC. Waiting for the pads to heat up in that instance causes more heat transfer to the chip. Whereas the high heat option allows a very short exposure - almost allowing the heat to dissipate before it reaches the chip because you are quickly removing the iron.

 More flux will help, rather than less - as long as there's not too much solder. The flux will not allow the solder to stick to anything that's not solderable. If you have pins soldered together, then that's too much solder - not too much flux. As I said, everyone has their method - braid didn't work for me. However, a clean, hot horizontal iron works very good to wipe away excess solder on the pins.

  Quote:


 <snip>
 * Trying a different solder. I've been working with Cardas Quad. 
 

That should be good enough - if it's thin. Maybe ~0.025"?

  Quote:


 * Really scrubbing the board with solvent again. I've been using Electrosolve contact cleaner (what my local shop stocks) and a tooth brush. I might soak in pure alcohol, etc. 
 

Agree with FallenAngel in this regard. 90% Walmart alcohol and a toothbrush are fine. It helps if you do all this before adding the electrolytics and the USB connector.

 You can check for continuity of the pins on the PCM chip with a meter. Check for some sort of resistance between adjacent pins. You'll get different ohm readings between adjacent pins, but as long as it's not zero, then it's OK. Then place one probe on a pin, then the other probe on the pad's destination across the board. If zero, it's a good connection. Note that there are a couple that are shorted together by the board, anyway.

  Quote:


 * I will try a much more precise application of rosin flux -- using a toothpick this time, instead of an earswab that tends to flood the whole area with flux. 
 

I use the flux pens. I don't use them for anything else, but for the Alien, they're great. The stuff is so sticky you can almost use it to glue the chips in place prior to soldering. Again, precise application of the solder is required, not the flux. The flux can't make the solder stick to an unsolderable surface.


----------



## CingKrab

New pics after I cleaned up the flux:


----------



## FallenAngel

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_New pics after I cleaned up the flux:







_

 

Well, you definitely have a few cold solder joints around, the ones that look dull, not shiny should be reflown. As for 0V off the other channel, you're measuring from the DAC pin to ground right? If this is the case, your PCM is likely fried, happened to me a couple of times before, usually when you apply power to it while it has a solder bridge. If that's not the way you measure, do so.


----------



## tomb

Yep. Looks like the 3rd pin from bottom left in the pic is bridged with the first two. The 4th and 5th pins look bridged, too.


----------



## CingKrab

Just double checked with the DMM, continuity test says no bridge with the bottom two pins and 3rd, as well as 4th and 5th. The 4th pin is bent for some reason, so it's pretty close to the 5th, but it's not touching. The white gunk left over from the alcohol I used from cleaning makes some of the areas look pretty dirty. Is there anything you guys do to avoid this?

 I did measure from the DAC on the left channel, and it gave me 0V. If the PCM is indeed fried, would you say it's worth the effort to remove and replace it or to start over with a new board/parts?


----------



## Pars

I would take your DMM and ohm out all the pins for the left channel to the board to make sure that they are all making contact. Ohm these from the chip itself to the board pad/trace and verify connection. I would also take some solder wick and clean things up some, many joints don't look too hot.


----------



## CingKrab

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_I would take your DMM and ohm out all the pins for the left channel to the board to make sure that they are all making contact. Ohm these from the chip itself to the board pad/trace and verify connection. I would also take some solder wick and clean things up some, many joints don't look too hot._

 

Just checked VCCL, AGNDL, and OUTL. All ~0 ohms (0.1 according to my meter) from top of the pin to the pad. VCCL is around 4.71V at the pin. AGNDL is connected to both the USB receptacle shield and OG according to the continuity test at the pin. I'll try reflowing some stuff related to those pins, but it looks like the left channel analog stuff is properly powered at least. I'll try reflowing R15 again.


----------



## tomb

Good luck!

 BTW, the white stuff is dried powdered flux. It means you need to rinse it more. I've found that toweling off the alcohol with a good absorbent paper towel works well. Otherwise, you're just spreading around the flux each time you rinse with the alcohol. You should start to notice your paper towel turn a bit brown as it soaks in.


----------



## Colonel Panic

Repeat after me:

 I will NOT sneeze while placing positioning C14.








 The behind of my desk is a black abyss where nothing returns from. I searched and searched but C14 was nowhere to be found.


----------



## Pars

Quote:


  Originally Posted by *CingKrab* /img/forum/go_quote.gif 
_Just checked VCCL, AGNDL, and OUTL. All ~0 ohms (0.1 according to my meter) from top of the pin to the pad. VCCL is around 4.71V at the pin. AGNDL is connected to both the USB receptacle shield and OG according to the continuity test at the pin. I'll try reflowing some stuff related to those pins, but it looks like the left channel analog stuff is properly powered at least. I'll try reflowing R15 again._

 

The only other thing I would do is with DMM check adjacent pins for shorts. Note that some of the end pins on one side of the PCM are intentionally shorted on the PCB (right lower side of chip, forget pin #s). You might also check OUTL to ground compared to OUTR to ground, etc. Large differences should point to a problem.

 I rebuilt one user's Alien, moving all parts to a new board, and after that abuse, the PCM still worked, so I'm not sure I'd give up on it just yet.


----------



## TimmyMac

disregard this


----------



## ruZZ.il

Hey fellas, I seek any suggestions, or confirmation of a dead chip ;( 
 This DAC was functional for quiet some time, and still partially is:
 Sound out of only a single channel (The right one). 
 I've scoped out the actual chip pin, OUTL, and only get a slight offset, but no signal at all. OUTR is fully functional, so its not a power problem, no data transfer problem.. in fact, other than a single cap and resistor in the way, there's nothing but a faulty chip if 1 channel works perfectly and the other has no signal, or am I missing something? Balance and all other settings are set right, so.. changing chips? or.. any suggestions?
 As always, much appreciated 
	

	
	
		
		

		
		
	


	



 Thanks

 -R


----------



## bhjazz

Weird. You mentioned that all other settings are right. Did you check the 3.3v and 5V test points? Perhaps one of the resistors between the usb power in and the chip has gone. I know the right channel is working...I'll have to take a look at the schematic.


----------



## tomb

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Hey fellas, I seek any suggestions, or confirmation of a dead chip ;( 
 This DAC was functional for quiet some time, and still partially is:
 Sound out of only a single channel (The right one). 
 I've scoped out the actual chip pin, OUTL, and only get a slight offset, but no signal at all. OUTR is fully functional, so its not a power problem, no data transfer problem.. in fact, other than a single cap and resistor in the way, there's nothing but a faulty chip if 1 channel works perfectly and the other has no signal, or am I missing something? Balance and all other settings are set right, so.. changing chips? or.. any suggestions?
 As always, much appreciated 
	

	
	
		
		

		
		
	


	



 Thanks

 -R_

 

It could be a pin that's pulled loose from being under tension over time. Check the chip's pins by placing a probe at the pin exit from the plastic shell. Put the other probe somewhere away from the immediate area, but still within the pad's conductive plane. Measure for zero ohm continuity and see if anything has changed. You might try something similar on the OL/OR caps and the resistors, too.


----------



## bhjazz

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_It could be a pin that's pulled loose from being under tension over time._

 

Excellent idea. This could also come from the mechanical nature of the USB plug being connected and disconnected. I know my USB cable is quite snug and requires a bit of force, so any force there could turn or twist the board itself.


----------



## ruZZ.il

Tom, I did something similar. I used my old scope to find a signal between OUTL and ground. I used a resistor clipping as my probe, nada. The power supplies are all good, too, and the right channel works perfectly. Little else to blame here, I'm afraid 
	

	
	
		
		

		
		
	


	




 Thanks for the suggestions so far guys, I hope one helps!


----------



## Colonel Panic

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Tom, I did something similar. I used my old scope to find a signal between OUTL and ground. I used a resistor clipping as my probe, nada. The power supplies are all good, too, and the right channel works perfectly. Little else to blame here, I'm afraid 
	

	
	
		
		

		
		
	


	




 Thanks for the suggestions so far guys, I hope one helps! 
	

	
	
		
		

		
		
	


	


_

 

I'm just a noob when it comes to DIY, but why not just reflow everything?


----------



## ruZZ.il

Quote:


  Originally Posted by *Colonel Panic* /img/forum/go_quote.gif 
_I'm just a noob when it comes to DIY, but why not just reflow everything?_

 

If there were a signal at the chips output, then the prob would be between the chip and the board, I'd reflow the contact and check the rest of of sig. path. Since there's no measurable signal there, it doesnt seem to be a contact issue. Also, since I measure dc offset at the output, there's no true short to ground, so I'd assume that if it were creating a signal, it would be measurable. Also, since I can measure the offset, its not a problem with contact... I'll probably switch the chip out soon. fortunately, I have one around..


----------



## Colonel Panic

How easy is it to fry PCM 2702?

 I missed a solder bridge between two pins before I plugged it in.

 The computer recognized it, and it works according to the computer, but i'm getting short values from the two test pads.


----------



## adamus

is in in the top right corner? if so check the schematic, two pins are shorted anyway.


----------



## Pars

Quote:


  Originally Posted by *Colonel Panic* /img/forum/go_quote.gif 
_How easy is it to fry PCM 2702?

 I missed a solder bridge between two pins before I plugged it in.

 The computer recognized it, and it works according to the computer, but i'm getting short values from the two test pads._

 

When you say *short values from the two test pads*, do you mean the +5V and +3.3V test pads measure as shorts (0 ohms) to ground? Or which test points are you referring to? OL and OR? Check all the SMT caps, etc. as this is usually the area that a short occurs in.


----------



## Colonel Panic

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_When you say *short values from the two test pads*, do you mean the +5V and +3.3V test pads measure as shorts (0 ohms) to ground? Or which test points are you referring to? OL and OR? Check all the SMT caps, etc. as this is usually the area that a short occurs in._

 

Sorry, I did in fact mean the +5V and +3.3V test pads to ground are giving me nothing near what they should.

 Check the caps eh? this is going to be fun!!


----------



## Pars

Do you mean voltage measurement when you say the 5V and 3.3V aren't giving you near what they should? Do they measure as shorts (ohms)? 

 Looking at the schematic, there really isn't anything in common between the two regs that would pull both voltages down, unless the input voltage is way low, which feeds both. C21 or C31 shorted could do that. See what V+ measures or if it is shorted to ground with your meter.


----------



## bhjazz

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_The formula for the -3dB cutoff point on a filter (high pass in this case) is:

 f = 1 / 2 * Pi * R * C

 where C is in farads.

 So for example, your 0.47uf cap with a 100K resistor to ground would give:

 1 / 2 * 3.14159 * 100000 * 0.00000047

 or 3.39 Hz

 The filter will have some effect up to an octave or so above this._

 

Hi pars, 

 I'm fiddling around with the comparison between the .47uf caps and the 33uf caps. I'm not getting the same numbers when I do this calculation, though. I'm getting 0.073827365! If I halve it again, I'll get closer, with 0.0369136825. 

 Ehm...what am I missing? Thanks!


----------



## tomb

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Hi pars, 

 I'm fiddling around with the comparison between the .47uf caps and the 33uf caps. I'm not getting the same numbers when I do this calculation, though. I'm getting 0.073827365! If I halve it again, I'll get closer, with 0.0369136825. 

 Ehm...what am I missing? Thanks!_

 

 A couple of parentheses
	

	
	
		
		

		
			





 :
 f = 1 /*(* 2 * Pi * R * C*)*


----------



## Pars

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_A couple of parentheses
	

	
	
		
		

		
		
	


	




 :
 f = 1 /*(* 2 * Pi * R * C*)*_

 

Oh yeah, parentheses... sorry about that! I just automatically calculate a formula like that as if the parens were there. Thanks for pointing that out Tom.


----------



## bhjazz

Hahaha! Well, cool. Thanks, you two.


----------



## bhjazz

Just installed the Muse ESs. Yow, baby! I know there's some break-in ahead, but the bass is excellent. Just what I was looking for. Even my HD600s have a good, solid, bass foundation from a PC source. Neat! I'd also like to mention how clean the rest of the audio band sounds. Excellent start and stop from top to bottom. Geez, Donald Fagen's Morph the Cat...thud! This is damn cool. Can't wait until they break in some more. Thanks for the tips!


----------



## ruZZ.il

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Just installed the Muse ESs. Yow, baby! I know there's some break-in ahead, but the bass is excellent. Just what I was looking for. Even my HD600s have a good, solid, bass foundation from a PC source. Neat! I'd also like to mention how clean the rest of the audio band sounds. Excellent start and stop from top to bottom. Geez, Donald Fagen's Morph the Cat...thud! This is damn cool. Can't wait until they break in some more. Thanks for the tips!_

 

At first, I was overwhelmed by the bass but really really liked it too! but that wore off and something was lacking.. I followed in TomBs footsteps and bypassed the ESs with some sonicap Gen IIs that I had. Wait till you do that!


----------



## bhjazz

Ah yes....I do have some Gen IIs waiting, but I want to break these in first to get a good idea of how they sound. I found a few tunes last night that were maybe a bit thick in the bass. I imagine a week or so of break in will do the trick for the ESs. 

 I did hear one thing that I really found odd. With Foobar and Asio output, before each tune I hear the initialization (I think...or the initial storage sequence)...it sounds like "bththbth". I don't think I heard it with Foobar and Wave Out. Does anyone else get this? I've got XP Pro. It's not terribly loud, but strangely irritating!


----------



## StanRex

Hello,

 I'm trying to build an alien dac using jeff rossell's kit

 however, I m having a little difficulty understanding something :

 i populated ic2 and ic3 with my low soldering skills

 but i decided to check the pins to see if there was a short circuit somewhere

 so I checked pins and got 0 ohms between nearby pins which to my understanding, meant that there was a short circuit

 I decided to remove ic2 and ic3 and cleaned the solder with a desoldering braid

 however, I still get the 0 ohms reading between some pins of ic2 and ic3. Example : between the two top left pins of IC2.

 so I was wondering if it was normal because those pins were somehow connected by the board, or if it was because somehow, my soldering operation had left some sort of residue that kept the pins connected together

 thanks in advance for your answer


----------



## MisterX

http://www.myexposition.com/diy/usbd...atic-1.0-4.png

 On IC2 & 3 Pins 5,6,7 & 8 are all connected
 and so are pins 1 & 2


----------



## StanRex

ugh, so it was normal. Well, thanks a lot for the tip ^^


----------



## royewest

I regret the cheap antistatic tweezer set I bought. One pair snapped and the other pair slipped and tossed c15 across my desk. I found it once, but not the second time.

 To my mild surprise, Electronics Plus in San Rafael is not too far and they carry smd caps that look equivalent ( item C1687 on the page Electronics Plus - Hard to find parts and accessories, available and ready to ship! ).

 My question is, do I need to worry about matching the other parts of the kit I purchased from Glass Audio, or are these apparently same-spec caps likely to be an OK replacement? Same .1uF value, voltage, etc., but who knows if its the same part. Could it matter?

 Thanks in advance...


----------



## error401

The 0.1uF caps are pretty generic, they serve for power supply decoupling only so their value and type is pretty non-critical. Any value from 0.01uF to 0.1uF should be fine, and they're operated at low voltage (5V or less). The only thing I would think about is that that site doesn't list the dielectric used in those capacitors, I don't know what's used in the Glass Jar kit, but the ones at that site might be inferior. As I said above though, the value of these caps is not critical at all, so even if they have very poor temperature stability (the consequence of using an inferior dielectric) I'm sure they'd be fine.

 Make sure they're the right size, but they will otherwise be fine. They should be 0805 size. It looks from the photo like they might be 1206 which are larger and might be difficult to fit, but it's hard to tell.


----------



## royewest

Thanks, error 401 -- your suspicion was right, I called and they are the 1206s and you saved me an hour in the car. Better yet, daylight revealed the wayward part under my desk.

 I plowed ahead today and got it all assembled. I find the SMD capacitors almost impossible to solder down neatly. I have huge hands and find working with objects the size of two grains of sand a particular challenge. Lots of soldering and resoldering. When I finally plugged it in (voltages checked out) and then got zip on audio out I figured I'd melted something or had an invisible disconnect somewhere or a bridge in one of my sticky solder cellpools and despaired of ever figuring out what is wrong.

 But it turned out I'd just missed a switch in OSX to use the Burr-Brown for output and it works! Sounds great. The bass is excellent (listening to Percy Heath's "Suite for Pop" right now...) I'm just delighted. Can't wait to get it cased up.

 Thanks again to this fabulous community for another rewarding project.

 __Roy


----------



## rds

Just want to comment that Vitamin Q bypassed Black Gate Nx hi-qs in CR and CL sound beautiful.
 I have a few aliens here so I a/bed the just Black Gate to the version with Vitamin Qs and the Qs really bring the magic. In fact they've taken me from being lukewarm about the alien to really loving it


----------



## royewest

Very cool! What values are your CL/CRs and VitQs (can't seem to read the values in the pic)?

 I have some .18uF VitQs from beezar and my onboard CL/CRs are 33uF Nichocons. Any reason anyone can think of that these would or wouldn't be worth a try in combination? (I'm particularly nervous and clueless about the potential for defeating the circuit-protection role of the CL/CR caps).


----------



## Pars

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_Very cool! What values are your CL/CRs and VitQs (can't seem to read the values in the pic)?

 I have some .18uF VitQs from beezar and my onboard CL/CRs are 33uF Nichocons. Any reason anyone can think of that these would or wouldn't be worth a try in combination? (I'm particularly nervous and clueless about the potential for defeating the circuit-protection role of the CL/CR caps)._

 

As long as you have caps in there, and don't parallel them with a dead short, you won't defeat the circuit protection (i.e., DC blocking) role of the coupling caps, so play around to your heart's content. If you are still nervous, just check the DC offset on both channels with your DMM each time.


----------



## rds

Quote:


 What values are your CL/CRs and VitQs (can't seem to read the values in the pic)? 
 

Those are the .18uF Vit Qs from Beezar.


----------



## ruZZ.il

Tom, Your consistent persistence and ability to voluntarily and gladly help out here doesn't cease to amaze me. I'm like, <half your age and am usually too tired to do anything else but what I have to, lately. muchos kudos man!


----------



## tomb

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Tom, Your consistent persistence and ability to voluntarily and gladly help out here doesn't cease to amaze me. I'm like, <half your age and am usually too tired to do anything else but what I have to, lately. muchos kudos man!_

 

Calling me an old man, huh? OK - I admit it - I am definitely part of Ingwe's Team OAF.
	

	
	
		
		

		
			








 Seriously, thank you for your kind words.
	

	
	
		
		

		
		
	


	




 I've been busy with the Alien DAC, too - out of necessity. As mentioned over in the SSMH thread, I blew out a couple of my Aliens - the ES version being one of them. I needed quite a few sources for the Atlanta Meet held back on the 5th, so I replaced my ES Alien with a slightly different version in the same Penguin tin. It's packed in pretty good. I had to pop out the lid some, but a little strategic bending and the lid is still quite secure. What you see there are six 0.22uf VitQ's in parallel - three per channel.

 'Course, I'm coming to this late - FallenAngel and some others have been using appropriately sized film caps and removing the electrolytic output caps long before I tried this one. The question was whether paralleling several VitQ's would have the same effect. Dsavitsk revealed to me lately that he's been paralleling VitQ's successfully and thought they sounded better than one big one. So, I thought I'd try this - it worked out very well. There seems to be no lack of bass at 0.66uf per channel hooked to a MAX, while the mids and highs are superlative. Quite simply, it's the finest sounding Alien DAC I've built.


----------



## royewest

Hi TomB,

 Very cool build -- I was eying a tin of about that size myself tonight, wondering if I could fit some VitQs in with the Alien...

 Did you remove the electrolytics at CL/CR and replace them with the VitQs? Do they provide enough DC protection?

 Thanks,

 __Roy


----------



## rds

Wow, you really out Vitamin Qed me. That looks sweet. 
 What value are you using for R15/16? With a standard input impedance of 50k it seems you'd want something in the >=100k range. Even still you end up with a cutoff freq of about 10Hz, but I would imagine that is OK.

 EDIT: I see Jeff (Glass Jar) uses 332k - that should do it.
 EDIT 2: That'll do 5.5Hz cutoff - should be fine


----------



## tomb

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_Hi TomB,

 Very cool build -- I was eying a tin of about that size myself tonight, wondering if I could fit some VitQs in with the Alien...

 Did you remove the electrolytics at CL/CR and replace them with the VitQs? Do they provide enough DC protection?

 Thanks,

 __Roy_

 

Yes and yes.

 Please let me warn you though - this was not easy packing them in that tin. I essentially had to bend the tin sideways at the output jack and then screw the ring down until it popped into place, then bent the tin back. Even then, I had to bend the solder lugs back almost at right angles so that it would fit between the edge of the tin and the VitQ's. The bottom three VitQ's connect to the CL pads from the bottom up, while the top three VitQ's connect to the CR pads from the top. 

  Quote:


  Originally Posted by *rds* 
_Wow, you really out Vitamin Qed me. That looks sweet. 
 What value are you using for R15/16? With a standard input impedance of 50k it seems you'd want something in the >=100k range. Even still you end up with a cutoff freq of about 10Hz, but I would imagine that is OK.

 EDIT: I see Jeff (Glass Jar) uses 332k - that should do it.
 EDIT 2: That'll do 5.5Hz cutoff - should be fine_

 

Thanks!
 Yep - it's all stock except for the VitQ's at CL and CR. (Well, I used 1000uf for the power cap and 330uf everywhere else, but had tested those values earlier on another Alien.)


----------



## ruZZ.il

Ack, I meant to post that in the MHM thread  nonetheless, you've contributed here too though. Not any less worthy of praise are quiet a few other good folk around here. Pars, Error401, and others.. Thaks for making this place what it is!


----------



## tomb

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Ack, I meant to post that in the MHM thread  nonetheless, you've contributed here too though. Not any less worthy of praise are quiet a few other good folk around here. Pars, Error401, and others.. Thaks for making this place what it is! 
	

	
	
		
		

		
		
	


	


_

 

I sort of thought maybe you posted that because of all the Vitamin Q's floating around here lately. That, or either Pars' or Error401's first name is Tom, too.


----------



## royewest

At the risk of asking too much, really:

 * DC offset. I confess, I think I understand what this would be (+/- signal moving wave into all + or - voltage?), but I am not certain and have no idea how to measure it or what the cause can be and why the coupling caps prevent it. Obviously this is a pretty basic audio circuit issue and perhaps there is a place on line already that explains this?

 * Replacing the CL/CR electrolytics. What general guidelines can anyone offer about replacing these with film caps (VitQs, etc.) while preserving the DC protection the electrolytics offer. I'm currently bypassing the stock 33uF electolytics that came with the glass jar kit with .18 1000V VitQs. TomB has replaced them entirely with 3x(.22uF in parallel)=.66uF (correct math?) on each channel VitQs. Is there a range I should stay inside to experiment with here? I have some nice 1uF and 2uF 600V film caps from other projects, could I try them without risking the amp I connect to? Or are they way too high capacitance?

 Again, thanks in advance for your generous and ongoing support for beginners on this forum.

 __Roy


----------



## Pars

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_At the risk of asking too much, really:

 * DC offset. I confess, I think I understand what this would be (+/- signal moving wave into all + or - voltage?), but I am not certain and have no idea how to measure it or what the cause can be and why the coupling caps prevent it. Obviously this is a pretty basic audio circuit issue and perhaps there is a place on line already that explains this?_

 

DC offset is a quiescent state measurement (i.e., no signal present, as in no music playing, etc.). It is simply a static measurement of the amplification/output section. It is measured using a voltmeter (DMM) between the left output to ground, and the right output to ground (each channel separately).

 Capacitors block DC... unless the cap has failed, it will not pass a DC voltage. Capacitors will pass AC voltages (music, etc.). This is the basic property of capacitors that makes them useful in circuits.

  Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_* Replacing the CL/CR electrolytics. What general guidelines can anyone offer about replacing these with film caps (VitQs, etc.) while preserving the DC protection the electrolytics offer. I'm currently bypassing the stock 33uF electolytics that came with the glass jar kit with .18 1000V VitQs. TomB has replaced them entirely with 3x(.22uF in parallel)=.66uF (correct math?) on each channel VitQs. Is there a range I should stay inside to experiment with here? I have some nice 1uF and 2uF 600V film caps from other projects, could I try them without risking the amp I connect to? Or are they way too high capacitance?

 Again, thanks in advance for your generous and ongoing support for beginners on this forum.

 __Roy_

 

I don't want to get into cap wars too much, other than to say that in terms of the actual device approaching the ideal model, an electrolytic cap is awful, particularly when compared to most film caps. Most people think that film caps sound much better than electrolytics when used as coupling caps. Alot of tube amp builders are actually using film caps as the PSU caps as well (an amp with NO electrolytic caps in it). You could try your 1uf and 2uf film caps without worry.


----------



## error401

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_At the risk of asking too much, really:

 * DC offset. I confess, I think I understand what this would be (+/- signal moving wave into all + or - voltage?), but I am not certain and have no idea how to measure it or what the cause can be and why the coupling caps prevent it. Obviously this is a pretty basic audio circuit issue and perhaps there is a place on line already that explains this?_

 

DC offset refers to a constant voltage offset on the signal. Rather than swinging around 0V like an ideal signal, there is a constant offset which brings the centrepoint of the AC signal up. If your amplifier doesn't block it, the DC component will be amplified too, and driven into your headphones/speakers. Since it doesn't represent audio it's unwanted, and can harm the headphone/speaker by driving a constant current through it - this displaces the cone and can heat the voice coil enough to damage it.

 The use of coupling capacitors fundamental _electronics_ issue, and goes back to the basic function of a capacitor. Whenever you place a capacitor in series like these coupling capacitors, you end up with an RC circuit formed by the series capacitor and the input impedance of the circuit. This RC circuit is a high-pass filter with a 6dB/octave rolloff below the breakpoint - DC is completely blocked. To put it simply, capacitors pass high frequencies and block low frequencies. The larger the capacitor, the lower it goes before it starts to block the signal.

 'AC coupled' circuits block DC and only pass the AC portion of a signal. 'DC coupled' means that there are no DC blocking elements in the circuit.

 If you want to learn more, read any electronics textbook 
	

	
	
		
		

		
		
	


	




[/quote]

  Quote:


 * Replacing the CL/CR electrolytics. What general guidelines can anyone offer about replacing these with film caps (VitQs, etc.) while preserving the DC protection the electrolytics offer. I'm currently bypassing the stock 33uF electolytics that came with the glass jar kit with .18 1000V VitQs. TomB has replaced them entirely with 3x(.22uF in parallel)=.66uF (correct math?) on each channel VitQs. Is there a range I should stay inside to experiment with here? I have some nice 1uF and 2uF 600V film caps from other projects, could I try them without risking the amp I connect to? Or are they way too high capacitance? 
 

The DC protection will be present with any capacitor, since the RC filter impedance increases with decreasing frequency at 6dB/octave, and since DC represents effectively an 'infinitely low' frequency, the impedance of the filter will be infinite as well no matter the value, blocking the DC.

 You can calculate what value is appropriate if you know the input impedance of your amplifier and how low you want to have a good response. The point at which the filter as a -3dB response (called the breakpoint) is given by:




 Where R is the input impedance of your amplifier and C is the capacitor value in Farads (so divide your uF value by 1,000,000). You probably want the -3dB point to be about an octave below the lowest frequency you want to keep to ensure flat response. If you don't know the input impedance, 10K is a conservative guess that should work well with pretty much anything. The lower it is though, the larger caps you'll need, so film caps become unwieldy and electrolytics are used, like here.


----------



## tomb

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_At the risk of asking too much, really:

 * DC offset. I confess, I think I understand what this would be (+/- signal moving wave into all + or - voltage?), but I am not certain and have no idea how to measure it or what the cause can be and why the coupling caps prevent it. Obviously this is a pretty basic audio circuit issue and perhaps there is a place on line already that explains this?_

 

DC offset occurs because the typical power for IC circuits and PC's is +5VDC. Audio is AC; the signal "swings" between an upper voltage and a lower voltage. Ideally, that lower voltage is negative with pure AC. However, the way the PCM chip does it is by swinging between 62% of that +5V and 50% of the +5V. What that means is the bottom of the signal wave is ~+2.5VDC. Hence, there is 2.5VDC offset before anything is connected.

 Capacitors block DC, while fully passing AC. This allows us to use capacitors on the sound output of the PCM chip to zero out that +2.5VDC and allows only the AC music signal to pass. There's a lot of devil in those details, though - the caps must be charged first (DC offset is still present until then), caps have their own sound signature they impart to the music signal, and caps form an RC circuit with the resistance of the load - this causes the bass frequencies to be cut off.

  Quote:


 * Replacing the CL/CR electrolytics. What general guidelines can anyone offer about replacing these with film caps (VitQs, etc.) while preserving the DC protection the electrolytics offer. I'm currently bypassing the stock 33uF electolytics that came with the glass jar kit with .18 1000V VitQs. TomB has replaced them entirely with 3x(.22uF in parallel)=.66uF (correct math?) on each channel VitQs. Is there a range I should stay inside to experiment with here? I have some nice 1uF and 2uF 600V film caps from other projects, could I try them without risking the amp I connect to? Or are they way too high capacitance? 
 

As mentioned above, the output capacitors form an RC circuit with the load to which it's connected. Select a capacitor with a rating too low and you will lose some of the bass frequencies.

 You need to know the input impedance of your amplifier in the case of the Alien DAC. Most of the time, that's the impedance of the volume pot. For instance, in the case of the Millett MAX, a 50 Kohm pot is used for the volume control (ALPS RK27). The equation for determining the bass cutoff is:

 f = 1/(2*pi*C*R), where f is the frequency in Hertz, C is capacitance in farads, and R is in ohms.

 Rearranging to solve for "C", we have: C = 1/(2*pi*R*f).

 Let's say we want to be safe and want a cap that will give us at least 10Hz. The reason we want to do this is because the filtering starts at frequencies above that. "f" is only where the drop is down -3dB. So, solving for "C", we might have:

 C = 1/(2*pi*50000*10) = 0.3 x 10E-6, or 0.3uf.

 This is saying that a 0.3uf capacitor on the output of the Alien, connected to an amp with a 50K volume pot, should have a -3dB drop in frequency response at 10Hz.

  Quote:


 Again, thanks in advance for your generous and ongoing support for beginners on this forum.

 __Roy 
 

OK - hope that helped.
	

	
	
		
		

		
		
	


	




 PRE-EDIT: I see that we've had Pars and error401 post before me. I typed all of this in the meantime, so I'll post it anyway. 
	

	
	
		
		

		
		
	


	




 Maybe it will help to have different perspectives on the same subject.


----------



## royewest

You guys are wonderfully generous. Thanks to all three of you.

 __Roy


----------



## royewest

Alright, I already have a question. In a circuit like the Alien DAC, why would you bypass CL/CR instead of replacing them? This is assuming I have correctly understood "bypassing" to mean connecting another capacitor in parallel. I see that different knowledgeable folks have done both things.


----------



## error401

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_Alright, I already have a question. In a circuit like the Alien DAC, why would you bypass CL/CR instead of replacing them? This is assuming I have correctly understood "bypassing" to mean connecting another capacitor in parallel. I see that different knowledgeable folks have done both things._

 

Bypassing results in sort of a compromise between using an electrolytic and using a film cap. Because large value film caps are physically large and difficult to fit in the case, a smaller value film cap is placed in parallel with the 'lytic. The thinking is that at low frequencies, where the film cap value is too small, the electrolytics passes the signal, but at higher frequencies where electrolytics are said to have poorer response, the film cap can pass the signal.

 I'm not sure if there's a theoretical basis for this, but many claim that it works for them. It allows you to use a small film cap while still getting much of the benefits a larger one that wouldn't fit in the case would give.


----------



## StanRex

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_http://www.myexposition.com/diy/usbd...atic-1.0-4.png

 On IC2 & 3 Pins 5,6,7 & 8 are all connected
 and so are pins 1 & 2_

 

Ok, there s something I just don't understand here. I resoldered ic2 and ic3.

 when testing resistance between ic2 and ic3 pins

 I get 0 between pins 5,6,7 and 8 (left side of ic2 and ic3). Normal

 However I don't get 0 between pins 1 & 2 (the two top left pins when looking at the board http://www.myexposition.com/diy/usbd...-all-1.1-1.png )

 and I do get 0 between pins 3 & 4 (the two bottom left pins)

 Reading the schematic, i would have expected to get 0 on pins 1,2,5,6,7,8 and not 0 between 3 and 4, since pins 1 & 2 are connected directly and 3 & 4

 I'm wondering if i'm properly identifying the pins?

 if anyone can explain to me what I'm doing wrong, I'd be grateful

 thanks in advance

 edit : btw, while desoldering, I accidently dropped some solder in the 3V3 hole near IC2, I tried to clean as much as I could but I'm pretty sure there still some solder left in it. Is it bad news?


----------



## Pars

Looking at the view you referenced, note on IC2 and IC3, the little "o" at the bottom right of the chip body. This is the pin 1 indicator (bottom right pin on each IC). The numbering goes up the right side (1-4) then over to the upper left side (5-8) back down the left side.

  Code:


```
[left]5 4 6 3 7 2 8 1[/left]
```

Like that.


----------



## StanRex

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_Looking at the view you referenced, note on IC2 and IC3, the little "o" at the bottom right of the chip body. This is the pin 1 indicator (bottom right pin on each IC). The numbering goes up the right side (1-4) then over to the upper left side (5-8) back down the left side.

  Code:



		Code:
	

[left]5 4 6 3 7 2 8 1[/left]


Like that._

 

Ookkkk so it's not like on the schematic! thanks a lot, then my soldering should be ok!

 there s just the matter of the 3V3 hole left ^^ but thanks a lot for the answer!


----------



## MisterX

Quote:


 edit : btw, while desoldering, I accidently dropped some solder in the 3V3 hole near IC2, I tried to clean as much as I could but I'm pretty sure there still some solder left in it. Is it bad news? 
 

No, that is just a test point. 
 As long as you measure 3.3 volts there don't sweat it.


----------



## StanRex

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_No, that is just a test point. 
 As long as you measure 3.3 volts there don't sweat it._

 

ok, thanks for the info MisterX!


----------



## StanRex

just wondering,

 would 95° ethanol be ok to clean the pcb? Cause I can't seem to find isopropanol in France

 thanks in advance for your answer


----------



## JamesL

I've used 91% before, and although you need to work through it several times, it'll do the job on smaller boards.

 just for clarification - I don't recommend that people purchase 91% or 95% for everyday work, but it will get the job done with some extra scrubbing.


----------



## StanRex

ok, I'm just having a terrible doubt here.

 I think all the smd capacitors (which I just finished soldering) aren t polarized.

 However, I'm pretty sure at least some (if not all) of the through hole capacitors are...

 Is there a reliable way to find out their polarity?

 thanks in advance

 edit: just checked and it seems the theory is that longest lead is + and shortest is -


----------



## Pars

C2, C13, C23 and C33 are mose likely polarized electrolytics, with a stripe or other such marking for the negative lead. CR and CL *could* be polarized (I have no idea what you used for these). If so, they will also have the negative marked.

 The rest of the caps (SMD) should be non-polar so no worries there.


----------



## royewest

Quote:


  Originally Posted by *StanRex* /img/forum/go_quote.gif 
_edit: just checked and it seems the theory is that longest lead is + and shortest is -_

 

Yes, the longer lead is the positive lead. I found it frustrating that the datasheets and such for those did not include this tid bit, which must have seemed so obvious as not to be worth repeating, but set me back for an hour researching whether there was ever an exception to that rule....


----------



## StanRex

yay, well I've added all the components. I m now getting ready for wiring and testing, however there s one thing I'm not too sure about

 I m building usb regulated, so according to the wiring details, i should jumper s1a and s1b

 however, the 1st step of the testing phase tells us to connect a battery or an external power supply

 should i jumper s1a and s1b first and then proceed to testing

 or should i test first, then jumper s1a and b since during the testing, the amp will be "battery powered"

 btw, for the test, would a 9v battery do the trick?

 thanks in advance for your answers


----------



## tomb

Quote:


  Originally Posted by *StanRex* /img/forum/go_quote.gif 
_yay, well I've added all the components. I m now getting ready for wiring and testing, however there s one thing I'm not too sure about

 I m building usb regulated, so according to the wiring details, i should jumper s1a and s1b

 however, the 1st step of the testing phase tells us to connect a battery or an external power supply

 should i jumper s1a and s1b first and then proceed to testing

 or should i test first, then jumper s1a and b since during the testing, the amp will be "battery powered"

 btw, for the test, would a 9v battery do the trick?

 thanks in advance for your answers_

 

If you're building the USB-powered version, there's no point in connecting a battery. Connecting a hot USB cable will accomplish the same thing. More than that, you won't be able to check any voltages unless you jumper or close a switch on s1a and s1b, regardless of how you power it.


----------



## StanRex

Ok, then I'll just plug it into my computer's usb ports

 Do I risk damaging the computer if I'm wrong though?


----------



## tomb

Quote:


  Originally Posted by *StanRex* /img/forum/go_quote.gif 
_Ok, then I'll just plug it into my computer's usb ports

 Do I risk damaging the computer if I'm wrong though?_

 

No, you're not going to hurt your computer, but you may fry the Alien DAC if you've got something out of place. That's the damage to worry about. Check all your parts twice, make sure you've got continuity between your chip pins and the board traces. After that, it's the same for everyone else: strap it in and see if if you can get it off the ground - but watch out for the possibility of a crash and burn.


----------



## StanRex

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_No, you're not going to hurt your computer, but you may fry the Alien DAC if you've got something out of place. That's the damage to worry about. Check all your parts twice, make sure you've got continuity between your chip pins and the board traces. After that, it's the same for everyone else: strap it in and see if if you can get it off the ground - but watch out for the possibility of a crash and burn.
	

	
	
		
		

		
			



_

 

Plugged it in

 Windows recognized it

 I have 3.3V between 3.3 test point and G1

 and 4.7V between 5 test point and G1

 \o/


 too bad I dont have a jack to finish testing it though

 Thanks a lot for your help guys!


----------



## royewest

I found some old caps at my local store recently and was curious how they'd sound with the Alien. I have a small assortment (including the VitQs that TomB turned me on to) and put this little sub-board together so I can try them in different configurations, bypassing or replacing the Nichicon electrolitics that came with the kit I purchased from Glass Jar, without having to solder and desolder my collection.

 I'm mostly amused at how it turned out and thought I'd share the mirth with a pic. These Mallards sound just fine but the Alien itself is just built so we'll see how a dozen hours affect things....


----------



## StanRex

turns out I still have a few questions to ask regarding the alien ^^

 I built it using a kit made by jeff rossel, from glass jar audio. I still have 2 components left : a resistor (which is supposed to be used to o/c the chip using external ps if I understood properly)
 and some sort of dented component. If I look at the spreadsheet that came with the kit, I suppose that would be X1_Acc, a mylar spacer. But what would that be? some thing that i'm supposed to put between X1 and the pcb? is it necessary ?


 My other question would be regarding the wiring. If I understood properly, the advantage of 3.5 jack over RCAs is that it takes less room. However, RCAs are less risky for your amp & headphones because they don't create a short circuit when plugged in. Is that all the difference?

 And last but not least, is there some sort of tutorial for casing (I'm wondering how I'm going to "lock" the pcb into the hammond case and prevent it from moving. I think somehow tying it to the back panel , where the usb plug is would be the best solution but I don't know how that could be achieved) 

 and panel mounting jacks/rcas/leds ?

 thanks again for your answers to my previous questions and your help


----------



## MisterX

Does the part you referred to as "X1_Acc"

 look like this image------> 
http://rocky.digikey.com/weblib/ECS/...s/700-9001.jpg

 ?

 If so it is a Mylar insulator and it is not necessary. 

 The primary difference between a pair of RCA jacks and a single minijack is durability
 I guess shorting is also an issue but you should not be connecting your stuffs when it is turned on anyhow so...

 Case working tutorial = 
Electronic Construction Tutorial Part 3 - Enclosures

 And if you read this thread from start to finish you see any number of ways people have "locked" the PCB into the enclosure. 
 My preference was to just get the tin snips out of the tool box and cut a piece of sheet metal that fit between the board and the end of the case.


----------



## StanRex

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Does the part you referred to as "X1_Acc"

 look like this image------> 
http://rocky.digikey.com/weblib/ECS/...s/700-9001.jpg

 ?

 If so it is a Mylar insulator and it is not necessary. 

 The primary difference between a pair of RCA jacks and a single minijack is durability
 I guess shorting is also an issue but you should not be connecting your stuffs when it is turned on anyhow so...

 Case working tutorial = 
Electronic Construction Tutorial Part 3 - Enclosures

 And if you read this thread from start to finish you see any number of ways people have "locked" the PCB into the enclosure. 
 My preference was to just get the tin snips out of the tool box and cut a piece of sheet metal that fit between the board and the end of the case._

 

Thank you for your answer Mr X

 Yes, that's just the part! I'll see if I desolder X1 to solder it between it and the pcb. I suppose that since things didn't blow up when I powered the alien up, I don't really need it ^^

 Thanks for the casework tutorial. I'm going to check other people's ideas in this thread

 ((((((Regarding the led, am I supposed to use a normal one or a low current consumption one? will it make some sort of difference considering i'm powering from usb?))))) Nevermind, found out that low current Led was better. Low current it will be!

 (low current one is 1.9V @ 2mA, normal one is 2.1V @ 10mA. My limited knowledge would tell me not to bother with the low consumption one and to go with normal leds, but maybe I'm wrong)

 edit : and huh, is there any point in using shielded wire?


----------



## StanRex

Well, I bought some cheap, ****ty wire and rca connectors at a small shop and came back to home. I wired those (I think I ll need a few explanations on how to properly wire outputs though ^^) checked the beasts DC offset

 and it seemed fine. So I put my headsix and ibuds in for a first test. Sound was coming out of the ibuds.

 So I just plugged my SE530 which I'm listening to at the moment. And it sounds great ^^

 It's definitely not bass light btw. At least with the headsix and SE530 after it, the bass has some nice punch. 

 Gonna test it on some classical, but on the few electronic/rock tunes I've tested atm it behaved pretty well

 Anyway, I wanted to thank the people from this thread, MisterX, tomb and the others for answering my questions

 Thank you again guys!


----------



## ruZZ.il

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_Hey fellas, I seek any suggestions, or confirmation of a dead chip ;( 
 This DAC was functional for quiet some time, and still partially is:
 Sound out of only a single channel (The right one). 
 I've scoped out the actual chip pin, OUTL, and only get a slight offset, but no signal at all. OUTR is fully functional, so its not a power problem, no data transfer problem.. in fact, other than a single cap and resistor in the way, there's nothing but a faulty chip if 1 channel works perfectly and the other has no signal, or am I missing something? Balance and all other settings are set right, so.. changing chips? or.. any suggestions?
 As always, much appreciated 
	

	
	
		
		

		
		
	


	



 Thanks

 -R_

 


 Chip changed. Problem solved.


----------



## royewest

After moving the caps off an Alien board to more easily listen to different NOS caps (see pic of Frankenstein above), I realize that my life might be simpler moving the last step ortwo of the output circuit onto the another board, too, instead of returning to the Alien board to pass through the resisitors and out to the output jack. 

 In other words, leave the Alien board at the CL/CR + points and continue past the caps on the second board, inserting resistors and taking my output jack off of the second board, too. Obvious stuff.

 Here's my question. What restrictions are there on the type or wattage of 330K ohm resistors should I follow (for R15 and R16), after the caps? I don't really want to use surface mount resistors since I am not space-constrained. Will any ole resistor do, or should I aim for something specific?

 Thanks again, folks!

 __Roy


----------



## FallenAngel

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_After moving the caps off an Alien board to more easily listen to different NOS caps (see pic of Frankenstein above), I realize that my life might be simpler moving the last step ortwo of the output circuit onto the another board, too, instead of returning to the Alien board to pass through the resisitors and out to the output jack. 

 In other words, leave the Alien board at the CL/CR + points and continue past the caps on the second board, inserting resistors and taking my output jack off of the second board, too. Obvious stuff.

 Here's my question. What restrictions are there on the type or wattage of 330K ohm resistors should I follow (for R15 and R16), after the caps? I don't really want to use surface mount resistors since I am not space-constrained. Will any ole resistor do, or should I aim for something specific?

 Thanks again, folks!

 __Roy_

 

Pretty much whatever. I'd use a 1/4W metal film as the rest of the map, maybe 1/8W Dale for simplicity.


----------



## Jrossel

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_C2, C13, C23 and C33 are mose likely polarized electrolytics, with a stripe or other such marking for the negative lead. CR and CL *could* be polarized (I have no idea what you used for these). If so, they will also have the negative marked.

 The rest of the caps (SMD) should be non-polar so no worries there._

 

If CL and CR are Muse ES (green) they are non-polar 

 You could post a photo and we could help check for you.

 Jeff


----------



## royewest

Edit: Nevermind. I added the ground and all is better!

 In my ongoing effort to emulate TomB : ) I created a little sub board where I have set up 3 VitQ caps in parallel on each channel and then take the audio out from the sub board, rather than returning to the Alien board and using its SMD components.

 I got this cased up and get a bad hum instead of music.

 Looking back at the schematic (after plowing ahead, of course), I assume my error was not brininging the ground from the Alien board to a point after the resistors, before the signal ground goes to my audio jack?

 I'm moving ahead on that assumption now, but if anyone would be kind enough to confirm the error of my ways, I'd appreciate it.

 Here's a simple schematic of what I built -- revealing my error I hope...


----------



## royewest

All better now. The Vitamin Q enhancement idea from TomB and the caps themselved from his Beezar.com.

 Sounds wonderful with no time on it yet. Looking forward to listening more...

 Thanks again for the support on this forum.

 __Roy


----------



## tomb

Quote:


  Originally Posted by *royewest* /img/forum/go_quote.gif 
_All better now. The Vitamin Q enhancement idea from TomB and the caps themselved from his Beezar.com.

 Sounds wonderful with no time on it yet. Looking forward to listening more...

 Thanks again for the support on this forum.

 __Roy_

 

Very cool box! Great job, too. (Yes, as you discovered, you needed a common ground between the channels to take back to the board.)


----------



## lynxkcg

Just how mandatory are C11 and C12?
 I think I ended up with 2 pairs of R11 and R12 instead of the caps. Might a .1uf wima cap suffice?


----------



## error401

Quote:


  Originally Posted by *lynxkcg* /img/forum/go_quote.gif 
_Just how mandatory are C11 and C12?
 I think I ended up with 2 pairs of R11 and R12 instead of the caps. Might a .1uf wima cap suffice?_

 

They are capacitors used to load the crystal properly so that it will oscillate at the correct frequency. Leaving them out cause the frequency to increase slightly, but it will likely be close enough to work properly without them. Don't add a 0.1uF cap here, it's much too large. Try it without the caps, but I would eventually fit them even if it works without.


----------



## lynxkcg

L12 just fried taking traces with it ::cries::

 All the caps on top leeched out white powder also.


----------



## error401

Quote:


  Originally Posted by *lynxkcg* /img/forum/go_quote.gif 
_L12 just fried taking traces with it ::cries::

 All the caps on top leeched out white powder also. 
	

	
	
		
		

		
		
	


	


_

 






 There's no way that could've been caused by omitting C11 and C12. It sounds like there was probably a short somewhere. L12 is part of the pi filter on the input power, a short on the power rail would cause it to fail. It's strange that your caps failed too though, normally they would be fine.


----------



## keyid

does anyone have an extra X1 part? its the ECS 12.000000 MHZ 20pF HC-49US
 been looking through Mouser but cant find anything else to order. 

 Please pm if you have one available.
 Thanks


----------



## error401

Mouser carries lots of suitable parts. 815-ABLS-12-B2 is an appropriate substitute. Slightly more expensive and less temperature-stable, I believe the specified ECS part is available as part number 520-HCU1200-20X.


----------



## keyid

yea they do carry it but with shipping its $7. Wondering if someone might have one in their parts bin.
 I was looking for other things to order from them but cant find anything at the moment.


----------



## lynxkcg

wanna try my x1 from my build that went belly up? the leads are cut pretty short, but it should still have enough on there.


----------



## error401

Quote:


  Originally Posted by *keyid* /img/forum/go_quote.gif 
_yea they do carry it but with shipping its $7. Wondering if someone might have one in their parts bin.
 I was looking for other things to order from them but cant find anything at the moment._

 

Ah, I misunderstood why you mentioned Mouser.

 I've only got 4MHz and 20MHz crystals at hand, so I can't help ya out.


----------



## keyid

lynxkcg - thank you very much for the x1 and muse caps!!


----------



## Liquidretro

So I received the Alien DAC kit (GlassJar Audio) for my birthday as requested. This is my first big SMD project and I am excited and waiting for my tweezers to come so I can start the build. I have a few questions before I begin.

 I have a Mini3 (Amb.org) amp that I plan on using with this DAC. I will be plugging it into my Dell Laptop. I was wondering what is the best way to power this? Is USB the preferred method? Can I power it through a Powered USB hub if I need to? (I currently don't have one but may need to get one in the future if I keep adding USB devices.)

 I am also wondering what is the best way to connect this to my Mini3 Amp. I was thinking of using a 3.5mm jack out the front of the case. (Is RCA Better? I was thinking this would make more of a cable mess for the interconnect) The case I am planning on using is Hammond 1455C801BK (Al Ends) Should I cut the case down in length and then glue the 3.5mm jack to the front of one panel? or should I leave the case the way it is and just run longer wires? 
 What is a good 3.5mm jack to get? I was thinking of getting the jack that AMB Audio sells for his projects (http://www.cui.com/pdffiles/SJ1-3533NG.pdf) just because its cheap and more importantly he doesnt charge an arm and a leg for shipping for a simple part like some of the big electronics houses do. Is this a good part for this application? How is the best way to connect it? Last question, What type/size of wire should I use for my interconnect between the audio jack and board and for my jumps?


----------



## royewest

I am often listening to this exact combination. The stock configurations work just great for this:

 I built the USB-powered version of the Alien DAC. My Macbook provides sufficient power to drive the Alien without plugging it into a separate powered USB hub -- I'd be surprised if the Dell couldn't do the same thing. (I also plug it into a powered hub when that is more convenient, such as at work.) Several postings from reliable folks in this thread argue that the sound improvement achieved by other power configs is probably not worth the loss of convenience of USB power.

 I also use 3.5mm as the Alien output jack -- it allows a much smaller package. I connect the Alien to the Mini^3 with a 3.5mm-3.5mm cable. I have built some, but you can get a fabulous one from Zu by bidding on a Pivot on eBay and then asking them to configure the length and terminators you need: They are wonderfully accommodating and if you watch you'll see the price is much lower than list. Or if you decide to go with RCAs on the Alien, just take the Pivot as is.

 I've used 22ga silver-coated teflon wire for the board-3.5mm jack connection (you can see pics in some of my earlier threads). As for the jack itself, I've found it much more convenient to use chassis-mounted jacks, but the best I've been able to find have been these (they're available from lots of places): http://www.electronicplus.com/images/products/504KB.jpg


----------



## tomb

I concur with everything royewest has described, even down to the actual 3.5mm jack. That's exactly the one I've used on dozens of projects. Further, if you're not into small interconnect-making, you can get very good quality Stereo 3.5mm to RCA cables in Walmart and elsewhere (Belkin's are nice), due to the popularity of the iPod. I would not use the 3.5mm jack that you (Liquidretro) described and pictured. It's a board-mounted jack that has little usefulness on a board that doesn't use board-mounted jacks.
	

	
	
		
		

		
		
	


	




 As for powering, I might add that if you research the entire thread, the consensus early on was that there was no test-able difference between a USB-powered Alien and an externally-powered one.

 Let me qualify that a bit, though - I have tried grouping Aliens on a powered USB hub, and the results were pretty bad. It may have something to do with the cheap external power supply that some of these hubs use - perhaps throwing a lot of high-frequency noise onto the analog portion of the Alien through the power supply. Plus, if you don't use the external power, the volume level/gain of the Alien is cut in half when you pair them on the same bus. Since then, I got one of those USB repeater cables that seems to work quite nice, though. I needed that because my main PC is actually remote to the keyboard and monitor, which is where my headphone amp resides. So, just be cautious if you venture outside the normal one-to-one USB cable connection.


----------



## Liquidretro

Thanks for the ideas and suggestion guys. Do you know where exactly I can get that 3.5mm jack? I am having a hard time finding it.


----------



## royewest

Electronics Plus in San Rafael, CA, has a bin full of them (the photo link in my earlier post was from their site. Last time I was there the owner reminded me they have a web site and ship. I'm sure you can find them elsewhere.

 I think this is the same thing, from Mouser. It includes a link to the data sheet, which should help you search more broadly: http://www.mouser.com/Search/Refine....161-7400-EX%09


----------



## tomb

Quote:


  Originally Posted by *Liquidretro* /img/forum/go_quote.gif 
_Thanks for the ideas and suggestion guys. Do you know where exactly I can get that 3.5mm jack? I am having a hard time finding it._

 

161-7400-EX

 EDIT: Royewest beat me to it.


----------



## jamess71

No experience with external dacs. I'm wondering would there be improvement using the Alien Dac with my Oppo over using the analog out of my Oppo 980? I still have a bijou build in queue but I'm getting curious about dacs. 

 James


----------



## Liquidretro

Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_No experience with external dacs. I'm wondering would there be improvement using the Alien Dac with my Oppo over using the analog out of my Oppo 980? I still have a bijou build in queue but I'm getting curious about dacs. 

 James_

 

I am not sure how you would connect the Alien to the Oppo. I am not very knowledgeable with this dvd player but the Alien is designed to take an input over USB. It is also designed for output in stereo not multiple channels. I don't think this is what you are looking for. The Alien is designed to be used with a computer of sometype. Think of it more as an external sound card. 

 If you are looking to improve the sound in this dvd player I ran across this article the other day.
Modding the Oppo 980 for better audio output - Hack a Day


----------



## Liquidretro

Sorry for the double post

 I just got all my parts and am starting to build the DAC. I am still confused about IC3 though. I want to build a version that plugs directly into my USB port and is powered from USB. So do I need to populate IC3?


----------



## JamesL

It will work without it, but usb provides you with 5vdc unregulated power. 
 For regulated power from your usb-bus, you will need to use an adjustable regulator, and set it to output around 4.5v


----------



## Liquidretro

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_It will work without it, but usb provides you with 5vdc unregulated power. 
 For regulated power from your usb-bus, you will need to use an adjustable regulator, and set it to output around 4.5v_

 

Ok So i put in the chip named BBREG101UA0049 Now what do I do with the following?

 * If you use an adjustable regulator IC3, populate the C32 and R31 positions on the bottom side and R32 on the top side.
 * If you use a fixed regulator IC3, put C32 on the top side in the position that ambiguously says R32/C32. Do not populate R31 and R32.
 * If you do not populate IC3, then there is no need for C32, R31, and R32. 

 I am thinking the first option?


----------



## JamesL

I don't know if that's a adjustable chip or not.. burrbrown, 0049's probably a date code, but both share the same reg101ua prefix.

 If it is adjustable, you would use option one. Else, you would leave it out and use option 3 instead..


 That said, does anybody know where I can source some REG101UA-A's, or any alternative substitutes? I have two boards that I want to populate but can't find the reg101's anywhere.


----------



## srserl

Quote:


  Originally Posted by *Liquidretro* /img/forum/go_quote.gif 
_Ok So i put in the chip named BBREG101UA0049 Now what do I do with the following?

 * If you use an adjustable regulator IC3, populate the C32 and R31 positions on the bottom side and R32 on the top side.
 * If you use a fixed regulator IC3, put C32 on the top side in the position that ambiguously says R32/C32. Do not populate R31 and R32.
 * If you do not populate IC3, then there is no need for C32, R31, and R32. 

 I am thinking the first option?_

 

That's what Jeff (Glassjaraudio) shipped with my kit and I confirmed with him that it was an adjustable regulator, so yes, use the first option. Seems to be working fine.

 Scott


----------



## Liquidretro

Quote:


  Originally Posted by *srserl* /img/forum/go_quote.gif 
_That's what Jeff (Glassjaraudio) shipped with my kit and I confirmed with him that it was an adjustable regulator, so yes, use the first option. Seems to be working fine.

 Scott_

 

Thanks I have a glassjar audio kit too. Now another question about his kits. I have parts that are labeled C##,Just a few L##, and then just ##. Can I safely assume the just ## parts are R? as noted on the circuit board?


----------



## ruZZ.il

Quote:


  Originally Posted by *Liquidretro* /img/forum/go_quote.gif 
_Thanks I have a glassjar audio kit too. Now another question about his kits. I have parts that are labeled C##,Just a few L##, and then just ##. Can I safely assume the just ## parts are R? as noted on the circuit board?_

 

Although you probably could assume that the ## parts are Rs. I'd still keep an eye open. If you have the parts list in front of you, you could pretty easily deduct what's what. Most of the Resistors look the same, as is the case with the caps and inductors. All the inductors actually are the same, and probably come in a single strip. The SMD caps are lighter IIRC. The resistors are all black, and are marked... etc etc..


----------



## srserl

I don't remember having any parts not fully labeled, but yes, the resistors were dark colored and the caps were beige.

 Scott


----------



## Liquidretro

Ok I got the circuit board all populated and now I am moving on to the testing phase. I built the version where IC3 is populated and I plan on plugging it into the usb for power. The driections say to connect a battery and check the 5V and 3V pads. What size of battery do I connect and where?

 Edit I found my answer in a previous post. NVM


----------



## cobaltmute

Does anybody know if I could leave out C31? It looks as if it is just a filter capacitor for the regulator. It went flying out of the tweezers.


----------



## error401

You can leave it out and the DAC should work okay, but I'd still replace it when you get an opportunity.


----------



## cobaltmute

thanks, error401. I'll work on getting one. The Glass Jar kit listed it as coming from Mouser and it is not as easy as ordering from DigiKey for Canada.


----------



## FallenAngel

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_thanks, error401. I'll work on getting one. The Glass Jar kit listed it as coming from Mouser and it is not as easy as ordering from DigiKey for Canada._

 

Are you kidding me!?

 Digikey.ca


----------



## error401

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Are you kidding me!?

 Digikey.ca_

 

I think he meant that Mouser is more difficult to order from in Canada, which is true.

 See if you've got a local electronics shop. Though many of them don't really carry any SMD stuff, that part is about as generic as they come and it might be the one thing they actually have.

 Otherwise substitute DigiKey # 478-3352-1-ND, it's the same part.


----------



## cobaltmute

I didn't explore all the options for shipping but the last time I checked for Mouser they wanted $19US in shipping. DigiKey Canada is $8 flat rate, next day, no taxes or duty (they ship from Winnipeg).

 Thanks for the part number error401. I've got one or two items that I also want to get from DigiKey so it helps. 

 Back to soldering the through holes items...


----------



## cobaltmute

I do have a reasonable electronics shop, but the don't carry a single item that is SMD. 

 Should I be seeing any offset on the output? From OL to OG, I'm seeing 11mv and from OR to OG, I'm seeing about 8mv.

 I did hook it up to my cmoy with input caps, so nothing on the output there, and sound is good from both channels.


----------



## error401

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_I do have a reasonable electronics shop, but the don't carry a single item that is SMD. 

 Should I be seeing any offset on the output? From OL to OG, I'm seeing 11mv and from OR to OG, I'm seeing about 8mv.

 I did hook it up to my cmoy with input caps, so nothing on the output there, and sound is good from both channels._

 

Usually it's just the output caps charging. Connect a load for a few minutes and then measure again with the load connected.


----------



## Wilf

Thanks Alf!

 Received this kit from Jeff Rossel (thanks to you for the service you provide) yesterday, and put it together last night. It worked first time (more to do with ordering the pre-soldered dac chip than anything else!) and left it running overnight.

 Very, very impressed with the SQ. Like others have mentioned, you get a lot of air and space around the instruments, and a good dollop of detail. Massively better than the onboard sound of my Dell D610 (Work supplied), which had a very intrusive sound floor. 

 For reference, I'm listening via a Pimeta with LMH6321 buffers, biased to class A. It's supplied by an off-board dual rail PSU and filtered by an JLH ripple reducer, which makes a HuGe difference.

 Kings X has never sounded so good.


----------



## cobaltmute

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_Usually it's just the output caps charging. Connect a load for a few minutes and then measure again with the load connected._

 

I'll have to try it again later tonite. While testing, I had waited for the offset to come down (it had started much higher), but it seemed to have stabalized at the 10mV level. I didn't think that it would take that long for the capacitor to charge with no load.


----------



## Iniamyen

I hooked up the DAC to my laptop for the first time and I got some really bad sound... It sounded really garbled, almost like static on the radio.

 It works perfectly out of my desktop's USB, so I don't understand what could be wrong. I will check the voltages when I get home today (I forgot to do that) but is there anything else that could be causing this problem?

 In case it matters, the laptop is an old Sager 8790, Windows XP, and I installed the ASIO driver that Jeff recommended (although I don't know anything about ASIO per se.)


----------



## cobaltmute

Check your connector wiring. When I first hooked my up (with alligator leads), I had perfect sound from one side and garbage from the others. Turned out it was just bad connections.


----------



## Iniamyen

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_Check your connector wiring. When I first hooked my up (with alligator leads), I had perfect sound from one side and garbage from the others. Turned out it was just bad connections._

 

I'm certain it's not the connectors (I have it hooked up via alligator leads as well at the moment.) I can switch the USB cable between my desktop and laptop computers without changing anything else, and the sound on the laptop just sucks.


----------



## Heady

I have an AlienDAC which I built quite a while ago and have been using regularly. I loaned it to a friend and it stopped working when he has it. I found that there is now no output from the adjustable voltage regulator.

 Is it possible for the adj voltage regulator to get damaged when the 3.3V regulator is fine?

 Is there anyway to find out if the adj voltage regulator is damaged?

 Thanks.


----------



## FallenAngel

Quote:


  Originally Posted by *Heady* /img/forum/go_quote.gif 
_I have an AlienDAC which I built quite a while ago and have been using regularly. I loaned it to a friend and it stopped working when he has it. I found that there is now no output from the adjustable voltage regulator.

 Is it possible for the adj voltage regulator to get damaged when the 3.3V regulator is fine?

 Is there anyway to find out if the adj voltage regulator is damaged?

 Thanks._

 

5V reg is in no way dependent on 3.3V reg. If 3.3V is OK, your 5V is doing something funky. Just check on the input and output of that reg to check proper voltage.

 First though, check that it's installed properly in the correct direction and without solder bridges or cold joints. Check if it gets hot as well.


----------



## Heady

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_5V reg is in no way dependent on 3.3V reg. If 3.3V is OK, your 5V is doing something funky. Just check on the input and output of that reg to check proper voltage.

 First though, check that it's installed properly in the correct direction and without solder bridges or cold joints. Check if it gets hot as well._

 

Thanks. I know the 3.3V reg is not dependent on the 5V reg. What I meant to say is, if there were some anomaly with the USB power, both would have been affected. But since only the 5V reg is affected, what could possibly be the reason for the failure.

 The DAC worked for more than 6 months now, before this happened.


----------



## a1rocketpilot

Any of you guys happen to have a spare REG101UA-A and REG101UA-33 by any chance or know of where I can get some? All the major suppliers look like they're out.


----------



## tomb

Quote:


  Originally Posted by *a1rocketpilot* /img/forum/go_quote.gif 
_Any of you guys happen to have a spare REG101UA-A and REG101UA-33 by any chance or know of where I can get some? All the major suppliers look like they're out._

 

I'd try Jeff Rossel, first. You are correct that they don't appear to be available anywhere else.

 Alternatively, if you haven't built one yet, there's this version of a PCM2702-based DAC that's pretty close to production:
http://www.head-fi.org/forums/f6/com...layout-190876/


----------



## MisterX

Quote:


  Originally Posted by *a1rocketpilot* /img/forum/go_quote.gif 
_Any of you guys happen to have a spare REG101UA-A and REG101UA-33 by any chance or know of where I can get some? All the major suppliers look like they're out._

 


 I have a few......


----------



## Daveze

I've been using an Alien that was built by someone else but has recently given up the ghost...in only one of the channels. Is there a set of troubleshooting steps I can follow?
 Its been used as a portable DAC, so has seen a fair few bumps. It also has a pair of MCaps as the output, they're rated for like line voltage (off the top of my head) so I would be surprised if its them but could they be the fault?
 Also, a potentially dumb question but if my amp has DC protection, do I need the output caps?


----------



## FallenAngel

If your amp has "DC protection" (i.e. input caps), you don't need output caps on the DAC.

 As for what could have happened, open it up and take a look - see if there are any disconnected wires or shorts, then take your DMM and check if the PCM is outputting voltage on the signal pins (before the output caps).


----------



## MisterX

Quote:


 Is there a set of troubleshooting steps I can follow? 
 

Snag the free version of this----> 

True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software
 (TrueRTA)

 Set the signal generator to output a signal and then trace (measure) the output back to the pins on the PCM2702 with your DMM in AC mode (or oscilloscope if you have one).


----------



## Daveze

Cheers for that. I'll get into it when I get home tonight.


----------



## gurusan

Sorry if this info is easily found, but I looked to no avail....how large is the Alien DAC board?

 This will be my first project and will be stuffing the Alien DAC along with a CMOY into this pictured enclosure, and am just hoping both will fit. There is no battery as the cmoy will be powered by a wallwart.

 The enclosure is 120mm x 100mm x 45mm (L x W x H )


----------



## MisterX

Board size: 45.4mm x 50.5mm. 

 (copy and pasted from the Alien DAC page which is located here----> Alien DAC - Overview )


----------



## gurusan

ok thanks, looks like i have loads of room to play with then


----------



## Daveze

~2.4V on CR, 0V on CL...

 Chip is bust?


----------



## tomb

Quote:


  Originally Posted by *Daveze* /img/forum/go_quote.gif 
_~2.4V on CR, 0V on CL...

 Chip is bust?_

 

If all the connections are good, yep. It's toast.


----------



## FallenAngel

Quote:


  Originally Posted by *Daveze* /img/forum/go_quote.gif 
_~2.4V on CR, 0V on CL...

 Chip is bust?_

 

Either that or there is a short.


----------



## Daveze

Poo.

 I might wait for the gamma...


----------



## Slaughter

Okay so I built this right after the group buy however long ago that was and it didn't work and it got pushed to the side. Now I am ready to try and get it working and would like your help. I get the Windows error message when I plug it in. Now my SMD soldering skills are not great, but it came out okay. All voltages seem to be good. I checked all the pins on the chip with a small pick and magnifying glass and they seem to be soldered down. Maybe I have something soldered wrong.
 Thanks

 Here are the links, the pics are about 200k so you can see my great soldering skills up close. I can upload better shots if needed.
ImageShack - Hosting :: img1100rqd2.jpg
ImageShack - Hosting :: img1101rtv4.jpg


----------



## SmellyEagle

I'm in the process of debugging my first alien dac. It seems to work OK, but its filtering out certain frequencies into the left and right channels. Most noticeable are lyrics--they only come through the right channel. Besides that, the music sounds fairly normal. During construction, I ran into some problems with C32. I put it on the top before realizing it needed to go on the bottom. I had some difficulties removing it, and it may have taken too much heat. I used it anyway as I had no backups.

 If needed, I can post pictures. Looking for a place to start. Thanks.


----------



## tomb

Quote:


  Originally Posted by *Slaughter* /img/forum/go_quote.gif 
_Okay so I built this right after the group buy however long ago that was and it didn't work and it got pushed to the side. Now I am ready to try and get it working and would like your help. I get the Windows error message when I plug it in. Now my SMD soldering skills are not great, but it came out okay. All voltages seem to be good. I checked all the pins on the chip with a small pick and magnifying glass and they seem to be soldered down. Maybe I have something soldered wrong.
 Thanks

 Here are the links, the pics are about 200k so you can see my great soldering skills up close. I can upload better shots if needed.
ImageShack - Hosting :: img1100rqd2.jpg
ImageShack - Hosting :: img1101rtv4.jpg_

 

Well, you don't need C31, but that can't be causing the problem. I can't see anything else from here, but the pins on the PCM look a bit suspect, maybe.

 One way I check mine and it seems to work OK - put one probe of your DMM on the PCM pin as it exists the chip - away from the solder joint. Then follow the trace that pin is supposed to be soldered to, and put the other probe at the end of that trace and see if you get continuity. Check it with the adjacent pins on either side and see what you get, too. If resistance is not zero, but not super-high, either - that pin is probably OK and it's not shorted with the adjacent pins. You can check all of the pins in pretty short order once you get going.


----------



## tomb

Quote:


  Originally Posted by *SmellyEagle* /img/forum/go_quote.gif 
_I'm in the process of debugging my first alien dac. It seems to work OK, but its filtering out certain frequencies into the left and right channels. Most noticeable are lyrics--they only come through the right channel. Besides that, the music sounds fairly normal. During construction, I ran into some problems with C32. I put it on the top before realizing it needed to go on the bottom. I had some difficulties removing it, and it may have taken too much heat. I used it anyway as I had no backups.

 If needed, I can post pictures. Looking for a place to start. Thanks._

 

I don't think the PCM chip can do what you describe, even if it was malfunctioning. It almost sounds as if you have the output wiring mis-wired. Yeah, pics might be helpful.


----------



## SmellyEagle

This was my first time doing SMD soldering, so I'm sure it could have been better. Let me know if you see any wiring mistakes or other misc problems.


----------



## TimmyMac

Anyone have a spare 2702 they'd be willing to sell/ship to me? I'm fairly sure mine is fried.


----------



## SmellyEagle

Well, its not a wiring mistake. I was building 2 at the same time, 2nd one worked without any issues off the bat.

 Problem with the first has been isolated, but not sure if its fixable. Measured OUTL and OUTR. OUTR was around 2.2v, OUTL was around 1.5 and would 'bleed' down to 0. Possible chip is fried?


----------



## tomb

Quote:


  Originally Posted by *SmellyEagle* /img/forum/go_quote.gif 
_Well, its not a wiring mistake. I was building 2 at the same time, 2nd one worked without any issues off the bat.

 Problem with the first has been isolated, but not sure if its fixable. Measured OUTL and OUTR. OUTR was around 2.2v, OUTL was around 1.5 and would 'bleed' down to 0. Possible chip is fried?_

 

It depends on your choice of wire colors. Most people use green for ground. If so, your green wire is on the Right channel, and red is Ground.

 Soldering looks OK from here - very nice macro photography, too, btw.


----------



## cobaltmute

Quote:


  Originally Posted by *SmellyEagle* /img/forum/go_quote.gif 
_Well, its not a wiring mistake. I was building 2 at the same time, 2nd one worked without any issues off the bat.

 Problem with the first has been isolated, but not sure if its fixable. Measured OUTL and OUTR. OUTR was around 2.2v, OUTL was around 1.5 and would 'bleed' down to 0. Possible chip is fried?_

 

Are you checking AC or DC? And is this without load or with load?

 You could just being seeing the output capacitor loading up and starting to filter DC. When I first tested mine it took forever for the output caps to "fill" with no load, but once I out my headphone amp on the end it happened quickly.


----------



## SmellyEagle

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_It depends on your choice of wire colors. Most people use green for ground. If so, your green wire is on the Right channel, and red is Ground.

 Soldering looks OK from here - very nice macro photography, too, btw.
	

	
	
		
		

		
		
	


	


_

 

You know what, I think I did mess that up. I guess thats what you get for trying to finish stuff up at 2am. I hope I didnt hurt the board as I was poking around... towards the end of the night, the left channel just stopped working. Praying it was temporary.


----------



## Jam_Master_J

Just put together a DAC here, can't get it to power up. It's USB powered. Problem seems to be no power is getting to PCM chip. I have AV+ jumpered to +5V. I can light an LED between +5V and G but not 3v3 and G. 

 Of the 4 pins that connect to the USB receptacle only one will light an LED and it is not the one that runs to R13 L13||L14. Do I have a faulty USB cable perhaps?


----------



## SmellyEagle

I might be wrong, but for USB power, I don't think you jumper AV+ to 5V+. Taken from myexposition:

 Power supply. I will refer to the S1 pad nearest to the USB receptacle as S1a and to the other one as S1b.

 * External PS or battery powered. Connect V+ to the AV+ pad and V- to the G2 pad (or S1b and G1 respectively).
 * USB powered. Jumper S1a and S1b or use a SPST switch.
 * USB and PS/battery powered. Use an ON-OFF-ON switch. Connect V+ to one throw, the S1a pad to the other throw, the S1b pad to the common pin, and V- to the G1 pad.
 * Amp powered. Connect the amp’s V+ to the AV+ pad, amp’s V- to the AV- pad, and amp’s ground to the AG pad. 

 On the previous page, I have posted pics of a successfully wired usb powered dac (well, minus OR and OG getting mixed up).


----------



## tomb

He can jumper AV+ to 5+ if he wants _unregulated_ USB power. He would not need IC3 (the REG101-A) in that case, either.


----------



## SmellyEagle

Thanks for the correction


----------



## Jam_Master_J

If I'm not getting voltage at the 3v3 point, I'm guessing I should be looking more closely at my IC2 soldering correct?


----------



## tomb

Quote:


  Originally Posted by *Jam_Master_J* /img/forum/go_quote.gif 
_If I'm not getting voltage at the 3v3 point, I'm guessing I should be looking more closely at my IC2 soldering correct?_

 

Yep - or the chip is bad.


----------



## Jam_Master_J

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Yep - or the chip is bad._

 

Thanks, I just re-flowed all my IC2 joints. DAC got picked up by Windows right away and produces nice sound, all is good


----------



## StanRex

Still using my alien DAC, enjoying it but wondering if this behavior is normal : sometimes, after listening to some music/ playing a game for some time, if I turn off my amp (a headsix) and have no music playing, and I can hear a slight high freq noise (using senn hd650). 

 It doesnt seem to last for a long time), but it kinda worries me, apparently it s a dc offset. I had tried measuring it by plugging a mini to mini ic instead of the senns in my headsix and using my DMM on the mini jack and had gotten pretty high values (2V I believe), but they decreased over time. I suppose it s the capacitors discharging

 what s weird is that it doesnt always happen. But it has me a tad worried. Does such an offset risk damaging my phones? 

 thanks in advance for your answers


----------



## lordvader

Hey all.

 I'm about ready to get building my Alien DAC (been taking my time on other projects !), and have a slight conumdrum.
 I want to put a buffer (Jisbos) after the DAC. Now, the buffer runs off 15V supply, while the DAC wants 5V. I'm thinking of just building a +/-15V supply, and use a resistor to drop the voltage enough for the DAC.
 Thing is, I'm not sure what the current draw of this DAC is, so am not sure what value resistor I should use.

 Any advice ?
 I guess a last resort will be a voltage divider to "ball-park" it, and let the onboard regulator do the rest.


----------



## MisterX

30mA is the max supply current specified in the PCM2702 datasheet. 


 to bad it's so big because otherwise Allied # 879-9999 would make for a very easy power supply for that combo.


----------



## lordvader

Would dropping the voltage to say 7-9 V be OK ? I don't want to put too much stress on the regulators is all.


----------



## pinkfloyd4ever

when paralleling a bunch of film caps to use at the output, like tomb and royewest did with their vitamin Qs, is 330k the best resistor size to use?


----------



## duncan!

Hi,

 What happened to the Alien DAC design thread mentioned in the Alien DAC Overview? I have several questions and hate to replow ground that has probably already been covered. The link to the design thread points to the Head-Fi "For Sale" section. I guess the forums were re-indexed at some point.


----------



## MisterX

I think that thread is here----> 
http://www.head-fi.org/forums/f6/pcm...sion-b-137298/


----------



## tomb

Quote:


  Originally Posted by *duncan!* /img/forum/go_quote.gif 
_Hi,

 What happened to the Alien DAC design thread mentioned in the Alien DAC Overview? I have several questions and hate to replow ground that has probably already been covered. The link to the design thread points to the Head-Fi "For Sale" section. I guess the forums were re-indexed at some point._

 

Yep - a fairly significant event.
	

	
	
		
		

		
			





 Try the search tool - it should get you there eventually.

 EDIT: Looks like MisterX got it for you - too many distractions between typing and posting again.
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *pinkfloyd4ever* 
_when paralleling a bunch of film caps to use at the output, like tomb and royewest did with their vitamin Qs, is 330k the best resistor size to use?_

 

I just used 330K - mostly because I ran all my leads back to the board and that's what was there anyway. I think FallenAngel and Royewest tied their resistors to ground up front with the capacitors. The resistor serves two purposes - to keep the capacitors charged when the circuit is active, and to drain residual charge when it's not. As such, I think the value is somewhat arbitrary - I've seen 50K elsewhere - but unless you have a good reason to use something else, you should probably stick with this value.


----------



## duncan!

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_I think that thread is here----> 
http://www.head-fi.org/forums/f6/pcm...sion-b-137298/_

 

Wonderful! I was searching for all things Alien and didn't catch it. Thanks again.


----------



## duncan!

Quote:


 Looks like MisterX got it for you - too many distractions between typing and posting again. 
 

Well I give you an A for effort anyway. Thanks.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_I just used 330K - mostly because I ran all my leads back to the board and that's what was there anyway. I think FallenAngel and Royewest tied their resistors to ground up front with the capacitors. The resistor serves two purposes - to keep the capacitors charged when the circuit is active, and to drain residual charge when it's not. As such, I think the value is somewhat arbitrary - I've seen 50K elsewhere - but unless you have a good reason to use something else, you should probably stick with this value._

 

ohhh I thought you guys were using extra off-board resistors for some reason. I'm confused; can I just parallel a bunch of Vitamin Q's and connect one end of them to one output cap pad and the other to the other pad (on the same channel of course); just as if it were 1 cap? If so, I guess I'm just confused about how royewest had it originally that didn't work


----------



## tomb

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_ohhh I thought you guys were using extra off-board resistors for some reason. I'm confused; can I just parallel a bunch of Vitamin Q's and connect one end of them to one output cap pad and the other to the other pad (on the same channel of course); just as if it were 1 cap? If so, I guess I'm just confused about how royewest had it originally that didn't work
	

	
	
		
		

		
		
	


	


_

 

Yes, that's correct.

 I think the confusion comes in because of the caps/method used. For instance, I remember seeing FallenAngel's Alien with Auricaps or Mundorf's at one time or another. If you lay the film caps out lengthwise, the far lead is as far away from the board as you can get. In that case, it's easier just to run a ground wire from the board to the end of the output lead of the film cap, then put a regular leaded resistor inbetween. That's what Royewest did also, I believe.

 In my case, I wired up the paralleled VitQ's as if they were batteries. So, all the leads ran back to the board.


----------



## steinba

Me and a buddy wanted to give the Alien kits from GlassJar Audio a shot yesterday, but have run into problems. (Actually, I left all the soldering to my byddy, because he's less afraid of SMD soldering than me) 
	

	
	
		
		

		
		
	


	




 When the boards were populated, one measures correctly on both voltage test points (3.3V and 4.7V if I'm not mistaken), but the other has about 1V on both points. (This is on USB power),

 Both DACs are detected in windows, but the one with the dodgy voltage readings disappear again after a short while. 

 We suspected the solder points around IC2, and tried reflowing those - among others. 

 At one point during the troubleshooting/messing around, there came smoke from - or from underneath - C1. (Uh-oh!)

 Does anybody have any good tips for us about what to do next?

 We haven't tried to play any sound through any of the DACs yet, btw.


----------



## tomb

I think you need to try to take clearer pics - there's not much anyone can tell from those, other than perhaps some cold solder joints. That's a stretch, though. They may look fine when you clear the photos up.

 BTW, you need to jumper S1 or neither board will work.


----------



## steinba

S1 was jumpered after thatshot was taken. I'll remove the pic until I get a better one of both sides of the faulty one,

 Thanks


----------



## SmellyEagle

[/QUOTE]

 Its been a few weeks and I've finally been able to get back to this project. There are a few posts a few pages back that refer to this project, though things have changed.

 Before, I was getting a weird filtering effect going on. I was measuring voltages across the board, and I think I must have goofed somewhere, because now there is no sound coming out of the left channel. When I measure the voltage at (+) CL, there is a slight blip in the meter, but not the ~2.3 I'm expecting. My guess is the PC2707 chip is fried. Does anyone have any other ideas?

 Thanks


----------



## cobaltmute

This is more of a casing question, but anybody know the best way to cut out the square hole for the USB in the aluminum end of a 1455C801?


----------



## steinba

Dremel, I guess.


----------



## Pars

Quote:


  Originally Posted by *SmellyEagle* /img/forum/go_quote.gif 
_Its been a few weeks and I've finally been able to get back to this project. There are a few posts a few pages back that refer to this project, though things have changed.

 Before, I was getting a weird filtering effect going on. I was measuring voltages across the board, and I think I must have goofed somewhere, because now there is no sound coming out of the left channel. When I measure the voltage at (+) CL, there is a slight blip in the meter, but not the ~2.3 I'm expecting. My guess is the PC2707 chip is fried. Does anyone have any other ideas?

 Thanks_

 

Visually it looks like there could be a short between pins 8 and 9. Also 11 and 12. I would take an ohmmeter and ohm out adjacent pins. Also, I would place one probe on the pin right by the chip body and ohm it out to the board trace or pad to verify connection. Do this with as little pressure as possible.


----------



## steinba

Quote:


  Originally Posted by *steinba* /img/forum/go_quote.gif 
_Me and a buddy wanted to give the Alien kits from GlassJar Audio a shot yesterday, but have run into problems. (Actually, I left all the soldering to my byddy, because he's less afraid of SMD soldering than me) 
	

	
	
		
		

		
			





 When the boards were populated, one measures correctly on both voltage test points (3.3V and 4.7V if I'm not mistaken), but the other has about 1V on both points. (This is on USB power),

 Both DACs are detected in windows, but the one with the dodgy voltage readings disappear again after a short while. 

 We suspected the solder points around IC2, and tried reflowing those - among others. 

 At one point during the troubleshooting/messing around, there came smoke from - or from underneath - C1. (Uh-oh!)

 Does anybody have any good tips for us about what to do next?

 We haven't tried to play any sound through any of the DACs yet, btw._

 

Status: There's a short between VBUS/V+ on both regulators and ground., and without the jumper on S1, it's only between VBUS and GND. Seems like C1 was the problem. Possibly dead. Reflowed it anyway.

 Voltages are still not good, and IC3 gets hot. Could a faulty C1 do that?


----------



## Ub3rMario

Alright guys i need help. I read through the directions a ton but i'm still a bit confused, as this is my first DIY other than cables.


 SO i've populated the board with everything except rled/led (my glassjar kit didn't include an LED...? Just a little rled chip i believe), cl/cr, s1 unjumpered, r32 (labeled 5v in its package, it's used if external power is used), and r15/16. (g1 is untouched as well...what is it?)


 I'm going to be using USB power and rca jacks. I'm using it with an Octavart The One desktop amp. So what should i do now? My main concern is cl/cr i'm not sure if i have to use them, and the LED situation. Help please!

 PS: Do you push x1 all the way down when soldering? I left some space because apparently it comes with this little mylar spacer...i didn't know how to use it so i just left about 2mm space from the pcb and soldered.


----------



## ruZZ.il

You almost certainly need to use CL/CR unless your amp has input dc protection. You should still populate them though in case you use a different amp (if you ask, you should).

 S1 is for a switch. If you don't want a switch, it has to be jumpered.

 The LED is not a problem to leave out.. RLED could even be left out.

 G1 is just a ground reference point. You can use it as another ground if you like, or just for measurements relative to ground.

 Don't worry about X1. I don't think 2mm will be a problem. You could always put the mylar spacer onto it (just push it over the pins) and re-do it. 

 The optional '5v' R32 is indeed used only with external power. It will set the voltage closer to 5v rather than the 4.8v that the regulator is set to while using bus power. 4.8v is used cause the reg needs some head room from the input voltage to function properly. 

 You should use CL/CR, so you should populate R15/16.


----------



## Ub3rMario

Alright thank you a ton! Then i'll try to figure out how to test it...i'm a noob with multimeters too haha. i have an old school one i guess that my dad bought at ratshack year and years ago.

 Should i jumper the LED pads and solder on rled?

 (goes off to solder)


----------



## ruZZ.il

Quote:


  Originally Posted by *Ub3rMario* /img/forum/go_quote.gif 
_...

 Should i jumper the LED pads and solder on rled?

 .._

 

NO. leave it open.

 Good luck, and enjoy the music!


----------



## Ub3rMario

Woo ok done soldering hopefully.


----------



## Ub3rMario

Um where do i check the voltages? And how high should it be? Do i connect a 9v batt with wires to somethign?


----------



## LostMoogle

Anyone know where I can find a pic by pic guide for the kit from glass jar audio?


----------



## ruZZ.il

Plug it in to USB.

 Check for voltage between, say:

 G1 -- 5v _ (should read 4.8v if set up properly for bus power) _
 G1 -- 3.3v _( should read close to 3.3v)
_
 your multimeter should be on a V-- setting, at say, 20v or so. _(15v = 20v or so.)_


----------



## Ub3rMario

Ok, i can set my multimeter to 15v, 150v or 1000v to check DC voltage. Is 15 good?

 And what should my results read on the multimeter when checking?


----------



## ruZZ.il

The AlienDAC generally isn't a first DIY project so most builders shouldn't really need a pic by pic. I don't recall coming across such detailed instructions for it.


----------



## rds




----------



## ruZZ.il

Nice! How does that cap combo sound there?


----------



## LostMoogle

Quote:


  Originally Posted by *ruZZ.il* /img/forum/go_quote.gif 
_The AlienDAC generally isn't a first DIY project so most builders shouldn't really need a pic by pic. I don't recall coming across such detailed instructions for it._

 

That is true but the thing is i wouldn't mind a pic by pic for troubleshooting.


----------



## ruZZ.il

1. solder the dac chip.
 2. solder the rest of the smd bits.
 3. solder everything else.

 It's pretty much a thing of convenience. Generally, start with the shorter things, and move from the inside out. It would be much harder to solder the chip in with everything else already in place, for instance.

 but the board is pretty small, and there aren't many pieces, so you cant really get stuck if you put the right things in the right places.

 I suggest going over to Tangents tutorials and going over the SMD stuff (third tutorial). His whole site is pretty informative on audio in general, too. I dont recall what method he suggests for that kind of chip, but I've used flood and absorb(with braiding) succesfully till now.

 Also, chances are that most questions you could come up with have been addressed here already.


----------



## error401

An alternative strategy (that I generally prefer for boards that aren't super dense) is to break down the circuit into functional blocks and build them independently.

 For example, build the power supply first and test it before soldering in the DAC chip. If you do something wrong, you'll minimize the damage and have less desoldering to do. It's a bit trickier sometimes to work around the parts you've installed, but the big stuff like the USB jack and capacitors can usually be left out until last even if you do this.


----------



## Ub3rMario

Alright so i checked the voltage at 3.3 and the reading was about 2.75. At 5v it was about 4. Is this bad since it isn't that close?

 PS: the computer recognized it and installed a driver too.


----------



## pinkfloyd4ever

hmm, my voltages are usually around 3.2 and 4.8, although if your computer recognized it and installed a driver, it may just be your old ratshack meter. Is it analog or digital? 

 I'd say install the ASIO driver that's linked to on the Alien site (assuming you installed CL/CR), hook the alien up to the amp, and if it seems to be working ok, it's likely the meter. Or better yet, go to Harbor Freight (or ratshack if you don't have a harbor freight near you-i just loathe buying DIY stuff @ ratshack) and buy a cheapo DMM. Harbor Freight has em for $5

 Has anyone tried to fit the 6 small Vitamin Q's+Alien in a hammond 1455C80x? Or a pair of 1uf sonicap Gen 1's? (the 200V ones)


----------



## JamesL

I haven't tried putting them in the hammonds, but I have the .22uF vitQ's from beezar, and my caliper reads 20mm(19.99 to be exact) bottom to top, and ~38mm back to front when they're stacked tightly in a pyramid as such.
 OOO
 .OOO

 If you space it out a little bit, you can get a smaller height, and longer length.


----------



## pinkfloyd4ever

hmmm, others more sane than I might say that's a no then (for the VitQ's anyway), but it may be possible if you lay C33 down flat


----------



## JamesL

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_hmmm, others more sane than I might say that's a no then (for the VitQ's anyway), but it may be possible if you lay C33 down flat 
	

	
	
		
		

		
		
	


	


_

 

It depends if you want to use rca jacks on the other end, or if you want to put a single 3.5mm jack on the usb-side. 
 If you're not going to have anything on the other end, I don't think you'll have a problem fitting the vitQ's in there, since the end-vitQ will overlap the pcb a bit, shaving off 5mm off the total.


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_If you're not going to have anything on the other end, I don't think you'll have a problem fitting the vitQ's in there, since the end-vitQ will overlap the pcb a bit, shaving off 5mm off the total._

 

you mean with C33 in the normal vertical position? That's the problem though, I have RCA jacks at the opposite end, you think it'll work with C33 flat? I'm starting to think I may have to go to a sawed-off
	

	
	
		
		

		
		
	


	




 1455C120x


----------



## JamesL

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_you mean with C33 in the normal vertical position? That's the problem though, I have RCA jacks at the opposite end, you think it'll work with C33 flat? I'm starting to think I may have to go to a sawed-off
	

	
	
		
		

		
		
	


	




 1455C120x_

 

Yes, with c33 in the vertical position.
 I have my 6 vitQ's laid out with my alien, and unless you're using some funky jacks that take up no space at all, your chances are extremely slim with RCA jacks.(and by extremely slim, I mean no chance at all)


----------



## Ub3rMario

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_hmm, my voltages are usually around 3.2 and 4.8, although if your computer recognized it and installed a driver, it may just be your old ratshack meter. Is it analog or digital? 

 I'd say install the ASIO driver that's linked to on the Alien site (assuming you installed CL/CR), hook the alien up to the amp, and if it seems to be working ok, it's likely the meter. Or better yet, go to Harbor Freight (or ratshack if you don't have a harbor freight near you-i just loathe buying DIY stuff @ ratshack) and buy a cheapo DMM. Harbor Freight has em for $5

 Has anyone tried to fit the 6 small Vitamin Q's+Alien in a hammond 1455C80x? Or a pair of 1uf sonicap Gen 1's? (the 200V ones)_

 


 Yeah its just an old analog rat shack meter. Thanks for the link i think i'll order one!

 I'm gonna install the driver, and try it out like you say. But first i need to solder on my rca jacks.

 One problem though: I'm unsure how to secure the jacks to the hammond case end cap...it's the jacks that Jeff from glassjar sends you if you ask him for them (i think they're called backmount types...).

 They look mostly like the top picture on this page. Is the tab that sticks out where i'm supposed to solder the ground wire? Do i have one of the skinny nuts on the outside of the end cap and one on the inside to secure it?


----------



## JamesL

Quote:


  Originally Posted by *Ub3rMario* /img/forum/go_quote.gif 
_One problem though: I'm unsure how to secure the jacks to the hammond case end cap...it's the jacks that Jeff from glassjar sends you if you ask him for them (i think they're called backmount types...).

 They look mostly like the top picture on this page. Is the tab that sticks out where i'm supposed to solder the ground wire? Do i have one of the skinny nuts on the outside of the end cap and one on the inside to secure it?_

 

The signal wire should connect to the pin protruding from the back.. the ring with the tab is where you're supposed to connect the ground wire, though technically, you can just connect it to anything. 
 If it's a backmount type, you should have a single nut that screws on from the back.


----------



## Ub3rMario

hmm maybe it isn't backmount then. It has one nut on the front side, with the gold tab behind that, and with two plastic...washers, if you will, behind that. Screws from front.

 Do i place the two washers & the tab inside the case, and the nut outside to secure it?


----------



## error401

The way I use this is, from the inside of the case:

 Nut - Ground Tab - Plastic Washer - Case wall - Plastic Washer - Nut

 The washers are there to isolate the chassis from the circuit, and the ground tab needs to go on the inside so you can solder to it. Usually one of the washers will have a raised lip; your mounting hole should be large enough that the lip fits inside the hole.


----------



## Ub3rMario

Thanks so much error!

 One last q about the washer, should the lipped one be on the inside or outside? or maybe it doesnt matter (which is what i'm thinking).


----------



## JamesL

It doesn't matter.
 The lip is only to keep the insides of the panel edge from making contact with the jack


----------



## pinkfloyd4ever

Quote:


  Originally Posted by *Ub3rMario* /img/forum/go_quote.gif 
_Yeah its just an old analog rat shack meter. Thanks for the link i think i'll order one!_

 

I wouldn't order one and pay as much as (if not more than) the meter itself in shipping...there are several stores in Washington


----------



## JamesL

I just saw sparks fly from my pcm chip as I was testing for shorts.
 Probably charge left from the caps. 
 Crap, that can't be good >_<

 I'm panel mounting the usb receptacle, so I hook up the 5v line, and I get no indication of anything. I was just about to toss it, when the led flickers on! 

 I should've probably drained the caps again before I tested for shorts, cause my meter touched one of the pins, and spark!

 Is there any remote possibility that the chip isn't fried yet?
 Would hooking up D+ and D- do anything?
 Also, I left pins 13/14 and 15/16 shorted when I tested the dac, with nothing connected to the output.


----------



## JamesL

Oh, and pictures...
top
bottom

 Yes, I scratched off some of the green; I got reaaally aggressive with that chip after a while.

 If the third from last pin looks bridged, it's because it is. (I accidentally bridged it after I tested it)

 This was my first smd job.. no tweezers, no flux, fatty solder and tip... I think building this thing was the most frustrating thing I've done in my life, specially since I had to hold down the smd parts with my finger (although it kind of safe-guarded against overheating the parts, it also melted off my fingers!) >=o


----------



## ludoo

I just finished my first Alien with the kit from GlassJar. Everything seems to work: voltages check ok, the Alien is recognized by the OS, and sound comes out of the hp socket. I'm only puzzled by the extra resistor in the kit marked 5V, I did not find a place on the board for it, and there's no mention of it in the schematics. Any ideas?

 It was my first shot at SMD soldering, and it took a while to get the hang of it, especially with my cheap iron, so the joints on the bottom are better made than the ones on top that I did first. My Dremel skills are not great, but I can always get a new tin case as they are so cheap.


----------



## pinkfloyd4ever

it's to use with external power, you don't need it. 

 Cool tin, I wish we could get em like that on this side of the pond


----------



## Pars

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_I just saw sparks fly from my pcm chip as I was testing for shorts.
 Probably charge left from the caps. 
 Crap, that can't be good >_<

 I'm panel mounting the usb receptacle, so I hook up the 5v line, and I get no indication of anything. I was just about to toss it, when the led flickers on! 

 I should've probably drained the caps again before I tested for shorts, cause my meter touched one of the pins, and spark!

 Is there any remote possibility that the chip isn't fried yet?
 Would hooking up D+ and D- do anything?
 Also, I left pins 13/14 and 15/16 shorted when I tested the dac, with nothing connected to the output._

 

The PCM will take some abuse, but hard to say. I rebuilt a users Alien (transferring all parts to a new board), and applied heat longer than recommended when removing the PCM from the old board. It still worked.

 I didn't catch what you meant about D+ and D- until I reread that you are panel mounting the USB jack. If you have proper 3.3V and 5V readings, then yes, I would hook them up and try it out to see if it works.

 Good luck.


----------



## MisterX

Quote:


  Originally Posted by *ludoo* /img/forum/go_quote.gif 
_



_

 

I would think you would want to use the green Capacitors (Muse ES) as output caps, not the blue and gold (Panasonic FC) ones.


----------



## ludoo

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_I would think you would want to use the green Capacitors (Muse ES) as output caps, not the blue and gold (Panasonic FC) ones._

 

Oh right. Late night DIY always sucks, especially if you are a noob. Thanks a lot for spotting it.


----------



## JamesL

Quote:


  Originally Posted by *Pars* /img/forum/go_quote.gif 
_The PCM will take some abuse, but hard to say. I rebuilt a users Alien (transferring all parts to a new board), and applied heat longer than recommended when removing the PCM from the old board. It still worked.

 I didn't catch what you meant about D+ and D- until I reread that you are panel mounting the USB jack. If you have proper 3.3V and 5V readings, then yes, I would hook them up and try it out to see if it works.

 Good luck._

 

oh... my... lord...
 Guess what the problem was.

  Quote:


 Jumper S1a and S1b or use a SPST switch 
 

..
 ..




 ........................................


----------



## lacrossebowe8

I almost forgot to jumper that too. But right before I plugged it in I remembered.


----------



## JamesL

So I'm measuring 4.9v at the input of the reg101ua, but I'm getting only 0.26v out.

 I've checked every single connection around the regulator, and everything looks to be ok. I thought maybe r31/r32 values might be off, but the resistance oscillates
 The markings and my BOM however show 11.81k at r32 and 31.62k at r31.
 I've spent over an hour trying to debug it, but theres not really much circuitry to look at.

 Any suggestions?

 Also, can I temporarily jumper between the AU+ and 5v pad, or will that hurt the components?


----------



## error401

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_So I'm measuring 4.9v at the input of the reg101ua, but I'm getting only 0.26v out._

 

There's almost certainly a short somewhere. Look again 
	

	
	
		
		

		
		
	


	




.


----------



## JamesL

Quote:


  Originally Posted by *error401* /img/forum/go_quote.gif 
_There's almost certainly a short somewhere. Look again 
	

	
	
		
		

		
		
	


	




._

 

I feel ashamed to call myself a diy'er... but oh how sweet victory tastes..

 No short. I just forgot to solder on one of the soic-8 pins.. 
 ADD + caffeine does not make for a safe soldering environment.


----------



## stoned22

is there any degradation to audio quality if i turn down the volume in the windows volume control to a value lower than 100? Cause when i connect it to my AMB Mini^3, its really loud on my ATH-AD700 with even a very small turn on the knob of the potentiometer.

 also, will it cause any problems if i run my desktop speakers (Logitech Z-2300) off the alien dac? since its connecting to an amp within the speakers it should be ok, right?


----------



## ruZZ.il

if you can't hear a degradation, then there aint much of one 
	

	
	
		
		

		
		
	


	



 Shouldn't be a prob with the speakers.


----------



## bhjazz

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_I feel ashamed to call myself a diy'er... but oh how sweet victory tastes.._

 

No worries. You got it finished yourself, right? That's DIY, myman. Pretty surprising little unit, isn't it? And just know that this is more difficult to build than some basic amps around here, so you've done well. Congrats!


----------



## wiatrob

Well, those film cap posts inspired me to make a 'DACApillar...' I found some Vitamin Q-alike .1uFs Sounds good...


----------



## lordvader

Hey all !!!

 My alien DAC lives ! I finally got round to putting the sucker together ! I'm still missing the output coupling caps, so only tested with a multimeter (just made sure that it actually put out an audio signal, not just DC).

 When I've got my caps and case ready, I'll be stoked !

 Question though, I've currently got it setup to run off USB. I'm going to build it to handle both USB and external power. Thing is, with external power, most wallwarts are switchmode supplies (prolly get a 6 or 7V one). Is there any issue putting an SMPS before a linear voltage regulator ?


----------



## cetoole

Quote:


  Originally Posted by *lordvader* /img/forum/go_quote.gif 
_Hey all !!!

 My alien DAC lives ! I finally got round to putting the sucker together ! I'm still missing the output coupling caps, so only tested with a multimeter (just made sure that it actually put out an audio signal, not just DC).

 When I've got my caps and case ready, I'll be stoked !

 Question though, I've currently got it setup to run off USB. I'm going to build it to handle both USB and external power. Thing is, with external power, most wallwarts are switchmode supplies (prolly get a 6 or 7V one). Is there any issue putting an SMPS before a linear voltage regulator ?_

 

Congrats on the successful build. The USB supply is a SMPS, so no, there isnt a big deal using a wallwart smps instead. You wont really gain any performance though, but it could be useful, especially if you are going to be using it with something like a laptop.


----------



## lordvader

OK, last question before I seal up this sucker !

 I'm mouting my caps off board, so I plan to mount the resitors to ground off board too (seems better than running a wire back to the board). Currently, the value is 330K, may a 100K suffice (I have some lying around) ?

 Am I correct in assuming those resistors are to discharge the caps, and prevent switch on/off thumps ?


----------



## ludoo

One of my Alien DACs suddenly has a muted right channel after a few months of use. I checked every solder joint from the PCM2702 to the hp socket and everything tests fine. Is there anything else I should check before trying to change the PCM2702?


----------



## lordvader

Ah ha !!!!!

 It's working !!! Rockin' out with it now !!!!


----------



## Richi

Hi guys,
 My name is Rich and I've just started building my Alien DAC today. Wow, this sucker is difficult for a newbie like me. I have quite a bit of soldering experience but this is my first SMD project and after about 3 hours I managed to get IC2 and IC3 down (the second with much more success) with just one apparent bridge to clear up. I'm nervous that I could have damaged the board or IC2 chip with too much heat so tomorrow I plan to test it out with the multimeter. Does anybody have any suggestions or know of any resources where I can see what to expect across the pins. I hope this chip isn't screwed because after I've finished the entire thing it would be gutting to discover this component or the board here is damaged.
 Cheers.
 Rich


----------



## royewest

Hi Richi,

 Welcome to head-fi (and sorry about your wallet).

 The Alien was my first smd project, too, and while I may just have been lucky, I was surprised at how tolerant the parts were to my ham-fisted soldering, after all the warnings I'd read.

 My advice is to just plow ahead. Use whatever magnification you have available and a strong light to check your work.

Alien DAC - Overview and this thread and related sites can help you with troubleshooting.

 Best of luck!

 __Roy


----------



## Richi

Cheers Roy. The tip about using the light and magnifying glass is great. When I inspect my work it looks like all is ok. I'll keep on with it and keep my fingers crossed. I only have a tight budget and my soldering iron is proving to be a pain (no heat getting to the fine tip) but I will perservere and I have hope.
 I'll no doubt be back with more questions soon enough.
 Thanks again.
 Rich


----------



## royewest

FWIW, one other thing this beginner found helpful is to look at each chip leg under high magnification and see whether you can use a sharp probe to nudge the leg -- if it moves, it's not soldered down. I have an old dissecting micoscope that my old eyes find essential for working at this scale....


----------



## Richi

Hi Guys,
 I've just completed my first Alien Dac tonight. I first tested it with a 9v battery and got 3.3v and 4.68v. It is the USB powered with adjustable regulator configuration so I think this is right(?). I then connected the DAC to my PC and windows recognized it and installed the device. All was good up til here. I then disconnected it and connected my amp and then again the Alien Dac. This time Vista says that the device has malfunctioned and that it doesn't recognise it.
 Obviously I have visually checked it all and all seems fine. WHen it's connected to my amp I can hear a low but audible hiss.
 Does anybody know where I should start debugging this.
 Thanks!!
 Rich


----------



## amb

Windows Vista's USB audio driver is broken (and for that matter, Vista's audio subsystem as a whole is problematic). If you haven't already, apply Microsoft's Hotfix 944681. It might help make things better.


----------



## cetoole

Quote:


  Originally Posted by *ludoo* /img/forum/go_quote.gif 
_One of my Alien DACs suddenly has a muted right channel after a few months of use. I checked every solder joint from the PCM2702 to the hp socket and everything tests fine. Is there anything else I should check before trying to change the PCM2702?_

 

Ludoo, sorry to hear about your difficulty. Do you have a DMM which can read AC voltage? Might be good to try measuring the output, and also make sure there is no continuity from output to ground. Sounds kind of like a burned DAC chip though, which would be unfortunate.


----------



## Richi

Thanks for the tip about the hotfix. Sadly after installing this the problem still persists. Vista recognizes a device but labels it unknown in device manager. I have been through all connections again and checked my work and it all looks ok. Does this problem sound familiar to anybody and would you most likely put this down to a driver/OS problem or could it be a problem with the build of the dac?

 Cheers.
 Rich


----------



## cobaltmute

Quote:


  Originally Posted by *Richi* /img/forum/go_quote.gif 
_Thanks for the tip about the hotfix. Sadly after installing this the problem still persists. Vista recognizes a device but labels it unknown in device manager. I have been through all connections again and checked my work and it all looks ok. Does this problem sound familiar to anybody and would you most likely put this down to a driver/OS problem or could it be a problem with the build of the dac?

 Cheers.
 Rich_

 

I might try reflowing all your joints on the USB connector. You might have a cold joint affecting the pull-up resistor. This would also make sense since in the act of unplugging and plugging in the DAC would would have had mechanical force on the USB jack.


----------



## tomb

Quote:


  Originally Posted by *Richi* /img/forum/go_quote.gif 
_Thanks for the tip about the hotfix. Sadly after installing this the problem still persists. Vista recognizes a device but labels it unknown in device manager. I have been through all connections again and checked my work and it all looks ok. Does this problem sound familiar to anybody and would you most likely put this down to a driver/OS problem or could it be a problem with the build of the dac?

 Cheers.
 Rich_

 

Sorry to say - I have two laptops and a PC running Vista. They never give any hesitation about recognizing an AlienDAC or a BantamDAC.


----------



## wiatrob

Quote:


  Originally Posted by *Richi* /img/forum/go_quote.gif 
_Does this problem sound familiar to anybody and would you most likely put this down to a driver/OS problem or could it be a problem with the build of the dac?

 Cheers.
 Rich_

 

I had this issue with my first Alien build. It turned out I had a solder bridge that I had missed under one of the caps - all your voltages are correct adn there are no bridges between the dac chip legs?

 I went over every passive component on the board with my meter, checking each for 0-ish ohms. Lo and behold a hidden bridge under one...


----------



## Richi

Thanks everybody and thanks Wiatrob, I did a thorough inspection of the capacitors and found a short beneath c12. I've fixed that and now windows recognizes the pcm2702! Great.

 Sadly I'm not there yet because I only have audio from my left channel. Looking at the schematic it doesn't look like there is much going off from the output of the dac, just one resistor to ground and CR. CL and CR both test good.

 Sorry for all the questions but I'm getting there. Any ideas what can cause this mono signal?

 Rich


----------



## Richi

A little more info on my one channel problem:

 I get 2.35v at the OUTL pin and only 0.08v at the OUTR pin. All the components that appear to be related to the right (faulty) channel, C19 and L18, appear to be connected ok and I get the full 4.7v here.

 I'm new to all this but I can't help but think that maybe the PCM2702 is damaged on the right channel. From what I have seen the chip has separate DAC sections for each channel so could this be the problem?

 It's a shame cos the left channel sounds dead nice! 
	

	
	
		
		

		
		
	


	




 Anyway, enough of this for today.
 Thanks again.
 Rich


----------



## tomb

Quote:


  Originally Posted by *Richi* /img/forum/go_quote.gif 
_A little more info on my one channel problem:

 I get 2.35v at the OUTL pin and only 0.08v at the OUTR pin. All the components that appear to be related to the right (faulty) channel, C19 and L18, appear to be connected ok and I get the full 4.7v here.

 I'm new to all this but I can't help but think that maybe the PCM2702 is damaged on the right channel. From what I have seen the chip has separate DAC sections for each channel so could this be the problem?

 It's a shame cos the left channel sounds dead nice! 
	

	
	
		
		

		
		
	


	




 Anyway, enough of this for today.
 Thanks again.
 Rich_

 

So sorry to agree with you, but I've fried a few Alien DACs and the symptoms are just as you describe - one channel loses voltage. Several of us agree that the most likely cause is back-offset in an amp's input connectors (measured on the SSMH) or tiny arcing when connecting to the input of a live amp.

 The only thing that protects the output of the DAC chip itself are the CL and CR coupling capacitors. If they are not fully charged, the DAC chip is completely unprotected. A good practice is to make certain the CL and CR connections are robust and reliable, and that you connect the DAC to USB power a few minutes before connecting it to an amp. This will ensure those capacitors are fully charged and blocking DC spikes that might hit the PCM chip. I typically leave my DACs connected to the PC all the time, so they're always well charged before I ever turn a headphone amp on.

 P.S. Note that the resistors to ground at the coupling caps are 330K - this is a relatively high value for loading coupling caps, probably intended to prevent putting undo current load on a PC's USB line (which can prevent recognition by the OS). However, it means that even for the very small coupling caps used by the Alien (or the BantamDAC), it still takes awhile to charge them.


----------



## Richi

Oh Dear! Sounds like I'll have to build another one. It's a shame the exchange rate isn't what it used to be for us Brits. Man I wish I knew that bit of info before I plugged it in. I have an old amp, a NAD 3020 so I bet this was the cause.
 Thanks for the help.
 Rich and his mono Alien DAC.


----------



## Richi

I just wanted to thanks to the guys who replied to my earlier questions. I got my new kit from Jeff yesterday and its up and running right now. Looks like I did indeed damage the Dac chip on my first attempt. Anyway this one works great and the soldering is much improved from my first effort. All in all a great little project. Time to look for what I can build next.
 Thanks again.
 Rich


----------



## refuzoid

Hello

 I just finished my second Alien Dac and im in the process of breaking in the caps. I always wanted to try the 47uF 6.3V NX-HiQ Black Gates as coupling caps, as suggested in the beginning of this thread. 
 My problem is that after 90 hours of continous break-in the dac still has almost no bass whatsoever. I really want to know if there will be a certain point where the bass will kick in. 
 I heard that the sound signature changes quite a lot within the first 100 hours, but the way i hear it nothing changed in the bass department 
	

	
	
		
		

		
		
	


	




 My idea was to switch to 4,7 uF Sonicaps Gen I´s if the bass doesn´t improve. Any expierence with these?

 Thanx


----------



## tomb

Quote:


  Originally Posted by *refuzoid* /img/forum/go_quote.gif 
_Hello

 I just finshed my second Alien Dac and im in the process of breaking in the caps. I always wanted to try the 47uF 6.3V NX-HiQ Black Gates as coupling caps, as suggested in the beginning of this thread. 
 My problem is that after 90 hours of continous break-in the dac still has almost no bass whatsoever. I really want to know if there will be a certain point where the bass will kick in. 
 I heard that the sound singature changes quite a lot within the first 100 hours, but the way i hear it nothing changed in the bass department 
	

	
	
		
		

		
		
	


	




 My idea was to switch to 4,7 uF Soniccraft Gen I´s if the bass doesn´t improve. Any expierence with these?

 Thanx_

 

Although it's true it takes this long or longer for the bigger Black Gate NX's, I have not experienced it taking anywhere near this long with BG's on the Alien - more like overnight, or something similar. Even then, it's a question of smoothness and detail, not lack of bass (on the small ones).

 I'm wondering if perhaps you have the output connector wired up incorrectly? That can sometimes be mis-interpreted as a lack of bass.


----------



## grendel23

I have 4.7uf NX-HiQ caps on my Alien and Gamma 1 DAC's. They took at least 100 hours to fully break in, but as Tomb said they were harsh and shrill at first, not lacking bass.


----------



## refuzoid

Thanks for the quick reply.

  Quote:


 I'm wondering if perhaps you have the output connector wired up incorrectly? 
 

I dont think so, but the wiring between RCA Jacks and the pcb is a litte long (3cm) and creates a loop inside the case (covering some caps). But then again I dont see how this could affect the bass. Perhaps 47uF is somewhat oversized and takes longer to be broken in?!? 

 How exactly could the wiring be incorrect without creating lots of static or buzzing sounds?
	

	
	
		
		

		
		
	


	




 Perhaps it would help if I´d use different values on the R15 R16 resistors? They form a highpass filter together with CL/CR, right?

 I want to emphasize that just the bass is affected. For instance in a song that has an exaggerated bassdrum the bass that should be a punch is only a slight flat knock. 

 Sorry i really dont see how i can improve the bass here.


----------



## tomb

Quote:


  Originally Posted by *refuzoid* /img/forum/go_quote.gif 
_Thanks for the quick reply.


 I dont think so, but the wiring between RCA Jacks and the pcb is a litte long (3cm) and creates a loop inside the case (covering some caps). But then again I dont see how this could affect the bass. Perhaps 47uF is somewhat oversized and takes longer to be broken in?!? 

 How exactly could the wiring be incorrect without creating lots of static or buzzing sounds?
	

	
	
		
		

		
		
	


	




 Perhaps it would help if I´d use different values on the R15 R16 resistors? They form a highpass filter together with CL/CR, right?

 I want to emphasize that just the bass is affected. For instance in a song that has an exaggerated bassdrum the bass that should be a punch is only a slight flat knock. 

 Sorry i really dont see how i can improve the bass here. 
	

	
	
		
		

		
		
	


	


_

 

No - all I've ever used are 47uf, that's the best quality/size option if you're using Black Gate NX's. I'd say a high number - if not the great majority - of Alien DACs have been built with the BG NX's, so it would easily be a recurring issue if the BG's were at fault - but it's not and they're not.

 If you lose the ground wire completely on the output connector, it can cause buzzing. However, if you swap the ground with one of the channels, it can cause a phase imbalance that will cause a loss of bass. It may even sound more "airy" because it's similar to what a crossfeed filter will do, and some people like the effect in small doses. However, bass is usually non-localized and depends on the combination of stereo channels to provide the most impact.

 Again, it's just a guess, but long wire leads and loops can easily lead to a bit of confusion and transposing the connection.


----------



## tomb

I just had a thought this morning - you wouldn't be attempting to connect your AlienDAC directly to a pair of headphones, would you?
	

	
	
		
		

		
		
	


	




 If so, stop right now.


----------



## refuzoid

Quote:


 I just had a thought this morning - you wouldn't be attempting to connect your AlienDAC directly to a pair of headphones, would you? 
 

No thats clearly not the case 
	

	
	
		
		

		
		
	


	




 I just checked the wiring and everything seems to be in order. So i guess I am back to square one


----------



## tomb

Quote:


  Originally Posted by *refuzoid* /img/forum/go_quote.gif 
_No thats clearly not the case 
	

	
	
		
		

		
			





 I just checked the wiring and everything seems to be in order. So i guess I am back to square one 
	

	
	
		
		

		
		
	


	


_

 

OK - I missed the part about the RCA Jacks. It was late and after the Super Bowl when I had that thought - sorry.

 If your wiring is OK, then I can't explain the rest of it. Even if your amp had a super-low input impedance, 47uf should be gracious plenty to cover any cutoff frequency issues.


----------



## chiefroastbeef

Hi guys,

 I just finished building my alien dac, but sadly, my macbook pro isn't recognizing it, and I don't know where to start the trouble shoot. I've noticed no solder bridges, cold joints, etc. The chip was soldered by Jeff, and mine looks exactly the same as the pictures from other glass jar alien dac owners.

 Here are so pictures, in the mean while I will continue to browse in this thread. Thanks.


----------



## tomb

Unfortunately, I see a few cold joints.
	

	
	
		
		

		
		
	


	







 Before you start worrying over that, however, plug the USB in again. Measure what you get at the 3V3 point and Gnd. Then measure what you get at the Gnd and 5V point. That should tell you if the regulators are working. Most likely, if the PCM chip is OK but your computer can't recognize it, there may be a problem with the 3V3 regulator.


----------



## chiefroastbeef

Thanks Tomb for the response! I tested both points, and got 3.3v at 3v3, and 4.7v at 5v. So I guess something is working. I tried plugging it into my brother's vaio(windows), it picks it up but the device is not recognized.

 I will reflow the joints again. In the mean time, what else should I check?

 And also, do i need to discharge the caps to protect the chips like I need to on the mini3?

 Thank you so much TomB, I really hope my $50 isn't going down the drain!


----------



## chiefroastbeef

Woohoo!! Just reflowed some joints, plugged it into this old pos windows tablet(forgot how slow windows boots up...), and it read burr brown japan! I then verified it on my bro's vaio as well! I then plugged it into my macbook pro, went into the audio set up, and viola! It is there!!
 Thanks TomB for making fun of my cold solder joints! You brightened my day!


----------



## tomb

Thanks for having such a good attitude and not giving up! Glad you got it working!!


----------



## ShinyFalcon

Yeah I feel that a lot of joints on my BantamDAC weren't soldered on properly/cold joints (applied solder to tip). I was thinking of doing a large soldering wick/resoldering adventure when I get a new iron. Do SMD components get damaged by heat easier due to their size/nature?


----------



## chiefroastbeef

In my experience with this alien dac and the mini3(smd op amps), they can take quite a beating. I pretty much raped two smd parts(flux everywhere, melt/scratch marks on the resistor from tweezers and iron) when I thought there were solder bridges. I was convinced my dac wouldn't work, but what do you know, the computer recognized it. I plan on redoing those parts as soon as I can get a hold of those components. As for cleaning the board, I've been having trouble finding pure alcohol, can I use contact cleaner(3in1 brand)?


----------



## Ub3rMario

You can get 99.9% isopropyl alcohol from Fry's if you have one near you. Otherwise just look online i'd say.


----------



## chiefroastbeef

I have a Fry's in Dallas, but I am in Hong Kong right now.. hehe. I did look on Farnell(wow they have great service, overnighted shipping from Singapore for free, and their packaging is meticulous), but none to be found. I will keep looking in chemical stores here in HK.

 What caps are you guys using for cl and cr? I want to try and put something else in it, do I have to stay within a certain voltage and uF range? Yes I am a newbie!

 Thanks


----------



## tomb

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_I have a Fry's in Dallas, but I am in Hong Kong right now.. hehe. I did look on Farnell(wow they have great service, overnighted shipping from Singapore for free, and their packaging is meticulous), but none to be found. I will keep looking in chemical stores here in HK.

 What caps are you guys using for cl and cr? I want to try and put something else in it, do I have to stay within a certain voltage and uF range? Yes I am a newbie!

 Thanks_

 

You can get 91% alcohol at Walmart. It works fine - it's all I ever use. As for contact cleaner, I'm not so sure. It's probably not nearly the solvent that alcohol is. Plus, many of those concoctions actually work by using a spreading type of viscous fluid that's electrically conductive - probably not something you'd want to put on your board to clean it.

 As for output caps, the SOP for the Alien DAC is the Black Gate NX Hi-Q, 47uf 6.3V. However, Handmade Electronics sell some nice substitutes that may work just as well - an Elna Cerafine at 47uf 10V, sometimes referred to as just as good as a Black Gate, but without the break-in period, - or an Elna Silmic II RFS at 47uf 6.3V, a favorite of many Alien builders. Both are very cheap, as is the Black Gate at that size, really (Soniccraft.com or Parts Connexion).

 The ES caps that come with Jeff's kits are very serviceable, but really benefit best from bypassing with a good film cap. That's a bit difficult in the Alien and I wouldn't recommend it starting out - better to just try the different ones I mentioned if you're itching for some improvement.


----------



## chiefroastbeef

Hello tomB,

 I was able to locate some 99.5% iso alcohol here in Hong Kong, in a gallon jug though, hehe. For aournd $19USD, not a bad deal. Is it safe for plastic? I was thinking about perhaps cleaning some other stuff with it since I have so much.

 I will give those caps a try, there are a lot of old school audio stores here in HK that carry the Black Gates, I will give those a try. WOuld changing the other caps to Black Gates as well benefit the sound signature? Or are cl and cr the only ones that matter?

 Thanks for your help brother.


----------



## tomb

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_Hello tomB,

 I was able to locate some 99.5% iso alcohol here in Hong Kong, in a gallon jug though, hehe. For aournd $19USD, not a bad deal. Is it safe for plastic? I was thinking about perhaps cleaning some other stuff with it since I have so much.

 I will give those caps a try, there are a lot of old school audio stores here in HK that carry the Black Gates, I will give those a try. WOuld changing the other caps to Black Gates as well benefit the sound signature? Or are cl and cr the only ones that matter?

 Thanks for your help brother._

 

CL and CR mostly. You can upgrade the other caps with larger, better quality power caps, but results are not nearly as significant as with upgrading the boutique caps at CL and CR.

 There's no point in using boutique, audio-quality caps in the power positions - they won't even be as good. You can easily go as high as 330uf for the regulator caps and 1500 for the large power cap. We use 1000uf and 1500uf for the BantamDAC with great success.

 Probably the biggest difference in the Alien is to go with nice film caps at CL and CR, but this requires some out-of-the-box planning and construction. There's no way you can get film caps on the CL/CR pads on the Alien without wiring off-board leads and perhaps the resistors, etc. Depending on the input impedance of the amp you're connecting to, you may have to get film caps that are very large physically and very expensive. Also, be very careful if you try something like this, because those caps are the only thing protecting the outputs of the PCM chip from getting fried. You should make sure you have secure connections before connecting it to anything if you try it.

 You will have very noticeable improvements by trying some of the electrolytic caps I mentioned earlier, however.


 P.S. The isopropyl alcohol you mention should be plenty safe for the board and parts. In fact, you can use it for immersion when building - prior to installing the electrolytic caps. Electrolytics are solvent-resistant, not solvent-proof. So rinsing a finished board with a toothbrush, etc., is fine, but I wouldn't immerse the whole thing once you have electrolytics on board.


----------



## chiefroastbeef

Thanks for the post Tom, very very informative, I appreciate it!

 I already cleaned the board, I'm sure alcohol was on the electro caps, but the dac works fine. Definitely make a note on that in the future!

 Unfortunately, the shops here in HK that carry Blackgates do not carry the 47uf 6.3v... nor do any of them carry the elna silmic IIs... I googled the parts but came up empty, checked on beezars as well. Would you happen to know where to purchase these boutique parts?

 *edit* I found this site that sells elna silmics, however they only have the silmic in 47uf, 35V, that won't work will it?

 *another edit* this site sells the cerafine and silmic II, but they don't ship overseas.. http://www.hndme.com/productcart/pc/...?idCategory=13

 I saw the pictures of the vitaminq film caps in the earlier posts, definitely a beautiful thing! I do not plan on doing films caps anytime soon, since I have no clue to what i'm doing(let alone finding the parts in HK)!

 Thanks tom.


----------



## tomb

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_Thanks for the post Tom, very very informative, I appreciate it!

 I already cleaned the board, I'm sure alcohol was on the electro caps, but the dac works fine. Definitely make a note on that in the future!

 Unfortunately, the shops here in HK that carry Blackgates do not carry the 47uf 6.3v... nor do any of them carry the elna silmic IIs... I googled the parts but came up empty, checked on beezars as well. Would you happen to know where to purchase these boutique parts?

 *edit* I found this site that sells elna silmics, however they only have the silmic in 47uf, 35V, that won't work will it?

 *another edit* this site sells the cerafine and silmic II, but they don't ship overseas.. Elna RFS SilmicII

 I saw the pictures of the vitaminq film caps in the earlier posts, definitely a beautiful thing! I do not plan on doing films caps anytime soon, since I have no clue to what i'm doing(let alone finding the parts in HK)!

 Thanks tom._

 

Note that it doesn't hurt to get alcohol on electrolytics - it's immersion that may be the problem.
	

	
	
		
		

		
		
	


	




 As for the vendors on those caps - I listed them in the original post where I described those caps. As you found, Handmade Electronics is the source for Elna Cerafines and Elna Silmic II RFS, although Silmics can be had at DigiKey, but not in the size we're talking about. The Black Gates (repeating this) are at Soniccraft.com or Parts Connexion, a Head-Fi sponsor. Parts Connexion is in Canada anyway, so I doubt they will have any issue with international shipping. Soniccraft is in Arkansas, so I don't know about their international policy, but they are so good it's worth a check/call.


----------



## chiefroastbeef

Ahhh, thank you so much Tom, I forgot about Parts Connexion. Will head over there now.

 I promise I won't go scuba diving in a pool of alcohol with my mini3 then! 
	

	
	
		
		

		
			





 I have one more small question, instead of jacks, I soldered my output wires straight to a neutrik plug. There is absolutely no fault in doing this is there? I thought I'd reduce an extra connection and make my setup a little cleaner.


----------



## tomb

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_Ahhh, thank you so much Tom, I forgot about Parts Connexion. Will head over there now.

 I promise I won't go scuba diving in a pool of alcohol with my mini3 then! 
	

	
	
		
		

		
		
	


	




 I have one more small question, instead of jacks, I soldered my output wires straight to a neutrik plug. There is absolutely no fault in doing this is there? I thought I'd reduce an extra connection and make my setup a little cleaner._

 

No - no problem doing that - might even be slightly better. We do the same thing with the BantamCableDAC - outputs are direct to a couple of RCA plugs, not jacks.


----------



## chiefroastbeef

Thanks for the reply Tom, I'm very grateful for your help!

 I have been unable to locate the caps you mentioned, so I'll just hold off for now. Maybe I'll come across them in the future. Can I use a cap with 47uf but at a higher voltage? Say around 25v? I found some of those on ebay.hk.

 I saw the pictures of your swith film caps, what specs are they? I see quite a bit of audiophile film caps in the audio shops here in HK. 

 Thanks again tom.


----------



## tomb

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_Thanks for the reply Tom, I'm very grateful for your help!

 I have been unable to locate the caps you mentioned, so I'll just hold off for now. Maybe I'll come across them in the future. Can I use a cap with 47uf but at a higher voltage? Say around 25v? I found some of those on ebay.hk.

 I saw the pictures of your swith film caps, what specs are they? I see quite a bit of audiophile film caps in the audio shops here in HK. 

 Thanks again tom._

 

If you can tell me what "swith" means, maybe I can tell you which ones.
	

	
	
		
		

		
		
	


	




 Yes, you can use a cap with higher voltage. Again, you need to be careful with the AlienDAC when it comes to larger caps. Once the lead spacing on the board pads is exceeded, then you have an issue with the integrity of the connection (and leaving the DAC unprotected from stray voltages). Sometimes, that causes no issues, but sometimes it does - it depends on the cap.


----------



## refuzoid

Hi
 My new Alien Dac has been working fine for the last month, but now the left channel suddenly goes mute from time to time. When i disconnect the corresponding RCA Jack and reconnect it again the left channel works for a while. Any idea where i might start looking?

 Thanks


----------



## tomb

Quote:


  Originally Posted by *refuzoid* /img/forum/go_quote.gif 
_Hi
 My new Alien Dac has been working fine for the last month, but now the left channel suddenly goes mute from time to time. When i disconnect the corresponding RCA Jack and reconnect it again the left channel works for a while. Any idea where i might start looking?

 Thanks_

 

I suppose this could be interpreted as a "copout" guess, but it sounds like something's loose - jacks, pins on the PCM, etc.


----------



## Curtisbeef

Does anyone have a Recent BOM typed up... from Mouser or Digikey? It would be much appreciated.


----------



## Netdewt

I've never soldered electronics before, but I'd like to try and could use a DAC. What kind of skill level does this thing require?


----------



## nightanole

Quote:


  Originally Posted by *Netdewt* /img/forum/go_quote.gif 
_I've never soldered electronics before, but I'd like to try and could use a DAC. What kind of skill level does this thing require?_

 

Um id stay away. Try the bamtek dac first. It has alot fewer parts and is much easier for a beginner.


----------



## Netdewt

You mean Bantam DAC? That's what I was considering instead after reading some a-b reviews.


----------



## Curtisbeef

Wow I feel stupid, the PCM2704 is not compatible with the PCM2702 is it? 
 I got a PCM2704 as a sample and thought it was compatible but i have everything soldered in and my (Reg 101-A) Gets really hot so i figure i have got a short. So i look up the pinout and realize that its got a different pinout from how the board is layed out then i compaired the PCM2704 to the origional PCM2702 and there a totally different pinout.
 Looks like im going to have to make another mouser order....


----------



## tomb

Quote:


  Originally Posted by *Curtisbeef* /img/forum/go_quote.gif 
_Wow I feel stupid, the PCM2704 is not compatible with the PCM2702 is it? 
 I got a PCM2704 as a sample and thought it was compatible but i have everything soldered in and my (Reg 101-A) Gets really hot so i figure i have got a short. So i look up the pinout and realize that its got a different pinout from how the board is layed out then i compaired the PCM2704 to the origional PCM2702 and there a totally different pinout.
 Looks like im going to have to make another mouser order...._

 

Yeah ... DAC chips are not like opamps - no standard on the pinouts. As you've noticed, even TI's PCM series is different, one to another.


----------



## Matez

Is it an replacement for the Reg101-33 and Reg101-A? Its very hard to get in US with international shipping and almost impossible to get in Europe...

 Or maybe some fellow Head-Fi'er has 2 Reg101-33 and Reg101-A for sale, and is willing to ship them overseas?


----------



## sygyzy

For an axial inductor, should I be looking under:

 Common Mode, Power, or RF?

 Thanks.


----------



## Curtisbeef

WOOT it WORKS!!!


----------



## Curtisbeef

Every now and then my DAC turns stops working and i have to unplug it and plug it back in and it starts working again... its happened 2 times in the hour i have been using it scene built.

 Also when having my amp and head headphones hooked up to it when i plug in the USB it makes a loud pop... i dont know if it supposed to do that... just wondering ...


----------



## Curtisbeef

I fixed the problem that was making it stop working... it was a problem with winamp.

 But now after extended listening i get large periods of Crackling sometimes it just goes away and sometimes it gets so bad i have to unplug it let it sit for a second then plug it back in. what could be the problem...

 Edit: also the Crackling is only in the Left channel Right channel is crystal clear.

 Edit2: Checked the DC offset on the Right channel it stays at 1-2mV but on the Left channel it spikes as high as 4-5mV.. is that bad?


 Thank you


----------



## Curtisbeef

Now my DAC wont even stay on for more than like 30 seconds.... I have no idea why its acting so unpredictably... 

 I pug it in it works Perfectly... crystal clear for 10-30 seconds then all the audio drops out.... and i hear nothing but a low static.

 I really have no idea what the problem could be... anyone out there that can help?


----------



## Toomonoforstereo

I would like to see a design of the alien dac which has seperated analog and digital ground, so that only the digital part is running on usb power. Hopefully this will reduce the need of a low pass filter on the output. For now my amplifier clips on the high frequency noise generated by the alien dac.

 I removed the caps after the reg101 and this helps. 

 It would be interesting if more have the need for this. If so it might be possible to release an update of the circuit board.


----------



## tomb

Quote:


  Originally Posted by *Toomonoforstereo* /img/forum/go_quote.gif 
_I would like to see a design of the alien dac which has seperated analog and digital ground, so that only the digital part is running on usb power. Hopefully this will reduce the need of a low pass filter on the output. For now my amplifier clips on the high frequency noise generated by the alien dac.

 I removed the caps after the reg101 and this helps. 

 It would be interesting if more have the need for this. If so it might be possible to release an update of the circuit board._

 

I think you may be missing a couple of things.
	

	
	
		
		

		
			





 There is no need to separate the digital and analog grounds - they are essentially the same thing. Secondly, the AlienDAC already provides the feature for separate digital and analog power supplies by using the regulators. The 5V reg may be supplied with an external 5V source - 9V battery, whatever.

 Neither of those is what causes the need for the DC coupling caps. The PCM chip itself is designed to be fed with +5V, thereby establishing an internal voltage reference of ~2.5V as analog signal "zero". This means the analog output coming from the PCM chip itself is offset by 2.5V. Unless a second stage is used that can zero out that offset, then coupling caps are required.

 As for the high-frequency noise and your amplifier clipping, I would suggest that you have a problem in how you've built the Alien or how you have it connected to the amp. That is not normal - at all.

 BTW, an updated design to the PCM2702 DAC is the BantamDAC.


----------



## Toomonoforstereo

Ok sorry for not beeing fully clear. The caps I was talking about are the ones direct after the regulators (the panasonics), not the output caps. 

 I'm aware of the dc ofset to remove the need for a dual power supply.

 As soon as I connect a battery as power source the module opperates very unstable. (left and right out of phase)

 The hf noise I measures was in the 2 to 4 mhz range which is not that strange for sigma delta designs, the newer pcm versions have filters build in hence the lower signal to noise ratio of the later ones.

 Has anyone a solution for the sudden white noise periods when running with cool and quiet on?

 Thanks for the name of the updated design I will investigate that one.


----------



## tomb

Sorry, but it still sounds like you may have something messed up in the build. It's true that the output caps are optional on the REG chips, but hf noise up that high is not something I've heard about before. Further, the newest versions of the PCM2702 have _worse_ noise specs, not better. The PCM2702 has a 105 SNR, the PCM2704, 2705, 2706, and 2707 all have 98 db SNR.


----------



## Jam_Master_J

Building an Alien DAC + Pimeta. Do I need the BUF 634 on the DAC if I'm isolating the output jack completely from the case?


----------



## pinkfloyd4ever

The Alien and the Bantam are the same circuit other than a couple of differences in cap values, correct? I know the regulators are different packages, but they perform the same right? Obviously the Bantam's layout is smaller.

 I guess I could've saved some time and just asked: With the same brands and type of caps and resistors, are the Alien and Bantam essentially identical performers?

 Can the Bantam be used with virtual ground amps? I've don't recall reading that it can't, but I remember on the Alien you have to use an additional IC (buffer), and I don't see a place for that 4th IC on the Bantam


----------



## pinkfloyd4ever

bump for my and jmj's questions


----------



## Ashkii21

I have the same question. Can the Bantam amp be used with a virtual ground amp?


----------



## tomb

Quote:


  Originally Posted by *Ashkii21* /img/forum/go_quote.gif 
_I have the same question. Can the Bantam amp be used with a virtual ground amp?_

 

Yes. Absolutely.

 Sorry I didn't see these questions before. The BUF634 option is a _power_ option if the AlienDAC is powered from the amplifier's power supply. There is a grounding conflict if this is done with a virtual ground amp. Being much smaller, the Bantam does not use the various power options available on the AlienDAC - only USB-power is used for the BantamDAC.

_It has nothing to do with how an Alien or BantamDAC connects through the audio connections - that is no different than any other source._

  Quote:


 I guess I could've saved some time and just asked: With the same brands and type of caps and resistors, are the Alien and Bantam essentially identical performers? 
 

Yes, this is pretty much a valid statement. However, we think we've had enough time now to optimize the parts selection for some better performing parts on the Bantam - such as the TPS chips, the output film caps, etc. Also, even though the Bantam doesn't have the different power options available with the AlienDAC, the Bantam's small size allows different building options - such as the BantamCableDAC.


----------



## schubert

I've built an Alien DAC form a Glass Jar Audio kit. I opted for regulated USB power. The voltages tested fine on the bench and at the computer (4.7V at the 5V pad, and 3.3V at the 3V3 pad), the computer recognizes the chip, but I get no sound. Does anyone have any ideas about what I should look at?


----------



## schubert

It works fine now that I cleared all the solder bridges from the main chip. I tried it in a USB 2.0 add-on card - terrifically noisy. A USB hub was better but still noisy. No problems with the computer's main USB ports though, and it sounds great.


----------



## tomb

Quote:


  Originally Posted by *schubert* /img/forum/go_quote.gif 
_It works fine now that I cleared all the solder bridges from the main chip. I tried it in a USB 2.0 add-on card - terrifically noisy. A USB hub was better but still noisy. No problems with the computer's main USB ports though, and it sounds great._

 

Yes, many hubs have questionable quality power supplies (or booster circuits) that add a lot of noise to the analog power output. As you've found out, you're better off using a USB connection that's native to the motherboard.


----------



## eddiewalker

Ugh, I've killed my second DAC, to the same problem as my first. I've worked from GlassJar kits using USB power. I've packaged then both up in the same small Hammonds case using a slot high enough not to short anything, and I've even lined the inside with electrical tape for good measure.

 With both boards, the DAC has worked wonderfully for months, then one side just stops outputting sound. I know there's not much to this thing beyond the main chip, so logic dictates that I'm doing something to kill the PCM2702s.

 I'm proficient with a soldering iron and cant find any shorts or cold joints. Voltage on the 3.3 pad is spot on, and I see 4.7v at the 5v spot.

 Any ideas what it could be? Bad hub power? Anything else?


----------



## cobaltmute

4.7 on the 5V spot is possible (bus power can drop to 4.75v per spec).

 What are you connecting the Alien to?


----------



## tomb

The symptoms you describe sound like the PCM chip is fried, unfortunately. One channel or another will go out, depending on which RCA jack/or similar "shocked" it. What amp have you been using with it?


----------



## eddiewalker

I've moved the DACs around between my SOHA and Millet Max, but mostly used them with my early-90s Yamaha Stereo Receiver (rx-v480, nothing special)

 I understand that there's very little to the Alien besides the PCM, but it was hard enough soldering it on an empty board. I cant imagine trying to replace one on an already-populated unit, and certainly don't want to try before i figure out what keeps killing them.


----------



## tomb

Quote:


  Originally Posted by *eddiewalker* /img/forum/go_quote.gif 
_I've moved the DACs around between my SOHA and Millet Max, but mostly used them with my early-90s Yamaha Stereo Receiver (rx-v480, nothing special)

 I understand that there's very little to the Alien besides the PCM, but it was hard enough soldering it on an empty board. I cant imagine trying to replace one on an already-populated unit, and certainly don't want to try before i figure out what keeps killing them._

 

Hmm ... well, there have been no reports of issues with the amps you mention. However, there have been cases (somewhere in this thread
	

	
	
		
		

		
			





 ) where one channel or another has quit working over time. I'm not sure there's been a consistent explanation but seems like some have had success at re-flowing the solder on the PCM chip.


----------



## refuzoid

Quote:


 However, there have been cases (somewhere in this thread ) where one channel or another has quit working over time. 
 

Yes thats (unfortunately) my Alien Dac. 
 My problem is similiar but in my case the left channel only goes mute for a limited time. Unplugging the RCA jacks for a short period often helps. With a different (but still old) amplifier the dac ran fine for a couple of months, but just recently it stopped for like 20 seconds. 
 Perhaps it has something to do with the impedance of the amplifier, because when i used it with a compact amp with digital stepped attentuator the symptoms where much more frequent. But thats only wild guessing. 
 Btw my PCM was pre-soldered so i doubt its the cause.
 Perhaps it could also be a faulty coupling cap? Dont know if thats possible though.
 Good luck in finding the error.


----------



## aut0maticdan

Hey guys,

 I read all 104 pages and then built my first Alien over the last two nights. It went really well. Everything worked great on first shot. Voltages test correctly, dac detected by mac os, sound is solid out both channels. I'm sure I lucked out a bit, but I also was very careful to test the destination of each pin with a DMM and spotted and fixed all bridges with a 30x microscope (cheapo one I bought from radio shack years ago).

 I finished up pretty late last night, so I didn't get in much sound testing. I'm going to hold off until I case it up and put it to use before I touch on audio quality. I do have an expensive tube-buffered DAC of scott nixon design to compare it to.

 If you are currently looking for parts, I have put together a pretty comprehensive BOM. Keep in mind that my BOM has a lot of extra parts to allow me to try different things (and build at least 3 aliens plus other stuff). Its more my inventory, so use it as a guide rather than a BOM. Definitely compare my parts to Alien DAC - Parts List to decide what you need. In all honesty, you aren't going to save money, time or aggravation over ordering the complete kit from glass jar. Its a great kit. I've marked which pieces come in the glass jar kit on my BOM in orange. I did purchase a kit and used some of the parts in this assembly.

 My BOM:

djw AlienDAC BOM

 I ended up using the Panasonic caps in C23, C33. On my next one I may use the Elnas since they are so cheap at digi right now and I have so many. I couldn't find the ESR on the Elnas, so I used the Lelons from my BOM on C13. They had the lowest ESR I could find.

 I've used desolder braids in the past with very mixed results (mostly radio shack crap), but digikey part: EB1085-ND is absolutely amazing. It sucked up the solder like a wick and required no additional flux. It will be your best friend on the pcm chip or when fixing cold joints. I used a weller ST6 tip (digikey: ST6-ND) on my iron (wlc100 set to between 3 and 4, but closer to 4). A larger tip doing flood and suck would have been fine with the help of the braid I mentioned. 

 My approach was to get a tiny bit of solder on the tip and "swab" it on to each leg of the chip. I then followed up with the braid. Do not leave the solder on the tip for too long before swabbing it on. Keep your tip tinned and clean frequently. Make sure to test continuity to the destination of each leg after you've finished them all (touch very gently to the legs of the chip to avoid pushing it down onto the contact and getting a false positive). I found one leg that wasn't well connected and had to reflow solder to it. I took a similar approach on the first side of each SM capacitor and resistor. This allowed me to position with tweezers in one hand and dab on some solder with the other to lock it in place. I'd then follow up with a more standard solder approach on the second half and follow up with touching up the first (meaning: heat lead and pad with iron and add solder).

 thanks to jeff of glassjar, tomb of here and diyforums and everyone here that had issues and posted them so I could learn from them : )

 -daniel


----------



## Ikarios

Sorry to drag up an old thread, but I need some help. Over the last couple days I put together three identical AlienDACs. Only one of them doesn't detect correctly in Windows. The main problem is that L12 gets extremely hot, hot enough to melt the solder on the ferrite. I searched through the thread but only found a couple instances regarding shorts.
   
  I've taken off L12, double-checked that it itself wasn't causing the short, and triple-checked the pins on IC1. I touched it up just now with some flux, making sure that there weren't any bridges using a stereo microscope at what I'd guess to be 15-20x magnification. I paid especial attention to pin 8, which I think is Vbus. I'm afraid to leave it plugged in for more than 5 or so seconds because I don't want anything else to melt or explode. Anyone have any ideas?


----------



## FallenAngel

Well, check for a short with you DMM from V+ to V- and both to ground.  Perhaps you have something shorting beside one of the regulators.


----------



## Ikarios

Quote: 





fallenangel said:


> Well, check for a short with you DMM from V+ to V- and both to ground.  Perhaps you have something shorting beside one of the regulators.


 

 Where should I check V+ and V-? I checked 5V and 3V3 to ground (the case of the USB jack), 5V gives 3.05KOhm and 3V3 gives 2.64KOhm.
   
  I think L12 is the only component that gets hot. I'm going to try reflowing the solder of the hole that connects the bottom path to IC1 in case there's a short under IC1 that I can't see. All of my other solder joints look okay, though. I can upload pictures when I get home.
   
  EDIT: okay, I just remeasured the bottom two pins on the USB receptacle (looking from the bottom side of the board) and can confirm there's a short between Vbus and GND. I never got a chance to reflow pin 8 of the PCM2702 but I have a feeling that's where my short is. If it's under the USB receptacle L12 wouldn't get hot, right? The Vbus path doesn't look very long...
  do ferrites die if they're exposed to too much heat?


----------



## Ikarios

I reflowed the connection to pin 8 of the PCM2702 on the bottom of the board and reflowed solder between pins 7, 8 and 9 just to make sure the IC wasn't causing the problem. I'm 95% sure there's no bridge under there. I reflowed C1 to make sure that wasn't the problem. Next, checking resistances with L12 removed... ground to negative C2 is ~0.5ohm, to positive C2 is 4.4ohm. Resistance across C1 is very high, increasing in the megaohm range (16-18Mohm). There's no connection between Vbus and ground on the USB receptacle with L12 removed. I'm stumped... does this still indicate a bridge under the PCM2702? Could it be a possibly blown IC? I had some difficulties soldering the pcm2702 on these boards, there's a chance I may have applied too much heat to this one.
   
  EDIT: well, I got it working... not really sure what fixed it, but I desoldered C2 and added a new cap, made another reflow attempt, and slid fine tweezers between pins 8 and 9 to scrape away anything I couldn't see under the IC. One of these things did the trick.


----------



## sbelyo

Whats the short story on performance when powered by the USB bus unregulated Vs. regulated down to 4.8v ?
   
  I'm building one of these to install into my son's BH quickie and I've got all the parts on the way.  Our plan is to power it from the USB bus.  We won't be adding a seperate psu or powering it from virtual ground.


----------



## tomb

Quote: 





sbelyo said:


> Whats the short story on performance when powered by the USB bus unregulated Vs. regulated down to 4.8v ?
> 
> I'm building one of these to install into my son's BH quickie and I've got all the parts on the way.  Our plan is to power it from the USB bus.  We won't be adding a seperate psu or powering it from virtual ground.


 

 Performance with USB regulated is noticeably superior than with unregulated.  That's documented in this thread somewhere, but obviously, it will take some deep searches.  Many people around here can easily attest to the lack of quality in virgin USB power.  I don't mean to get up on a soapbox, but sometimes the primary difference in audio quality with many audio designs is the quality of the power supply.  Its effects should not be under-estimated.
   
  The real question in power options with the AlienDAC is whether to choose the external power option with a separate, regulated supply.  I think the law of diminishing returns is hit in that case.


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## mik000000

Have finished my 1st alien using an adjustable regulator for IC3. I am planning to use it powered from USB. I have tested the voltrage and get 3.3v from the 3.3 pad, but only 3.96v from the 5v pad. I used 31.6k for R31 & 11.5k for R32 and all the joints look good and no bridges i can see.
  any ideas?


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## Jxmatranga

Anyone have any success connecting the alien dac to an ipad via the usb dock connector?  Im not sure if this is the right thread for this but I have searched the site and this thread and haven't found anything.  I just built and alien dac with regulated usb power from glass jar audio.  I know if i plug in a powered usb hub that would probably work but im looking for a battery powered portable solution. Any help would be greatly appreciated.


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## pinkfloyd4ever

Wow. Been awhile since anyone built one of these, huh?
  
 Anyway, does anyone use one with Spotify? I'm using one on an old Dell laptop with Windows Vista Basic. It worked well until very recently, then i started getting this damn "Spotify can't play the current track" error...for every f'ing song I try to play! ARRGHHH
  
 Any ideas?


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## pinkfloyd4ever

Neverrrmind. Not an Alien issue.
  
 Apparently a weird bug just surfaced with a recent update.
  
 I used to have Spotify Premium and let it expire maybe a year ago. If you never unchecked the box for "High-Quality Streaming" in the preferences, you get this error with the most recent version update.


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