Soekris "dac1541": DAC/Amp - Stream of Consciousness Impressions

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Torq, Jul 27, 2017.

  1. atomicbob

    atomicbob dScope Yoda

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    Soekris and ADI-2 Pro in the house. Will measure at least the Soekris before going off-grid for a week or two (vacation.)
    DSC_0201a.jpg
     
  2. travelfotografer

    travelfotografer New

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    My phone is in another room and there is a wireless router in the same living room as the audio system. But the noise is not just high frequency, it is from high frequency digital-processing-type noise (heard from the tweeter and mid-range driver) to low frequency humming-like noise (heard from the bass drivers).

    Good news is Soekris Europe has replied my email and we are trying to isolate the problem.
     
  3. Collusion

    Collusion Friend

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    Just tried it and yes, no hiss or noise of any kind at all.
     
  4. gepardcv

    gepardcv Almost "Made"

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    I received my dac1541 a couple of days ago, and have been using it (with an Eitr). Not ready to share substantive listening impressions yet, particularly how it compares with my Gungnir Multibit+gen5, but have a couple of early points to make.

    1. There really needs to be a way to turn off the LEDs. In a dark room, they attract way too much attention, which sucks. The best ergonomics is to light them up when an adjustment is made, then turn them off a few seconds later. For now, I stuck LightDims stickers over them, but that's ridiculous.

    2. Using line output and the volume set to 0 (feeding an external amp), the clip light flashes on tracks with a bit more dynamic range. I expect that with volume >0, but doesn't 0 mean "pass through signal"?
     
  5. bengo

    bengo Friend

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    @gepardcv On pro audio gear, the clip light usually has some dBs of headroom before actual clipping occurs. If it is only flickering very briefly on peaks then most likely you are fine. If you are listening to stuff with real dynamic range (i.e. classical rather than brickwall-mastered rock/pop) and the light is on a lot, better turn it down a bit.

    @soekris Care to confirm about the headroom?
     
  6. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    Do you have any DSP prior to the Soekris unit that may be pushing the signal into clipping?
     
  7. soekris

    soekris MOT - Soekris Engineering

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    The crossfeed function is really the responsibility of the headphone amplifier, but I can see you point as the dac1541 can do it pretty good with digital processing and some people would like to use an external headphone amplifier....

    I see plenty of advantages using switch mode power supplies, like world wide power input, less heat, smaller and lighter. Can't see any advantage using an old fashioned linear power supply, it just looks more impressive with big trafos and large capacitors.

    Both create electrical and inductive noise, just something you need to handle.... The dac1541 have first LC filters, then six low noise, low esr and high speed discrete regulators for the analog power, plus low noise standard regulators for the digital power.


    The "Clip" LED is very sensitive, light up when there is just a single sample that overflows. The dac1541 volume control goes up to +10 dB, I believe it's a good thing to be able to add gain as some material need it, but I added the "Clip" LED so there is no doubts.

    The levels in the dac1541 is set so that 0 db is actually digital -1 dB, to leave a little headroom for the digital filters, the different filters will have more or less ringing. If you're really sensitive you can just stop with the volume control at -1 or -2 to avoid any clipping by the filters.

    In the end, it's your ears that decide where you set the volume control at, often you're fine with a little clipping so you get higher volume.... At least in my youth I liked my music at what I call realistic levels :)
     
  8. atomicbob

    atomicbob dScope Yoda

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    There is a digital anti-alias filter in the path. Almost all DACs have an anti-alias filter, either SW or HW or combination. The ones that don't, should. Filters ring on transients. This ringing can go over 0 dB. You will see this in my upcoming posts on additional DAC technical measurements.

    A good clip indicator also will catch inter-sample overs. This also contributes to occasional flashing of the clip indicator. Percussive transients may illuminate the clip indicator and 99.9% of the populace won't be able to determine any sound degradation. If sustained tones as from an organ illuminate the clip indicator, nearly everyone will hear the increased distortion. Soekris provides an excellent gain adjustment system. Set the gain for -4 and no clipping will ever occur; the clip indicator will never illuminate.
     
  9. gepardcv

    gepardcv Almost "Made"

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    Thanks for the explanations! All that makes sense. To clarify, yes: orchestral music; yes, the clip light only flashed. There was nothing audible.
     
  10. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    As a matter of interest, has anyone tried the remote control capability on the DAC1541?
     
  11. Luge

    Luge Acquaintance

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    Thanks @Torq and all others for the evaluation of dac1541. It is hugely helpful for me.

    I have noticed in another thread (http://www.superbestaudiofriends.or...is-dac1101-r2r-dac-amp.153/page-8#post-137425) that there may be an audience (incuding me) for a review of the only Soekris standalone DAC - the dac1321 (http://soekris.dk/dac1321.html) and that @soekris may be willing to spare one dac1321 for SBAF Loaner program.

    I believe the review of dac1321 would be interesting for SBAF community (including me) mainly for three reasons:
    1. It may be seen as direct competitor to recently reviewed Denafrips Ares (its 100 € cheaper (not taking into account import duties) but it also lacks balanced output so we may call it even);
    2. According to Torq one of the main disadvantages of dac1541 is not really ideal price/value ratio if it is not used as integrated unit. Many users therefore expressed opinion that they would be rather interested in standalone dac from Soekris (although probably in the higher end spectrum of Soekris's range);
    3. From various threads on SBAF I perceive there is currently raised demand for R2R dacs in this price range.
    With all due respect to all involved parties I would like to ask:

    @soekris if his offer to send one dac1321 (even if in prototype stage with unfinished casing) still stands;
    @Torq @atomicbob and other great reviewers around if they will be interested in a Loaner tour of dac1321 and will have time for this.



    PS: I am aware this is probably not the correct way to ask for a review tour as it is not my intention right now. My aim here is to see if there is a possibility of "getting things going". If so, I will do my research and contact the right people / step somehow into the process if needed.
     
  12. Torq

    Torq MOT: Headphone.com

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    If there was a unit with the just the "DAC-relevant internals" of the dac1541, without the crossfeed, no USB, no head-amp and no digital volume control, for about $1,000 I'd buy one to have around as a solid, neutral, reference and exemplar of a discrete R-2R sign-magnitude DAC. And if my personal signature preferences were towards the analytical then I'd probably listen to it quite a bit as well.

    That product doesn't exist though ... and I'm generally allergic to paying for stuff I won't use.

    If you look at some of the other things I've reviewed that have multi-faceted functionality, or lots of tweakable settings, I've made the same comments about those in regards to apparent value. The iFi Pro iCAN is a good example. I think it's a great little amp ... but it's value isn't fantastic if you're not going to make use of all of it's SS/tube modes and use it with a broad enough array of headphones/IEMs to warrant employing using some of it's other features.

    I don't have any personal interest in it, but if one is started I'll run it through my "LaY" cycle. There will be a couple of conditions on that, however. The first is that I'm last, or 2nd to last on the tour, and the seconds is that me doing "my thing" is preceded by impressions being posted by those earlier in the tour.
     
  13. soekris

    soekris MOT - Soekris Engineering

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    Some ask for a "cut down" dac1541. The problem is that we can't make all variations, not with the current size of the company, we need to try to make a product range that meet the needs of most.

    Torq, to make one that fit your exact needs don't make that much sense, as: most people want USB, crossfeed is almost free, just a switch and LED, all the processing is done in the FPGA that's there anyway, same with volume control. The head-amp is also not that expensive, use same amplifier as the line out, just with higher class A bias current when used as head-amp.

    We have the dac1421 coming for people not needing the balanced parts, and then the really cut down dac1321, which will sound much the same as the other ones, use same Sign Magnitude R-2R core (just only 25 bits), same discrete power regulators and output buffers.

    We are happy to make a dac1321 available for a tour, but would prefer to wait for a production unit, things have been delayed a little as putting the dac1541 into production took more resources than expected, especially as we ran into the Danish vacation time, here almost every business shut down in all of July....

    I also prefer not to pay for things I don't use, but I also like small integrated units, don't want a lot of boxes for every single function....
     
  14. Torq

    Torq MOT: Headphone.com

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    I totally get, and respect that.

    My intention was more to reinforce the fact that a) it was not down to any deficiency in performance that precludes me buying my own dac1541 (as stated in my write-up, I think it's excellent) and b) if I was told the difference between the existing dac1541, and the version I'd personally desire, was trivial (say €150/$200 or so) then I'd likely re-evaluate my comments on perceived value.

    I can appreciate multi-functional boxes ... at the same time, I like very focused solutions to very specific problems ... both from an engineering perspective and as a customer. This is, of course, purely down to personal preferences and circumstances.
     
  15. Luge

    Luge Acquaintance

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    @soekris , thank you for a response. Do you have idea about a date when the production unit of dac1321 will be available?

    Thank you for being available to review this dac (under your conditions) and your clear stance here. I appreciate that.
     
  16. sacredgates

    sacredgates Audio-Technica's high priest

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    The small apple remote control works right away without any adjustments and is a nice feature to have. For other remotes you have to go through a setup, which is explained in the manual. I did not try this.
    The remote functions control input source and volume, both for line out and headphone out. Sensitivity is good, you can be quite a few meters away, but you need to direct the apple remote towards the dac.
    Both the remote functions - volume and input source selection - are operated through the apple remote four point top navigation button, the two lower buttons have no function for controlling the Soekris dac.
     
    Last edited: Aug 28, 2017
  17. atomicbob

    atomicbob dScope Yoda

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    The 1421 is of considerable interest to me. If it has the same extraordinary low noise floor as the 1541 Single Ended output then you have a definite winner for those not needing balanced interfaces. I am currently quite impressed with the 1541 SE into Cavalli Liquid Crimson, which is single ended input as is the EC Zana Deux series. One of the few DACs that truly has inaudible hum, hiss, residual noise etc. with both DAC and Amp gains set to maximum levels, which is important for certain audio forensics tasks.
     
  18. soekris

    soekris MOT - Soekris Engineering

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    The dac1421 will have a little higher noise, due to not being balanced, but otherwise it's just half a dac1541....
     
  19. Walderstorn

    Walderstorn Friend

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    I am curious why is the dac-only 25 instead of 27. Is it resources related or...?

    Thanks
     
  20. atomicbob

    atomicbob dScope Yoda

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    Does the 1541 Single Ended RCA output use only half of the R-2R ladders or is it derived from the balanced output?

    *edit* - never mind. As was pointed out, the answer is found a few posts above. mea culpa on not going back to re-read.
     
    Last edited: Aug 28, 2017

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