Holoaudio Spring R-2R NOS DAC

automojo

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Read a great review in the current Stereophile, comparing this DAC, particularly in NOS mode, to several popular Delta Sigma DAC's, including another R-2R DAC.
While I haven't listen to these particular DAC's. I have found a similar experience in comparing the NOS Project DAC Box S FL, MUSE NOS TDA 1543x4, and the French battery NOS ladder DAC's to some pretty good DS based DAC's, and a few popular R-2R DAC's. By a slight margin, the Project sounds the best. Fine details, and a more natural flow. (All require at least a hour warmup to sound their best.) However, I have a Muse 4x1543 board I plan on experimenting with better supporting parts on, particularly the output caps.
I have to agree, I don't think it's the ladder chip, in so much is it enables you to, if you choose, eliminate any over sampling/digital filtering, and it's drawbacks.
Of course a lot of this can surely be a matter of taste. But it explains for me in my personal experience why I could not fully enjoy on a regular basis, DS DAC's or non NOS R-2R Dac's.
I totally agree with the glass wall description.
It would be a very interesting listen to compare the Holoaudio Spring DAC, in NOS, to my current stable of NOS DAC's.
It may be worth saving my penny's up for.
http://www.sakurasystems.com/articles/Non-oversampling-DAC.html
 
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NOS is just a different set of compromises. If you like it so much there are less expensive ways to significantly improve on your TDA1543s for less money than the Spring. Metrum Acoustics will soon be releasing a sub $500 NOS DAC based on their excellent 24-bit R2R modules. There is also Soekris dac1321 and its brothers, it's not NOS in its stock form but you can flash custom filters to it to enable it. There are also DACs from Audio-GD that can run in NOS mode, but Audio-GD has been getting bad rep lately due to its products measuring badly, so I'm not sure if I'd want to go that route.
 
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NOS is just a different set of compromises. If you like it so much there are less expensive ways to significantly improve on your TDA1543s for less money than the Spring. Metrum Acoustics will soon be releasing a sub $500 NOS DAC based on their excellent 24-bit R2R modules. There is also Soekris dac1321 and its brothers, it's not NOS in its stock form but you can flash custom filters to it to enable it. There are also DACs from Audio-GD that can run in NOS mode, but Audio-GD has been getting bad rep lately due to its products measuring badly, so I'm not sure if I'd want to go that route.

I've been following these as well. I'm pretty close to choosing the Soekris dac1421, but will be interested in the Metrum Flint.

Been wanting to try a R2R DAC with NOS option. I like that you can flash the Soekris. Holo would be nice but my budget is ~$800 so baby steps

Currently my Maverick D2 has been great, and i hear it comes close to NOS, so looking forward to trying one.
 
Found some pics.
It would be an interesting comparison between this and the DAC BOX S FL
 
A82E3F47-5749-4EC0-A1B8-A8F0F701DB65.jpeg 22027C16-6AF8-4F36-A860-EBBB35A9B685.jpeg Found some pics.
It would be an interesting comparison between this and the DAC BOX S FL
 
I didn't have a direct experience with these latest 24 bits Transient modules but they should be very nice. The best part is unlike the TDA1543 you can properly oversample them externally after you realize what a mess NOS really is. They will excel at playing true hi-res material as well.
 
Sure.. well personally I don’t have a problem with ‘straight’ NOS.
I thoroughly enjoy my DAC Box S FL.
Not a huge fan of high res, what I’ve heard so far.
So I guess it depends on what you’re looking for.
I do think NOS may sound better on some systems then others.
My modded ESS AMT3’s w Great Heil and custom woofers... NOS sounds wonderful.
I think if any of these DAC’s it’s too far from what I have now, I doubt I’d be interested long term, but would be a fun listen.
But again you never know...
If they are akin to the Schiit R2r sound, I enjoyed it short term, but wasn’t what I was looking for.
 
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Sure.. well personally I don’t have a problem with ‘straight’ NOS.
I thoroughly enjoy my DAC Box S FL.
Not a huge fan of high res, what I’ve heard so far.
So I guess it depends on what you’re looking for.
I do think NOS may sound better on some systems then others.
My modded ESS AMT3’s w Great Heil and custom woofers... NOS sounds wonderful.
I think if any of these DAC’s it’s too far from what I have now, I doubt I’d be interested long term, but would be a fun listen.
But again you never know...
If they are akin to the Schiit R2r sound, I enjoyed it short term, but wasn’t what I was looking for.

What's your source, a CD player? The Metrum is NOS so rest assured it will sound very close to your DAC Box S FL signature-wise unless you oversample in software, even then it will still sound much different than Schiit.
 
CD/Smart TV, also USB with a dongle at times.
My slightly modded Maverick D1 is the only oversampling DAC I’m using..and that’s through the tube buffer..
 
I also picked up a second DAC Box S Fl when I get my second system fully up and running
Basically same speakers with slightly differ mods and crossovers..
Upgraded Cit 21, Big Sky Audio, and Sig 1.5 amp... similar CD player
They have them reduced for $199 on Amazon, and I couldn’t resist, as I really like their sound. Picked up a linear power supply as well for $10, although I haven’t been able to tell the difference between the stock power supply and upgraded one
Frankly one of the biggest differences I found with this DAC, and really my over all system was the Quiet Line wall wart noise reducers.
I have their plug in analyzer that lets you know just where, and how many to use.
 
I have no problem with NOS but the honeymoon is over. I thought I liked NOS when I heard it initially, but in retrospect I just liked multi-bit DAC sound. I do listen to NOS occasionally but I can't see myself switching back to it full-time. Also if you like your music loud be careful, the energy of ultrasonic content from a filterless DACs can damage the amp or tweeters on high volume, especially true for inefficient speakers.
 
Interesting.
Sure, well the AMT3,s are very efficient I played it loud without any issues.
I’m not sure whether it’s Rtr, or lack of filter..
Personally I could also live with just the Maverick D1.
Uses a Crystal 4398 chip.
I sometimes use it without the Tesla Tube, but usually not for long and switch back to the buffer stage.
The Project and my D1, in its current configuration have a very similar sound.
There are some minor differences, but you really have to listen for them in the project needs to be fully warmed up, actually they both do.
I think I have the benefit of the Heils, being able to extract detail on a level, that may negate some of the drawbacks people have with this type of DAC.
I have these speakers fined tuned on a level your frankly not going to get from store bought speakers.
Frankly, I probably understand the ins and outs of the AMT threes, how they interact with different amplifiers room acoustics etc, ported, sealed, damping, crossovers, etc better than ESS even came close to.
 
I'm going to step out on a limb here. The NOS as well as an Over Sampler has to get rid of the Digital Artifact image which starts at approx. 22kHz, (44.1kHz CD format). That image has a lot more power at the low end, i.e. one over the square route of the frequency for equal sound pressure level at any given point in the audio frequency band. An oversampler is used to filter the image digitally. The NOS has to filter that image with an aggressive analog filter. Think sharp cutoff. Digital filters are more precise and can be a brick wall at the cutoff with no phase shift. Phase shift is one of the consequences of using an analog filter. Anyway food for thought, corrections, discussion.

Regards,
John
 
Sure, thanks!
I think the NOS, from my understanding either has a simple low order analog filter, or none at all.
The Stereophile article made the point that Rtr, by its nature, doesn’t necessarily require aggressive filters.
The author also suggested that maybe this had more to do with the sound then Rtr itself.
 
The thing is, the NOS crowd gave up on analog filters long time ago because of that phase shift or rather lack of skills and associated costs necessary to design a good analog anti imaging filter, and modern NOS DACs either have no filter at all or a very gentle one none of which are capable to filter the ultrasonics to acceptable levels. If a recording happens to have a lot of energy in 15-20kHz range (electronic music?) it may result in images that powerful enough to do some damage to the equipment, or cause powerful enough intermediation distortion whose products end up in the audio band. Fortunately this is usually not an issue as high frequency content in music is at relatively low levels and while the ultrasonic junk is there it's at levels low enough to not cause major issues.
 
Also on phase shift, the so popular "apodizing" digital filters that many favor these days have non-linear phase shift and impulse response similar to that of analog filters
 
Interesting.
I haven’t really done any research into Schiits “closed form” digital filters.
Personally I liked their sound for a short time. Powerful, solid, forward in front of your speakers sound. But couldn’t deal with it on a long-term basis.
Frankly, I think most of it was they were a poor match for my system.
It’s too bad, because I think they put a lot of effort into their products.
NOS is probably not in their future from what I’ve read.
 
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The Schiit filter is proprietary, not much known about it. Schiit folks seem to be very proud of it, because it "preserves original samples", too bad their hardware cannot reproduce them (the samples) precisely to a good depth, so it is a moot point if that filter property has any practical importance.
 
Sure, I do recall the preserving part. The MB's I had did lend them self to being fairly bright at times, and that was part of the issue I had with them in my system. Not sure if that's a filtering scheme, lack of it or what.
I think part of their "proudness" is a marketing ploy, as it definitely appeals to a certain segment of the market. Whatever works for them, I appreciate their products for what they are, and it's a plus they are made state side.
I do like the Holo's one box solution with experimenting with different filtering schemes. It would be fun to play with. But if your basically using the mildest/no filter, then it's probably not money well spent.
I will be very interested in hearing some reviews on the Metrum Flint. Anyone that get's one, please feel free to post your review thoughts here. I see they have a preorder special. Who knows, It may be in my future.
 
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