# AMB mini3 by hohodiy.com



## xlin58

My sister was in Taiwan until Thursday so while she was there, I told her to order a kit for me. The kit is from hohodiy.com and it follows the amb site exactly except that it includes a set of aluminum faceplates and uses a red LED instead of blue for power. The kit was easy to assemble and a first time solder-er like me was even able to build i without a hitch. 
 Here are some pictures of me building them.







 All unboxed.







 The pcb clipped in. The pcb was surprisingly good quality. I've just solder-ed the op amps on. 




/img156/dsc09429re2.jpg/1/w768.png
 Some resistor etc solder-ed on. EASY!







 There it is. Alll done. BTW the dude didn't send me the screw for the voltage refulator but luckily i found one in y house. So the real screw and nut is smaller. 







 Case, plates, and cord (which i also ordered from hoho. becasuse I am lazy).







 All done with my old ass creative zvm and Beyer dt770. I'm getting a D2. 


 Overall I'm very happy with this kit. It came out looking sharp and it sounds great. The soundscape and balance are high points for me. My only complaint was that the included LED was red not blue .


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## G-man

looks very nice indeed. what's the cost, and do they ship to the UK? the website isnt in english, and required you to join, which i cba to do.


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## LeBuLLeT

Yea how much did this cost?

 Did a little google search and a different forum said that it was less than a $100 dollars.


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## m0b1liz3

That looks very nice with that vol knob and end panels. Is it something that you have to be there locally to get? I wont be in Taiwan for a long time but a friend of mine goes every few months. Can you post more info on the company, where you ordered it from etc?


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## sunnysocket

this one 
Hohodiy.com


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## n_maher

I wonder if this guy has permission to be selling any of the kits that he is.


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## mwofsi

Quote:


  Originally Posted by *n_maher* 
_I wonder if this guy has permission_

 

He seems to think so,
  Quote:


  Originally Posted by *Alvin1118* 
_AMB Mini3 assembled set is manufactured and assembled by hohodiy, Taiwan. hohodiy is the authorized AMB lab dealer/distributor in Taiwan._

 

From Amb Lab Mini3 Headphone Amp - www.hardwarezone.com.sg .

 I'm assuming that hohodiy and alvin1118 are one and the same!


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## sid_

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_I wonder if this guy has permission to be selling any of the kits that he is._

 

Other than for courtesy, does one need permission to resell PCBs?


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## amb

hohodiy has permission from me to resell the boards and make kits, much like glassjar audio does. The guy started with local group-buys for Taiwan DIYers to save on shipping costs and now runs a DIY-oriented blog and website.


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## n_maher

Quote:


  Originally Posted by *sid_* /img/forum/go_quote.gif 
_Other than for courtesy, does one need permission to resell PCBs?_

 

Yes, you certainly do. That board layout is Ti's property, I'm not sure of the status of the MHM pcb and what issues there would be if someone were to use that without permission.

  Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_hohodiy has permission from me to resell the boards and make kits, much like glassjar audio does. The guy started with local group-buys for Taiwan DIYers to save on shipping costs and now runs a DIY-oriented blog and website._

 

I'm glad to hear of this Ti. There are far too many instances of abuse of the information and knowledge that people like you share.


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## sid_

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_Yes, you certainly do. That board layout is Ti's property, I'm not sure of the status of the MHM pcb and what issues there would be if someone were to use that without permission._

 

Ah right, okay. I thought that hohodiy was just ordering PCBs from AMB then reselling them abroad. I didn't realize he was making his own PCBs with the board layout.


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## amb

Quote:


  Originally Posted by *sid_* /img/forum/go_quote.gif 
_Ah right, okay. I thought that hohodiy was just ordering PCBs from AMB then reselling them abroad. I didn't realize he was making his own PCBs with the board layout._

 

No, hohodiy's Mini³ boards are genuine, official boards from me. It does appear that he uses a custom case rather than the standard Hammond.

 Full kits have their place, but I feel that the DIY experience would be enriched by including the parts selection and collection process, rather than having someone else spoon-feed you the whole package. The latter is easier, but you don't learn as much.


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## m0b1liz3

Quote:


  Originally Posted by *sunnysocket* /img/forum/go_quote.gif 
_this one 
Hohodiy.com_

 

Did you actually go to the site? It says under construction when you go to select english.


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## xlin58

I am Taiwanese but born in the US. I had my dad help me out haha. I agree with amb that collecting the parts etc is better but I dind't want to wait for another shipment to come in to mouser for a resistor and it was cheaper this way. Also I didn't have time since I'm being shipped off to college soon.


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## keyid

I just did one of my first parts selection for ck2III, it took about a week to read through all the info on headwize, collected other people's BOM, and read up on different configs for gain, input / output transistors and in the end I took AMB's suggested BOM. Through all that I did wish there was the easy button and jeff still had the kits, not sure how much info I gained. I do know I would had a horrible weekend if I didnt catch alot of ordering errors. I guess once completed I will know if all that was worth the trouble, the ends and the means. 

 btw AMB hope my ck2iii board and matching jfets come soon


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## Gautama

Quote:


  Originally Posted by *keyid* /img/forum/go_quote.gif 
_I just did one of my first parts selection for ck2III, it took about a week to read through all the info on headwize, collected other people's BOM, and read up on different configs for gain, input / output transistors and in the end I took AMB's suggested BOM. Through all that I did wish there was the easy button and jeff still had the kits, not sure how much info I gained. I do know I would had a horrible weekend if I didnt catch alot of ordering errors. I guess once completed I will know if all that was worth the trouble, the ends and the means. 

 btw AMB hope my ck2iii board and matching jfets come soon 
	

	
	
		
		

		
			



_

 

Sorry to burst your bubble, but Jeff _does_ still offer kits. He doesn't have them on his website but if you email him he still sells them. I just ordered mine


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## pabbi1

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_Full kits have their place, but I feel that the DIY experience would be enriched by including the parts selection and collection process, rather than having someone else spoon-feed you the whole package. The latter is easier, but you don't learn as much._

 

I so agree - developing and provisioning the BOM is the highlight (or at least the most optimistic part) of all my builds. This is also where you make a decision to live with design / parts choices.


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## keyid

I emailed him couple weeks ago and didn't get an answer so I took it as a silent no. Oh well but no bubbles burst. 

  Quote:


  Originally Posted by *Gautama* /img/forum/go_quote.gif 
_Sorry to burst your bubble, but Jeff does still offer kits. He doesn't have them on his website but if you email him he still sells them. I just ordered mine 
	

	
	
		
		

		
		
	


	


_


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## nickyboyo

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_No, hohodiy's Mini³ boards are genuine, official boards from me. It does appear that he uses a custom case rather than the standard Hammond.

 Full kits have their place, but I feel that the DIY experience would be enriched by including the parts selection and collection process, rather than having someone else spoon-feed you the whole package. The latter is easier, but you don't learn as much._

 

 Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I so agree - developing and provisioning the BOM is the highlight (or at least the most optimistic part) of all my builds. This is also where you make a decision to live with design / parts choices._

 

Unfortunately for us folks living in Australia, access to a decent supplier that is close enough to visit yourself, or an online supplier that doesn't charge through the roof postage fee's are non existant.

 Dick Smiths or Jaycars just don't stock the goods you folks specify. I have made do with components i can source locally, and compared to these kits you can buy, the final product is sonically way behind the full kit's some folks are offering.

 I wish it wasn't the case, but unfortunately it is just the way it is. You folks in USA, Canada etc should count your component access blessings


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## kipman725

the BOM is where I watch my wallet bleed.... I have no idea how these kits are so cheap every time I build anything it goed hugley over budget!


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## mars9tw

Quote:


  Originally Posted by *nickyboyo* /img/forum/go_quote.gif 
_Unfortunately for us folks living in Australia, access to a decent supplier that is close enough to visit yourself, or an online supplier that doesn't charge through the roof postage fee's are non existant.

 Dick Smiths or Jaycars just don't stock the goods you folks specify. I have made do with components i can source locally, and compared to these kits you can buy, the final product is sonically way behind the full kit's some folks are offering.

 I wish it wasn't the case, but unfortunately it is just the way it is. You folks in USA, Canada etc should count your component access blessings 
	

	
	
		
		

		
		
	


	


_

 

HoHoDIY can ship your package to Australia, the postage is about 13 AUD, here is the rate
http://www.hohodiy.com/express-post.aspx
 Although the English website is under construction, you still can mail him to place the order.


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## G-man

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I so agree - developing and provisioning the BOM is the highlight (or at least the most optimistic part) of all my builds. This is also where you make a decision to live with design / parts choices._

 

Although i agree with what you say, there is a significant cost to that to most people outside of the USA. i mean i sourced all the parts for my Millet starving student, and that was 60 pounds without the power supply, or the tubes/sockets, both of which i will have to get from the usa. Even though i used sightly better and upgraded parts, even taking that into account the price is 2 times as much. And this is for the cheapest (well one of them) build around. if i decide to (and i won't, but this is just an example) do it for something like the bijou, i dread to think how much extra i will have to pay.


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## alvin1118

multi languages site www.hohodiy.com site will be up by this week.

 stay alert


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## JamesL

The panels are no doubt customized, but I wonder if the extrusion is custom-made as well. The corner screws looks nicer than the 2-screw hammonds, and I'd buy a couple if there was a stock-model.


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## insyte

Quote:


  Originally Posted by *alvin1118* /img/forum/go_quote.gif 
_multi languages site www.hohodiy.com site will be up by this week.

 stay alert 
	

	
	
		
		

		
		
	


	


_

 

That's good to hear


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## steinba

What makes these kits different from the ones available at Glassjar Audio?


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## insyte

english now available, just checked their site... unfortunately some of the product names are still in chinese and im not sure what currency the prices are in (NTD)?


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## alvin1118

Hi,

 Yeah, finally, hohodiy is up with English, Chinese, Singapore, and Malaysia version!

 Please view the Singapore version at the current moment, English site is under maintenance 
	

	
	
		
		

		
		
	


	




 Regards,
 Alvin, hohodiy S'pore & Msia Division
 msn: alvin1118@hotmail.com


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## nsx_23

I wonder how much the kit it shipped to Australia.


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## DaMnEd

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_I wonder how much the kit it shipped to Australia._

 

At max. 2480 TWD aka 106 AUD.

 It will be less because the prices for the shipping on the page are for 1kg, so once the actual shipping is calculated it will be less than quoted price (530 TWD by EMS, less if you go for normal, slower postage), the kit does not weigh 1Kg, nowhere near.

 I purchased a kit a few months back, great price.


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## nsx_23

Hmm, looks like I should build one once I get some sort of magnification aid so I can see solder the op-amps properly. 

 Should I order extra op-amps just in case?


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## chiefroastbeef

Getting old are we?


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## chiefroastbeef

I'm about to order the mini3 kit myself as my first diy amp, it is so cheap! Plus I am in HK, so shipping is quicker than glass jar.

 Just wondering, are there anything worth upgrading? Like capacitors and such?


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## nsx_23

Woot! Just ordered a kit from hohodiy.

 Can't wait to smell the solder fumes. Might go and pick up a helping hand with magnifying glass, some 0.015 solder and flux first though. I'm slightly worried my cheapo Nicholson soldering iron might not be fine enough for the op-amps though. Already have some good tweezers at home, so they should come in handy. 

 Chiefroastbeef, did you use any flux with yours?


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## chiefroastbeef

Oh definitely pick up a helping hand and mag. glass. I did all the soldering, both my mini3 and alien dac with my cheap $8USD iron. But I'm thinking about getting a station, though I'm not sure if I will be in this diy for the long term.

 You should also pick up a bottle of pure alcohol and clean the board after you are done. Mine was a mess, flux everywhere for a couple of weeks before I was able to locate some pure alcohol. I finally found some, drowned the board in alcohol(don't dunk the electrolytic caps), and scrubbed it with a toothbrush. Man it looked beautiful and clean.

 The solder I use already has a flux core, so I didn't need an extra tub of flux. Just remember to clean the tip often with the sponge.

 If you want, I can take some detailed photos of my board, so you can check your work with it. I'd look at the pictures of the mini3 board I've found on the web, and compare mine against the one in the picture.

 For the op amps, like most have mentioned, do this:

 1. Put solder on one of the op amp pads on the board. 
 2. Use tweezers to position the op amp, solder the leg to the pad.
 3. Do the rest of the legs, making sure the legs touch the silver pads on the board


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## nsx_23

Yep, some detailed pics would be cool to check op-amp positioning. The SMD op-amps are what worry me; The through-hole stuff I've done before, so that is fine. Might also order a power adapter from them as well (Only $8AUD, so why not 
	

	
	
		
		

		
		
	


	




). Taiwan is 220V/240V, no?

 I'm currently trying to read as much of the Headwize mini3 thread, and am studying the AMB mini3 website silkscreen and BOM to understand where all the parts go. 

 Damn the helping hand is expensive though......


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## amb

Taiwan is 115V 60Hz.
 Btw, the rosin core in the solder is not really sufficient for SMD work. I strongly recommend getting some liquid flux (either bottle or a flux pen). It will make your job a lot easier.


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## chews89

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_
 Damn the helping hand is expensive though......_

 

I went to Dicksmith the other day and the helping hand there was on special so i got one for $12.99AUD. Might be the same for melb


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## nsx_23

Hmm, I think I shall give Dick Smith a visit tomorrow morning on the way to the gym. 

 Thanks AMB. I always thought Taiwan was 220V for some reason. The sales rep at hohodiy said that they had a transformer that worked, but I fired off another email to them to make sure its compatible for 240V.

 Got any good construction tips? I think I'll take my time with this one, but should probably get it done in 1 day. The SMD soldering tutorial video looks so easy....


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## Kitarist

The kits looks nice but when you count the duty fees + tax + shipping its not really a deal anymore


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## chiefroastbeef

Hong Kong has no customs tax, woohoo, it was a deal for me!


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## jamess71

They have some cool stuff. 






 What is this? It looks like an ALPS pot but what is the circuit with it??


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## chiefroastbeef

It is the Grado RA-1 clone, they offer this amp with a dac designed by Neo(I assume he is from Taiwan as well, and no the main character in the Matrix).


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## nsx_23

Quote:


  Originally Posted by *Kitarist* /img/forum/go_quote.gif 
_The kits looks nice but when you count the duty fees + tax + shipping its not really a deal anymore_

 

I haven't been slapped with custom fees as well.

 The RA1 clone looks interesting. I wonder if its difficult to construct. Sent them an email to get more info about it (e.g. RCA/mini IO, power source) since I might build one.


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## nsx_23

Here's a high-res shot I found on google 
http://blog.neochen.com/pic/06051829.jpg

 EDIT: Comprehensive construction tutorial on hohodiy blog: http://blog.neochen.com/article.asp?id=66

 Heck, there's a comprehensive construction tutorial for the mini3 kit. Hurray for being able to read Chinese! http://blog.neochen.com/article.asp?id=486

 I'm going to order one. Not too expensive (heck, at $14AUD, I'll just buy one less car magazine for the month 
	

	
	
		
		

		
		
	


	




), and looks like a simple and fun project. I'm going to do as much DIY as possible before uni starts.


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## nsx_23

Right, just got the kit this morning.

 SMD soldering wasn't too hard, just took time. I'm still not sure how to check whether the joint is any good though.

 What is pissing me off at the moment is that after all the SMD was done, the holes for resistor R1L were not drilled out, and I have no drill bit that small. Actually, "pissing me off" is a big understatement; This build could've been finished today, and I could've been enjoying sweet music 
	

	
	
		
		

		
			





 I sent hohodiy an email, but I'm wondering what they will do since the op-amps are already on the board.


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## amb

nsx_23, that's not possible. The boards are supplied by me, and all holes are pre-drilled and through-plated (to connect between the two copper layers). You probably allowed solder to flow into the hole. The fix is to heat the pad and insert a stainless steel pin through the hole to work the solder out. Solder will not stick to stainless steel, and you need something that won't bend easily. Do not drill the hole or you'll ruin the through-plating.


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## nsx_23

I'm not too sure if its solder, since everytime I poke my soldering iron at the spot it doesn't "flow" like solder...


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## amb

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_I'm not too sure if its solder, since everytime I poke my soldering iron at the spot it doesn't "flow" like solder..._

 

Due to the through-plating, once there is solder in the hole it won't really "flow" and would just stick to the plating unless you work it out.


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## TzeYang

simplest method is to flow more solder onto it, forming a bigger blob. Then work your way out with the soldering pump.


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## nsx_23

Right, managed to clear it out.

 Thanks guys! Once again I've proven just how much of a noob I am 
	

	
	
		
		

		
		
	


	




 Let the build continue. Can't wait to hear this baby sing. 

 Is there a good way to check whether my SMD joints are ok? I checked with my helping hand's magnifying glass that there are no solder bridges between the op-amp pins, but I'm not too sure how to check for a cold solder joint.


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## MisterX

Quote:


 Is there a good way to check whether my SMD joints are ok? 
 


 I would strongly suggest that you read the instructions. 
	

	
	
		
		

		
		
	


	



The Mini³ Portable Stereo Headphone Amplifier

  Quote:


 Use your multimeter and check the resistance between each pin of the opamp and the pad to make sure you don't have a cold solder joint (i.e., your meter should read close to zero ohms). Also check continuity between adjacent pins for solder bridges (meter should read infinity). 

 Repeat the above procedure for the U4 opamp. When you are done with the opamps, use a Q-tip and isopropyl alcohol, or specialized electronics flux remover to clean off the flux.


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## nsx_23

Righto, all my readings from the multimeter say 1.


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## chiefroastbeef

Glad everything is going well! I laughed at the "no hole in R1L." I'm happy that you didn't drill through it as well!

 Are you almost down with it?


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## nsx_23

Hang on, I just double checked with my multimeter, and I'm getting some readings between pins.

 However, I reflowed the joints many times, and they seem fine....


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## MisterX

What reading do you get when you touch the two meter probes together? 
 (not all meters will read zero ohms all of the time, especially cheap ones with crappy probes)


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## nsx_23

It sort of flickers between 1 and then some large reading.


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## chiefroastbeef

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_What reading do you get when you touch the two meter probes together? 
 (not all meters will read zero ohms all of the time, especially cheap ones with crappy probes)_

 

Don't diss the people(like myself) with crappy probes, it is the best we can do.


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## MisterX

OK, I think it's a safe bet to assume that a couple of ohms here and there is not an indicitaion of a problm then. 
 I also think it's time to move along and start installing some resistors. 

 Just don't try to be funny and install them on the wrong side of the board like someone I know did. 
	

	
	
		
		

		
		
	


	




http://i23.photobucket.com/albums/b3...s/IMG_2674.jpg


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## MisterX

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_Don't diss the people(like myself) with crappy probes, it is the best we can do._

 

Do you have any more asinine comments to add or are you done now?


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## nsx_23

Righto, I'm finished! I have no power adapter on hand at the moment, so I can't really test the charging circuit. I wonder if its possible to make a Corda XXS/Headsix style rear plate to make swapping in batteries easier. 

 I'm getting sound out of the amp. Maybe its my ears, but it seems to sound a bit unrefined at the moment. I'll give it a better listen to see if its a construction issue or maybe just my ears being picky as usual.

 Oh yeah, I couldn't manage to get a screw for U2. Is it ok to leave it unscrewed and just folded flat down?


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## chews89

Dude, where are the pictures?


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## nsx_23

I'm too busy enjoying the mini3 at the moment. I'll post some later 
	

	
	
		
		

		
		
	


	




 It looks like the one in the pics on first post.


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## chews89

Haha fair enough.

 How much did it cost in total to ship to Aus? Do you reckon someone like me(who only just finished a cmoy), would be able to tackle a mini^3?

 Ohyeah, I just realised you finished it in only 2 and a half hours or so! Nice!


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## Ishcabible

nsx23, what kind of caps are used in the kit?


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## chiefroastbeef

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Do you have any more asinine comments to add or are you done now?_

 

Relax buttercup. 
	

	
	
		
		

		
		
	


	





 Post some pictures please!

 Are you using it with line-out? And just curious, how does it compare to the soundrigor(go petite)?


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## nsx_23

Wow, question overload.

 chews89: Its around $100AUD shipped express post to Australia. Yes, I think it is actually rather easy to build. The SMD stuff really wasn't hard (Heck, I didn't even use the helping hand); Just be generous with the flux and it'll be fine. Also, have a look at the hohodiy blog pages I linked to earlier. Even though you might not be able to read chinese, the pictures are excellent, and were very helpful for my build. 

 Ishcabible: The caps are Panasonic FM caps. My small issue is with the 0.1 caps; The leg spacing is too wide for the PCB, so it doesn't go all the way in. Its a small issue though, and clearance isn't a problem anyway. 

 chiefroastbeef: Yes, I'm using it via Line-out with my iRiver H332. Absolutely brilliant sounding amplifier by AMB! I haven't heard the soundrigor in a long time, so I can't give a fair comparison right now. I think it sounds kind of like a blend between the D2 Boa and XXS I have. 

 I had a look around the house just then. I have a laptop charger which has the right plug, and its 19V 4.74 output (I'm assuming its DC). Would this work?

 Now, by request:


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## chews89

Looks pretty sweet 
	

	
	
		
		

		
		
	


	




 Nice work


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## chiefroastbeef

Very nice, looks just like mine!

 I'm not sure if the power adapter would work, the voltage is right, but you need 300mA or more I believe, mine is rated at 400mA.

 If you were still in HK, I could have gotten you an adapter, Shum Shui Po's street vendors sell thousands of old power adapters, of all specs and sizes.

 Enjoy listening to it!


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## nsx_23

Sounds pretty sweet too 
	

	
	
		
		

		
		
	


	




 You should consider this as your 2nd project after the CMOY.

 I decided to try my laptop adapter anyway (its 4.74A, not ma), and everything seems ok at the moment.


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## chiefroastbeef

Quote:


  Originally Posted by *chews89* /img/forum/go_quote.gif 
_Haha fair enough.

 How much did it cost in total to ship to Aus? Do you reckon someone like me(who only just finished a cmoy), would be able to tackle a mini^3?

 Ohyeah, I just realised you finished it in only 2 and a half hours or so! Nice!_

 

You are definitely ready for the mini3, the mini3 was my first amp, and I had no trouble building it. Have fun!

 Do you plan on building a DAC now NSX?


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## nsx_23

Well, hohodiy has the neomini digiamp dac/headphone amp kit which looks pretty interesting, so I'm considering that.

 I also built the Grado RA1 clone kit today, but I need to find an enclosure and buy some 9V battery clips before I can test it. Took 5 minutes to put together, so I'm not expecting much....

 Gamma1 would be interesting to look at, but that might be a bit complicated.


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## chiefroastbeef

I thought about the gamma, but thought the alien will be sufficient for me. I think my next project will be a tube amp.

 Please let me know how the RA-1 compares, if it is half decent, I want to get the neo mini for my brother.

 Thanks.


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## amb

RA-1 clone ~ cmoy with an old NJM4558 opamp


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## nsx_23

AMB, do you think a full config gamma 1 is out of my reach?


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## nsx_23

Quick question: Does the battery charging LED for the mini3 go off once the battery is fully charged?

 I left my mini3 plugged into the laptop power adapter (19V DC, 4.71a output) for the whole of last night, and the LED still hasn't gone off this morning. Using a BTY 280mha 9V battery http://www.dealextreme.com/details.dx/sku.6390 .

 Speaking of batteries, who stocks the 270mha GP batteries?


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## Nemo de Monet

No, the LED stays on; the charger is basically an always-on trickle charger, not a "smart" charger.


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## amb

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_AMB, do you think a full config gamma 1 is out of my reach?_

 

Only you could answer that for yourself. The γ1 has a few more SMD parts than Mini³, and a couple of them have closer pin pitches, but if the opamps on the Mini³ was easy for you, then perhaps the γ1 is do-able. The only way to know is to try it.


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## nsx_23

Quote:


  Originally Posted by *chiefroastbeef* /img/forum/go_quote.gif 
_I thought about the gamma, but thought the alien will be sufficient for me. I think my next project will be a tube amp.

 Please let me know how the RA-1 compares, if it is half decent, I want to get the neo mini for my brother.

 Thanks._

 

Hopefully I'll have the RA1 cased today once I go pick up a few more bits and pieces, so hopefully I'll have impressions soon.

 AMB, is the BB chip difficult to solder on the gamma 1? I didn't find the op-amps too hard for the mini3, but I feel that my Nicholson iron might not be fine enough for more delicate work. Maybe I should invest in a good station?


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## amb

A temperature controlled soldering station with at least a couple of different tip sizes is always a good investment if you plan to do more DIY work. If you haven't watched the SMD Soldering 101 video that's linked from both the Mini³ and γ1 websites, please do. Both websites also describe the recommended soldering techniques.


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## nsx_23

Yep, I watched that video before I did the mini3. 

 Hmm, I wonder if there are any kits for the gamma 1 out there.


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## amb

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_Hmm, I wonder if there are any kits for the gamma 1 out there._

 

No there isn't. I have made the γ1 website parts list page as easy to follow as possible, so you should be able to source all your parts without difficulty.


----------



## nsx_23

Right, just finished casing my RA1 clone.

  Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_RA-1 clone ~ cmoy with an old NJM4558 opamp_

 

If thats true, then this thing sounds like a CMOY on crack. It pairs really well with my Grado SR60: Aggressive, punchy bass and very sharp vocals if a bit lacking in refinement. Rage against the machine and audioslave sound fantastic out of this amp, and Norah Jones and Diana Krall aren't too bad either. 

 Either way, it certainly isn't a bad kit for the cost. Please excuse the crap caseworking/wiring 
	

	
	
		
		

		
			





 Here's what I'm listening to at the moment:






 And some shots of the amp:
















 My local electronics store seems to be out of everything at the moment, including switches, so I'll have to wait on that.

 Now I'm scratching my head over what to build next. Damn this DIY thing is addictive.


----------



## j2kei

does the hohodiy mini3 kit come with front and back plate? also, where do you guys get the voltage regulator screw/bolt?


----------



## alvin1118

yes, hohodiy mini3 Kit comes with the front and back plate. screw and bolt can be purchased from electronic components shop


----------



## nickyboyo

nsx, great work on the RA-1 clone bud. Ok it looks a bit like a bowl of spaghetti at the moment. but it works and it's kicking it with the Grado's. I'm sure with a bit of thinking and a lot of luck with the casing your RA-1 will be top drawer ( i say luck only because i am very lucky in finding old boxes and managing to put amp circuits into them ). 

 Great work, i am more interested in making this amp compared to the mini3 kit.


----------



## nsx_23

Well, it isn't expensive and takes like 5 minutes to put together. I say give it a go! I'm pondering if a bantam DAC and this could be built and go into the 1 enclosure...

 I'll go past Jaycar tomorrow on the way to uni to pick up a power switch (local dick smith is absolutely rubbish, and has almost nothing in stock). 

 I might just leave it in the current case though since I hate caseworking with a passion. I just seem to suck at it for some strange reason. Having said all this, a custom wooden box might not be a bad way to go. Wanna make me something nickyboyo? 
	

	
	
		
		

		
		
	


	




 j2kei, I didn't even bother with the screws on the mini3, and it works fine. The mini3, without a doubt, is a great little amplifier. I'm loving mine.


----------



## ericj

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_RA-1 clone ~ cmoy with an old NJM4558 opamp_

 

NJM4556 actually. 

 The 4558 is really only sensible in things like guitar pedals, at 1V/uS. If you have truly old JRC rather than NJM branded 4558's you can sell them at inflated prices to musicians, who spin bizarre lore about the tone of this old jellybean and think it sounds different if it came out of the same flippin fab 10 years later. 

 The 4556 is still slow at 3V/uS but has the added bonus of being able to dump 70mA into a load. Which is impressive for a chip that costs 42 cents from mouser and probably cost john grado less than 20 cents. Almost twice as much current as you'd get from an opa2134, iirc. 

 The ad8397 in the mini3 on the other hand comes in at 53V/uS and 310mA, and the performance is worth the added expense and difficulty

 The fastest chips we use in diy audio are usually around 100V/uS (like an ad8066) but there comes a point where the speed isn't doing anything additional for us - we don't typically listen to square waves, after all. 

 I know amb knows all this and the 4558 statement was probably a typo, just explaining for people who don't.


----------



## nickyboyo

"I might just leave it in the current case though since I hate caseworking with a passion. I just seem to suck at it for some strange reason. Having said all this, a custom wooden box might not be a bad way to go. Wanna make me something nickyboyo? "

 Leave it with me bud, i will keep my eyes open. I have a great box in mind, and if i can get hold of a couple i will fix you up no problem whatsoever. I'll drop you a message mate if things come together


----------



## nsx_23

Awesome 
	

	
	
		
		

		
		
	


	




 So I take it you're going to build one?


----------



## compicat

Quote:


  Originally Posted by *sunnysocket* /img/forum/go_quote.gif 
_this one 
Hohodiy.com_

 

hi, i signed up the site, i saw they can ship international. but i couldnt change the currency. is it taiwan dollar?


----------



## j2kei

it is taiwan dollar, NTD = new taiwan dollar. hmm...i think its a good choice purchasing the kit from hohoDIY, i just bought mine from glassjar thinking it came with front plates, and it doesn't 
	

	
	
		
		

		
			





 . anyone know if hohodiy sells just the front and back plate?


----------



## DaMnEd

Quote:


  Originally Posted by *j2kei* /img/forum/go_quote.gif 
_it is taiwan dollar, NTD = new taiwan dollar. hmm...i think its a good choice purchasing the kit from hohoDIY, i just bought mine from glassjar thinking it came with front plates, and it doesn't 
	

	
	
		
		

		
		
	


	




 . anyone know if hohodiy sells just the front and back plate?_

 

HohoDIY's kit uses a custom enclosure, not the hammond you got from glassjar, so the HohoDIY panels wont do you any good, the panels from HohoDIY have 4 holes to match the 4 holes on the enclosure corners, the hammond you have uses only 2, one on each side centered.

 So your better of fabricating your panels or getting the official panels from AMB's website, those are made for the Hammond.


----------



## j2kei

ahh gotcha, thanks a lot. very interesting that they use their own custom enclosure.


----------



## nsx_23

The hohodiy enclosure is actually not too bad. The front and rear panels are plastic, but I can live with that.


----------



## ralliart12

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_The hohodiy enclosure is actually not too bad. The front and rear panels are plastic, but I can live with that._

 

As a matter of fact, I have the Mini3 from hohoDIY. I DUN tink the enclosure's plastic though; I tink it's metal.


----------



## nsx_23

The panels are plastic.


----------



## ralliart12

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_The panels are plastic._

 

R we talking about the same enclosure? It really doesn't feel/bend like plastic to me...


----------



## nsx_23

Quote:


  Originally Posted by *nickyboyo* /img/forum/go_quote.gif 
_"I might just leave it in the current case though since I hate caseworking with a passion. I just seem to suck at it for some strange reason. Having said all this, a custom wooden box might not be a bad way to go. Wanna make me something nickyboyo? "

 Leave it with me bud, i will keep my eyes open. I have a great box in mind, and if i can get hold of a couple i will fix you up no problem whatsoever. I'll drop you a message mate if things come together 
	

	
	
		
		

		
		
	


	


_

 

Any word on that special box?


----------



## nsx_23

I'm considering build this next: ZKIT3 Personal battery operated headphone amplifier kit

 But does it come in a kit with the enclosure?


----------



## nsx_23

I have a question for all of you mini3 owners: How much battery life are you getting from your mini3?

 I seem to be getting about <20 hours from mine (280mha rechargeable from dealextreme), and I'm wondering if its not charging properly or something...

 Anyone of a place that sells the 300mha batteries on the AMB website? The linked store wants to charge $30USD to send a battery.....


----------



## Good Times

What capacity 9V are you running? I'm using a 280mah cell and getting about 16hrs, which I think is excellent.


----------



## nsx_23

I don't know, maybe I've been spoilt by the battery life of my Corda XXS and D2...


----------



## alvin1118

here's my home use Mini3, powered by AC Adapter. 

 hey! why Mini3 x 2?





 it's NeoMini USB DAC (cased in Mini3 chassis) + Mini3 combo for laptop solution


----------



## nsx_23

Ah, how's the neomini DAC? Difficult to construct? I thought about building that or the neomini digiamp (Essentially the neomini usb DAC + RA1 clone on 1 boad). 

 I'm surprised the DAC fits inside a Mini3 casing.......

 Nice job!


----------



## chews89

I didn't know hohodiy stocked just the mini^3 cases

 Yeah how hard was it to build in comparison to the mini^3? How is it performance wise as well?

 I might order a kit when I order in a mini^3 kit.


----------



## alvin1118

NeoMini USB DAC is simpler to build as compared to Mini3, since the PCM2702 chip is already pre-soldered.

 I would say the performance is simply too good for the price! 
	

	
	
		
		

		
			





 NeoMini USB DAC Assembly Guide


----------



## chews89

Oh dear, I don't know how to read Chinese 
	

	
	
		
		

		
		
	


	




 Where are the outputs? Do we have to include it ourselves? Just a normal headphone jack right?


----------



## nsx_23

Quote:


  Originally Posted by *alvin1118* /img/forum/go_quote.gif 
_NeoMini USB DAC is simpler to build as compared to Mini3, since the PCM2702 chip is already pre-soldered.

 I would say the performance is simply too good for the price! 
	

	
	
		
		

		
		
	


	




 NeoMini USB DAC Assembly Guide



_

 

I was thinking of building the complete DAC and headphone amp on one PCB kit. However, I wasn't sure about how to wire up the power supply since the blog wasn't very specific when it came to wiring that up....


----------



## decayed.cell

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_I was thinking of building the complete DAC and headphone amp on one PCB kit. However, I wasn't sure about how to wire up the power supply since the blog wasn't very specific when it came to wiring that up...._

 

It's described here

 "再來上跳線針腳,如果要使用USB內建電源,請直接將右邊jump 2 pin
 的孔短路起來,左邊的3 pin將USB那端的2 pin短路...

 外接電源的話,左邊的3 pin要將EXT那端的2 pin短路,右邊jump 2 pin
 的孔一樣短路.."

 It describes which pins to short to select power. To use USB power, short the middle and the USB pin, if you want EXT power, short EXT and the middle pin, also short out the two pins on the right of the 3 pin connector [then wire up VIN and GND on the board]

 "板子上的設計是3.3V是從5V的再穩壓出來的,所以如果3.3V的您也要
 獨立供電,右邊的jump開路就行了..剩下的自己搞吧..搞到這個階段
 的同學應該看了就會做了"
 He also notes that the 3.3V power is derived from the 5V, you can use the VIN and GND pins to independently supply 3.3V if you like

 Looks interesting, and similar to a Alien DAC. I might build one


----------



## chews89

Hey guys!

 I'm in the process of building my first mini^3 and I'm up to the last few steps. However, I have a question:

 Does the orientation of the LEDs matter when I solder them onto my board? I know the longer leg is the positive side but does it matter? It doesn't mention anything in the AMB instructions.

 I would appreciate if anyone could help me out ASAP as I'm excited to get my mini^3 done!

 Thanks


----------



## decayed.cell

Quote:


  Originally Posted by *chews89* /img/forum/go_quote.gif 
_Hey guys!

 I'm in the process of building my first mini^3 and I'm up to the last few steps. However, I have a question:

 Does the orientation of the LEDs matter when I solder them onto my board? I know the longer leg is the positive side but does it matter? It doesn't mention anything in the AMB instructions.

 I would appreciate if anyone could help me out ASAP as I'm excited to get my mini^3 done!

 Thanks_

 

Its a polarized component so yes, otherwise you will shortcircuit the LED


----------



## nsx_23

Quote:


  Originally Posted by *decayed.cell* /img/forum/go_quote.gif 
_It's described here

 "再來上跳線針腳,如果要使用USB內建電源,請直接將右邊jump 2 pin
 的孔短路起來,左邊的3 pin將USB那端的2 pin短路...

 外接電源的話,左邊的3 pin要將EXT那端的2 pin短路,右邊jump 2 pin
 的孔一樣短路.."

 It describes which pins to short to select power. To use USB power, short the middle and the USB pin, if you want EXT power, short EXT and the middle pin, also short out the two pins on the right of the 3 pin connector [then wire up VIN and GND on the board]

 "板子上的設計是3.3V是從5V的再穩壓出來的,所以如果3.3V的您也要
 獨立供電,右邊的jump開路就行了..剩下的自己搞吧..搞到這個階段
 的同學應該看了就會做了"
 He also notes that the 3.3V power is derived from the 5V, you can use the VIN and GND pins to independently supply 3.3V if you like

 Looks interesting, and similar to a Alien DAC. I might build one_

 

I was only looking at the diagrams. I can read chinese, but still wasn't too sure about the configuration.


----------



## chews89

Ok guys, I've "finished" my mini3 but it doesn't work..I'm pretty depressed 
	

	
	
		
		

		
		
	


	




 When I plug everything in, I max out the volume, the sound is there but it's really really tiny. Does anyone have any ideas?

 I'll get some pictures up soon.


----------



## nsx_23

^Cold solder joint? Directional components soldered in the other way round?


----------



## chews89

I reflowed all the joints and I was extremely careful to make sure the components were in the right orientation. 

 I used my solder iron to flow the solder of the opamps and now the right channel is working whereas the left channel is completely dead..


----------



## chews89

Does anyone have any ideas why the left channel is specific is dead?


----------



## amb

chews89, did you go through all the "initial check" steps described at the Mini³ website? If so, did any step fail? In particular, the rail splitter check, the quiescent current check and the DC offset check results are vital.

 Without concrete info, "left channel dead" isn't very useful for anyone to help with.


----------



## chews89

Thanks amb. I did the quiescent current check and rail splitter check and everything seemed fine. But when I tried the DC offset check, I seem to be getting all kinds of values.

 However I'm not even sure I'm using my multimeter correctly. Can you help me out and teach me how to set my multimeter to measure DC mV ?

 Ohyeah, another thing I've noticed is that when I turn the amp on, there's an audible click in the left channel whereas the right channel is working fine. I don't know if this means anything though.


----------



## amb

chews89, for DC offset check, set to "A" as shown below for DC (up to 200mV). If there is excessive DC offset, it may exceed the display range. You should then change to "B" (up to 2000mV) or "C" (up to 20V) to see what the actual offset voltage is.


----------



## chews89

Thanks again AMB.

 When I set my multimeter to "A", OG reads -1.2 and OR reads -4. I have to set my multimeter to "B" and I get a reading of -1124 for OL. 

 So I guess something is seriously wrong here..? I really hope I haven't damaged my Opamp..


----------



## amb

Your OG reading of -1.2mV and OR of -4mV are fine. OL at -1.124V is too high.

 Remove the battery, turn the power on to let the capacitors drain, and then reflow the solder joints on U5 pins 5 through 7. Reconnect the battery and check the DC offset again.


----------



## chews89

Ok so I've tried to reflow the solder joints a few times like you said but OL is still about -1.124V..


----------



## TzeYang

reflow the accompanying resistors?

 if it still does not work, the OPAMP might have fried 50%


----------



## chews89

OK I just had a though. With U2 there's a hole for a screw to go through. Does a screw have to be in place for my mini3 to work properly? I have some pictures. Any help would be really appreciated, it's quite frustrating..


----------



## chews89

Ok so I fiddled around with the battery contacts and both channels seem to be working. However, it doesn't sound good at all 
	

	
	
		
		

		
		
	


	




 Plus after a while i realised U5 was heating up considerably so I quickly turned the amp off..


----------



## amb

The mounting screw for the 7812 is not required for functionality. It's just there to secure it because the 7812 and the DC power jack also serves as a battery "guide".

 Btw, randomly fiddling with the board won't really help you. The fact that your left channel DC offset is high means that that channel is not working properly. You should never have plugged in your headphones because you risk damaging it. If reflowing U5's joint (and the associated resistors) does not correct the DC offset issue, there is a high likelihood that your U5 is blown. Perhaps as a result of the "fiddling around". The Mini³ has explicit warnings about handling of the board while the battery is in place, and about discharging the capacitors after removing the battery. It's a powered circuit and any accidental short circuit to the wrong place could fry the opamps.


----------



## chews89

Thank you for your insight amb, I really appreciate it and I think I have learnt my lesson.

 So how should I go about trying to fix it now? Purchase a new opamp and try installing it? Is it possible? I'm a bit daunted because I think it will be quite hard to reach the opamp due to all the other components surrounding it.

 How could I avoid this problem in the future? I actually purchased two mini3 kits to build and would dread making the same mistake again..


----------



## amb

The opamp can be replaced. The easiest way to do it is to simply cut the pins right at where they come out of the opamp (using a sharp Xacto blade) and the remove the opamp body. Then, carefully use your soldering iron to melt the solder on the pads and wipe away the remaining pins. Be careful with the iron so you don't touch the jacks, caps, etc., and burn an ugly mark on them. Use a desoldering braid to soak up any accumulated solder on the pads (be careful so you don't overheat and cause the pads to come off the board).

 Then, solder in the new opamp, same procedure as the first time, except now you need to work in a more confined space.

 The Mini³ website has all the instructions/warnings/notes that you need. Read and follow them to the letter and you should have success.


----------



## BradJudy

It also looks like there are possibly some cold solder joints and solder bridges. There appear to be solder bridges from U5 to the nearby resistors, but I think those just duplicate the traces, so they shouldn't be a problem. There also appear to be some solder strings/flecks here and there, which means there could be shorts somewhere.


----------



## chews89

Hey BradJudy, I don't quite understand what you mean by "solder strings/flecks", do you mind elaborating? Which picture do you see it in?


----------



## BradJudy

chews89 - I mean the stray blobs and splatters of solder I see here and there. They could be bridging or break loose and short out connections. I highlighted a couple in this image:


----------



## chews89

Thanks BradJudy, I tried to get rid of the excess solder but it still doesn't seem to work. I guess I'll just wait for my opamps to come in.

 However, I was thinking of starting my 2nd mini3 build meanwhile. But I thought I should ask some questions first to clarify some things. 

 Firstly, are my notations in this picture correct? The longer leg of the LED is positive hence it should be positioned so the longer leg goes through the upper hole? So in other words, am I right about which side is positive and negative? Anyone please?

 Also I kind of have a dilemma. Should I start building the new mini3 or should I take the opamp of that mini3 and use it on my old screwed up mini3? OR should I wait till my new opamps come in to use on my old mini3?


----------



## amb

The longer LEG pin is positive (actually, to be pedantic, it's the "anode"). The shorter leg is the "cathode". Cathode is denoted by the line on the board silkscreen.


----------



## helzerr

Yes, chews89, normally the longer lead of the LED is the anode (positive) side, while the shorter lead is the cathode (negative) side, often accompanied by a slight "flat" on that side of the LED body.

 (amb is too quick...)


----------



## chews89

Oh Ok cool. Also, on the Amb instructions, when testing the opamps it says: 

 "Use your multimeter and check the resistance between each pin of the opamp and the pad to make sure you don't have a cold solder joint (i.e., your meter should read close to zero ohms). Also check continuity between adjacent pins for solder bridges (meter should read infinity). "

 What does it mean by the "pad"? Also, I think I know which settings I need to set my multimeter to check resistance, but how about for continuity? Same settings? Still ohms? Is it possible to somehow damage the opamps while trying to test them? Sorry, I'm a huge noob.

 Again, thanks for the much needed help, amb.


----------



## amb

Quote:


 What does it mean by the "pad"? 
 

The shiny portions on the board that the pins are supposed to be soldered to.

  Quote:


 how about for continuity? Same settings? Still ohms? 
 

Yes, continuity = 0 ohms, no continuity = infinite ohms (or really high resistance)


----------



## chews89

Ohyeah, another quick question that I forgot before. Is flux absolutely essential when installing the opamps? Because I don't have any at the moment.


----------



## v3nom

Continuity doesn't have to be 0 ohms. If you have a completed circuit it will have continuity and most likely will have resistance. Now a SHORT on the other hand will be 0 ohms because it bypasses any circuit components.


----------



## amb

Quote:


  Originally Posted by *chews89* /img/forum/go_quote.gif 
_Ohyeah, another quick question that I forgot before. Is flux absolutely essential when installing the opamps? Because I don't have any at the moment._

 

Yes, IMO flux is absolute essential for SMD soldering. It's mighty difficult to do a good job without it.

  Quote:


  Originally Posted by *v3nom* 
_Continuity doesn't have to be 0 ohms. If you have a completed circuit it will have continuity and most likely will have resistance. Now a SHORT on the other hand will be 0 ohms because it bypasses any circuit components._

 

In this context (well soldered or cold joint), it is 0 ohms if continuous. Now, in real life any conductor will have a tiny amount of resistance but it will be less than the resolution of any DMM. In fact, most DMMs will read a fraction of an ohm across a well soldered joint, but that's besides the point.

 I should also mention that many DMMs have a continuity tester mode where it would "beep" when it thinks that you have continuity. This is not a good use of that function because one doesn't know what the beep threshold is. Is it 10 ohms? 100 ohms? Just because it beeped doesn't guarantee a good solder joint.


----------



## chews89

Hey amb, from my problems stated before, how do I know which opamp needs to be replaced? U4 or U5? Or both? Or I just can't know for sure?


----------



## amb

Whichever that has a high DC offset problem. U4 is for G, U5 for L and R. You could have looked at the schematic diagram and saw this for yourself.


----------



## chews89

I actually have no idea how to read a schematic diagram but I think I have an idea of what you're talking about. Thanks


----------



## dhp

general question about the mini3 - can the LM6172/6171 opamps be used in lieu of the ad8397? I know there are only 2 recommended opamp combos at the moment.


----------



## nsx_23

Chews, got the mini3 working?


----------



## amb

Quote:


  Originally Posted by *dhp* /img/forum/go_quote.gif 
_general question about the mini3 - can the LM6172/6171 opamps be used in lieu of the ad8397? I know there are only 2 recommended opamp combos at the moment._

 

The answer is it would sort of "work", but you will suffer major performance loss. Its specified minimum supply voltage is 10V, but we have only about that much after the battery is just freshly charged, and will drop to around 8V-8.5V over most of the operating life of the charge.

 The LM6172 is not rail-to-rail, it will give you no more than about 1.3Vrms output voltage swing into a mid-Z load (100 ohms) before clipping, and it gets worse into lower Zs. Contrast this to the AD8397, which will give you 3.2Vrms (mostly load invariant). With 10V supply voltage, the LM6172's maximum output current is about 25mA into 100 ohms (not specified at anything lower than that), whereas AD8397 can deliver up to 10x that (rated down to 25 ohms load).

 Given this, the LM6172 won't drive high-Z or low-Z headphones effectively in the Mini³.


----------



## chews89

Quote:


  Originally Posted by *nsx_23* /img/forum/go_quote.gif 
_Chews, got the mini3 working?_

 

Haha well yes and no.

 I actually completed my 2nd mini3! I was extremely careful with going through all steps thoroughly especially the testing stage after making dreadful mistakes by rushing through it and taking some very good advice from amb, and it works! It is definitely a step up from my cmoy. 

 As for my first mini3, I'm waiting for the opamps to come in to try and fix it up. But until then, I'm pretty happy with my working mini3 
	

	
	
		
		

		
			





 Thanks for asking, nsx


----------



## nsx_23

It's a brilliant little amplifier isn't it 
	

	
	
		
		

		
		
	


	




 I'm looking for something to build actually, but damn uni work has kept me extremely busy. Maybe the CTH, but it'll have to be during the mid-year break 
	

	
	
		
		

		
		
	


	




 The urge to build is strong.


----------



## chews89

Yes it is, indeed 
	

	
	
		
		

		
		
	


	




 Yeah, same here. Mid semester exams are coming up as well, so there isn't much time for anything else. CTH? Ohyeah there's a kit available right? Making one would be pretty sweet. Do you know how much it would cost all up though?

 How about a Starving Student? Did you see the one that fred_fred put together? I guess it is possible to source components in Australia


----------



## nsx_23

The problem is that I suck at reading schematic, so it'll be a bitch to put together for me.....


----------



## chews89

Ah I'm in the same boat. Although given some effort and time, perhaps reading a schematic wouldn't be too hard? The SS is really appealing to me because it's a lot cheaper than the other DIY desktop amps. Hey random question, how would you compare your Mini3 to your XXS?


----------



## nsx_23

Mini3 bit bolder, but not as resolved in terms of treble compared to the XXS. XXS is a lot cleaner, but mini3 can be more fun.


----------



## dhp

Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_The answer is it would sort of "work", but you will suffer major performance loss. Its specified minimum supply voltage is 10V, but we have only about that much after the battery is just freshly charged, and will drop to around 8V-8.5V over most of the operating life of the charge.

 The LM6172 is not rail-to-rail, it will give you no more than about 1.3Vrms output voltage swing into a mid-Z load (100 ohms) before clipping, and it gets worse into lower Zs. Contrast this to the AD8397, which will give you 3.2Vrms (mostly load invariant). With 10V supply voltage, the LM6172's maximum output current is about 25mA into 100 ohms (not specified at anything lower than that), whereas AD8397 can deliver up to 10x that (rated down to 25 ohms load).

 Given this, the LM6172 won't drive high-Z or low-Z headphones effectively in the Mini³._

 

cool, thanks.


----------



## nsx_23

I'm absolutely bored as hell, and itching to build an amp.

 I think I might tackle the hohodiy neomini digiamp when I can get the money. Anyone interested in a tutorial?

 Or maybe I should just build it and post impressions


----------



## alvin1118

build in progress tutorial + impression would be nice bro


----------



## nsx_23

^Wait till I get the money together first 
	

	
	
		
		

		
		
	


	




 Unless you want to sponsor me


----------



## chews89

Yea, do a step by step tutorial like that jac guy did for the mini3, and post impressions! 
	

	
	
		
		

		
		
	


	




 Or you could just save up for the CTH..


----------



## nsx_23

At current exchange rate, the base CTH kit is $240AUD before shipping and other stuff like panels.........


----------



## chews89

Hey nsx! I just came across an awesome DIY project that looks quite achievable. Have you ever heard of the Nixie Tube clock? It has nothing to do with audio but it looks awesome nonetheless 
	

	
	
		
		

		
		
	


	




 Here's an example:

Nixie Tube Clock Kit For Z570M, Z573M, Z574M, ZM1080 - eBay Tubes Acoustics, Electronic Components, Electrical Test Equipment, Business Industrial. (end time 13-Apr-09 15:45:34 AEST)


----------



## nsx_23

I think I'll save the money I have to build an amp instead.

 Jaycar amp is next on my list due to its low price, and it seems to have quiet a high ranking amongst DIYers.


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## mojo

Now hohodiy.com has gone, does anyone do full kits?

 Otherwise I'll have to source most of the parts myself.


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## markt1600

Glass Jar Audio has mini^3 kits:

Glass Jar Audio : Home


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## mojo

Thanks.


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