NOS DAC Interface for all?

[Flecko]

Hi Peter,
I was looking for some info about usb-spdif converters. Have you thought about making the interface you created for NOS DAC avaiable as interface only option to the mankind I think it would be the most consequent solution on the market beside your dac. And people with a good DAC can upgrade easy.

[PeterSt]

Hi Adrian - A bit of a late response; sorry for that.

Well, I am not sure whether I brought this up myself somewhere (I think I did), but indeed it *is* an option. It only would need to leave out the real DAC stuff, and there you'd have it.
And yes, I sure will agree with you that this is the best interface possible. But but but ...

I would really like to know the real merits of it first. I mean, I don't have any other good DAC with SPDIF-in myself to test it, and otherwise it would be a "non comparison" for me anyway. A bit like testing the analogue-outs (you will recall that I assume), which is so (relatively !) poor that there's no way for me to really judge it for any merits. So, it may take someone like you (or another candidate) to test it. And, I sure want to make one or two test units just to see what comes from it. There's a small warning though, and that is that it's relative expensive just because of the cabinet which is (count 180 euro for that only, excl. VAT) - and at this moment I don't like to develop another smaller cabinet. If it is really good I will of course, but without knowing that, I obviously want to use the cabinet as it is now. Thus, a tad overdone and unnecessary expensive.

Counting quickly I'd say that the total price (ex VAT and shipping) would be 1.200 euro.
Yes, I'm scared from it myself (thought it would be more cheap).

For this you would have very low jitter SPDIF 24/192 output.
Or ultra low jitter i2s output (RJ45 Neutrik) for those who can use it. -> Specs 100% the same as for the NOS1, but up to the RJ45 terminal).
A display to be utilized by XXHighEnd (the display actually needs to be there because of the hole in the case otherwise).
Uhm ... A cabinet to build in your own DAC ? (with 11 spare (Neutrik fit) input/output provisions).
or
The possibility to upgrade later to the NOS1 (just deduct 1200 from the normal NOS1 price).

This is just a first setup, and I'd say that this 1.200 can be refunded just the same, although it really wouldn't need 90 days for testing. 30 days should be enough for this (there's nothing to break-in).


Please keep in mind that I won't give any high expectations about the SPDIF output; I just don't know - plus it depends on the (PLL) jitter rejection in your own DAC in the first place (the better that is, the less the difference will be).
The i2s output is another matter, and for that I *will* present the best expectations. But not many people will be able to utilize it ...

Well, just answered the question, but it could be a good idea ...
Peter

[Flecko]

Ok, I read this also a little late I have already ordered an Audio-GD Digital Interface but I think this is no problem. So, there is no hurry and for testing the NOS1 SPDIF, there will be somthing serious to which I can compare. 1200€ is of course not little money. And for that, the SPDIF driver should also be state of the art. I like experiments and testing, but developing while sending the gear 10x around would be difficult. You could design a spdif input for your NOS1. Maybe someone like to connect a bluerayplayer.., ah forgot, you would need a filter here. Anyway just an idea. So you could feed the nos own input. Maybe that would work without filter, just using 192/24 and arcpred.
Hmm... Investing 1200€ with the option of an upgrade to the real thing is attractive and makes sense. Without that option it would be not that interesting.
The PLL of my dac is quite good. It has 21ps jitter typically. Maybe there is a possibility to use the i2s signal (it will be possible somehow)
Is the spdif converterd to i2s before or after it passes the digital filter? It would be a nice option to use the analog part of the ref7 while using the digital part of the NOS1.

http://www.audio-gd.com/Pro/dac/RE7/RE7USB4.jpg

[Flecko]

It looks very appealing to use the i2s output. I think the i2s input of the ref7 is on the left side of the dsp and on the right side could be the output...I could try the ref7 with dsp and without, both feeded by the nos1. That would be VERY NICE!
Do think this is possible (also using 8xarcpred)?

[Flecko]

I searched the internet and yes, it is possible to feed the ref7 with i2s. I just don't know how, yet. It is even better: The Digital Interface also has an i2s output and that is very easy to use (I guess it will be equally easy for the ref7). So I can manage to use i2s with the DI and then order the NOS1-i2s-spdif-only and can see how it compares. And then,...I can disable the DSP by dipswitch and use 8x arcpred (Can you affirm this?). That would be so great!
If this all is possible, I would start to dance immediatly!

[PeterSt]

First a small disappointment : 8x AP will not be useable for SPDIF nor the i2s output.

SPDIF input ? I tried. Under W7 it can be utilized (but the one time I tried measurements were lousy), under Vista it can not.
Maybe later I can try to work this out again, but I have few hope for this (to work decently).

Is the spdif converterd to i2s before or after it passes the digital filter?

There is no digital filter. Haha.
Anyway, i2s is native, and SPDIF is created from that. This is not 100% true (it would more be "in parallel") but for 100% sure it isn't the other way around (so, it's not that i2s is created from SPDIF or something).

I searched the internet and yes, it is possible to feed the ref7 with i2s. I just don't know how, yet.

It should be in those white wires (6 per side) somewhere. But there might be more to it than just electrically connect it.
Those dip switches might do wonders though ...

[Flecko]

First a small disappointment : 8x AP will not be useable for SPDIF nor the i2s output.

So, is the i2s also limited to 192khz? But at least, 4XAP should work then, if my dac will accept it. At the moment, it just accepts 96khz (spdif), even if I will disable the DSP and make it a NOS. I thought maybe, if I use i2s, I could go higher than that (192,384). I guess the i2s input of my dac is also on the DSP module in the middle of the picture. At least, that is where the i2s output is on the Digital Interface (it uses the same module but different programming). And if I go to the point, where the signal leaves the DAC's DSP, and connect the i2s there, then , I hope, it could work with maybe 4XArcPred?
That is the DSP module in the Digital Interface:
http://www.audio-gd.com/Pro/dac/USBface/USB9.jpg

There is no digital filter. Haha.

Yes I know I meant in my DAC

, Anyway, i2s is native, and SPDIF is created from that. This is not 100% true (it would more be "in parallel") but for 100% sure it isn't the other way around (so, it's not that i2s is created from SPDIF or something).

So, if I switche from SPDIF to i2s with the Digital Interface, there might be no improvement because quality stays the same, just different "format"? With the NOS1-Source it will, because the signal is simply better.

Those dip switches might do wonders though ... Happy

At the moment I try doubling to 32bit/88.2khz with softer filter (90db instead of 130db). Seems to give more microdetails and a more relaxed sound. But that is just a small improvement...

[PeterSt]

So, if I switche from SPDIF to i2s with the Digital Interface, there might be no improvement because quality stayes the same, just different "format"?

Assuming you mean interfacing by the Audio-gd Interface to the DAC ... there sure should be a difference. But it's a bit unpredictable how. The i2s coming from the interface will have to be created from "something" (USB, FireWire). The quality of that will determine the quality of the interface. Next there must be a clock somewhere. Where is it ? how is it derived ? is it a different oscillator for 44.1 and 48 ? Jitter ?
After this the Ref7 won't change much to it anymore (depending on your soldering qualities ) although the length of the cable matters (and quality of the cable of course).

With SPDIF the clock is embedded in the signal, which is a totally different situation, and *now* it depends on the PLL, but also on how much jitter the SPDIF signal contains in the first place. It's all quite unpredictable.
Also : where does the SPDIF originate from. Here too (like with i2s) it can be (re)created in the interface, but it also can come from a PC soundcard (as SPDIF already) and be reclocked by the interface.

So many options ...
.

[Flecko]

I will go one step after the other. Waiting fro my DI. Then listening to SPDIF. managing to use i2s. Compare sound to SPDIF. Ordering the NOS1-Source. Comparing again. Beiing happy for a while And then upgrade to NOS1. Sounds like a plan!