[winders]

True, there are no caps in the direct signal path. But there are caps in nested NFB loops that perform the necessary anti-imaging reconstruction filtering.

What caps did Mike choose to use there and what caps would be better choices and why?

 

[Jones Bob]

What caps did Mike choose to use there and what caps would be better choices and why?

From the Schiit page, photos looks like WIMAs. More than likely MPK 2 metalised film polypropylene due to their small footprint for PCB mounting. A competent all around good film cap. There are "better" (film and foil PP, or PTFE) but usually much larger physically for the same value. Trying to mount those larger caps with long leads to the PCB would increase the inductance the filter sees and alter the designed response. How much? You would need to measure the result.

 

[winders]

From the Schiit page, photos looks like WIMAs. More than likely MPK 2 metalised film polypropylene due to their small footprint for PCB mounting. A competent all around good film cap. There are "better" (film and foil PP, or PTFE) but usually much larger physically for the same value. Trying to mount those larger caps with long leads to the PCB would increase the inductance the filter sees and alter the designed response. How much? You would need to measure the result.

From the web:
 
The Wima caps are just to bypass the electrolytic caps with (decoupling caps) and are fine for doing that. They are not coupling caps and have no music signal passing through them all.
 
Again, why would Mike pick what he did if he could have chosen a better part for similar money??

 

[Jones Bob]

From the web:

[COLOR=0000CD]The Wima caps are just to bypass the electrolytic caps with (decoupling caps) and are fine for doing that. They are not coupling caps and have no music signal passing through them all.[/COLOR]

Again, why would Mike pick what he did if he could have chosen a better part for similar money??

Sigh... I can't help you.

 

[winders]

Sigh... I can't help you.

I don't need any help. I am not contemplating modifying my Yggdrasil.

 

[Jones Bob]

I don't need any help. I am not contemplating modifying my Yggdrasil.

Then I won't argue with you.....

 

[winders]

Then I won't argue with you.....

Hmm, where was I arguing?

 

[hifimckinney]

Hmm, where was I arguing?

 


But both of you ate some portion of our brains ...

 

[Superdad]

One of those large "transformers" is a PS choke.
 

 
I do not believe that is the case.  All 3 are transformers from MCI's 4-02 series of horizontal PCB mount units.  The part numbers are right on them.

 

[Jones Bob]

I do not believe that is the case.  All 3 are transformers from MCI's 4-02 series of horizontal PCB mount units.  The part numbers are right on them.

From the Schiit Yggy specs page:

http://schiit.com/products/yggdrasil

 

[Superdad]

From the Schiit Yggy specs page:

http://schiit.com/products/yggdrasil

Excellent, thanks!  Interesting that they got MCI to make a dual-choke (seeing all the pins threw me off until reading that they had it wound as a dual choke for their bi-polar supply).
 
I love true DC choke-filtered power supplies (and I don't mean little common-mode chokes).  In fact, the big DC filter choke of our own JS-2 5-7A LPS is the heart of its design.
 
Thanks again for correcting me.  I should not have made that assumption.  Makes me want to get a Yggy!  

 
Best,
 
--Alex C.

 

[Jones Bob]

 
Excellent, thanks!  Interesting that they got MCI to make a dual-choke (seeing all the pins threw me off until reading that they had it wound as a dual choke for their bi-polar supply).
 
I love true DC choke-filtered power supplies (and I don't mean little common-mode chokes).  In fact, the big DC filter choke of our own JS-2 5-7A LPS is the heart of its design.
 
Thanks again for correcting me.  I should not have made that assumption.  Makes me want to get a Yggy!  

 
Best,
 
--Alex C.

 
Glad to help you.
 
I'm a little busy now, right in the middle of triage on my KGST..... popped a 150V Zener in a 400VDC stack. Arggggh!

 

[Superdad]

   
Glad to help you.
 
I'm a little busy now, right in the middle of triage on my KGST..... popped a 150V Zener in a 400VDC stack. Arggggh!

 
Mjolnir Audio?  Good stuff.  Best of luck on the repair!

 

 

[Jones Bob]

DIY. An early builder.

BTW Alex, your Uptone LPS-1 is a game changer.

 

[Superdad]

BTW Alex, your Uptone LPS-1 is a game changer.

 
Thanks very much.  I can only take credit for the inspiration/idea to start the project (close to two years ago) and to pouring lots of money into it.  But ALL the engineering credit belongs to my brilliant partner John Swenson!  The actual journey--through multiple topologies and approaches to making it a reliable, buildable product--is a story unto itself.  The first pass of all the logic was done all discrete.  The thing would have had about 380 parts and reliability would have been questionable.  But once he had done it all discrete, it was obvious then (at least to him) how to write all the code and do in an FPGA.
 
We eventually will scale it up into high voltage, high current versions, but doing so quickly multiplies size and cost.   A multi-rail 6-7 amp unit would likely end up selling for about $3K.