A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

[studiostevus]

Originally Posted by clivem

Yes, but that's 96k at 8x OS. ie. 768kHz.

Correct, it should do 192 in nos mode. I am contemplating on designing a pcm1704 dac, but i am not sure if it's worth it. I generally find there is limited hi-def material around...

[Jackal29a]

Wouldn't it even do DXD in NOS mode?

[clivem]

Originally Posted by studiostevus

Correct, it should do 192 in nos mode. I am contemplating on designing a pcm1704 dac, but i am not sure if it's worth it. I generally find there is limited hi-def material around...

There are several 192k/24 bit NOS designs built around the PCM1704 out there. Although the data-sheet states a max of 96k @ 8x OS, I believe Kingwa (Audio-GD) is running 192k @ 8x OS from his DSP to the 1704, which would imply that the chip is actually capable of a 1.536MHz word clock.

I have a little 96/24 material. Based on my own experiences, I still prefer that material run through 16 and 18 bit R2R DAC's, even with the loss of resolution.

[dddac]

Originally Posted by clivem

Yes, but that's 96k at 8x OS. ie. 768kHz.

Very valid Point. I simply overlooked that in the early days. High price and output arguments played a role as well of course, as well minus power supply. After that I hold on to the PCM1794. Might have had still oversampling specs in mind then. Anyway, 96kHz was not the only showstopper. Does not change a thing on the fact the PCM1794 in NOS is performing great

Nevertheless it is tempting to try a pair of 1704 though

[dddac]

Originally Posted by Jackal29a

Wouldn't it even do DXD in NOS mode?

DXD must be supported by the USB Receiver. The WaveIO does not Support that according to specs (max 192kHz)

You would expect that the DAC as such would support this, as the 8x oversampling is omitted, but I have not been able to test this...

I see the next experiments coming

[dddac]

Originally Posted by studiostevus

I generally find there is limited hi-def material around...

well have a look at my 3TB drive than

I believe there is more than enough out there and of excellent quality.
But that is my personal opinion of course

[Jackal29a]

Originally Posted by dddac

DXD must be supported by the USB Receiver. The WaveIO does not Support that according to specs (max 192kHz)

The WaveIO does not go over 192KHz but at 39€ the Amanero board does (PCM up to 384KHz and also DSD):

http://www.diyaudio.com/forums/vendo...converter.html

[clivem]

Originally Posted by dddac

Nevertheless it is tempting to try a pair of 1704 though

Deode,

I've been pondering. I'm biased, a fan of the PCM1704, but you really should try this. Having already designed your main-board outputting right aligned, 7 delay right channel, 39 delay left channel, which from memory, is exactly what is needed for a 1704 design, without any changes. So an optional 1704 daughter board using your stackable design would be really cool! Sure, it means also adding a negative supply for the DAC chips and it would mean having to use an active output stage...... I'd buy a complete kit plus an optional 1704 daughter board if it was available........

[dddac]

exactly my thoughts... mainboard is ready to go ;-) that is the advantage of modular work .... Of course I do see issues in the extra supply and stage, but hey, this is hobby and I was already thinking what to do next.... :-) no promises though

[clivem]

Of course, the other issue is cost. Using 4x K grade chips for 2 channel +/- @ $75 each, is $300 per daughter-board. A little more expensive than a pair of 1794's.

BTW, I just ordered a complete 1794 kit from your web store. Will be interested to hear how it compares to my own NOS DIY DAC's. I'll probably use Salas shunt regs for the power supplies and although I'll give it a go with passive out, I'm more than likely to drop the I/V resistor value and hook up a tube output stage...... CCS'd 6C45, or triode connected EF810 or d3a. We'll see.