# Unofficial: Schiit DIY Coaster Amp



## Rensek (Jul 12, 2018)

Greetings, this is the unofficial thread for all things related to Schiits DIY Coaster Amp. To everyone interested in creating or using low performance amps made from leaky coasters, without company support, we hope this can be the place where folks share ideas, progress, and results, & give assistance to their fellow Schiitheads.

The goal early on will be to consolidate as much coaster amp info as we can from the main Schiit thread.

Welcome - assistance and participation appreciated.

Edit - Disclaimer Taken From Jasons last official comment on the coaster.

*So How Do You Build This Thing?*

First, a disclaimer. We have applied this disclaimer, I think, pretty much to every chapter. We have applied it on the product page. And on the downloads page. But it bears repeating again:

*We are not experts at DIY. We do not sell parts, and cannot provide support for your build. Literally any other company doing DIY will do it better than us. If you aren’t a moderate to advanced DIYer, it’s probably bestto use these coasters as, well, just coasters.*

Here are the links you need:

*Coaster boards:*schiit.com/products/coaster
*Schematic and BOM: *schiit.com/coaster

PLEASE TAKE THE ABOVE WARNING TO HEART. I hope to build a coaster amp someday so I am consolidating info as time allows from the main Schiit thread

This thread took off before I got the all chapters quouted.  Jasons coaster chapters have been pasted In order on posts 87, 88, 89, & 90.

I will be working to add his non indexed coaster posts as edits to the chapters they are apart of.


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## RCBinTN

Subscribed. Thanks for the new, fun thread.


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## Paladin79

Here is a test board, an IC socket cut in half has the proper hole spacing for the coaster amp. So far I have five matched pairs of tubes. I may supply some down the road to those who do not want to purchase five or more tubes in order to get a matched set.


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## the finisher

Subbed, should be fun.


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## Paladin79

Here are the six smallest transistors, three per board with a 3.5 mm connector laying across the boards for reference. This might help you understand why a magnifier light is useful. I pre-tin the pads and then measure for continuity once I have soldered the parts in place. Keeping an extra board near by for reference on the etching pattern helps. If your soldering iron tip is about the size of the 3.5 mm tip, I wish you luck soldering these. My technique is to hold the part in tweezers or long nose pliers in my right and and solder with my left, at least one leg. I am right handed. This is not easy but if you get past this stage all the parts are a bit bigger except for the LED's.


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## Paladin79

One last photo and this is a fairly important one if you cannot read a schematic. I have marked diode polarity, standard diodes have a bracket around the cathode end but the LED's are unmarked on the boards as best I can tell, thus I have marked the boards. On these particular LED's there are tiny green dots on the cathode end. D102 and D202. Find the center of the board and go straight to the left and straight to the right, those led's are the last parts facing up and down.  Hopefully anyone who attempts this is not a first time DIYer, if you are, I hope you enjoy them as coasters. I mean that in the nicest possible way.


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## JohnnyCanuck

Subbed.


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## sam6550a

Rensek said:


> Greetings, this is the unofficial thread for all things related to Schiits DIY Coaster Amp. To everyone interested in creating or using low performance amps made from leaky coasters, without company support, we hope this can be the place where folks share ideas, progress, and results, & give assistance to their fellow Schiitheads.
> 
> The goal early on will be to consolidate as much coaster amp info as we can from the main Schiit thread.
> 
> Welcome - assistance and participation appreciated.


Subscribed. I build a lot of DIY stuff, but the very small SMT devices exceed the pixel resolution of my Mark I Type 2 eyeball. At 3/4 century old, I will stay with [mostly] thru-hole technology.


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## Paladin79

Thru hole is much easier by far. A gentleman on here was asking about class A speaker amps earlier in case you have any recommendations, The Finisher is his id. I am building some myself but they are ten watt monoblocks and I am figuring them out as I go, they are not your standard kit build.


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## CAPT Deadpool

I sub’d too.


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## riffrafff

Buncha sub-versives 'round here.


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## Paladin79

And many who want to be.


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## CAPT Deadpool (Jul 7, 2018)

Deleted. i see now


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## the finisher (Jul 7, 2018)

@Rensek any chance you could quote Jason's last post about the coaster amp build to the first post of this thread for reference?

https://www.head-fi.org/threads/sch...bable-start-up.701900/page-2296#post-14340296


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## Paladin79

Yes black marks on all diode locations


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## kimbo

Paladin79 said:


> ... an IC socket cut in half has the proper hole spacing for the coaster amp.



Good thinking!
[subscribed]


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## kimbo

Thanks for starting the thread Rensek.

I've got a couple of unbuilt decade old Oatley Electronics K272 6418 headphone kits plus some spare tubes at the bottom of my parts bin so I'm up for a coaster build. 
http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/
I may even build up one of the K272 kits so I can make a comparison.


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## kimbo

Shipping to Australia is double the cost of the board.  Ouch!
Ordered.  
Oh well, the cost of having fun!


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## zztopps

Thank you @Paladin79 .  Probably won’t ever build one, but have enjoyed following you building yours.


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## Paladin79 (Jul 8, 2018)

kimbo said:


> Thanks for starting the thread Rensek.
> 
> I've got a couple of unbuilt decade old Oatley Electronics K272 6418 headphone kits plus some spare tubes at the bottom of my parts bin so I'm up for a coaster build.
> http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/
> I may even build up one of the K272 kits so I can make a comparison.



I may have to see if those kits are still around. I am always looking for something portable to take outside. I can use a large battery pack but something small and handy would be nice.

I have built the Whammy from DIYaudio, a class a headphone amp and while I am more of a tube guy, that amp is amazing. Right now i listen to it more than most amps I own.

I have experienced shipping to other countries and will probably avoid it from now on. 


zztopps said:


> Thank you @Paladin79 .  Probably won’t ever build one, but have enjoyed following you building yours.




Thank you ZZ, if I get the time I may do a few extra builds to help folks out, I have been involved with electronics since college but like many, I am more used to thru-hole circuit boards.Pretty much every company I have been with has moved me into management and paid for a lot of post grad education but I still like to work with tools and build a few things myself. It is never easy for me to teach a person something that I cannot do myself and I like to stay up on technology.

This is not an easy build by any means but I am adapting to it, I may need to get other tweezers and adapt a bit but I am used to figuring things out.


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## jimmers

Paladin79 said:


> I may have to see if those kits are still around. I am always looking for something portable to take outside. I can use a large battery pack but something small and handy would be nice..


the latest version 
http://oatleyelectronics.com//product_info.php?products_id=1102
there is a pdf there that can be downloaded


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## CAPT Deadpool

jimmers said:


> the latest version
> http://oatleyelectronics.com//product_info.php?products_id=1102
> there is a pdf there that can be downloaded


I went to the link but is it out of stock I dont see an add to cart button.  Do I need to use a VPN so I have an Aussie IP?


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## Paladin79

I need to get with Jason tomorrow on a slight issue but my amps are working fine once the relay kicks in, luckily I have one to experiment with sitting around.


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## zztopps

Paladin79 said:


> Thank you ZZ, if I get the time I may do a few extra builds to help folks out, I have been involved with electronics since college but like many, I am more used to thru-hole circuit boards.Pretty much every company I have been with has moved me into management and paid for a lot of post grad education but I still like to work with tools and build a few things myself. It is never easy for me to teach a person something that I cannot do myself and I like to stay up on technology.
> 
> This is not an easy build by any means but I am adapting to it, I may need to get other tweezers and adapt a bit but I am used to figuring things out.



Absolutely.

If you've ever thought about it or find yourself with the time to, where would you (or anyone else here) direct me (or anyone else), if I was interested in getting into DIY amps.  I'm guessing a complete noob would start with something other than an amp.  But with what or where would that be?


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## Paladin79

Bottlehead or DIY Audio. Build a Bottlehead Crack first


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## zztopps

Paladin79 said:


> Bottlehead or DIY Audio. Build a Bottlehead Crack first



Thank you!  I'll let you know when/if I get a chance to try it.


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## Paladin79 (Jul 8, 2018)

I built a few and they are well documented and have a big following on here. $200 on sale, completed ones for $650 on EBay, I have turned down much more for mine but it was serious work.


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## zztopps (Jul 8, 2018)

The Bottle(head)neck website is interesting.  If nothing else, the name gave me a good laugh (and I can always use more of those)!  Thanks, again.


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## the finisher

@Paladin79   That rig is ridiculous, steam punk and oh so cool


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## Paladin79 (Jul 8, 2018)

1/8 inch copper plate, top, front and back, I added the patina. Cabinet is one inch thick quartered oak. I modified headphones to match, changed low impedance closed to high impedance open.


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## the finisher

I've been spending time at these links studying up on class A speaker amps.

https://www.passdiy.com/
https://www.passdiy.com/project
http://www.diyaudio.com/forums/pass-labs/

I'll comment more when I know what the hell I'm talking about


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## Paladin79

Fascinating stuff. His preamp designer did the Whammy, the guy has been designing them for 25 years.


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## the finisher (Jul 8, 2018)

Found this at the project link, DIY subwoofers 

Best secure your plumbing lol! "El Pipe-O, an adventure in over-the-edge woofer construction"


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## Paladin79

Wow!  

I have a few, built two myself. Read about infrasound sometime. Sound below 20 cycles. Large mammals use it to communicate, large cats can use it to freeze their prey.


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## jimmers

CAPT Deadpool said:


> I went to the link but is it out of stock I dont see an add to cart button.  Do I need to use a VPN so I have an Aussie IP?


I don't know
At what point did it fail?
I was able to add one to my cart OK but didn't want to go any further with the test.


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## the finisher

Paladin79 said:


> Wow!
> 
> I have a few, built two myself. Read about infrasound sometime. Sound below 20 cycles. Large mammals use it to communicate, large cats can use it to freeze their prey.



And I use it to piss off my Wife!


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## CAPT Deadpool

jimmers said:


> I don't know
> At what point did it fail?
> I was able to add one to my cart OK but didn't want to go any further with the test.


I found the add to cart.   It was not showing on my phone.   Browser has been acting up the last three days


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## Paladin79 (Jul 8, 2018)

the finisher said:


> And I use it to piss off my Wife!



My 7.2 surround has caused bows to vibrate off of my archery rack. I rarely crank it up too much with my wife home.


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## the finisher (Jul 8, 2018)

She worked all weekend so speakers and my ears got a nice workout. Now back to the X's 

My nearfield room is next to the upstairs bath. It will open cupboard doors and shake out the contents.
For some reason she is not impressed


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## Paladin79

My wife travels next weekend so I can crank it up then. Mostly I will be finishing an amp for a friend, and maybe working on rental property.


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## the finisher (Jul 8, 2018)

I'll be working on my shop space/garage to do some woodworking and finishing.


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## Paladin79 (Jul 8, 2018)

Cool, the electronics I am used to but I like to challenge myself on DIY aesthetics but I lack space for woodworking.

Since this is the Coaster thread, I have three finished amps, all three have a 20 second wait until the relay switches and there is signal. That is with R6 at one meg ohm.  I will talk to Jason tomorrow but that could be normal.


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## stled

Paladin79 said:


> Cool, the electronics I am used to but I like to challenge myself on DIY aesthetics but I lack space for woodworking.
> 
> Since this is the Coaster thread, I have three finished amps, all three have a 20 second wait until the relay switches and there is signal. That is with R6 at one meg ohm.  I will talk to Jason tomorrow but that could be normal.



Subscribed


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## CAPT Deadpool

Paladin79 said:


> Here is a test board, an IC socket cut in half has the proper hole spacing for the coaster amp. So far I have five matched pairs of tubes. I may supply some down the road to those who do not want to purchase five or more tubes in order to get a matched set.



So I think you are saying a 10 pin IC socket cut in half can be used to mount the tubes without using solder.  So you can more easily match tubes and replace them when burnt out.

Is this what you used (or close enough)?  https://www.jameco.com/z/6100-1X10-R-Socket-SIPP-10-Pin-Machine-Tooled-Pins-Soldertail_102201.html


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## RCBinTN

Paladin79 said:


> My 7.2 surround has caused bows to vibrate off of my archery rack. I rarely crank it up too much with my wife home.


Not much of an audiophile story, but we have Sonos gear in our living room - sound bar, sub and two rear speakers.
It will crank. One night, we were watching Star Trek with the home security system enabled.
The Sonos was kinda loud, to the point where it set off the glass break sensor and the alarm.
We didn't realize it until the monitoring company called us...


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## Paladin79

What you show in the photo appears to be fine. I think I just cut up an new 8 pin DIP socket I had laying around. I do not have a Coaster in front of me but there are five pins used per tube as I recall.

I soldered those sockets in an extra board and I just plug tubes in and out to test there. Once I get a good match, I solder the tubes in finished boards. It is a test fixture, I would not suggest you use one on a continual basis if that is the question. The board with the sockets is also one I use if I want to experiment with parts other than what are posted in the BOM.

Down the road i will try other tubes and they may need other plate load resistors so that test board will be very handy to have.


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## the finisher (Jul 9, 2018)

This DIY audio thing is my next hardware addiction fix, the wheels are turning.
This is the Wammy Paladin79 was referring to before, very cool.
https://diyaudiostore.com/collections/printed-circuit-boards/products/whammy
@Paladin79  this is all your fault 

Construction guide is here for the whammy http://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide.html


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## Paladin79

The thing is, you have a wood shop and your amps will be a thing of beauty I bet. Do you happen to have a wood lathe?

I may have a couple recommendations on the Coaster by way of Jason, I will post it once I have experimented myself.


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## the finisher

No lathe, I'm no cabinet maker, but have made a living in the trade for 25 years, mostly as a finisher/painter.
I have some of my own tools, but I know people. A lathe would be tough, you can buy turnings for not a lot.

Cool that Jason is indirectly involved with this Coaster amp building, it will be fun to see what folks come up with.

In my exploration of all things class A, I'd point to this as a good starting point>https://www.passdiy.com/project/amplifiers/construct-a-class-a-amplifier


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## Paladin79

He is clearly busy so i try not to bug him too much.
 Suddenly I am much happier about the Coaster build! Which is a good thing cause I just quadrupled a parts order with Mouser on the base parts.

 When one of you gets one up and going I will talk to you about some tweaks that will help. First, concentrate on just making it operational.


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## the finisher

Oh man Schiit are just swamped, It's a good and bad problem to have.


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## Paladin79

Hopefully the tariffs and parts shortages do not affect things. I had to get creative to build a few amps. Each time I look, more parts are out of stock.


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## the finisher

Yes This will be my worst problem going forward with DIY, world wide parts shortage, and tariffs. dam.

A problem for Schiit as well I'd imagine.


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## dieslemat

late in the game... but subscribing now


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## CAPT Deadpool (Jul 10, 2018)

Paladin79 said:


> Hopefully the tariffs and parts shortages do not affect things. I had to get creative to build a few amps. Each time I look, more parts are out of stock.




I would be very interested to hear Jason’s take on the impacts of the “trade war” from perspective of a small-midsize company.   So much propaganda these days would be good to hear directly.

I don’t mean to imply I don’t trust the mainstream media, actually the opposite infowars and propaganda trolls are the problem.


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## Paladin79

dieslemat said:


> late in the game... but subscribing now



Welcome Dieslemat, right now this seems like a safe place to be lol.


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## dieslemat

Hahaha. Very very true! I dread to join the childish fray!!


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## the finisher (Jul 10, 2018)

This feels like home comparably speaking for sure.

What happened to audio talk over there anyway?


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## Paladin79

I just thought a post was funny, otherwise I am as pure as the driven slush.


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## the finisher

Some don't do funny


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## dieslemat

Actually it is very funny. 
Now it seems like a pity party.

Anyway just curious about the tubes used. Im not very familiar on tubes but in Jason’s post he said something about making sure that the tube matches. How do I check on this? There are other websites that I looked into but they are very generalized. So with this specific tube to the coaster amp, how does one check that the tubes match?


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## dieslemat

Also I must say that splitting the IC socket/holder to make it as a tube socket is a brilliant idea!


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## Paladin79

There is a gentleman on here out of the east coast with a wood turning lathe, I may have to get with him sometime on a round container for a Coaster amp, I searched all over for wooden products and it was hard to find one with the 3.5 inch or bigger diameter. The input jacks take up a little bit of room but a small file or chisel could be used to set those into the cabinet side.


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## CAPT Deadpool

Paladin79 said:


> There is a gentleman on here out of the east coast with a wood turning lathe, I may have to get with him sometime on a round container for a Coaster amp, I searched all over for wooden products and it was hard to find one with the 3.5 inch or bigger diameter. The input jacks take up a little bit of room but a small file or chisel could be used to set those into the cabinet side.



A friend of mine and I discussed either 3D printing or repurposing some sort of hockey puck shaped case (preferably clear).  What other case ideas have been discussed/demonstrated in the main Schiit forum?  

My friend wanted to add the coaster to a Raspberry Pi to make an all in one ("only one man would dare give me the raspberry!").  I have about 8 or 10 Pi's around the house.


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## Paladin79

There are measurements you can make for matching the tubes and I follow Jason on that, but listening is a factor too. I  have one set in my test jig that is so bad it is obvious. I bought five tubes and found one good matching pair, then I bought ten and got five pairs so it is a matter of luck on what you end up with. The easiest way for me to do it is with a calibrated dual trace scope and signal generator.


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## Paladin79 (Jul 10, 2018)

CAPT Deadpool said:


> A friend of mine and I discussed either 3D printing or repurposing some sort of hockey puck shaped case (preferably clear).  What other case ideas have been discussed/demonstrated in the main Schiit forum?
> 
> My friend wanted to add the coaster to a Raspberry Pi to make an all in one ("only one man would dare give me the raspberry!").  I have about 8 or 10 Pi's around the house.



I have mounted one in a magic 8 ball, tobacco tins, and a headphone rack. I will mount one in a scotch bottle at some point. You can see those photos in the main thread but it can take some looking. Later today maybe I can re-post some here. Beer cans could work, maybe something like a Fosters lager can.

Once I get done with basic builds I was considering stacking a couple of them and combining channels and power but I need to think it through some. It can be done with power amps.


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## Paladin79 (Jul 10, 2018)

I should mention too, if you only build one Coaster amp, you can add sockets to it, test your tubes and just listen for best result, then when done, remove the sockets and solder the tubes directly to the board. I am keeping a test board just as a test board but I may be doing a lot more modifications than the rest of you and building one Coaster or ten of them is not an issue for me as long as I can get parts.

I talked to the guy who does MrSpeakers headphones, they are the first company to make 3d printed headphone cups as I recall. He directed me to a company that would do most any 3d printing for you but that was a while ago and I may have a hard time locating it again. Having the initial drawing would be the biggest part of it and that is not one of my skill sets at this time. Maybe making a wooden model and sending it to a company could work but setup is the expensive part.


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## dieslemat

Hoping that if this diy picks up, Schiit can then provide an option to purchase a circle case for the coaster amp. ive seen photos of it in one of Jason’s posts.


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## Paladin79 (Jul 10, 2018)

Hmmm I have not seen that but I may have missed it. If you find it copy and paste it here. A magic 8 ball is the perfect size for the Coaster amp, they are hard to take apart but they only cost $6.00 or so, it is a toy made by Mattel.  

AI also did a copper frame then added patina but I like the looks of pure copper better, I am doing something with that soon and I will post a photo.

I am not sure about them doing a case, it would surprise me but I have been surprised before.

 I need to go through my PM's and message several people about this thread who have contacted me asking about Coaster amps. Maybe some of those folks can help with cases.


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## CAPT Deadpool (Jul 10, 2018)

Paladin79 said:


> There are measurements you can make for matching the tubes and I follow Jason on that, but listening is a factor too. I  have one set in my test jig that is so bad it is obvious. I bought five tubes and found one good matching pair, then I bought ten and got five pairs so it is a matter of luck on what you end up with. The easiest way for me to do it is with a calibrated dual trace scope and signal generator.



I have none of that test gear. 

But I did just get an email offer for a free multimeter with the purchase of an oscilloscope.   

https://www.newark.com/MarketingPro...X1618,29X1619,29X1620,29X1621,29X1622,29X1623

Very affordable, starting at $3.5K and going up to $14.5K!

I think the best I could do is listen and guess and/or play tones to headphones and measure with my $15 SPL meter from amazon.  https://www.amazon.com/gp/product/B00ECCZWWI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1





Not ideal.  I'm suggesting anyone else try that, I'm just using to illustrate my idea.  I bought it to ensure I'm not listening too loudly with my Jotunheim.

I've got 10 tubes on order from E-bay.


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## Paladin79 (Jul 10, 2018)

You can tell quite a bit just listening but I am willing to help if it comes down to it. I used to run my own electronics business so I have lots of equipment. There might even be apps that will show you signal level.

Virtual Bench might be a good one.  Look for oscilloscope app and many come up.


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## CAPT Deadpool

I have this book at home.  I'll check to see if it has any advice.

https://www.amazon.com/Vacuum-Tube-..._rd_t=40701&psc=1&refRID=3CEGZY4E7KW4WXFW8AJP

or maybe this book (I don't own), but I'm think this would only be good for making sure the tube functioned (i.e. it's not broken) vice tube matching.

https://www.amazon.com/Make-Your-Te...F8&qid=1531240396&sr=8-6&keywords=tube+tester

Does anyone have any links to tube matching methods?


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## Paladin79

*How Do I Get Better Results?*

No, this won’t be a missive about how you can swap out the capacitors for audiophile-grade products the size of a beer can, or use specially formulated solder with silver and gold to increase performance. Boringly, but fittingly, this is about a few engineering-y, measure-y things you can do to improve the results of your build.

*Use a tube cushion. *The original Vali used 30 durometer Sorbothane pads under the subminiature tubes, as well as another piece of foam under the board to keep the tiiiiinngggggg (microphonic) noise down.
If you don’t have Sorbothane, use a soft rubber or foam pad under the tubes—you’re looking for something very soft. 30 duro Sorbothane feels a lot like bacon.
Different tubes have different levels of microphonics. Some never settle down. Listen while you match the tubes (below) and get rid of any perma-ringers.

*Match the tubes.*These tubes do vary. Actually, quite a bit. This matters because the variation changes the gain of the amplifier. If you use two unmatched tubes, you could have gain that’s off by a couple of dB on one side. Lower gain tubes also tend to have higher distortion, at least in our measurements.
To match tubes, measure the gain of each side with a 250mV RMS sine wave input at 1K. The amp will put out something like about 1V RMS. However, one channel might be 1.08V RMS, and the other one 0.92V RMS. Swap the tubes until they’re closer (say, 1.08/1.02V RMS, or about 5%).
Consider adding pin sockets to the build to speed up tube testing. There are small machined sockets you can use for this purpose. They’re not perfect, but they are better than soldering and desoldering a half-dozen tubes. You can solder in the tube when you find the right one.
The 6418s seem worse than the 6088s in terms of variation, but the 6418s also have better measured performance in terms of THD.

*Adjust plate load for true midpoint operation.*You’ll get maximum output from the amp when the output DC level (before the coupling capacitor) is 7.5V. This allows the amp to swing the rails (or pretty close).
I’ve provided a 10K recommended plate load (R101 and R201) for both 6418 and 6088 tubes, but, depending on the tube (see above, they vary), you may want to change the plate loads to get the output DC closer to 7.5V.
If the voltage is lower than 7.5V, increase the plate load
If the voltage is higher than 7.5V, decrease the plate load.
If you’re going to do this, change both loads to the same value, and don’t stress if one comes out at 7.7V and one comes out at 7.3V. That’s the tube variation again.

So, if you do all three of these steps, does it transform the amp into a super-high-performance product suitable for all headphones from CIEMs to HE-6s?

In short, nope. It’s still going to be a simple, limited, slightly noisy, high distortion, slightly microphonic little tube hybrid. But that doesn’t mean it sounds bad.

To go farther with the design, you’re moving into flying-parts-land. Adding feedback would lower the gain, noise, and THD. But that’s more parts, and it adds feedback, which some people like to avoid. Going to a Darlington output stage would improve performance as well, but that’s a huge change, and, again, more parts. Increasing voltage would be welcome, but then we’re getting well beyond what this was supposed to be—a coaster, which can also be built into a simple little hybrid amp.


*Time To Build Your Own Coaster?*

I hope you enjoyed this engineering odyssey, and learned a few things about the many decisions that go into making even the simplest product. Now, imagine the engineering decisions needed on something as complex as, say, an Yggdrasil (which has three different sets of firmware, a couple of dozen power supplies and voltage references, and both analog and digital sides to worry about. Or even a Freya, with its relay ladder, tube and buffer stages, and remote control.

Sounds like fun? Yep, it is.

Or at least we think so!


Here is part of Jason's last post from around July 4th, he talks here about tube matching and such.This is the last post on the Coaster amp and probably the most important one IMHO>


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## CAPT Deadpool (Jul 10, 2018)

Paladin79 said:


> To match tubes, measure the gain of each side with a 250mV RMS sine wave input at 1K. The amp will put out something like about 1V RMS. However, one channel might be 1.08V RMS, and the other one 0.92V RMS.



Hmm I guess that would require the use of an oscilloscope or an oscilloscope app maybe?  I'm going to be learning a lot it appears.  Thanks to all for putting up with my questions.  If they get to be too much let me know.


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## Paladin79 (Jul 10, 2018)

yes this part requires at least an o-scope or equivalent, as I said earlier, the biggest thing at first is just building the working amp. I can help with tube matching later if you like.

You also need a sound source but you can get that from the sound output of a computer I would think if you do not have a signal generator.

I grabbed some sorbothane on ebay and a three inch by three inch piece is way more than enough. It may get me through 8-10 amps.

https://www.ebay.com/itm/SORBOTHANE...573942&hash=item5670b40aa7:g:a9EAAOSwDlxU3TYd


----------



## kimbo (Jul 11, 2018)

Yes, Paladin is quite correct, a scope makes this a very easy process.  However you could probably also do the matching with a reasonable quality ‘true RMS’ multimeter.  The requirements for tube matching are to produce a 250 mV sinewave at 1000 Hz.  And to measure approx. 1 V at 1000Hz. But as the aim is to find a matched pair, the precision does not need to be great….just repeatable to within a few percent.

These are some options that spring to mind.

*Use your PC to generate the test signal*.  Sound cards are OK for generating waveforms in the audio range.  There are numerous ways to do this.  One is to download some software such as NCH Tone Generator https://downloads.tomsguide.com/Tone-Generator,0301-61791.html .  Your PC should be able to output 250mV.  I just tried this by plugging into the headphone socket on my cr*ppy PC speakers.  I set the output on the NCH to – 3db and adjusted the volume on the speakers to get close to 250mV.  Close enough for our purposes.

Right click on _*Sine 1 Frequency > Edit value > 1000 > save*_​
_*Play*_​








You can also use this software to create a wave file you can save to play on any device or burn to a disk [ File > Save as wave ]
You should also be able to then use the multimeter to measure your coaster amp outputs.  If the voltage is too high then you can make a simple voltage divider from a couple of resistors….say 1000 Ohm (1K) and 3300 Ohm (3k3).  Put them in series across the output and then take your measurement across the 1k resistor.

But of course a scope makes this much more visual (and more fun)

*Scope Option one*

You can also use your soundcard as a scope for audio frequencies.

For example there is https://www.zeitnitz.eu/scope_en  A long time ago I used this or something very similar and it worked fine for the sort of low resolution work here.  
Note however this requires you to input voltages directly into your soundcard.  No problem if nothing goes wrong, but if you accidently input a high voltage into your card, you may fry it.  Perhaps you have a really old PC or sound card you can use without risk.  You can also build a simple preamp to act as a buffer and this will allow you to protect the card and also select the gain in hardware.  I built the Electronics Australia version 20 years ago https://dalmura.com.au/static/K2875 Soundcard Preamp EA Aug 1998.pdf







Option two

There are plenty of cheap kits on ebay for build your own low quality mini-scopes.  Bandwidth is low (200kHz) but good enough for fooling around with audio.

https://www.ebay.com.au/itm/DSO138-2-4-TFT-Digital-Oscilloscope-Kits-DIY-Parts-1Msps-Prob-for-Assembling-K/222791647275?hash=item33df6ac02bmnFZxNGikQwR3MQ4ugVoY6A&var=521643693991

Option three

Cheap USB scope – about $80 on ebay.  25Mhz (claimed) I have no experience of these.  But has advantage of coming with probes and no assembly required.

Option four – (the best?)

Buy an old analog scope from ebay.  If you are in the US then I am very jealous!  There are plenty of Tektronix, Hitachi etc scope at around $100.  20 MHz and above and dual channel.  Ensure that it shows images of both channels working and comes with a pair of probes (not cheap to buy). If you can local pick up even better to avoid damage in transit.  There are plenty of youtube videos to get you started in using it.

Personally I’ll be using my trusty old BWD 35MHz analog scope and my function generator…but I am waiting for the board to arrive downunder.

Have fun! 
[Edited to fix some images]


----------



## kimbo

PS.  As you are only making comparisons, even an el-cheapo multimeter (without true RMS) may do the trick.


----------



## dieslemat

Wow! Thanks @kimbo for taking time in explaining it. Very well written.


----------



## Paladin79

That was an excellent and well thought out response Kimbo, I get busy at times and my answers can tend to be brief. You also have the option of my matching the tubes for you but if you plan on doing much DIY or you want to learn, it never hurts to have the right equipment.

On the subject of true RMS multimeters. This is one of my favorites:

https://www.ebay.com/itm/Vintage-Si...076767?hash=item4b45f2a3df:g:qTUAAOSwm4NbDJD2

They were used by the military a lot and are rugged and well made. They can measure up to 10kv, not that you need to that often. I have a few that are 30 years old and still functional.


----------



## kimbo

No worries Dieselmat!

Hi Paladin. For $30 they look hard to beat. And 10kV! Not the sort of voltages you'd want in a headphone amp.   
I also love the 'how to repair telephones' photo in the ad.  

The one shown in my photo is my current favorite.  
EEV Blog Brymen BM235
https://www.eevblog.com/product/bm235-multimeter/

Not sure of the US price but here in Oz it is amazing value for money.


(I think it may be available from Amazon)

But as mentioned earlier, even a cheapy 'may' do the job.  I will think about taking out some of my older ones and putting them to the test.


----------



## Paladin79 (Jul 11, 2018)

Kimbo I am glad to have you on board with these amps, you obviously have a good background and electronics knowledge.

They have a ten amp shunt resistor as I recall and a probe built for the higher voltages. I never had much reason to use it because I used to deal more with 25kv and up on crt computer monitors. I used to use curve tracers a lot and as I began to troubleshoot the first Coaster amp I put together I had a scope go down as well as other pieces I had not touched for ten years. I have a power supply that goes up to 300 volts dc and even provides filament voltages for tube circuits and that is down as well.

I also have one of these that is in mint condition:

https://www.ebay.com/itm/Vintage-Si...167875?hash=item3b1454bbc3:g:OScAAOSwEIJbRTg5

Every now and then it is extremely useful.


----------



## CAPT Deadpool

Paladin79 said:


> That was an excellent and well thought out response Kimbo, I get busy at times and my answers can tend to be brief. You also have the option of my matching the tubes for you but if you plan on doing much DIY or you want to learn, it never hurts to have the right equipment.
> 
> On the subject of true RMS multimeters. This is one of my favorites:
> 
> ...



Luckily i work with a former 33W.  Aka an electronics technician who would have used that device.


----------



## riffrafff

Paladin79 said:


> Kimbo I am glad to have you on board with these amps, you obviously have a good background and electronics knowledge.
> 
> They have a ten amp shunt resistor as I recall and a probe built for the higher voltages. I never had much reason to use it because I used to deal more with 25kv and up on crt computer monitors. I used to use curve tracers a lot and as I began to troubleshoot the first Coaster amp I put together I had a scope go down as well as other pieces I had not touched for ten years. I have a power supply that goes up to 300 volts dc and even provides filament voltages for tube circuits and that is down as well.
> 
> ...




Nice old meter.  We still see them come in from time to time for calibration.


----------



## Paladin79

Very cool, I had friends that bought and sold a lot of military electronics out of North Augusta  SC. They made me aware of such things and how much they originally cost and the quality that went into their builds. I got my company into custom cables and brought a few of those meters in when I began setting up builders about 12 years ago, all meters are still functioning and they were built in the early 80's as I recall.

I noticed on Amazon and such places you can get assortments of surface mount resistors and capacitors for very little money. I am grabbing some of those to make experimentation a lot easier.


----------



## sam6550a

Paladin79 said:


> Kimbo I am glad to have you on board with these amps, you obviously have a good background and electronics knowledge.
> 
> They have a ten amp shunt resistor as I recall and a probe built for the higher voltages. I never had much reason to use it because I used to deal more with 25kv and up on crt computer monitors. I used to use curve tracers a lot and as I began to troubleshoot the first Coaster amp I put together I had a scope go down as well as other pieces I had not touched for ten years. I have a power supply that goes up to 300 volts dc and even provides filament voltages for tube circuits and that is down as well.
> 
> ...


You are so right! I have a Navy an/PSM4A meter, which is a waterproof Simpson 260, as well as a Triplett 630. Both get weekly use and are in good condition.


----------



## Paladin79

I have always liked the quote, "I may not know a lot, but I know some things very well."  When you hang around the industry long enough you develop some likes and dislikes. 

This weekend I hope to wrap up a Coaster amp headphone rack build, I am pretty happy with the little amps and if you push them with a DAP, they take up little space on a desktop.


----------



## Rensek

Chapter 1 of the Coaster Amp. 


Jason Stoddard said:


> *2018, Chapter 2:
> Engineering, Part 1*
> 
> Ready for something different? How about a deep dive into engineering of an audio product? A dive that goes into the choices, constraints, and decisions on everything from the initial design goals to the characteristics of the devices used, to the finished product itself?
> ...


----------



## Rensek

Chapter 2 of the Coaster



Jason Stoddard said:


> *2018, Chapter 3:
> Engineering, Part 2*
> 
> 
> ...


----------



## Rensek

Coaster chapter 3




Jason Stoddard said:


> *2018, Chapter 4:
> Engineering, Part 3*
> 
> 
> ...


----------



## Rensek

Coaster Chapter 4



Jason Stoddard said:


> *2018, Chapter 7:
> Engineering, Part 4*
> 
> In the last chapter about the coaster amp, I was agonizing over an unexpected outcome—variable noise in its output. At the time, I thought it was probably oscillation, since the tubes I’m using have very high bandwidth. But I’d never seen anything like it on the original Vali, so it was really, really weird to see it on an even simpler, lower-performance amp.
> ...


----------



## Rensek (Jul 12, 2018)

Paladin79 said:


> I have mounted one in a magic 8 ball, tobacco tins, and a headphone rack. I will mount one in a scotch bottle at some point. You can see those photos in the main thread but it can take some looking. Later today maybe I can re-post some here. Beer cans could work, maybe something like a Fosters lager can.
> 
> Once I get done with basic builds I was considering stacking a couple of them and combining channels and power but I need to think it through some. It can be done with power amps.



I would be very interested In knowing how to combine channels and power. Power specifically. One of my earlier posts on the Schiit thread asked about how to use a headphone amplifier to power speakers. I have studied up on parallel and linear circuits as a way to increase ohms and improve efficiency of low ohm speakers. I am hungup on how to combine power. From the reading I did I would need to construct a passive summer.


----------



## Paladin79

I know combining power can be done on some power amps and I was just thinking out loud. It is typical for me to explore other possibilities for Coaster boards. I think they would look cool with two or three stacked so I began to think it through but most likely it is a bad idea.

Thanks so much for consolidating all the Coaster chapters into this thread. I am not as skilled searching for them and I found the last chapter by date (July 4) when I wanted to reread parts of it. I did work with Jason a bit more to reduce an audible pop when the relay kicks in and he does have a 25 second delay on the Coaster board before that happens and you get sound.


----------



## Paladin79

In order to mount Coaster Amp board vertically, I made a frame out of tinned, braided, copper. I have cut out a small notch to allow the power plug to sit properly against the pc board. This is just a test setup, the mesh will go on a completed board later today or tomorrow.


----------



## Ripper2860

Very nice!!!!


----------



## Paladin79

Glad you like it, it should hold well in place and it is not close to touching any etches, they are pretty well sealed anyway.  Most likely I will use a removable hook to hold it in place that will slide over an anodized aluminum rod so it can be dismantled from a headphone rack pretty easily.


----------



## Paladin79

A finished coaster amp.  It is being suspended by a black, anodized aluminum tube that used to be someones prized target arrow. I hope they can get by with eleven. It is late in the day and I was cutting these angles on the arrow as I held it in one hand and a jigsaw in the other. Don't try that at home kids, some builds should be left to those of us who still have all of their fingers and toes.


----------



## cricket

Paladin79 has shown lots of finished coaster amps, but there has been no pic of how they start. I'm always surprised by how many bags of components it can take for some really small projects. On the left are passive SMD. The right column contains active SMD components. The middle column is all through-hole parts plus the SMD relay.

The following quote that a friend found applies to Jason's board:
Every good PCB designer has the heart of an artist and the mind of a mathematician, and each PCB design is a different piece of art with mechanical precision. Good PCB designers take pride in their workmanship as they strive to make each new PCB layout more perfect than the last.   =Tom Hausherr=


----------



## Paladin79

Were you able to get all needed parts Cricket? I am happy to share a few tips if you like.

I had way too many bags of parts so I dedicated a parts cabinet to coaster parts. I also got a very nice set of tweezers for handling surface mount devices, I think around $12 for 8 different configurations.


----------



## cricket

Paladin79 said:


> Were you able to get all needed parts Cricket? I am happy to share a few tips if you like.
> 
> I had way too many bags of parts so I dedicated a parts cabinet to coaster parts. I also got a very nice set of tweezers for handling surface mount devices, I think around $12 for 8 different configurations.



I don't plan on assembling more than two for myself, although I accidentally ordered parts for three.  If I planned to build more, I'd get an anti-static compartmented tray from McMaster Carr.  I have an idea for that extra board if it passes Head-Fi rules.

My favorite pair of tweezers are these: http://www.dx.com/p/weitus-stainless-steel-precision-angled-tweezers-19866#.W0tCoJ-uOUk
Sparkfun sells others that are very nice: https://www.sparkfun.com/products/10602

All the parts?  Not exactly.  I made some substitutions that shouldn't affect operation.  I'll report on these if there aren't any problems.


----------



## Paladin79 (Jul 15, 2018)

I have naturally found alternate parts myself for some items and I have a few things still on back order. I have anti static table and floor mats, wrist strap etc. and I generally just line drawers with anti static material when needed.  I use anti stat tweezers as well.

https://www.amazon.com/gp/product/B06XXXQHS8/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

These have been fine for my builds.

I talked to Jason the other day about one slight change, if you get one up and going I can get with you on that. Having those tools it sounds like you are familiar with surface mount devices so you will probably be fine.

You certainly sound capable, folks are approaching this with different electronic skill levels so it is easy for me to say the wrong thing at times.


----------



## the finisher

I need to start my parts hunt. @Paladin79 do you really need all that anti-static gear? 
I've voided warranty on all kinds of PC gear and never killed anything. I use a mat, and have several straps I don't use.


----------



## Paladin79 (Jul 15, 2018)

If you are using a mat and make contact with it while working with semiconductors you should be fine IMHO. This is a DIY project and you are not responsible if something happens six months down the road if you are building for yourself.


----------



## drtechno (Jul 15, 2018)

Its cute, not to many z-foils needed, even though its not a 9-a tube base design, I would still build one. Maybe putting it into a little box like the ones I use for storing my sewing stuff.

Its small enough to do the toaster oven soldering method too. But I'm also crazy (and skilled) enough to solder this with a standard iron (with a modified tip) .

The only think I would change is the volume control: I would set the gain on the tubes, then apply the volume after the tube stage so that it would maintain that warmer sound regardless of volume setting.,,


----------



## Ripper2860 (Jul 15, 2018)

I don't use those annoying straps, pads or mats.  I use a stainless steel bench on a carpeted floor, and wear wool slacks, an angora cardigan, and leather sole shoes when working on my my electronics DYI projects with no problem what-so-ever.  The fact that nothing ever works when I'm done is solely due to the fact that there is a problem with the BOM and/or design.  







Seriously -- don't do this.  Do not listen to  a single word I have to say about any component-level DYI projects.


----------



## Paladin79 (Jul 15, 2018)

Ripper2860 said:


> I don't use those annoying straps, pads or mats.  I use a stainless steel bench on a carpeted floor, and wear wool slacks, an an angora cardigan, and leather sole shoes when working on my my electronics DYI projects with no problem what-so-ever.  The fact that nothing ever works when I'm done is solely due to the fact that there is a problem with the BOM and/or design.



I know you are allergic to cats so you probably rub a glass rod over a rabbits fur as you build devices as well.

But in all seriousness, I do enjoy trying to figure out ways to mount a circular pc board. I saw you in the Crack thread I believe DrTechno, this is one of my crack builds. I rarely take the easy route. Next to it is a Whammy but I just went with a basic box on it.


----------



## Ripper2860 (Jul 15, 2018)

Paladin79 said:


> I know you are allergic to cats so you probably rub a glass rod over a rabbits fur as you build devices as well.



Nah.  I rub a balloon on head.  

Nice BCH and Whammy.  You sir, are an Arteest!!


----------



## drtechno (Jul 15, 2018)

I love the texture top of this box!!! how you do that! That is cool  The meters in the front dresses it out nicely too. 



Oh back on topic: I only saw one part that was critical static wise in this kit: its the output ic (because its a mosfet a/b amp) but as long as you don't sit there and roll it around in your hand you should be fine. I would get a couple of those ic chips anyways because of the off chance one would get damaged in shipping or just faulty to begin with.


----------



## Paladin79 (Jul 15, 2018)

The Crack is an easy build so I just like to concentrate on other areas. I was in a hurry on the Whammy but others in here did beautiful cabinets on them. I am going to make my class a monoblocks fairly good looking with the help of a talented woodworker.

I added a blue patina to 1/8 inch copper plate, that top weighs two pounds. Front and back plates are the same thickness and I used one inch thick quartered oak and went with a taller box. The patina can be done in a day in a well ventilated area using ammonia and sea salt. Vinegar will give it a more greenish tone as I recall. The copper just sits above the liquid in a chamber overnight, I generally spray the copper with diluted salt water as well. If you do a google search for Steampunk Bottlehead Crack under images, you will see some photos of my build. I made a matching headphone rack and modified some headphones to match. I also turned them into high impedance headphones. I have messed around with copper on the Schiit Coaster amp as well.


----------



## Ripper2860

Are you building a 7.1 AV system out of Coasters??


----------



## Paladin79 (Jul 15, 2018)

I am absolutely not building a 7.1 system, I prefer 7.2 cause the subwoofers help drive moles out of my yard and into my neighbors. Today I am working with half inch copper pipe and I will play around with mounting a coaster in the center of it just to see how it goes with the headphone rack when completed. I get to take a break while the copper is undergoing a chemical reaction. i think a convertible headphone rack would be nice, one easily switched from Coaster amp with headphones to pure steampunk by plugging in two different devices.


----------



## Ripper2860

Very nice and very creative!


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## Paladin79 (Jul 15, 2018)

I had already made one so it was mostly muscle memory. I did fill a small tub with water so I could cool the copper quickly, that sped things up. This is after about an hour of copper, salt and ammonia fumes doing their thing. The flat plate at the bottom is already taking on a blue color, by this time tomorrow, all copper should have some patina.


----------



## the finisher (Jul 15, 2018)

Paladin79 said:


> I prefer 7.2 cause the subwoofers help drive moles out of my yard




I always buy my subwoofers in pairs    Nice work!


----------



## JohnnyCanuck

How about a pair of these?  As seen at the Munich High End show:


----------



## Paladin79 (Jul 15, 2018)

Very nice, that looks like Paul McGowan in the lower left of the photo.

Ok I have what is probably the greatest idea yet for a coaster amp build but I will not reveal it till I actually do the build. It is something any one of you can do and it allows for the coaster to be used as a coaster or as a headphone amp. Provided you can build, or coerce someone into building the amp.

You can make the device, or the vessel if you will, and you will kick yourselves for not thinking of it already. Unless you already have that is. This is going to be sooooo cool I may try to talk the Finisher out of a square of granite to place it on once done with maybe a smaller square of cherry. It deserves a pedestal, it will be that wonderful. You will be able to make your own just as easily as I make mine, very little skill required and the results could be mind boggling.

I may make a video or take a series of photos and I will try to let everyone know precisely when I will make the reveal. This idea could be so good that Jason might decide to post a photo on his website, stranger things have happened.


----------



## Ripper2860 (Jul 15, 2018)

Oooooh.  Sounds pretty exciting.   Give us a hint.  Is it a Vessel with a Pestle or a Chalice from a Palace?


----------



## riffrafff

Ripper2860 said:


> Oooooh.  Sounds pretty exciting.   Give us a hint.  Is it a Vessel with a Pestle or a Chalice from a Palace?



"They say they've already got one."


----------



## Paladin79 (Jul 16, 2018)

Here is a hint, you can buy what is needed on Amazon. Of course you can probably buy everything except for opioids, human body parts and guns there but that is beside the point.

Another hint is, if you build one, it will be unique; just like the build of everyone else who builds one.


----------



## cricket

Paladin79 said:


> Here is a hint, you can buy what is needed on Amazon. Of course you can probably buy everything except for opioids, human body parts and guns there but that is beside the point.
> 
> Another hint is, if you build one, it will be unique; just like the build of everyone else who builds one.



Play-Doh?


----------



## Paladin79

Oh man, now I have to come up with a new idea before Wednesday!!

Another clue, read the sci-fi writer Kilgore Trout, the idea I am working on has a lot to do with one of his books as well as a Dutch artist who shall remain nameless till the final reveal is made. There is a drawing that should hint at my inspiration.


----------



## riffrafff

Paladin79 said:


> Oh man, now I have to come up with a new idea before Wednesday!!
> 
> Another clue, read the sci-fi writer Kilgore Trout, the idea I am working on has a lot to do with one of his books as well as a Dutch artist who shall remain nameless till the final reveal is made. There is a drawing that should hint at my inspiration.



Man, it's been years since I read any of Vonnegut's Kilgore Trout stuff.  I'm afraid you have me at a disadvantage, sir.


----------



## Paladin79

At least you know who he was or was supposed to be lol. I am going back and rereading a lot of it, a great Indiana author.(Vonnegut) Another was Jean Shepherd, A Christmas Story is based on his short stories. Funny, funny man.


----------



## kimbo

That's a nice coincidence...a bunch of Vonnegut fans. 
I'm in the middle of reading a book of Kurt's letters.  Great man.  A little mixed up, but a great human.
To this day Slaughterhouse Five is one of my very favorite books. And Kilgore Trout and Billy Pilgrim are my favorite literary characters.  
First read it as a teenager about the time it came out.  Hmmm, I must be getting old.

PS. As an engineer, this makes me smile...


----------



## Paladin79 (Jul 16, 2018)

I used that Vonnegut video as an argument against a book in one of my book clubs.

There is still a Vonnegut hardware in Indianapolis last I heard. Vonnegut’s grandfather invented the safety bar on commercial doors because of a fire that killed many. His brother co-invented cloud seeding.

The Dutch artist has more to do with my design but I wanted to see who knew Kilgore Trout. Well done!  Venus on the Half-shell could be a clue.

I work within a half hour of where Kurt grew up. One friend used to talk to him on occasion, a book editor.


----------



## jimmers

Paladin79 said:


> I used that Vonnegut video as an argument against a book in one of my book clubs.
> 
> There is still a Vonnegut hardware in Indianapolis last I heard. Vonnegut’s grandfather invented the safety bar on commercial doors because of a fire that killed many. His brother co-invented cloud seeding.
> 
> The Dutch artist has more to do with my design but I wanted to see who knew Kilgore Trout. Well done!  Venus on the Half-shell could be a clue.


When you said Dutch artist I was hoping for





I had wanted you to do Coaster in snow dome





Botticelli was Italian, so not this


----------



## Paladin79 (Jul 16, 2018)

Jimmers, for some reason you always impress me. I hesitate to say much right now except for the fact it is not a snow globe.

Later you will see why you are very close provided this works. I have not gathered all of my parts yet.

Venus on the Half-Shell was a Kilgore Trout book, many thought Vonnegut wrote it.

I am re-reading God Bless you Mr. Rosewater today, Kurt’s early works impressed me most.

Above is my patinated copper after 24 hours. Nearly ready for a clear coat after a mild brushing. This is another project that might entail a Coaster amp.


----------



## riffrafff

_"I tell you, we are here on Earth to fart around, and don't let anybody tell you different."_ -- Kurt Vonnegut

I used to have that quote above my desk at work for years.


----------



## the finisher (Jul 16, 2018)

Paladin79 said:


> Oh man, now I have to come up with a new idea before Wednesday!!
> 
> Another clue, read the sci-fi writer Kilgore Trout, the idea I am working on has a lot to do with one of his books as well as a Dutch artist who shall remain nameless till the final reveal is made. There is a drawing that should hint at my inspiration.



Ok I'll play, my guess is "She sells _seashells_ by the sea shore" 

So either this one.  






But more likely this one is the real clue


----------



## Paladin79 (Jul 16, 2018)

Vonnegut was amazing. In a letter to a friend he predicted a small dog would kill him. He tripped over his dogs leash and tumbled down some stairs at his apartment in New York, he died shortly after.

A friend who wanted him to forward a book of short stories used to call him and oftentimes Vonnegut would pretend to be the butler. The guy had an amazing wit.

There is one guess that is very very close but I have only thought through half of the process, the remainder will come to me by Wednesday, with a reveal no later than Friday if all goes well and I am not called out of town.

I always liked the cover art on Venus on a half shell.


----------



## Paladin79 (Jul 16, 2018)

riffrafff said:


> _"I tell you, we are here on Earth to fart around, and don't let anybody tell you different."_ -- Kurt Vonnegut
> 
> I used to have that quote above my desk at work for years.



I love that quote and I tend to work very hard, but the Coaster amp is serious fun for me. I am trying to get Jason on board for the reveal but he stays pretty busy.

I should do an amp based on the works of Thomas Pynchon, that would give you a lot of food for thought but I am not sure how to involve V2 rockets real easily, Star Wars is easier.


----------



## Ripper2860

Paladin79 said:


> Jimmers, for some reason you always impress me. I hesitate to say much right now except for the fact it is not a snow globe.
> 
> Later you will see why you are very close provided this works. I have not gathered all of my parts yet.
> 
> ...




Looking good!!!


----------



## Paladin79 (Jul 16, 2018)

Thanks, doing a patina is a lot like the stock market, you invest your time and energy and leave it alone. Of course with president you know who in office, with one tweet the market is up and down  more often than a hookers panties.

When the reveal is made, I should at least offer to build a Coaster amp at no charge for the person who is closest with their guess if they cannot build one for themselves. That is the least I can do.

Van Gogh was also Dutch as I recall, and I can imagine a coaster board fitting inside some headphone cups, or maybe just one cup, acting as a source directly to both drivers. But then, where does Kilgore Trout enter into this?

I have done some headphone modification so this is plausible, yet, this vessel will be something most anyone can do and a bare board is little use inside a headphone.


----------



## Ripper2860 (Jul 16, 2018)

Put me down for a Dutch Fez Wine Coaster Coaster.  Looks like it might fit  ...


----------



## Paladin79

If only life was that simple.
time for a Vonnegut book.


----------



## Ripper2860 (Jul 16, 2018)

A Big Mouth Billy Bass Coaster with integrated speaker!!  You are a Genius.

(It wasn't easy, but after putting the pieces together -- Vonnegut.  Kilgore *Trout*.   Fish.  Makes perfect sense!!)


----------



## Paladin79

That is a strange looking trout.


----------



## Ripper2860

Well, they didn't have a Billy Big Mouth Trout, so I had to improvise.


----------



## Ripper2860 (Jul 16, 2018)

Well, whadda ya know...

And now, without further adieu, I introduce Travis the Singing Trout!

(Mystery Solved.  Everyone can now sleep easy, although I'm curious as to where you'll put the headphone jack.)


----------



## Paladin79

Ok you win fish identification, you could be a game warden I guess.


----------



## Ripper2860

OK.  My last entry into the 'what could it be' Coaster Contest ...

A Kurt Vonnegut Coaster Coaster


----------



## Paladin79

I like it but you would be closer with a Dutch artist.


----------



## Ripper2860

You're going to mount a Coaster in a replica of Van Gogh's severed ear??


----------



## Paladin79

No but my diversion may be working.


----------



## Ripper2860

Well,  I'm completely out of ideas, so I'll let this thread return to its regularly scheduled programming.


----------



## Paladin79

It will make sense very soon and spray paint should be involved.


----------



## the finisher




----------



## riffrafff

the finisher said:


>


----------



## Th3Drizzl3

^ lol. ill have some of them to mess with soon also


----------



## gr8soundz

Paladin79 said:


> It will make sense very soon and spray paint should be involved.



Something to do with The Great Space Coaster?


----------



## jimmers

Paladin79 said:


> ... But then, where does Kilgore Trout enter into this?...



Not the upcoming design, more like one of your previous copper wire creations.





(you did say Amazon didn't do body parts


----------



## Paladin79

gr8soundz said:


> Something to do with The Great Space Coaster?



Nope. Spray paint is not required but it might help the appearance of the container.


----------



## Paladin79 (Jul 17, 2018)

Th3Drizzl3 said:


> ^ lol. ill have some of them to mess with soon also



Cool, hopefully a few more people will build the amps. Some of my supplies should arrive tonight for my latest build and I will try to get started on it then. Not counting spray paint, there is probably 15 minutes or less of actual work involved and the paint is optional.

Thinking back to Jimmers idea of a snow globe, pure water (distilled water) is a poor conductor, it is the substances in water that makes it conductive. Maybe ground white plastic chips or white nylon for snow. The problem is if the connectors are mounted in glass, they do have openings that would let water out. I could make three short extension male to female cables and seal the openings around the cables with clear silicone. Maybe seal the board and connections with a clear, non-conductive sprayed conformal coating made for electronics. Glass can be drilled but a clear acrylic ball might be better and easier to work with. This could be done but right now I have a bit too much on my plate to take it on as well.


----------



## the finisher

Paladin79 said:


> Thinking back to Jimmers idea of a snow globe



Mineral oil would work.


----------



## Paladin79 (Jul 17, 2018)

Good choice. I will let someone else take this on if they want to, I could help with the construction of short extension cables if any of you try this.

https://www.amazon.com/Chenille-Kra...1531833807&sr=8-7&keywords=clear+acrylic+ball

There are four inch clear acrylic containers that could be opened. The board is 3.5 inches across so something this size may do the job. You have to leave a bit of room for the female jacks on the board and this could suffice.


----------



## the finisher

Be challenging for sure


----------



## Paladin79 (Jul 17, 2018)

If molded cables are used, those where the connectors are over molded, that part of the connector should be sealed pretty well. The pc board is gold plated and that does not corrode but I would worry about the solder joints without some kind of coating on them. The Coaster amp is not an expensive build but I do not want to lead anyone down the wrong path by suggesting something that might not last too long.

I double checked and mineral oil is used as a non conductive liquid for cooling


----------



## the finisher

Yup seen several pc build over the years, but incredibly messy.


----------



## Paladin79 (Jul 17, 2018)

Someone else should do this build, it  should be functional. 
This style molded 3.5 mm male to female could work. Seal it half way down the body of the connector into the plastic ball, your 3.5 mm cable from player or headphones plugs into the female extension. On the other side you would need a 5.5 x 2.1 mm molded power plug that is already on your wall wart, seal half way down the body of that connector and you should be in business. Pretty much just three identical holes with these connectors, seal them with clear silicone glue, use some ground white plastic or nylon for snow, mineral oil and you should be in business. A coaster amp snow globe!



If a computer works that is submerged in mineral oil, this should work as well and it is a lot smaller.
And no, this is not what I am building, my build is easier.


----------



## Paladin79 (Jul 17, 2018)

I did not get the angles right but this is my idea for a Coaster amp holder. A kit with which you can make an exact replica of your hand holding a circular coaster amp. I really need to change the angle a lot for this to work but I was trying for the M.C. Escher reflection image. Jimmers was surprisingly close. I will have to get another kit and try again sometime.


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## Ripper2860 (Jul 18, 2018)

Well, I'm out ...


----------



## Th3Drizzl3

fyi i once ran a car amp in mineral oil just to try it without the bottom screwed on and flipped upside down. worked fine. looked awesome as hell in the car


----------



## Paladin79

Yeah, I doubt I will try for the snow globe myself. Anyway the process I used got tricky because no matter how you position your fingers, it is tough to flip your and over and keep all your fingers at the proper angle within the molding material. The kit was also around $30 and I would probably go through several of them just trying to get the fingers perfect so they would support the Coaster amp. I imagined this spray painted with faux marble paint, sitting on a desk, holding the amp or just a coaster. It should be obvious I had Escher in mind and Kilgore Trout is supposed to have written a book about a hand that had skin cells removed and a group of men was cloned from those. 

I considered holding a coaster board inside the molding material but there was a good chance it would mess up the process so I declined. You have a very small window of opportunity to get your hand into the material once it starts to set up so I probably rushed things a bit. Back to the drawing board for me.


----------



## jimmers (Jul 18, 2018)

Paladin79 said:


> I considered holding a coaster board inside the molding material but there was a good chance it would mess up the process so I declined. You have a very small window of opportunity to get your hand into the material once it starts to set up so I probably rushed things a bit. Back to the drawing board for me.


When you said it would be one of a kind, personal to the maker, I thought it might be a hand moulding, but you said that anyone could make it so I thought it couldn't be. 

How about a dome with no snow
https://www.amazon.com/Acrylic-Outd...coding=UTF8&psc=1&refRID=MDRP2DC90Y87RHCNW85K



You could put it on a plinth, could have a brass or copper ring around the bottom for a steam punk porthole vibe

I like the look and sensitivity of the Klipsch La Scala, but wouldn't a higher impedance speaker be better for bridged ACAs to reduce the current requirements?.


----------



## Paladin79 (Jul 18, 2018)

Hmmm, I really like that and the size is decent. I may have to try that out down the road. I looked for such things early and many were made of glass and not exactly what I wanted.

That is a very good idea!  Oh and every one can stick their hand in a bucket of molding goop, it is just holding the fingers at the perfect angle that is tricky lol.

I have one on the way with free shipping, I found them on EBAY.


----------



## the finisher

https://www.snowdomes.com/product/1-XL-Round-Glass-Snow-Globe-Kit.html


----------



## CAPT Deadpool (Jul 19, 2018)

So I have a Weller WPS18MP Solder Iron with a .03125 tip that I think will be small enough based on the webpage below on cheap tools to use for SMD work.  Those of you who have built a coaster what are you using?  Any soldering tips?  Pun intended. 

I found this webpage that should help many of us like me.  Gosh these parts are so small.  I think all of mine have arrived.

http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Tools


----------



## riffrafff (Jul 19, 2018)

CAPT Deadpool said:


> So I have a Weller WPS18MP Solder Iron with a .03125 tip that I think will be small enough based on the webpage below on cheap tools to use for SMD work.  Those of you who have built a coaster what are you using?  Any soldering tips?  Pun intended.
> 
> I found this webpage that should help many of us like me.  Gosh these parts are so small.  I think all of mine have arrived.
> 
> http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Tools



Heat the leg and pad, not the solder.  And it doesn't take much solder at all.  Use the thinnest solder you can find, and a decent light and a loupe help.

Edit:  I just looked up your tip...are you using the chisel tip or the conical one?   I use a conical tip, but about half that diameter (maybe; hard to tell from photos on the web).


----------



## Th3Drizzl3

i like the Kester 331 solder myself. super easy to work with and flows really nice. doesnt need crazy high heat either. its my go to for inexpensive solder. a whole lb on amazon at times is under 20$ when you catch it on sale. also cleans up really easy. i also have pure silver solder (among a bunch of others lol) but i dont use it often on boards because it needs a lot of heat. and imo the best soldering iron for the money (79$ on sale often at fry's) is the hakko 888d. i use a 951 myself. but for the money the 888 is really hard to beat especially when on sale. easy to find a TON of tips for hakkos also.


----------



## CAPT Deadpool

riffrafff said:


> Heat the leg and pad, not the solder.  And it doesn't take much solder at all.  Use the thinnest solder you can find, and a decent light and a loupe help.
> 
> Edit:  I just looked up your tip...are you using the chisel tip or the conical one?   I use a conical tip, but about half that diameter (maybe; hard to tell from photos on the web).




Conical.  I saw a 50$ one with a tip your size on amazon.  Think it was the WES120.  The link i post said to use 1/32 aka .03125.  They recommended a $100+ Weller that had analog controled temp


----------



## cricket

Your iron and tip will be fine for the small components.  The regulators may require something a little heftier.  

I will strongly recommend a flux pen for the SMD devices, only.  Apply the flux to the pads and hold the component in place with tweezers.  Melt a tiny amount of solder on the iron's tip and touch it to the joint.  The flux will let the solder flow.  How much is a "tiny amount"?  You'll have to practice.  I just sort of brush the tip against the solder.  I also run my iron pretty hot, around 700F, which reduces "dwell time" on the joint.  With the flux, it's almost a gentle tap and release.  

What kind of flux?  For a beginner, I'd recommend a flux pen with no-clean flux.  After soldering, scrub the flux off with an old toothbrush and alcohol.  Resist the urge to use the flux on through-hole components, especially parts like switches, pots, and connectors where you wouldn't want it to intrude.


----------



## riffrafff

I use this soldering station, with two irons.   And this one for de-soldering.   The first one uses RF energy to heat the tips; coming up to 750° F from cold in about six seconds.  Plus, the tip/elements can be changed out whilst hot (with a bit of caution, of course).


----------



## Th3Drizzl3

nice! ive been eyeing the 203 for a while. my 951 so far has done everything ive used it for so i just have been putting it off.


----------



## riffrafff

Th3Drizzl3 said:


> nice! ive been eyeing the 203 for a while. my 951 so far has done everything ive used it for so i just have been putting it off.



Both are decent stations, indeed.  I use the dual-iron version because I deal with a lot of RF power transistors, and sometimes need two high-wattage irons at the same time, on the same part.


----------



## cricket

Here's a video I found that shows the method I use.  Soldering doesn't start until about 2:30.  Note the relative size of the tip compared to the component.


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## Paladin79 (Jul 20, 2018)

This is all good info, personally I use .025 or smaller  Kester rosin core solder so I do not have to flux separately. I tin the pads before attaching the components. I use Weller Stations but I do keep a Hakko nearby with a larger tip. There are very pointed tips that Weller puts out that fit my WTCPT station. The tips control the heat, one marked with an 8 is 800 degrees f, 7 is 700 f, 700 is fine for this application. 
I have built five working Coaster boards with this iron, tip combination and all are fine. I do use a magnifier light, tweezers, etc. I start with the smallest items first so I am not trying to fit them around other parts. The through hole stuff is pretty simple at the end so I leave it for last. I use a meter to check continuity for all small connections. Also you will need either solder wick or a solder sucker of some kind. It is very easy to get solder where it does not belong on the small three legged transistors. Either of those things will remove solder shorts.


----------



## Paladin79

My latest build, a four headphone rack that can hold a Schiit Coaster amp or brass gears as a center piece. All materials are either copper, brass or oak.


----------



## kimbo

As we have been discussing SMD soldering I have a question re the regulators.  I have not soldered any SDM with rear pads before.  Is there any special technique?

Or do I just ensure that I have flux on the PCB pad and let the solder flow as usual?


----------



## cricket

The regulators and SOT-23 (tiny) transistors, would have benefited from oversize pads for easier hand soldering.  I applied flux to all regulator pads and soldered the legs first, making sure the tab was flush to the board.  There was barely enough of the large pad exposed that I could get a well tinned tip against the pad and regulator tab, then add some extra solder.


----------



## Paladin79

My technique is the same except I use rosin core solder, tin all pads before installing components and especially on the tiny transistors and led, I check for continuity with an ohmmeter. As mentioned previously I keep a blank board close by so I can see where all etches go.


----------



## kimbo

Thanks guys.
[I see my dyslexia has struck my post.   Remember....Dyslexia Rules!  KO!]

PS.  If there are any Aussies thinking about ordering a board, I have a spare pair.  PM me if you are interested


----------



## Paladin79 (Jul 24, 2018)

Here is the 4 inch security camera dome that someone mentioned, pretty well a perfect size, they are cheap out of China and well protected when they arrive. I just laid this one over the bottom half of an eight ball. Two of these with the mounting brackets removed and it gets more and more Escheresque.


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## the finisher (Jul 24, 2018)

Very cool sir 

So how are you finding multibit?


----------



## Paladin79

I will have to read back and give proper credit to whoever thought of this, maybe Jimmers or Kimbo.

I like the Multibit, sound quality is much better than the DAC's I was using before. I always heard power supply and preamp stage were very important with them but I am sure it is also how they are reading the info.  I do believe it is a keeper, and I have run it into four class a headphone amps, switched with Freya and that is a great combo.


----------



## the finisher

I am still amazed at the diffrence from several D/S dacs I've tried and 2 I still have compared to Yggy
With the exception of the speakers/cans it is such a difference maker in sound.

My Yggy did not sound great till it was running for 2 weeks at least, so Gumby is bound to improve more.


----------



## Paladin79

Cool, I had little time to listen tonight .


----------



## jimmers (Jul 24, 2018)

Paladin79 said:


> I will have to read back and give proper credit to whoever thought of this, maybe Jimmers or Kimbo...


You mean just some random Aussie? 

I cannot lie, it was I.
https://www.head-fi.org/threads/unofficial-schiit-diy-coaster-amp.883624/page-11#post-14366498

Looks really good with the Coaster inside.


----------



## Paladin79

Aussies are unique and rarely random.   My memory is not what it used to be but I was taught at an early age to always give credit, where credit is due so thanks for clearing that up.


----------



## Th3Drizzl3

finally got most of the parts on the way with a few left to find. work was more busy then normal past couple weeks so i put it off a bit.


----------



## CAPT Deadpool

Yeah I've got all the parts, but I think I need to get some different solder and some flux and such.  Right now I'm working a pi project for a friend on here.


----------



## Paladin79

Whatever works best for you on soldering. Personally I just used a tiny diameter hollow core solder that already contains flux but then I started soldering in the seventies and even went through a six week soldering course. 

If you do have issues with the Coaster, I hope you know I would send you a working one that I built.


----------



## CAPT Deadpool

Too bad we can't use tetrodes like the TH-558 or the new 4CM500,000G on the coaster.  It would really boost the wattage up.  I guess if we could get Jason to use them that would be some "hot crap"


----------



## Harry Manback

Paladin79 said:


> Yes black marks on all diode locations



So, the side with the line goes on the pad marked in black?  Could you post a closeup of the diode placements?


----------



## Paladin79

That photo is about as close as i can get and show all of the diodes. If you look closely at the lines for the diodes, there is one end that is actually closed in while the other side is open, the side that is closed is the cathode side and the bar on the diode needs to go there. It is also represented by a line on the schematic, that is the cathode side.

The LED's are a bit trickier, there is a small green dot on the cathode end as I recall, on those both black lines would go to the end of the board with the power plug, CN2.

I have an appointment this morn but if I get a chance later I may be able to get a closeup of an individual diode.or you can copy and paste the photo and expand it in a picture program on your computer or tablet or even smart phone.


----------



## CAPT Deadpool

So I just inventoried my parts.  I have a few extras if someone is having trouble finding a particular part let me know and I'll see if I have what you need.

Looking at the pictures, the schematic, and the BOM.  I ordered 10 switches cause I've got 4 coasters and the BOM says you need 2 switches for each board.  But I can only find one switch on the schematic, marked on the board, or in the pictures.  Am I missing something here or is there a mistake in the BOM?


----------



## cricket

The BOM is in error.  Only one switch is needed.


----------



## CAPT Deadpool

CAPT Deadpool said:


> So I have a Weller WPS18MP Solder Iron with a .03125 tip that I think will be small enough based on the webpage below on cheap tools to use for SMD work.  Those of you who have built a coaster what are you using?  Any soldering tips?  Pun intended.
> 
> I found this webpage that should help many of us like me.  Gosh these parts are so small.  I think all of mine have arrived.
> 
> http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Tools



So for everyone on here.  DO NOT buy this Solder Iron.  It boasts that it can heat up to 950 degree f.  That is NOT a good thing.


----------



## CAPT Deadpool

cricket said:


> The BOM is in error.  Only one switch is needed.



Thanks much.  I emailed Schiit about it once you confirmed.


----------



## Paladin79

Here are some slightly larger photos but note D4 and D3 in the left photo, there is a closed portion of a rectangle on the cathode, black mark end of the diode. Photo on right shows the direction for D102, D202 points in the same direction.


----------



## riffrafff

CAPT Deadpool said:


> So for everyone on here.  DO NOT buy this Solder Iron.  It boasts that it can heat up to 950 degree f.  That is NOT a good thing.



Okay, back in my day, young-uns, we used to simply change out the heating elements if we needed greater or lesser temperatures.  None of this variable temp voodoo magic you kids have today.


----------



## sam6550a

riffrafff said:


> Okay, back in my day, young-uns, we used to simply change out the heating elements if we needed greater or lesser temperatures.  None of this variable temp voodoo magic you kids have today.


Just dial it back to 650-700.


----------



## riffrafff

sam6550a said:


> Just dial it back to 650-700.



Well, yeah, nowadays.   I use a dual-iron station at work with variable temp, but, *back in the day*, I had to wait for the iron to cool, unscrew the tip, unscrew the element, replace the element with one of a different wattage, re-attach the tip, and wait for it to come up to temp again.  Today, at least with the Hakko stations, it's no problem to replace a hot tip, and of course the temp is continuously variable.  Better living through technology.


----------



## jimmers (Aug 18, 2018)

CAPT Deadpool said:


> So for everyone on here.  DO NOT buy this Solder Iron.  It boasts that it can heat up to 950 degree f.  That is NOT a good thing.


I think your post can mislead, I read your comment and clicked on the quoted link and the only iron was a Weller temperature controlled one - which would be just fine.
Looking earlier in the quote I see Weller WPS18MP which I assume is the one you are giving the warning for.
It would appear others have mistaken your post as well e.g. sam6550a "Just dial it back to 650-700."

Edit: Oh no, the  Weller WPS18MP uses an SMPS, so no good for Schiit Hi-Fi then


----------



## CAPT Deadpool

jimmers said:


> I think your post can mislead, I read your comment and clicked on the quoted link and the only iron was a Weller temperature controlled one - which would be just fine.
> Looking earlier in the quote I see Weller WPS18MP which I assume is the one you are giving the warning for.
> It would appear others have mistaken your post as well e.g. sam6550a "Just dial it back to 650-700."
> 
> Edit: Oh no, the  Weller WPS18MP uses an SMPS, so no good for Schiit Hi-Fi then



Yeah I was referring to the wps18mp.   I made it work so far (with coaching from a 33W, tips from Paladin and u tube.  im halfway through my first coaster.  My technique is improving.  I’ve lost 2 resistors so far damn things are so small.

I’ve got a weller 1010na in route as well.


----------



## jimmers (Aug 19, 2018)

CAPT Deadpool said:


> I’ve got a weller 1010na in route as well.


Nice.
Really like Wellers, I used to use Weller WTCPT60 until someone broke it, got a deal on a Hakko, does me fine, big advantage is you can get loads of different tips for cheap as opposed to the Curie point Weller tips.


----------



## Paladin79

I have used Weller, Hakko, and Pace but I used Weller for so many years and parts are readily available so they are generally my choice. My employees use them 8 hours a day and they hold up well. I have not had the same, good experience with Hakko but in my home shop one is still doing well.

As far as the coasters, I generally have two soldering irons going and might solder with either my left or right hand. I just find it easier to hold surface mount parts with my right hand and solder with my left. On through hole I go back to my right hand.


----------



## CAPT Deadpool

Yeah I've been going back and forth between hands.  Should finish with it today, God willing.


----------



## Paladin79

If you get the board going all right, I will help you with reducing the audible pop when the relay kicks in. Jason gave me a fix for that.


----------



## Paladin79 (Aug 19, 2018)

A raspberry PI as music source for a Coaster amp. I am running 300 ohm headphones and it works fine, I do not even have the music source on maximum.  Of course a Lyr 2 sounds better but it costs a lot more and this is going to be a portable system for use outside. Listening to Pink Floyd's The Division Bell.

You too can have an Escheresque hand by submerging your hand into some kind of molding goop and then using what appeared to be plaster of Paris. So far the Pi has been solid as a rock, thanks to CAPTDeadpool.


----------



## Harry Manback

Do D1 and D2 look correct?


----------



## Paladin79

Harry Manback said:


> Do D1 and D2 look correct?


Yep, see the closed ends on the board markings? Cathode / band to that side is right.


----------



## CAPT Deadpool

So I got my first coaster going.  Sounds better than I expected.  This was my first build of an audio device of this type.  RPis audio projects dont generally require soldering or at least not much.  I had never done Surface mount parts before. 

A huge thank you to Paladin79 for helping me with locating parts, selecting tools and supplies, answering noob soldering questions, and long distance troubleshooting when of course it didn’t work when I first turned it on. Or the next 10 or so times.

I kept notes during the assembly and I’ll try to post the steps of assembly.  And some tips that I learned.  If anyone gets stuck in building it or can’t find parts I’ll do what I can to help you.


----------



## Paladin79

I am not sure I have heard of anyone else getting a Coaster amp going yet so congratulations on your efforts!


----------



## Harry Manback

It is alive!!!!!!  

My tubes aren’t glowing though...sniff sniff.


----------



## CAPT Deadpool

Harry Manback said:


> It is alive!!!!!!
> 
> My tubes aren’t glowing though...sniff sniff.



Mine neither.  Sniffle.  I feel the same way.  Hey we could do like on some of the cheap amps like my crappy Bravo V2 (I don't even use it, although I might now repair it.  At least one of the jacks needs repair, it came with some crappy solder joints) and just wire up some LEDs to sit under the tubes.  Then like Al and the rest of the Bundys we can put a flashlight under a teepee of sticks and pretend its a fire (or tubes glowing).


----------



## Paladin79

Harry Manback said:


> It is alive!!!!!!
> 
> My tubes aren’t glowing though...sniff sniff.



We are now a league of three, not counting Jason at Schiit Audio.

I meant to comment the other day when you were asking diode polarity that your solder work looked very good. Did you use standard solder or is that solder paste?

Those tubes do not glow, that is why I made this configuration for Ripper:

 At least the LED's can look like glowing eyes with a headphone rack hood.


----------



## Harry Manback

Paladin79 said:


> We are now a league of three, not counting Jason at Schiit Audio.
> 
> I meant to comment the other day when you were asking diode polarity that your solder work looked very good. Did you use standard solder or is that solder paste?
> 
> ...



Thank you!  I used a hot air station and paste.  My brother is into HAM radio and builds lots of SMD stuff.  This was my first attempt at non-through-hole soldering.  It has it's own set of difficulties.


----------



## Ripper2860




----------



## CAPT Deadpool

Ripper2860 said:


>



Is your thumbnail a real character from South Park or something made up?  I would die laughing if South Park had an anti-social snobby audiophile character.


----------



## Ripper2860

There's an SP avatar generator that I used.  I just created the avatar and then used Windows snipping tool to save as JPG and uploaded.  

http://www.customsouthparks.com/  (my preferred tool)

http://southpark.cc.com/avatar


----------



## Paladin79

Harry Manback said:


> Thank you!  I used a hot air station and paste.  My brother is into HAM radio and builds lots of SMD stuff.  This was my first attempt at non-through-hole soldering.  It has it's own set of difficulties.



After you listen a while you will have to post your impressions, I know it is hard to compare the Coaster to full size headphone amps but I am always curious what others think.


----------



## jimmers

Ripper2860 said:


> There's an SP avatar generator that I used.  I just created the avatar and then used Windows snipping tool to save as JPG and uploaded.
> 
> http://www.customsouthparks.com/  (my preferred tool)
> 
> http://southpark.cc.com/avatar


Surely his hair, if any, should be grey


----------



## Ripper2860 (Aug 20, 2018)

My new avatar is an approximation of me, except...

1. I am far more handsome.
2. I am far more jovial.
3. My actual hair is better coiffed
4. Salt and pepper hair and and facial hair would more closely approximate my distinguished look, but alas it was not an option on the SP avatar generator.  

See for yourself …



Actually -- the older avatar bears a very striking resemblance of the real me.


----------



## jimmers

Ripper2860 said:


> My new avatar is an approximation of me, except...
> 
> 1. I am far more handsome.
> 2. I am far more jovial.
> ...


Sure not this


----------



## CAPT Deadpool

Ripper2860 said:


> My new avatar is an approximation of me, except...
> 
> 1. I am far more handsome.
> 2. I am far more jovial.
> ...




Watch out for power lines


----------



## Ripper2860

jimmers said:


> Sure not this



Not yet.


----------



## cricket (Sep 22, 2018)

Make that a league of four.  I evidently finished my coaster 29 July, when I started the notes for this:

It took 1.5 hours to install surface mount components. Most of that time was determining a sequence so I wasn't blocking components that would be added later. A lot of SMD time was spent locating the correct component location on the board. I found out it's better to install U3 before C11, even though U3 is larger and taller than the cap. The tab of the regulator is difficult to solder with C11 in the way. Overall, Jason's design is nice and open compared to many boards I've designed and built.  I'd call the coaster a good beginner's project.

Through-hole components took about 30 minutes.

I used machine pin sockets to make tube swaps easier than repetitive soldering and desoldering, but they're still a pain. If I were planning a lot of tube matching, I'd use terminal blocks like https://www.mouser.com/ProductDetail/Phoenix-Contact/1725685?qs=sGAEpiMZZMvPvGwLNS67143eXz6yLKIOODcchidcDdY%3d

Jason has mentioned that the tubes have microphonic characteristics. The first thing I noticed when listening was a constant oscillation around 4KHz. The oscillation can't be measured on my oscilloscope, although it fades to near inaudibility after about a minute. The least amount of movement brings it back, however.

Bass and midrange are quite good, while highs seem a little attenuated. This quality is what I imagine when someone describes an audio component as having a 'warm sound'. I have no other headphone amp, so can't make any comparisons.

I have an idea for mounting the amp and a unique concept for an alternate power switch.  Given the way things are right now, it may be a month or so before that gets started.


*Important edit:*  For anyone following this thread, don't order the terminal blocks I linked to above.  The pins are square and oversize for the holes.  There are similar designs that have smaller round pins, but I haven't looked for any yet.  Knowing the hole diameter would help in the search.


----------



## Paladin79

And now we are four. Congrats cricket!


----------



## CAPT Deadpool

So I'm going to put this out to the group.  I have a crackle that seems loud when the attenuator is a low volumes in the left channel.  But the crackle is not really noticeable once you get up into the 85db-90db range.  I'm guessing it is a problem with the left channel tube.  I've only got the two tubes right now as I sent my other 10 tubes off for some help with matching.

Anyone have any thoughts on what else it could be or agree that it is likely the tubes?


----------



## cricket

CAPT Deadpool said:


> So I'm going to put this out to the group.  I have a crackle that seems loud when the attenuator is a low volumes in the left channel.  But the crackle is not really noticeable once you get up into the 85db-90db range.  I'm guessing it is a problem with the left channel tube.  I've only got the two tubes right now as I sent my other 10 tubes off for some help with matching.
> 
> Anyone have any thoughts on what else it could be or agree that it is likely the tubes?



Swapping left and right tubes might be the easiest way to test.


----------



## Paladin79

Good answer. Hopefully you have solder wick or a solder extractor. It takes a while but it can be done.


----------



## CAPT Deadpool

Paladin79 said:


> Good answer. Hopefully you have solder wick or a solder extractor. It takes a while but it can be done.



Unfortunately or fortunately I do.  I've almost used up the super wick roll I have.


----------



## Ripper2860 (Aug 21, 2018)

Posted in error


----------



## Th3Drizzl3 (Aug 22, 2018)

for the time being my coasters have been put on the waiting shelf. i have some alpine car amps i was given for free that im looking for parts for to repair. they are turning out to possibly be paperweights. these are the pdx line i was given 4 of the pdx 1.1000's all had a fet blow but these are controlled by the "ice" chips and im finding parts almost impossible to find. i was hoping to use them since i loved my pdx amps i had back when they came out. that and im building my mainline and a couple other tube amps. i did get most of the parts in this week though for the coasters. i ordered enough to build 4 to start with


----------



## cricket

CAPT Deadpool,

I'll make another suggestion about the crackling noise based on your pic on Schiit Happened.  Try cleaning the flux from your board.  We have to be obsessive about flux removal where I work or we don't get readings of ~48 gig ohms on leakage tests.  I'm guessing you used the no-clean variety and alcohol should remove it.  Gently scrub with denatured alcohol and a brush then flush again with alcohol.  Avoid getting it in the jacks or the pot.  Blow the board off with compressed air when you're done.  All the usual precautions apply when working with flammable liquids.


----------



## CAPT Deadpool

Thanks much, I'll do that.  My 33W at work suggested much the same yesterday.  I was using 70% iso to clean with less than stellar results.  Yeah there is even more flux on it now.  I'll get that stuff soon and try it out.  Learning a lot here.  Thanks again for the tips.


----------



## CAPT Deadpool

cricket said:


> CAPT Deadpool,
> 
> I'll make another suggestion about the crackling noise based on your pic on Schiit Happened.  Try cleaning the flux from your board.  We have to be obsessive about flux removal where I work or we don't get readings of ~48 gig ohms on leakage tests.  I'm guessing you used the no-clean variety and alcohol should remove it.  Gently scrub with denatured alcohol and a brush then flush again with alcohol.  Avoid getting it in the jacks or the pot.  Blow the board off with compressed air when you're done.  All the usual precautions apply when working with flammable liquids.



Do you have a recommended brush type?  My friend the 33W gave me a recommendation but I can't remember what he said.


----------



## cricket

CAPT Deadpool said:


> Do you have a recommended brush type?  My friend the 33W gave me a recommendation but I can't remember what he said.



An acid brush, the type with a tubular sheet metal handle, with bristles trimmed to about 1/4" works well.  An old toothbrush with the handle bent slightly backwards works, too.


----------



## CAPT Deadpool

https://www.amazon.com/AES-Industri...=flux+brushes&refinements=p_89:AES+Industries

I found these on Amazon.  Made in USA.  I probably won't use a gross though.


----------



## Paladin79 (Aug 22, 2018)

Most any hardware store carries them, they are used a lot with paste flux for soldering copper pipe.

If any of you are getting a very noticeable audio pop when the music kicks in after 20 seconds or so, there are 10k bleeder resistors than can be lowered to around 3k , I believe they are R106 and R206 but I left my schematic at home and only have a Bom in front of me right now.

This weekend I hope to test some replacement transistors for the 2SA1312-BL, if all parts arrive by then I hope to be building a couple more coaster amps. 

I got the transistors and the size looks pretty good, all other specs look identical from what I can tell.


----------



## cricket

Don't forget the BOM and schematic are available on Schiit's website.

I'm sure I've got some 3K3 resistors in 0603 size.  Those should barely fit Jason's 0805 pads.


----------



## Harry Manback

I haven't decided on whether to mount the tubes horizontally or vertically yet.  It's VERY microphonic, but this really doesn't bother me that much.  I just don't mess with it much while listening, so it's ok.  I'm working on a case design that I will print using wood based filament.

I'm listening on HD58X headphones.  I'm feeding the amp with a ODAC rev B and iTunes on my mac.

Sound impressions:

Better than expected.  Based on Jason's writings, I expected it to be noisy and have bad channel imbalance from the combination of tube mis-match, and the volume pot used.  I must have gotten double lucky there.  Channel balance sounds ok going off of what I hear.  I don't know if I could tell tubes from solid state, so I won't get all crazy with describing the lush tubey sound.    It basically just sounds right.  I can hear details, and everything sounds balanced.  Lows aren't too low, highs aren't too high and mids are mids.

I could be happy with this as my everyday headphone amp.  I may build a 2nd and use off-board RCA jacks, and a full size headphone jack.  I will definately use a switch with a taller toggle.  Mine is a tiny bit below the 2 caps it sits between.  That will probably be off board too.

Kudos to Schiit for making a fun and good sounding coaster.  

Here is my first stab at a simple case for it.  Not really creative or fun, but it will protect it until I can think up something more interesting.


----------



## CAPT Deadpool (Aug 22, 2018)

Harry Manback said:


> I haven't decided on whether to mount the tubes horizontally or vertically yet.  It's VERY microphonic, but this really doesn't bother me that much.  I just don't mess with it much while listening, so it's ok.  I'm working on a case design that I will print using wood based filament.
> 
> I'm listening on HD58X headphones.  I'm feeding the amp with a ODAC rev B and iTunes on my mac.
> 
> ...




Can you provide more details on the off board RCA jacks?  Could they be mounted horizontally, but stacked vertically on the coaster (i.e. left on bottom/coaster and right mounted above it?  Could you provide part links if you find a way or on how you already described?  Edit: So I found this PJRAS1X2S01AUX at mouser.  It is through hole.  How could we attapt it to the coaster?

Can you provide part #s for the full size headphone jack?  And how you are connecting it?  I found this 

ACJS-MHD985 on Mouser which is interesting. 

I found both green and red leds that I think can be subbed in for the amber ones.  I'll post a link later.

I also found a potential Cap upgrade for the 470s and ordered them.  UKW1V471MPD  Arrow and Mouser have them.

I don't have any cases yet.  Please keep posting about your case designs and how you are doing it.  I have don't access to or experience using CAD or 3D printing.  I might hit you up for a case or two if you don't mind.


----------



## Paladin79

Yeah I know I can get the BOM and schematic on the Schiit site, I just get really busy at times so I did not go to the site.

I have used 1/4 watt and even half watt standard resistors on those pads. What I do is just stand the resistor straight up so it has two legs sticking out the bottom, then I bend little "feet" onto the bottoms of the legs, these are maybe 2 mm long and I solder those to the pads. It makes for a very stable and secure method of mounting them. One lead is of course bent across the body of the resistor so I have the two legs, I can trim it back so it does not stick up very far. I did the same thing when I used some ceramic caps in place of the 10 ufd that are so hard to come by right now. What I tend not to do is let one part keep me from completing a board. Naturally I know about combining resistors in series and parallel but I have not had to resort to that yet lol.


----------



## Harry Manback

CAPT Deadpool said:


> Can you provide more details on the off board RCA jacks?  Could they be mounted horizontally, but stacked vertically on the coaster (i.e. left on bottom/coaster and right mounted above it?  Could you provide part links if you find a way or on how you already described?  Edit: So I found this PJRAS1X2S01AUX at mouser.  It is through hole.  How could we attapt it to the coaster?
> 
> Can you provide part #s for the full size headphone jack?  And how you are connecting it?
> 
> ...



By off board I meant that I would run wires from the board to wherever I mounted those parts, instead of soldering the parts directly to the board.  I usually buy connectors and such are markertech.com.  Very reasonable prices and shipping.  They sell Rean/Neutrik and the other big name brands.  You can also get some nice Mogami wire there too.

I'd be glad to share/print something for you guys/gals.  I will upload the files to thingiverse.com too.


----------



## Harry Manback

Just thought of a good name for this product.  The Schiit Phuck (pronounced puck).  The accompanying dac will be called the Dam.  As a set, you'd have a Schiit Phuck Dam.


----------



## CAPT Deadpool

Harry Manback said:


> By off board I meant that I would run wires from the board to wherever I mounted those parts, instead of soldering the parts directly to the board.  I usually buy connectors and such are markertech.com.  Very reasonable prices and shipping.  They sell Rean/Neutrik and the other big name brands.  You can also get some nice Mogami wire there too.
> 
> I'd be glad to share/print something for you guys/gals.  I will upload the files to thingiverse.com too.


Thank you.

So if I understand you correctly you will use narrow gauge wire to connect them to coaster and attach/if them to the case.  What I don't understand then is which wires go where when you swap for the other ports/jacks.  

Further what if you wanted to try to use 1 or 2 coasters to make a balanced head amp what would you have to change?  I realize the ohms output would double if I understand right and I guess you'd have to match the tubes and coasters (pairs of tubes).  Also not sure how volume would be controlled.  After all I have 4 coaster boards and no warrenty to break so I'd like to learn this stuff.


----------



## Harry Manback

CAPT Deadpool said:


> Thank you.
> 
> So if I understand you correctly you will use narrow gauge wire to connect them to coaster and attach/if them to the case.  What I don't understand then is which wires go where when you swap for the other ports/jacks.
> 
> Further what if you wanted to try to use 1 or 2 coasters to make a balanced head amp what would you have to change?  I realize the ohms output would double if I understand right and I guess you'd have to match the tubes and coasters (pairs of tubes).  Also not sure how volume would be controlled.  After all I have 4 coaster boards and no warrenty to break so I'd like to learn this stuff.



Right on with the narrow gauge wire.  As for the connector pinouts, I would have to look at the datasheet for the connector to see which pins do what.

I have zero idea about how you would make a balanced amp out of two of these.  That would be a Schiit Double Phuck.


----------



## CAPT Deadpool

so the part we are using for the jack is https://www.mouser.com/datasheet/2/670/sj1-355xng_series-1312965.pdf  the 3555NG version.

If you look at page 2 bottom right corner you will see what the five pins on the connector are for.  That means that on the schiit schematic 1 ground, 2 Left, 3 Right, 4 Left Switch, 5 Right Switch.

Another lesson learned for me.


----------



## Paladin79 (Aug 22, 2018)

I haven't decided on whether to mount the tubes horizontally or vertically yet. It's VERY microphonic, but this really doesn't bother me that much. I just don't mess with it much while listening, so it's ok. I'm working on a case design that I will print using wood based filament.

I have had the best luck with laying the tubes down on dampening material.

https://www.ebay.com/itm/Isolate-It...04-x-4-x-6in/323319114473?hash=item4b47522ae9

This is what Jason recommended and I happened to own some.

I can help with any pinout on connectors when I get freed up more. I would be careful just running wires to off board RCA connectors, most all wire associated with them is shielded like coaxial cable. The very least you best do is use twisted pair, that is a form of shielding.

I will post results when I start working with two coaster boards but balanced is not an easy option and you are better off with another DIY kit IMHO.


----------



## CAPT Deadpool

Ok, the only balanced DIY kit I know of is the Bottle Head Mainline.  But looking at it I can't help but think it needs more tubes.  I realize that is silly but anyway.

I did some more reading on balanced.  I reread some stuff I read before.  It is starting to sink in better now.  I also have a much better understanding now of the Coaster schematic.

Normally I can learn without hands on, but I guess in the case of electronics hands on really helps for me.


----------



## Paladin79 (Aug 22, 2018)

You can bridge the outputs on some amps to increase power. I am considering using two separate Coaster boards and seeing what I can do once I read up on some theory.

I still have these thoughts about building headphones with a Coaster amp on each side powering the left and right channels or I could do it single entry with one amp but two would look better. Maybe incorporate a clear plastic dome. I have an extra set of rugged dual entry headphones that I have modified before but the cup is rather small for a Coaster.  These were closed headphones, 32 ohm, I turned them into 250 ohm open headphones for use with a specific amp. I need something larger like HifiMan but they should be closed and probably require less power.


----------



## 100VoltTube

Mouser lists the 2SA1312-BL as out of stock and has a lead time of a couple months. Where did all of you get your 2SA1312-BLs from? Digikey doesn't stock them either.


----------



## Paladin79 (Aug 26, 2018)

There is an alternate part number that Digikey lists. I will post it later on today. I should be trying some soon. I talked to their technical people about the part and it should be fine.

2SA1163-BL is a possible alternate source, I grabbed some and when possible I will test them.


----------



## riffrafff

Ha!  I found a companion for the coaster! 






https://www.ebay.com/itm/Magic-Eye-Audio-visualizer-driver-board-Suits-EM84-tube-or-Equivalent-VU-Meter/152545581369?hash=item23846cd939  

Erf.  Sorry 'bout the size.


----------



## Paladin79

riffrafff said:


> Ha!  I found a companion for the coaster!
> 
> 
> 
> ...


I have some magic eye tubes, I just need to make sure they match up. Good find!


----------



## CAPT Deadpool

riffrafff said:


> Ha!  I found a companion for the coaster!
> 
> 
> 
> ...


That’s pretty damn cool.  HOW does it do that with the tube?  Only one left


----------



## Paladin79

This video shows the style I have, there are a few different configurations. The quick answer is that you can think of them as a little cathode ray tube, there is a florescent material inside the tube that glows. As the grid voltage varies, the glowing material varies so they can basically be used a a visual VU meter. I put them on an amp I built just to win a bet, I had one for each channel. Some were made years ago with just a circle at the top and they were used as tuning indicators on radios, thus the magic eye name.


----------



## CAPT Deadpool

Paladin79 said:


> This video shows the style I have, there are a few different configurations. The quick answer is that you can think of them as a little cathode ray tube, there is a florescent material inside the tube that glows. As the grid voltage varies, the glowing material varies so they can basically be used a a visual VU meter. I put them on an amp I built just to win a bet, I had one for each channel. Some were made years ago with just a circle at the top and they were used as tuning indicators on radios, thus the magic eye name.



Do you have any pictures or video of the amp you built?  That must have been amazing!  What did ORT think?


----------



## Paladin79 (Sep 8, 2018)

I did not know ORT then. I will have to look for videos of the tubes. That amp may go into production and I had to sign a non disclosure agreement so I cannot go into a lot of detail. I can show this one, I was goofing around with different finishes but kept it all shiny copper when done. The blade switch controlled the magic eye tubes but those are hard to come by so most likely It will just have a toggle switch.


----------



## CAPT Deadpool

I have parts for 2 more coasters and could easily get the few parts I don't have for a third.  If anyone wants a kit with all the coaster parts or a completed coaster please PM me.  If demand is high I'll look into doing orders for more parts (which may require a couple subs due to some parts non-availability) to make more kits or coasters available.


----------



## Paladin79

I finally got the chance to test 2SA1163's in place of 2SA1312 transistors. I have had them running for a few hours and they seem to be a good replacement part. Digikey has them and show them as a feasible substitute.


----------



## CAPT Deadpool

Why we are having trouble with some of the capacitors on the Coaster BOM:

https://www.newark.com/survive-mlcc...RO-MLCC&et_cid=30255422&et_rid=958015275&cmp=


----------



## Paladin79

Here are the early stages of a coaster amp build, a flying saucer whose lights will respond to music. Under the red cup is a plastic dome that will cover the coaster. I am running the headphone outputs into headphone drivers whose sound will trigger the lights. What will also be fun is the fact it will respond to conversation, or a coffee cup being set down, or basically any sound within ten feet without music being present. That part should annoy my son but my granddaughter should love it. I will do the wiring tomorrow, lights are activated by remote control.


----------



## Paladin79

with LED's engaged.


----------



## sam6550a

Paladin79 said:


> with LED's engaged.


Amuse the grandkids, let the parents be annoyed!


----------



## Paladin79

I just have the one but she is pretty incredible. There is not much voltage involved and more than likely I will seal everything up so it is safe. The amp will just supply tiny speakers so I can leave it at full volume and it can be controlled by a DAP I will connect. 

I need to look through my music for Star Wars theme, Close Encounters of the Third Kind music, and maybe some of War of the Worlds.


----------



## sam6550a

Paladin79 said:


> I just have the one but she is pretty incredible. There is not much voltage involved and more than likely I will seal everything up so it is safe. The amp will just supply tiny speakers so I can leave it at full volume and it can be controlled by a DAP I will connect.
> 
> I need to look through my music for Star Wars theme, Close Encounters of the Third Kind music, and maybe some of War of the Worlds.



Try the theme from "Twilight Zone"-----.


----------



## Paladin79 (Oct 28, 2018)

Hmmm good one, among my music collection I found the soundtrack from Blade Runner, my son would appreciate the final narration entitled Tears in Rain.

I also found The Empire Strikes Back and A Clockwork Orange soundtrack. 

Also 2001 A space Odyssey.


----------



## Harry Manback

Paladin79 said:


> with LED's engaged.



I LOVE it!


----------



## Paladin79

Harry Manback said:


> I LOVE it!


Thanks it is one of my easier builds and friends contributed ideas.


----------



## Ripper2860

You MUST post a video of it in action when complete!!!


----------



## Paladin79

I am working on it but file size gets to be a problem, it is far enough along to show the lights working but then they will work with any sound in the room.

I have some tiny speakers on the way, I tried headphone drivers but even at 50 ohms they were a little hard to push with the Coaster so I will try four ohm later this week.


----------



## the finisher

Paladin79 said:


> I am working on it but file size gets to be a problem, it is far enough along to show the lights working but then they will work with any sound in the room.
> 
> I have some tiny speakers on the way, I tried headphone drivers but even at 50 ohms they were a little hard to push with the Coaster so I will try four ohm later this week.




Post on YouTube then link back to Head-Fi


----------



## Paladin79 (Oct 29, 2018)

I will get it done somehow.  I found an inexpensive DAP to give away with it. I will record a lot of old Disney songs for my granddaughter. I will also put a song on there by the Proclaimers that my son used to hate, the official title is I'm Gonna Be (500 miles).


----------



## Paladin79 (Nov 1, 2018)

https://drive.google.com/open?id=1yEnnKrrlWUM-rQEMtduGyGpOuxvUXsUv

Here is a link showing somewhat how the flying saucer Coaster amp works, Ripper was kind enough to help with said link.


----------



## the finisher

Very cool, you are an artist


----------



## Paladin79

the finisher said:


> Very cool, you are an artist



Thanks, toward the very end you hear Woodstock barking in the background. I do believe my granddaughter will like this. I picked up an new DAP for $50 that I will load with music, and I got some miniature 4 ohm speakers that I will test tomorrow.


----------



## CAPT Deadpool

Please share the details on the DAP and speakers when you can!  I can't watch the video right now.


----------



## Paladin79 (Nov 1, 2018)

I am off work tomorrow so i will experiment then, these are just tiny speakers that I will mount inside so there is sound to activate the lights. Luckily I found a DAP that is really simple and a three year old should be able to operate it.

https://www.amazon.com/gp/product/B072ZXH8VS/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I was using it last night to drive some HD 6xx headphones, you add your own memory of course but not too bad for the price.

https://www.amazon.com/gp/product/B0177ABRQ6/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

I may have said four ohm but these are obviously 8 ohm, I may mount all four though. They are just tiny speakers about the size of a quarter. I tried headphone drivers but they did not have the volume level I seek.  The lights are ridiculously easy and that is just a frisbee I painted with hammered spray paint. The plastic dome is available on Ebay.

I will use right angle 3.5 mm connectors so the wires run straight down to the inside of the saucer or I will just hardwire everything so I do not have to cut a lot of holes in the dome. The DAP will act as volume control and the Coaster will be a dedicated unit.

It is not complete yet but the lights work with any source of sound so it is easy enough to demo right now.


----------



## Ripper2860

Those speakers should do just fine.  I'm not 100% sure, but I think they are the same drivers used in Klipsch La Scala IIs. 

Those folded horns work miracles, don't they??


----------



## Lord Bobbymort

I'm thinking of doing a DIY DAC, as well, and putting it in the same enclosure as the coaster, but I want to try using the same power supply.

a raspberry pi-based DAC is out because of the USB 5v power. Any ideas?
Any good cheap DAC kits y'all know of?


----------



## Paladin79

The Coaster uses a pretty unusual voltage so it is hard to think of a dac with a similar supply. If I come across anything I will certainly post it. I do believe there are power supply boards out there that give you different voltage options out but take 110v ac in, something like that with a Pi might be doable. Pi's are relatively inexpensive and someone whom I believe has worked with a couple supply boards as well as Pi's is @CAPT Deadpool, maybe he will have some ideas.


----------



## Lord Bobbymort (Nov 28, 2018)

Paladin79 said:


> The Coaster uses a pretty unusual voltage so it is hard to think of a dac with a similar supply. If I come across anything I will certainly post it. I do believe there are power supply boards out there that give you different voltage options out but take 110v ac in, something like that with a Pi might be doable. Pi's are relatively inexpensive and someone whom I believe has worked with a couple supply boards as well as Pi's is @CAPT Deadpool, maybe he will have some ideas.



It brings in a 16vac supply from the wall-wart, right? I believe we can comfortably run a 18vac supply... I think... right?
I wanted to see if there was a daisy chain wall-wart that I could run the both off of but none of the DAC kits I've found show what supply they actually need, they just show the barrel connector as a part.

You're right, though, if I run an independent power supply and branch off with 16barrel for the coaster and usb5 for the pi it should work. hmm


----------



## CAPT Deadpool (Nov 28, 2018)

Paladin79 said:


> The Coaster uses a pretty unusual voltage so it is hard to think of a dac with a similar supply. If I come across anything I will certainly post it. I do believe there are power supply boards out there that give you different voltage options out but take 110v ac in, something like that with a Pi might be doable. Pi's are relatively inexpensive and someone whom I believe has worked with a couple supply boards as well as Pi's is @CAPT Deadpool, maybe he will have some ideas.



I can't think of any easy solutions off the bat due to the need for 16V AC for the coaster.  By far the cheapest option would be just to use the 2 standard power supplies respectively.  Any other custom solution would end up costing more than the PiDAC and Coaster combined.

The Pi and PiDacs as a category require 5v DC.  My current RPi DAC build actually has 3 power cables.  1 for the pi, 1 for the 7in touch screen, 1 for the HDD.  I'm going to get that down to one power cable soon I hope by adding an iPower power supply and a lower power drawing ext SSD.


----------



## Lord Bobbymort (Nov 28, 2018)

CAPT Deadpool said:


> I can't think of any easy solutions off the bat due to the need for 16V AC for the coaster.  By far the cheapest option would be just to use the 2 standard power supplies respectively.  Any other custom solution would end up costing more than the PiDAC and Coaster combined.
> 
> The Pi and PiDacs as a category require 5v DC.  My current RPi DAC build actually has 3 power cables.  1 for the pi, 1 for the 7in touch screen, 1 for the HDD.  I'm going to get that down to one power cable soon I hope by adding an iPower power supply and a lower power drawing ext SSD.



Yeah, there should be other DAC kits that run barrel connectors at higher voltages, though. The only reason I mentioned the PI was because I have a Pi Zero that I want to utilize.
I just want the DAC in the same unit (and a DAC at all) because I don't trust the output on my work laptop to be great at all (I know it isn't already).

Just trying to create something unique and useful for me until I get an actual upgrade.

The only thing I worry about with the PI DACs as well is I've seen them report as line level output (and not to use headphones). I'm unsure with the details for coaster input, but is line level amped more than I want to feed the coaster to begin with?

As well, I don't necessarily need it to have the LCD or the HDD because I plan on feeding the dac via computer USB.


----------



## CAPT Deadpool

Lord Bobbymort said:


> Yeah, there should be other DAC kits that run barrel connectors at higher voltages, though. The only reason I mentioned the PI was because I have a Pi Zero that I want to utilize.
> I just want the DAC in the same unit (and a DAC at all) because I don't trust the output on my work laptop to be great at all (I know it isn't already).
> 
> Just trying to create something unique and useful for me until I get an actual upgrade.
> ...




The 16Volts AC the coaster requires is rather unusual unless you are talking a Schiit product.  Most consumer DACs and such require DC voltage. 

The Coaster uses 16AC via a rectification design using 3 voltage regulators to provide the coaster with 3 different voltages ~30VDC, ~15VDC, and ~1.5VDC.  See the lower left part of the schematic.  

The line level will be adequate for the coaster.  It is what a headamp would expect to be fed.


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## Lord Bobbymort

CAPT Deadpool said:


> The 16Volts AC the coaster requires is rather unusual unless you are talking a Schiit product.  Most consumer DACs and such require DC voltage.
> 
> The Coaster uses 16AC via a rectification design using 3 voltage regulators to provide the coaster with 3 different voltages ~30VDC, ~15VDC, and ~1.5VDC.  See the lower left part of the schematic.
> 
> The line level will be adequate for the coaster.  It is what a headamp would expect to be fed.



All the DAC kits I can find have a couple screw terminals for 9 VAC and 15-0-15VAC  Yeah, if I could find a transformer with a bunch of stuff, but it's gonna be difficult.
Poop, cool idea pretty much down the drain.


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## jimmers (Nov 28, 2018)

Lord Bobbymort said:


> ... As well, I don't necessarily need it to have the LCD or the HDD because I plan on feeding the dac via computer USB.


If you are using only USB input why not use a USB powered DAC, kits might be a bit awkward unless you are comfortable soldering multi pin SMDs
An easy option would be to get a PCM2704 type finished PCB (ebay $6), this solution was used by the early headphone DAC-Amps e.g.  Lehmann Black Cube Linear, or you could look for a more modern one like those from HiFimeDIY ($30 and up)

(or you could go multibit with  4 x parallel TDA1543 USB DAC finished PCB, ebay ~$19)


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## 100VoltTube

When choosing sockets for the tubes, can you just use any IC socket or do you need to choose one with extra deep sockets for the tube leads?


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## the finisher

No sockets soldered to the board AFAIK.


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## CAPT Deadpool

You only need the sockets if you plan to frequently swap tubes for matching purposes.  I've got some but haven't even used them.  I had a friend match me a few pairs and I'm good to go.


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## bdinnerv

As these Coasters are also Headphone amps, has anyone tried making a pair of "headphone" amps? 




I figure with a little bit of luck, the PCB's will mount into the cups 

110mm Large Headphone Housing


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## Rensek

bdinnerv said:


> As these Coasters are also Headphone amps, has anyone tried making a pair of "headphone" amps?
> 
> I figure with a little bit of luck, the PCB's will mount into the cups
> 
> 110mm Large Headphone Housing



Looks fun, but how are you managing the two wall warts this build would take?

They run off the same wall wart that is used for modi multibit, loki mini, etc


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## Paladin79

Rensek said:


> Looks fun, but how are you managing the two wall warts this build would take?
> 
> They run off the same wall wart that is used for modi multibit, loki mini, etc


I have converted two of them to mono and used a fairly serious battery pack outside.


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## bdinnerv

To clarify, I was not thinking of mounting them along with drivers, more just using the frame as mount for the PCB's for display purposes, and then you could hang them on a headphone stand.

I do like the idea of converting them to mono, definitely justifies using both headphone cups for mounting PCB's.


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## Paladin79

bdinnerv said:


> To clarify, I was not thinking of mounting them along with drivers, more just using the frame as mount for the PCB's for display purposes, and then you could hang them on a headphone stand.
> 
> I do like the idea of converting them to mono, definitely justifies using both headphone cups for mounting PCB's.


I have hooked them to Beyer-Dynamic drivers as well as running mine speakers as a pair but never had headphone frames that fit them.


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## bdinnerv (May 13, 2020)

Time for the fun to begin


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## Paladin79

Good luck with that, I built quite a few a while back.


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## bdinnerv

All I can say is that I hope it makes a good amplifier, it is a pretty Schiity coaster . . .


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## Paladin79 (May 13, 2020)

bdinnerv said:


> All I can say is that I hope it makes a good amplifier, it is a pretty Schiity coaster . . .


LOL yeah but a good dual function advertisement. They are decent sounding and there is such a feeling of accomplishment when you finally get one going. There was an error in the original BOM so I may well have been the first person outside of Schiit to have a working  after I caught the mistake.

It is a fun challenge to find a round enclosure for the amp, I probably had a couple dozen ideas and a few actually worked lol.


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## bdinnerv

I finally pulled my finger out, ordered the last couple of bits I needed to do this project and got stuck into it last night. All complete!

It seems to power up without letting out any magic smoke and the led's turn on. I dont have a cable at present to connect to the input (have one turning up tomorrow) so cannot test audio at the moment. Hooking up headphones and cranking the volume up does reveal a  little bit of noise which I think is a good thing. Not sure what other steps / measurements I can take to verify all is OK.

The smaller SMD parts were a bit tricky, especially after a coffee in the morning which did not help but managed to get it all done in a couple of hours. I have parts to complete a second one (minus 2 resistors that I put in in the incorrect position and damaged when removing so had to raid the second parts set) so may have a go at a second one sometime soon but at the moment just looking forward to testing this one out. 






Cheers,

Ben


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## Paladin79

bdinnerv said:


> I finally pulled my finger out, ordered the last couple of bits I needed to do this project and got stuck into it last night. All complete!
> 
> It seems to power up without letting out any magic smoke and the led's turn on. I dont have a cable at present to connect to the input (have one turning up tomorrow) so cannot test audio at the moment. Hooking up headphones and cranking the volume up does reveal a  little bit of noise which I think is a good thing. Not sure what other steps / measurements I can take to verify all is OK.
> 
> ...


It looks to be very nice work!


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## bdinnerv

Just fired it up for the first time with a pair of Audeze iSine-20's - input is coming from the pre-out of a Schiit Fulla at the moment so not the most direct route but have to say, I am pretty happy with this little thing! There was some distortion to start with but then realized I have the volume on the Fulla too low for pre-outs, bumped it up to the prescribed 3am and the coaster sounds great. 

I have not checked the tubes yet but there is no noticeable level difference from L->R so may just leave it. Will have to give it a go with the LCD-GX's and see how they go on it but with the iSine 20's, am only running it at about 7:15pm on the volume pot.

Am pretty chuffed with this!


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## Paladin79 (Jul 22, 2020)

bdinnerv said:


> Just fired it up for the first time with a pair of Audeze iSine-20's - input is coming from the pre-out of a Schiit Fulla at the moment so not the most direct route but have to say, I am pretty happy with this little thing! There was some distortion to start with but then realized I have the volume on the Fulla too low for pre-outs, bumped it up to the prescribed 3am and the coaster sounds great.
> 
> I have not checked the tubes yet but there is no noticeable level difference from L->R so may just leave it. Will have to give it a go with the LCD-GX's and see how they go on it but with the iSine 20's, am only running it at about 7:15pm on the volume pot.
> 
> Am pretty chuffed with this!


I set up a separate coaster amp with sockets so I could plug in various tubes and match them but then I built a lot of those amps and helped friends with their tubes. There are a couple ways to do it but I ran identical square wave signals to each channel then monitored the outputs on a dual trace oscilloscope. It was quick and easy and left little doubt.  

I have since moved on to my own design on a tube amp but it was fun to mess around with kits and try to figure out what kind of cabinet might work with a round circuit board. This is one of my current projects under test, before I began adding control pots and jacks.


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## bdinnerv

Paladin79 said:


> I set up a separate coaster amp with sockets so I could plug in various tubes and match them but then I built a lot of those amps and helped friends with their tubes. There are a couple ways to do it but I ran identical square wave signals to each channel then monitored the outputs on a dual trace oscilloscope. It was quick and easy and left little doubt.



I saw your original post re sockets and thought about doing it but then figured I dont have the test equipment so what is the point. I have 8 or so spare boards and another amp project under way (this time SS) so may have to invest in some basics. In this instance, it seems I just got lucky.


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## Paladin79 (Jul 22, 2020)

bdinnerv said:


> I saw your original post re sockets and thought about doing it but then figured I dont have the test equipment so what is the point. I have 8 or so spare boards and another amp project under way (this time SS) so may have to invest in some basics. In this instance, it seems I just got lucky.


To be honest, many I tested were very close matches to each other when dealing with new tubes so you are probably fine as the amp sits.

I did a few solid state kits and have owned a lot of it through the years but at this stage in my life, I only do Class A tube amps but that is a personal preference.


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## sam6550a

Paladin79 said:


> To be honest, many I tested were very close matches to each other when dealing with new tubes so you are probably fine as the amp sits.
> 
> I did a few solid state kits and have owned a lot of it through the years but at this stage in my life, I only do Class A tube amps but that is a personal preference.


Correction please---Class A tube amplifiers with world class woodwork packaging.


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## bdinnerv

Paladin79 said:


> I did a few solid state kits and have owned a lot of it through the years but at this stage in my life, I only do Class A tube amps but that is a personal preference.


I have a pair of LCD-4's that are on the warmish side coupled with a Yggy + MJ2 at present and want to hear what the LCD4's will sound like with a non-tube amp / more "true" / no tube coloration amplification (Still with the Yggy) so am building a Kevin Gilmour CFA3  + GRLV + digital stepped attenuator as a dual mono balanced setup - bit of a step up from the Coaster but should be easier in a lot regards due to through-hole vs SMD. I may look at a larger tube project after this.


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## Paladin79

sam6550a said:


> Correction please---Class A tube amplifiers with world class woodwork packaging.


Check out this rainbow poplar I cut yesterday, it is now one of my favorites.


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## tod-hackett

Would it be possible for one to stare at pictures like this and solder together a working amplifier? Other than a soldering iron, what else would one need?


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## damaged ears

Here is my coaster build, for the smb parts I used solder paste and a toaster oven. Sounds great. Thanks to Jason for the pcb. The pads are huge making placing parts much easier and the space between the pads helps avoid solder bridges.


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## JamminVMI

damaged ears said:


> Here is my coaster build, for the smb parts I used solder paste and a toaster oven. Sounds great. Thanks to Jason for the pcb. The pads are huge making placing parts much easier and the space between the pads helps avoid solder bridges.


Looks brilliant!


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## damaged ears

tod-hackett said:


> Would it be possible for one to stare at pictures like this and solder together a working amplifier? Other than a soldering iron, what else would one need?


Well you can get the Bill of Material from the Schiit website along with the schematic. Assuming you have a history of soldering through hole devices, but no smb experience, you could, for very few dollars, buy a smb solder practice board off Amazon. With less than an hour practice you should be ready to solder. But this project does require some skills beyond soldering. Due to the chip shortage you will need to find alternatives for some of the parts called out by Jason in the BoM. There are also some errors with regards to part count in the BoM so you need to be careful of that as well. One of the parts is obsolete and the only one holding stock of that part is in China and shipping to the US is very expensive from that company. The good thing is that the substitute part suggested by Mouser is pretty much a drop in replacement. I bought the parts a couple of months ago and then sat on it while I finished other projects. One night I decided to learn how to solder smb parts. Because I already had an appropriate hot air gun I decided to learn how to solder with that. After the first one I decided to try the toaster oven. That required more careful placement of solder paste and stuffing the whole board at once. 

The good news is that, as I stated above, the pads are huge, the parts are big, the spacing between pads helps avoid bridging and the traces are easy to see, so figuring out diode orientation is pretty straight forward. I would suggest that you get a magnifying desk light to help. And good quality tweezers, toothpicks help also with the small moments of parts on the board.


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## Paladin79

tod-hackett said:


> Would it be possible for one to stare at pictures like this and solder together a working amplifier? Other than a soldering iron, what else would one need?


I got the first Coaster amps going (other than those done at Schiit) and soldered all parts with a standard soldering iron so it can be done. I still have a full parts cabinet if any of you cannot locate parts.


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## damaged ears

Paladin79 said:


> I got the first Coaster amps going (other than those done at Schiit) and soldered all parts with a standard soldering iron so it can be done. I still have a full parts cabinet if any of you cannot locate parts.


The part that is obsolete is Q102,202 Toshiba-2SA1312BLTE85LF, the suggested remplacement part is: 2SA1163-BLLF and it seems to work fine in the coaster.


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## pravous

My daughter and I built the coaster amp this weekend.  I hand soldered all the smd and she handled all the through hole components.
Soldering in some sockets




First power on. 



All cased up in a 3d printer case I found online. 



Used a VU meter and test tone to match the tubes as per Paladins suggestion.  All in all a fun project.


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## Paladin79

If I may ask, where did you find the 3D case?


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## pravous

I got the files from here.
https://www.thingiverse.com/thing:4607793
I then used craftcloud to have the case printed.


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## tincanear (Mar 9, 2022)

since the power switch couldn't be mounted on the back panel (coaster doesn't have an enclosure per se,) @Jason Stoddard did the next best thing, and placed it between the tallest components on the PCB


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## KrazyDiamond (Jan 5, 2023)

Where do you guys tend to source the tubes from? I just finished my build, except need tubes and power supply. I noticed a site called piexx.com that has them for $1.75 per tube with over 9000 in stock. Anyone know if this is reliable?

Edit: Went with an eBay lot. Piexx looks good, seems legit, but crazy shipping to anyone outside US.

Side note: How big of a difference does the sorbothane make? Anyone add it under their tubes? How thick of a pad did you go? Thx


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