A New Take on the Classic Pass Labs D1 with an ESS Dac - Page 9

PierreQuiRoule · 13th April 2010, 09:56 PM

Very interesting thread!

As it turns out, I have been using a D1 I/V stage with an original buffalo DAC for about a year now. Sound is laid back, with layers and layers of detail. It compares favorably to anything I have heard.

As Owen pointed out, new DACs like the ESS swing more current than the PCM63. Referring to the original schematic, I made the following changes to increase bias threefold:
- R26, R33 decreased from 3.3 K to 1 K
- R27, R34 decreased from 1.5 K to 470 ohms

To keep the same cutoff frequencies (RC) for the low pass filters, the following capacitors were adjusted accordingly:
- C40, C45 increased from .01 to .033 uF
- C15, C16 increased from .0027 to .0086 uF

I could not trim the output voltage to 1.65 V without reducing R24, R31 from 100 K to 68 K. The rest of the D1 I/V circuit is stock. Never had the imagination of trying it without the buffer stage. Now I'm curious...

Let me see if I can attach a picture in my next post.

Pierre

PierreQuiRoule · 13th April 2010, 09:59 PM

I hope an image shows up (fingers crossed)...

Pierre

lauret · 14th April 2010, 07:20 AM

Quote:

Originally Posted by PierreQuiRoule

I hope an image shows up (fingers crossed)...

Pierre

Thanks for your report on modifying an original D1 for the Buffalo DAC!

BTW. Did you make those boards? Got any left?

PierreQuiRoule · 14th April 2010, 09:45 PM

Quote:

Originally Posted by lauret

Thanks for your report on modifying an original D1 for the Buffalo DAC!

BTW. Did you make those boards? Got any left?

Yes I made those board, and I have a few left - strictly for DIY use. Send me PM if you are interested. I'll sell below cost. Just glad if they end up playing music instead of gathering dust.

Pierre

PierreQuiRoule · 15th April 2010, 12:27 AM

Here's a picture of a naked pcb. Nothing fancy: connect ESS Sabre to input (+IN, -IN), provide power (+30, G, -30), and hook outputs (+M, -M) to XLR connector. You may connect an external volume control (+VOL, -VOL), trim volume with a pot, or skip that portion of this circuit if you prefer. Part numbers match the D1 schematic.

I have a few pcbs left, available on a first come first served basis.

Pierre

igwt · 15th April 2010, 03:10 AM

Pierre , have you experienced any turn-on/off transiant thumps with this setup?

toufu · 15th April 2010, 03:33 AM

I will take one... you have pm

qusp · 03:53 AM

me too, YGPM, maybe 4 if you have enough; enough for 2 balanced dacs. actually if you have 8 would be awesome, because I have plans to go dual mono in the future and the other person already is.

flocchini · 05:00 AM

I would like two please.

Will send PM

lauret · 15th April 2010, 10:09 AM

A bit redundant probably, but you got PM.

13th April 2010, 09:56 PM	#81
PierreQuiRoule diyAudio Member Join Date: Feb 2004 Location: Ottawa	Yet another D1 I/V clone Very interesting thread! As it turns out, I have been using a D1 I/V stage with an original buffalo DAC for about a year now. Sound is laid back, with layers and layers of detail. It compares favorably to anything I have heard. As Owen pointed out, new DACs like the ESS swing more current than the PCM63. Referring to the original schematic, I made the following changes to increase bias threefold: - R26, R33 decreased from 3.3 K to 1 K - R27, R34 decreased from 1.5 K to 470 ohms To keep the same cutoff frequencies (RC) for the low pass filters, the following capacitors were adjusted accordingly: - C40, C45 increased from .01 to .033 uF - C15, C16 increased from .0027 to .0086 uF I could not trim the output voltage to 1.65 V without reducing R24, R31 from 100 K to 68 K. The rest of the D1 I/V circuit is stock. Never had the imagination of trying it without the buffer stage. Now I'm curious... Let me see if I can attach a picture in my next post. Pierre

15th April 2010, 03:41 AM	#88
qusp Sometimes a square peg fits a round hole just fine diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	me too, YGPM, maybe 4 if you have enough; enough for 2 balanced dacs. actually if you have 8 would be awesome, because I have plans to go dual mono in the future and the other person already is. Last edited by qusp; 15th April 2010 at 03:53 AM.

15th April 2010, 04:52 AM	#89
flocchini diyAudio Member Join Date: Feb 2004 Location: Davis,CA	I would like two please. Will send PM Last edited by flocchini; 15th April 2010 at 05:00 AM.

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15th April 2010, 03:10 AM	#86
igwt diyAudio Member Join Date: Mar 2009	Pierre , have you experienced any turn-on/off transiant thumps with this setup?

15th April 2010, 03:33 AM	#87
toufu diyAudio Member Join Date: Jun 2008 Location: San Francisco	I will take one... you have pm

15th April 2010, 10:09 AM	#90
lauret diyAudio Member Join Date: Oct 2007 Location: Amsterdam	A bit redundant probably, but you got PM.

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