Steve Deckert
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Hi EVO, and everyone!
An UPDATE regarding the DAC:
As most of you know the NOS DAC that started this thread is a one-off that I've been developing for myself as my personal DAC. It's too elaborate to put into production (nice way of saying it's too expensive to get a reasonable return on the investment after I buy the parts and chassis to build 100 of them).
The Zen Triode NOS DAC is a 3 block system. We've talked about perhaps making it available as separate blocks so that people could purchase one block at a time, or only those blocks they felt they needed or wanted. I've been working on such a concept ever since October.
At the same time, I've been exploring other paths to reach a similar end result in my R&D. NOS sounds good to me because it is more phase coherent and lacks the typical dryness oversampling brings. However we all know there are many great sounding DACs out there that use some oversampling... WADIA comes to mind.
Jitter is the main enemy in both formats and can bring either one to it's knees. And honestly, any format is subject to it's implementation and voicing.
The NOS chips I used are the simplest 20 year old design available - so just to add credibility to the result I decided to try the newest DAC technology today and see if by setting it up right I could get similarly pleasing results with oversampling against my reference NOS dac.
This is what I've been up to lately. Just the opposite of the Zen Triode NOS DAC I am developing a 24/192 up-sampling design around the Cirrus Logic's flagship hi-end chip. This has an advantage over my reference dac in that USB is now compatible with 24/96 bit for bit output and further up-sampled to 24/192.
To my surprise the results are on par with my reference dac, and a more usable product. So I have moved to working on the 3 piece block approach and have come up with a chassis that will match the ZBOX chassis in size and finish. We will be making a ZBOX that is configured as a gain stage (same thing I have inside my reference DAC) and calling ZBLOCK-2. The ZBOX itself will be re-named ZBLOCK-3. The dac will be named ZBLOCK-1.
This way you will be able to purchase the DAC alone, and add the tube gain stage or the tube buffer stage or both at any time and all three pieces will match and fit on an 18 inch shelf.
I hope to have this stuff on the site and ready to take orders in the next 30 days if all goes well, or shortly thereafter if not.
The DAC itself will sell for less than a grand and each optional tube stage around 500 each.
I'll also be putting my original reference NOS DAC on the site should anyone want to pay me to personally hand make them one.
Final note on what I'm hearing. When comparing the 24/192 dac to my reference NOS dac the following is what takes place: I mostly use the USB on my reference DAC and it only works with 16/44 on USB even though the dac is 24/96. And when I listen to my reference dac I can switch between the DAC alone, DAC plus tube stage, DAC plus tube stage and buffer stage. The DAC by itself is very transparent but not exactly liquid. I enjoy going back and forth for my own amusement but 80% of the time I have all three stages (blocks) active and the main reason is the smoothness.
Now that I'm in the final weeks of evaluation and voicing of the 24/192 dac I have not yet let myself listen to it with any further stages, only the dac by itself. I find that the upsampling everything including the USB to 24/192 is as smooth and liquid sounding as the NOS dac was with all three stages. While the big shoot out hasn't taken place as of yet, there's more than a good chance this will actually be better.
Steve
UPDATE
Well, I've had a brief shoot-out between the upsampling dac and the NOS dac. To make the comparison is difficult since I can't set both up exactly the same way. The NOS dac is 12 DAC chips in parallel giving it excellent current to drive an amplifier by itself. The upsampling dac is a single chip that requires a gain stage and buffer to accomplish a similar result.
What this really comes down to is the comparison between the NOS dac with the tube stage engaged against the upsampling dac's two OP AMPS. I spent a fair amount of time selecting the op amps for the gain and buffer, each one different.
Listening to the NOS DAC by itself with no tube stage is excellent about 1/2 the time, the other half of the time it sounds better with the tube stage and even the final stage activated.
Comparing then the NOS dac by itself with no tube stage and the upsampling dac by itself, the upsampling dac is better because it has the buffer. When I add the tube stage I used in the NOS dac, the sound changes, a bit more musical, a touch less resolution. This is not so much the case with the NOS unit. I will have to design the tube stage specifically to compliment the oversampling dac to get similar results. And I will.
Bottom line is that I have actually been enjoying the upsampling dac by itself with similar satisfaction to what I was getting from the NOS dac with at least both additional stages activated. For those who heard the NOS dac at the Decfest this year, you understand this is rather significant. When I compared my NOS dac with both stages activated and adjusted perfectly to where I'm really getting off on the sound quality I switch it to the new upsampling dac by itself and it hangs right in there, but with more transparency. This is what my confidence is keyed on.
So I continue to move forward. Chassis will be here in another 4 weeks with any luck and then I'll be able to take pictures and make the web page.
I've changed my mind on the BLOCK1, BLOCK2, BLOCK3 naming scheme. The dac performs so well on it's own, that I don't want to indicate a need for more with it's name. I called it the ZDAC-1. This way I can also leave the name of the ZBOX alone. I'll just do the gain stage and call it the .... something... I'll figure that out at the last minute like I always do.
The thing is, all three components will be the same size and visually match each other. The ZBOX and the Gain Stage will be optional. Using the gain stage will simply add a touch of tube joy to the sound and give you control over the dynamics. The ZBOX will have little effect on dynamics but will relax the presentation and make the system as a whole more forgiving of less than top notch recordings.
-Steve
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