Pass D1V3 DAC - build thread

[spzzzzkt]

Works with the jumpers set to 16bit output from the receiver - no need to mod around M2.

Grounding M2 puts the cs8412 into mode 0 which is "Out, L/R, 16-24bit". You then need to mod the pmd-100 board to pull JUST low so the PMD-100 will accept the 16-24bit input.

There is probably little benefit in doing this unless you want to run 24bit 48khz source material.

The PMD-100 is quite nice sounding. The tops are a little more restrained than the SM5842 so there seems to be a bit less "air".

 

[regal]

What ground pad on the D1V3 board should I tie to chassis earth ?

 

[spzzzzkt]

use the pads near the I/V stage PSU caps. There are 6 positioned together.

 

[Filburt]

Are there extra boards available?

 

[spzzzzkt]

for d1v3 boards you'll need to contact spencer. vcxo boards are a work in progress and still at least a couple of weeks before i order them.

 

[tenorsaxophone]

Balanced power amplifier

Hello!
To use with this excellent DAC, can anyone indicate to me a good DIY balanced power amplifier? For my ambient and my Loudspeaker system, a 50 Watts/8ohm would be enough.
Thanks in advance. Best regards.
Davide.

 

[meezger_seep]

Problem building a Spencer I/V-stage

Hello all,

I built an I/V stage and power supply according to Spencer's schematic. I just made my own layout and PCB. Today I finished the I/V stage and attached it to my DAC (CS8416 -> AD 1896 -> DF1704 -> ISO150 -> 4x PCM1704U-K).
It looks like the stage is working, but what concerns me is the response to square signal (see attached screenshot of my scope with 1000 Hz).

Any ideas what’s the problem here?

Many thanks in advanced for help.

Best wishes

Ralf

 

[meezger_seep]

.. and here is my pcb

 

[spzzzzkt]

I'm not sure it's a fault.

There is a thread discussing this on diyaudio:

http://www.diyaudio.com/forums/showthread.php?threadid=6901


So how does the I/V stage sound?

cheers
Paul

 

[meezger_seep]

Hello Paul,

Thanks for the hint. It’s always embarrassing if you don’t know the physics behind the device you DIY. My 15 year old NOS Pioneer CD-Player can produce a nearly perfect square so I thought that the new DAC should be even better Ok, no more concerns about square waves. At least the responce is near the mathematical square funktion limited to 22 kHz.

I didn't have the time for excessive test hearing yet. The good thing is that I can do direct A/B comparisons with the internal DACs of my CD- and DVD-player and the same CD over digital out and my DAC.

My measuring equipment is very limited. I have a semi professional recording A/D converter and a PC software tool to do some measurements. This software says that the DAC has a severe problem with harmonics even on sine signals and a THD of 1%.
There is a commercial HiFi manufacturer in the neighbourhood. I try to get my DAC measured there.

Best wishes

Ralf

 

[spzzzzkt]

Ralf,

don't worry. your pics made me search for more information about this as I hadn't checked the square wave and they looked a bit odd. I learnt something too 😉

I be very interested to see the results of the tests. I tried using RMAA test tones on cd and recording the output into a semi-pro digital recorder then analyzing the resulting file and got high levels of THD. The whole process was a bit dubious so I haven't put much stock in my results.

cheers
Paul

 

[regal]

I measure high 2nd order harmonic distortion as well, higher than a tube DAC. Its just the nature of the D1 I/V (no NFB.)

 

[spzzzzkt]

Regal,

You obviously have your D1V3 running if you're measuring harmonic distortion. Congratulations 🙂 Have you had a chance to listen?

cheers
Paul

 

[meezger_seep]

Hello,

here is the distortion I measured with my ADC. I think the level I measured is near the limit of accuracy of this thing. So I would not put too much weight on these figures.

The HiFi manufacturer around the corner made very drastic clear that he is not interested in DIY-freak's affairs. But I know some other HiFi developper who is more open. Let's see what he charges for a precise measurement.

Today I listened to my DAC and it looks like it (or my ears) need a few hours burn in. I like it more and more. But I just enjoyed music and made no analytic listen tests.

Some more pictures are on my website .

Best wishes

Ralf

 

[tenorsaxophone]

Hello!
Mr. Spencer, in his Bill Of Materials actually sells DIR9001 Digital Receiver.
What do you think about this component confronted to 8412/14?
I have not experience to decide the choise.
Many thanks. Best regards.
Davide.

 

[regal]

Regal,

You obviously have your D1V3 running if you're measuring harmonic distortion. Congratulations 🙂 Have you had a chance to listen?

cheers
Paul

Good accurate sound, but I guess I'm just a tube guy 'cause it doesn't compete with my budget tube DAC. I will be replacing the D1 stage with a tube.

 

[analog_sa]

it doesn't compete with my budget tube DAC.

It will be interesting to know what is your tube dac. What does the tube do?

 

[regal]

There is a small I/V resistor then a single ended totem pole tube gain stage.

For the D1 I am going all out with a Sowter step-up transformer which will allow a 2 ohm I/V resistor.

 

[tenorsaxophone]

There is a small I/V resistor then a single ended totem pole tube gain stage.

For the D1 I am going all out with a Sowter step-up transformer which will allow a 2 ohm I/V resistor.

Hi regal.
is it possible to see the schematics of your works? Your DAC and the D1 I/V stage too?

 

[Filburt]

Argh, got an email from Rauch but didn't see it till some time after. I feel bad 🙁

Is this board the whole dac or just the i/v?