New R2R DAC

[Juancho]

It WILL do. I have made changes myself to equipment putting in better caps, better resistors in crucial places, better transformers etc. The guys who design this will have listened and tested the mods to get the different Levels of performance. The one I heard this week blew me away.

If I were you I'd get to hear one of these, and you can hear the whole range at Magna hi fi in Holland. One person's night and day upgrade may be another person's not worth the brass uptick. It's a bit different to going to a specialist and describing what you want / agreeing a budget

 

[Cable Monkey]

My car has a speedometer that goes up to 180mph but it doesn’t mean it can do it. Denafrips DACs do not do true NOS. I’m not saying that the button does not exist or that it doesn’t do something but it isn’t what it claims to be.

It can do it. It might just need a tow or a handy cliff edge! Actually the cliff edge wouldn’t work because the terminal velocity of a falling object is about 160mph.

 

[pmcuk]

I've been very curious about the sound of R2R DACs for a while.

At last I can compare R2R and a conventional DAC in my system. I'm now listening this evening for the first time to my Soekris DAM 1021 DAC, having finished the power supply. Additional USB input board being fed from my Mac. Listening to Ravel Valses Nobles with Boulez plus other tracks like Jazz, Steely Dan etc.

Soekris: Very smooth. Natural, clear and detailed. Excellent tonality to acoustic instruments. Absolutely nothing remotely hard or edgy. Sound is neutral and balanced top to bottom. Very refined. The output is single ended via the onboard chips. I haven't started to consider any mods and I haven't read the long thread on the Soekris build. I build with tubes and digital isn't my realm.

AK4490 - basic Chinese board with op-amp output. Sound is detailed and clear and involving. It's not as smooth and natural as the Soekris, and in those terms the Soekris is definitely a step up. But it is direct and more dynamic, and as such it's a little more involving for the listener. Where the Soekris is smooth and refined, the AK4490 is a trifle more "unrefined." Another way of putting maybe it is that the Soekris is like listening to a very good recording while the AK4490 is closer to live music. So where's the bottom line? I don't know - will have to do more listening. I have to satisfy myself that the R2R isn't a trifle "flat" sounding for all its refinement, which is a joy in itself.

All this seems to echo some of the comments I've read about R2R being neutral, natural, smooth and refined but not necessarily as "involving" as the best conventional DACs. Early days. The Soekris could be modified in various ways - if I can make myself read all the stuff written about it by users.

 

[rabski]

Not 'involving'? I'd say 'natural' combined with 'involving' sums up non-oversampling, but my experience is with NOS chip-based (AD1865 mainly) rather than true resistor ladder.

My current one actually makes the borrowed 'conventional' ones I've tried sound flat and lifeless by comparison. I could assume it's adding something and I've no doubt it measures poorly, but to my ears, it makes things sound 'real'. The output stage and the IV conversion are major factors though.

 

[wHIZZY]

Another NOS DAC to consider. Lab12 Reference.

I have spent the last couple of years trying to find my ideal DAC. For this purpose I have bought numerous S/H DACs at good prices and sold them on, if they did not totally convince me with their musical interpretation. Most were very good but I thought there were probably better DACs out there. DACs tried -

Chord Hugo,
Pontus 2,
Lindemann Musicbook source,
BMC Ultradac,
DiDiT 212,
Linn Renew Akurate DS,
Lab12 Reference DAC1 (as picture above)

I have owned the Lab12 Reference 1 (NOS valve DAC) the longest and have no intention of selling it. It sounds so sweet and detailed whilst still being musical and tonally correct. By far the best DAC I have owned but not necessarily the most impressive at the first hearing. Only negatives are, it has no volume control or headphone output.

 

[pmcuk]

Not 'involving'? I'd say 'natural' combined with 'involving' sums up non-oversampling, but my experience is with NOS chip-based (AD1865 mainly) rather than true resistor ladder.

My current one actually makes the borrowed 'conventional' ones I've tried sound flat and lifeless by comparison. I could assume it's adding something and I've no doubt it measures poorly, but to my ears, it makes things sound 'real'. The output stage and the IV conversion are major factors though.

The Soekris is a true resistor ladder. After listening for a couple of hours what I'm wondering is whether there's sufficient attack on the leading edge of notes. I get the feeling there isn't, which is why the music is very detailed, refined and smooth but possible a little "flat"?

So I wouldn't quite say the music sounds "real" in terms of sounding like live music. The tonalities of acoustic instruments, however, are very faithful with that one reservation.

Does this make any sense?

 

[antonio66]

The Soekris is a true resistor ladder. After listening for a couple of hours what I'm wondering is whether there's sufficient attack on the leading edge of notes. I get the feeling there isn't, which is why the music is very detailed, refined and smooth but possible a little "flat"?

So I wouldn't quite say the music sounds "real" in terms of sounding like live music. The tonalities of acoustic instruments, however, are very faithful with that one reservation.

Does this make any sense?

No. I use a Soekris which has been upgraded with a separate LPS, and it does all the good things you mention above, but I would never call it 'flat'. It also replaced a dCS Rosinni in a rather expensive system when it went away for the Apex upgade and we never felt the Soekris let itself down.

 

[pmcuk]

No. I use a Soekris which has been upgraded with a separate LPS, and it does all the good things you mention above, but I would never call it 'flat'. It also replaced a dCS Rosinni in a rather expensive system when it went away for the Apex upgade and we never felt the Soekris let itself down.

Do you mean LPS = Limited Power Supply? Why would this improve the sound? I have a LM317/337 supply for the +-12V, and the 3.3V and 5V are from bench DC supplies. I have a Wave IO card outputting I2S on a separate USB board. Output is the most basic, direct from the Dac ladder with about 600R o/p impedance. The o/p level is 1.4V rms or +/- 2V in old money.

The Soekris as it is right now isn't right. Something about tonality and dulling the leading edge of notes. My AK4490 DAC definitely has a more realistic Steinway piano sound - more steely and percussive. The Soekris is flat in comparison. Same with vocals. The guy who set it up changed the original mode (?) by downloading another. Maybe it's that.

 

[Psilonaught]

Do you mean LPS = Limited Power Supply? Why would this improve the sound? I have a LM317/337 supply for the +-12V, and the 3.3V and 5V are from bench DC supplies. I have a Wave IO card outputting I2S on a separate USB board. Output is the most basic, direct from the Dac ladder with about 600R o/p impedance. The o/p level is 1.4V rms or +/- 2V in old money.

The Soekris as it is right now isn't right. Something about tonality and dulling the leading edge of notes. My AK4490 DAC definitely has a more realistic Steinway piano sound - more steely and percussive. The Soekris is flat in comparison. Same with vocals. The guy who set it up changed the original mode (?) by downloading another. Maybe it's that.

I can't remember the name of the chap but there is a member here who has experience with the DC-DC Vicor power modules that Acuhorn use. Might be worth trying to copy their approach given you have the same OEM board that my Acuhorn uses.

My hunch is that is why the Acuhorn Soekris implementation is so special to my ears and a LOT better than my previous favourite NOS DAC from Abbas Audio.

 

[MartinC]

Do you mean LPS = Limited Power Supply?

LPS means Linear Power Supply, as opposed to switch-mode.

 

[Juancho]

I may be wrong but I thought the Vikor modules are a form of SMPS?

 

[Cable Monkey]

I tried on several occasions to contact the company to purchase Soekris modules from the official source and failed. The Chinese supplied modules are flooding the market and despite their availability I chose not to purchase from their market places.
The notion that this and other R2R devices sound ’soft’ isn’t new. It was a criticism of earlier versions of the DAC I now own but there is no doubt that as they are improved either by development or spending more, that aspect reduces significantly. My comparisons are with a couple of AK4497 DACs and I certainly recognise your description of their primary characteristics. Right now, my metric of how much I like a DAC is how much I listen and to what. Right now I am listening a lot more and am genuinely reluctant to put either of my 4497’s back in the chain.

 

[jobseeker]

No mention of the Gustard 26 series yet?

 

[rabski]

The Soekris is a true resistor ladder. After listening for a couple of hours what I'm wondering is whether there's sufficient attack on the leading edge of notes. I get the feeling there isn't, which is why the music is very detailed, refined and smooth but possible a little "flat"?

So I wouldn't quite say the music sounds "real" in terms of sounding like live music. The tonalities of acoustic instruments, however, are very faithful with that one reservation.

Does this make any sense?

Makes perfect sense, and I understand exactly what you mean.

Maybe it's inherent in a resistor-ladder application, but I don't see why it should be. Assuming that it isn't, I'd start off by looking at exactly where you'd look to 'cure' similar ills in a valve circuit: power supplies.

The LM317 and 337 are inherently noisy, so possibly try much heavier filtering on the output. CLC wouldn't hurt. Better still, try a different regulator altogether.

 

[zeta4]

I'm the one who set up Andy's Soekris. for him You can implement various o/p filters, there's a whole thread on this on diyAudio. I forget what I set it at but it was the one most recommended on the thread. I use a self built true R2R ladder Dac and it sounds anything but dull.

The power supply for the Soekris can be ac or dc. Either way this then powers various supplies
on the board via on board regulators. It will be sensitive to this main supply to an extent but in the end the on board ones will be the limiting factor. Again there is a lot on diyAudio etc about updating these supplies but it does involve some smd surgery.

I prefer the AKM sound to others like the Ess Sabre. I'm also building a AD1865 one

 

[StingRay]

I have spent the last couple of years trying to find my ideal DAC. For this purpose I have bought numerous S/H DACs at good prices and sold them on, if they did not totally convince me with their musical interpretation. Most were very good but I thought there were probably better DACs out there. DACs tried -

Chord Hugo,
Pontus 2,
Lindemann Musicbook source,
BMC Ultradac,
DiDiT 212,
Linn Renew Akurate DS,
Lab12 Reference DAC1 (as picture above)

I have owned the Lab12 Reference 1 (NOS valve DAC) the longest and have no intention of selling it. It sounds so sweet and detailed whilst still being musical and tonally correct. By far the best DAC I have owned but not necessarily the most impressive at the first hearing. Only negatives are, it has no volume control or headphone output.

No volume control is a good thing according to some people,I wish mine did not. Running the sound through a volume control will affect it.

 

[rabski]

I'm the one who set up Andy's Soekris. for him You can implement various o/p filters, there's a whole thread on this on diyAudio. I forget what I set it at but it was the one most recommended on the thread. I use a self built true R2R ladder Dac and it sounds anything but dull.

The power supply for the Soekris can be ac or dc. Either way this then powers various supplies
on the board via on board regulators. It will be sensitive to this main supply to an extent but in the end the on board ones will be the limiting factor. Again there is a lot on diyAudio etc about updating these supplies but it does involve some smd surgery.

I prefer the AKM sound to others like the Ess Sabre. I'm also building a AD1865 one

Possibly 'bingo' in the second part? I've seen occasional strange issues in the past with LM series regulators feeding other regulators, with instability and HF oscillation. I never got to the bottom of this, but in the current build here, I've got regulators close to the chip(s) and the offboard power supply is extremely well filtered, but doesn't regulate at all.

If the Soekris board regulation is sufficient, then why not just feed it with (very clean) unregulated DC. As long as the voltage isn't too high, wouldn't this be OK?

 

[zeta4]

Possibly 'bingo' in the second part? I've seen occasional strange issues in the past with LM series regulators feeding other regulators, with instability and HF oscillation. I never got to the bottom of this, but in the current build here, I've got regulators close to the chip(s) and the offboard power supply is extremely well filtered, but doesn't regulate at all.

If the Soekris board regulation is sufficient, then why not just feed it with (very clean) unregulated DC. As long as the voltage isn't too high, wouldn't this be OK?

Yes that might be a good solution and easy to try. Even something like cap multiplers might
also work well. Or a couple of small 12V batteries ?

 

[StingRay]

Can you live with these sharper sounding DACs or would softer sounding one be better for longer listening?

I would probably go for natural over detail in my system.

 

[pmcuk]

Can you live with these sharper sounding DACs or would softer sounding one be better for longer listening? I would probably for natural over detail in my system.

It isn't a case of "natural over detail" - you need both. That's not the issue with my Soekris in its present state. Or possibly R2R in general. It's a false binary. There's plenty of detail in most DACs. Natural has a number of ingredients, amongst which are instrumental tonality and dynamics, and this is closer to the issue.

I'm pretty sure that the issue is in the dynamics of the sounds created. The AK4490 clearly has more attack to the leading edge of notes, and so sounds more "live" or "involving". If you soften the leading edge you get a flat sound. I'm very familiar with this effect from using Garageband for writing songs. If you create notes with no attack or decay using your computer keyboard that's exactly what you get. If you input from a touch sensitive keyboard you get the full attack and decay, as you would on an acoustic piano. In other words the "natural" dynamics of acoustic instruments. It's a Steinway piano that sounds most obviously "flat" on the Soekris in its present state.

I'm starting my journey towards a solution. One step is to take out the LM317/337 regs and use a CLC or even LCRC supply to the board. Just be careful it doesn't exceed 12V. I'll have to look at the current in the +-12V supply to figure out how to do this. I haven't ruled out a Rod Coleman reg. as an option.