Archive for the ‘DAC’ Category

D1V33 with external super clock 256Fs

Friday, January 29th, 2010

D1V33 can be slaved to a master clock with frequency (256fs) at max fs 48kHz.  The limitation is due to the digital filter SM5842.  If SM5847 is used, the Fs max can be up to 96kHz.

1. Cut the trace as shown on the pdf document.  This is to remove the MCK from CS8412 / DIR9001.

2. Solder a jumper wire onthe via hole as shown.  This is connected to pin 6 of SM5842 XTI –  Master Clock Input.

3. Locate a ground connection on the pcb top (can scratch out the green solder mask near the via hole).

4. Solder the coxial cable for the master clock input (+ve to jumper and shield to ground). 3.3 ~5V TTL logic or CMOS clock source should be working fine.

5. The clock source of the SPDIF input (eg CD player or Media player) and the master clock to the SM5842 must be in sync in order for the DAC to work properly.


D1V33 at 24-bit 96k Fs – using SM5847 & PCM1704

Monday, January 4th, 2010

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

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.

New FFT measurement for Yamaha DA202, DA2X and TDA1541 SZ DAC

Thursday, November 12th, 2009

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





Friday, November 6th, 2009

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.


D1V3 Silk Top

D1V3 PCB Dimension

D1V3 Circuit Diagrams


D1V3 Assembly Manual

Upgrade from D1V3 to D1V33

Some discussion in forum:

D1V3 with AD1862 20bit DAC

Wednesday, November 4th, 2009

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.

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