FET Audio | Hi-End Audio & Electronics DIY Electronics & Repair

Finally D1V33 is working at 24 bit and 96k Fs after using the better digital filter NPC SM5847 and PCM1704.  Both chips are put on a converter board and plug into D1V33.

The set has been tested using Audio Precision and confirm the set is working at 24 bit & 96kHz sampling frequency.  The FFT measurement are attached below:

D1V33 FFT with the 1kHz signal filtered off, very low noise floor -135dBV!

D1V33 FFT 24bit 96k 5847+1704

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On the last photo, you can see that I change the decouple capacitors for Servo DC, Ref DC, BPO DC pins of PCM1704 to Black Gate N series and Elna Stargate type.  The result is that the bass performance of PCM1704 is much better than using FC capacitor.  Now the bass is as deep as PCM63 but with a little bit better clarity in all aspect.

Here is the FFT at -90dbFS and -110dbFS digital signal and you can see the harmonics is better than the on posted on PCM1704 Datasheet.

D1V33 FFT -90dbFS 96k 24bit 5847+1704

D1V33 FFT -110dbFS 96k 24bit 5847+1704

Frequency response and Distortion vs Frequency:

Freq Response & Distortion D1V33 5847+1704

Update on Jan 7th, 2010:

After listening for a week, the conclusion is that PCM1704 bass response is still way far away from PCM63 DAC in the D1V33 platform.  It is still inline with the poorer design of the current output of PCM1704 relative to PCM63.

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Please go back to Yamaha DA202 and DA2x for FFT measurement on Nov 12, 2009.

DA202

DA2X

TDA1541 SZ DAC

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Update on Nov 6, 2009:

Please look at the document below “Upgrade from D1V3 to D1V33“.  This is a worth while upgrade for the jfets to K369BL.  The major impact is that the input impedance of Jfet IV will be half which is estimated to be about 12 ohm while original D1 is about 10 ohm. The final result can be easily observed on the sonic improvement of the sound!

Project completed on Nov 11, 2007:

This is D1V3: Please refer to D1V3 Assembly Manual for details.

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Documentation:

D1V3 Silk Top

D1V3 PCB Dimension

D1V3 Circuit Diagrams

D1V3 BOM

D1V3 Assembly Manual

Upgrade from D1V3 to D1V33

Some discussion in forum:

http://www.head-fi.org/forums/f6/pass-labs-d1-clone-kit-324197/

http://www.diyaudio.com/forums/vendors-bazaar/97504-np-d1-dac-clone-enhancement.html

http://www.diyaudio.com/forums/pass-labs/116699-pass-d1v3-dac-build-thread.html

http://www.diyaudio.com/forums/digital-source/126799-reclocking-balanced-pcm63.html

http://www.diyaudio.com/forums/pass-labs/124891-jfet-d1-i-v-stage-ess-sabre-dac.html

http://www.diyaudio.com/forums/pass-labs/138734-d1-clone-without-enhancements.html

http://www.wretch.cc/blog/cs691208/17142644

http://www.diyplus.net/phpBB3/viewtopic.php?f=38&t=230

http://www.homecinema-fr.com/forum/viewtopic.php?f=1054&t=29924957

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AD1862 is a 20 bit R2R DAC made in the same period of PCM63 by Analogy Device.  This chip size is small using DIP16 package.  The performance of this chip is also outstanding but this DAC was not so widely used in CD Players relative to PCM63 in the past.

To use this chip, the DAC analogy supply of D1 need to be at +/-12V and the digital supply can be remained at +/-5V in the D1V3 or D1V33 board.  To change the analogy supply to +/-12V, 4 resistors has to be remove and re-solder from 300 to 850 ohm (I use 750 ohm + 100 ohm).  The designation of the 4 resistors are R105, R109, R126 & R127.  Besides the resistors change, the capacitors of the analogy supply has to be ensure using 16V or above capacitors.  I have 8 pcs 6.3V blackgate on the board and thus I have to change them to 22uf 16V Duorex capacitors.

Since AD1862 is not pin compatible with PCM63 and thus I have to hard wire 4 converter boards as shown on the pictures.  The pins that connect to PCM63 sockets are Pin 2, 6, 7, 11, 12, 13, 18, 20, 21, 28.  The two E-caps (1u and 12u) on the board is for AD1862 filtering and Red wima is 0.1u for power supply decoupling. This is a bit time consuming but it is a cheap way to test out how AD1862 perform in the D1 platform.

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The result is quite satisfying as the AD1862 also sound very good.  It has darker sound due to its strong bass (good current source driving capability using +/-12V supply).  The distortion is also lower compare to PCM63 in D1 platform due to its lower +/-1mA output range.  Noise floor is better than PCM63 a bit (1~2db) as seen in the FFT measurement.  But there is more high frequency odd harmonics when input is at 20bit/44.1k at 0 or -80dbFS.

All measurements are in balance output mode unless otherwise specified.

FFT DAC D1V3 AD1862 vs PCM63

FFT DAC D1V3 AD1862 @ -80dbFS 16 vs 20bit

FFT DAC D1V3 AD1862 Single end output

FFT DAC D1V3 AD1862 Balance output 0dbFS log

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 Since the SM5842 can only receive signal with maximum Fs at around 48kHz, it is not possible for D1V3 and D1V33 to receive 96k signal.  Due to that I have find one solution to do that using a AD1896 (or SRC4192) ASRC below.

DIR9001 –> AD1896 + 11.2896MHz XO –> SM5842 –> PCM63.

With above configuration, the input Fs can be from 32k till 96k while the output Fs from AD1896 is fixed at 44.1kHz.  AD1896 is set to Async mode with slave input mode and master output mode.  Both AD1896 and SM5842 is using master clock from the XO at 11.2896MHz.  Thus the jitter at SM5842 XTI will 100% depend on the quality of the XO.

Of course I can use a XO frequency of 12.288MHz to have a ouput Fs at 48kHz but I do not have this XO frequency on hand.  With higher Fs and later 8x over sample in the SM5842, the output noise after Jfet IV with single pole filter will be minimized.

Here is the picture of my implementation:

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