AMB Gamma 2 DAC (or how NWAVGUY fooled us all)

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by purr1n, Nov 19, 2020.

  1. chakku

    chakku Friend

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    So based on this review a completed Gamma 2 was around ~$250 https://www.headfonia.com/preview-amb-labs-gamma-2/

    Take out the enclosure (~$17USD, https://www.newark.com/box-enclosures/b2-080bk/enclosure-instrument-aluminium/dp/26K9019), the front and rear panels ($50 https://www.amb.org/shop/) and that still leaves you with $183 for a completed board. I would argue the 5V power supply can't be taken out of this cost as the ODAC is run off USB power. $99 for a completed ODAC board is just over half this cost. With this in mind I would certainly expect the Gamma 2 to be a better product, especially when you consider it's DIY and needs to be assembled.

    I'm trying to take the person out of the equation entirely and looking specifically at the product in question, not turn this into a 'why I hate nwavguy' shitstorm.
     
    Last edited: Nov 24, 2020
  2. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    the product is the product of nwavdeuce. They can’t be separated. The product is instilled with all of his bullshit propaganda. If you buy the product you are buying the nwavdeuce marketing and nonsense. It’s one and the same. And that’s neavdeuce’s doing. He connected his product to a world of bullshit.

    the gamma2 is just a DAC and can be seen as just a product because unlike the ODAC it’s not attached to an entire worldview.

    I don’t give out dislikes almost ever but trying to give him or his product any positive credit makes me nauseous.
     
    Last edited: Nov 25, 2020
  3. 427428429

    427428429 New

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    I feel like I've found my people here. Telling other forums that NVAWGUY was just shilling how perfect his own design was in his own opinion and therefore that it (o2/ODAC) was unimpeachable was met with deaf ears for years. It started a f'ing measurement based cult that persists to this day. Actual listening impressions!? Hogwash, placebo, bias, numbers are all, audibly transparent, blah blah blah. Dude linked to wine tasting trickery as evidence that all sighted listening is biased to an extreme and said that any rebuke of the o2 was due to negative bias of it being a small and simple little box. I like that little box for what it is, but his writings and collections of info were a sales pitch.
     
  4. atomicbob

    atomicbob dScope Yoda

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    Which label Honeymoon album, Polydor or Interscope?
     
  5. purr1n

    purr1n Desire for betterer is endless.

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    ODAC price was a result of mass manufacturing. Buying parts individually from Digikey and Mouser will cost x3 more. DIY isn't cheap. Never was. Gamma 2 would have still been a bit more because it relies on an LPS for power instead of USB. Gamma 2 also has selectable filters, anti-clipping toggle, and numerous inputs and outputs, including mini phono and RCA and digital coax and TOSLINK outputs.

    When it comes down to price, it needs to be apples to apples in terms of features and also production quantities.

    The point wasn't about value, mass production, or the benefits or drawbacks of DIY with respect the Gamma 2 DAC. It was that NWAVGUY was a skilled marketer, who used AMB as a straw-man, to advance his agenda, and also possibly make a decent dime from it. And that ultimately, he really didn't design a DAC which significantly outperformed other grassroots efforts. Especially considering that NWAVUY had the benefit of a few more years where higher performance DA chips from ESS were available.

    Also, I am pretty sure that NWAVGUY didn't design the ODAC either. The Objective 2 amp PCB layout was too noobish to indicate that he could have designed the ODAC.

    Finally, the documentation of the AMB Gamma 2 (design considerations, schematics, BoM, test procedures) was very very comprehensive: https://www.amb.org/audio/gamma2/

    Not so much, or not at all for ODAC. It was few measurements and then some magic hand waving. I don't recall ever seeing a BoM or schematics for ODAC.
     
    Last edited: Nov 24, 2020
  6. Armaegis

    Armaegis Friend

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    I remember years ago there was some strongly suspected collusion between nwavguy and JDS labs based on writing patterns and jds posts. It certainly springboarded his company shortly afterwards.
    edit: but meh, I'm just bringing up old rumours, pay no attention to the man behind the curtain
     
  7. cameng318

    cameng318 Friend

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    I have a really complex feeling about this. I'm kind of glad the Nwavguy craps happened, so I will not be the next Nwavguy. My first lesson in electronics is from his craps that poopooing the competitors is really the worst thing to do. I try to be humble, but I know I'm not doing it good enough. Apologize for everyone I offended in the past. (Kinda wish some ASR folks learn that lesson too, then some of them might be cool folks to hang out with) On the other hand, many of Nwavguy's design choices would make sense in all other fields, but audio is entirely another category.

    About the PCB layout, I know the O2 PCB looks super duper sketchy, but I can see there's actually a lot of thoughts went into it. All grounds are joined together between C8 and C9, and the ground branches are separated at certain places to maintain star ground. Such grounding technique is really a pain in the ahole to implement on a 2 layer PCB this compact. The traces width also varies with current loading. On contrast, ODAC is a much simpler design. Digital circuits are just wiring up the chips according to the datasheets, and the rest is bada bing bada boom. It doesn't even need to worry about charging and discharging the batteries and other power craps like O2 does, so the design is a lot easier to implement. Most of its problems probably come from blindly trusting the datasheet figures. (while datasheets are sorta expected to be that reliable in all other fields)

    Ti Kan uses ground plane in a lot of his designs, including the analog circuits like Beta22 or Sigma22. It's easier to implement and the result is cleaner. Ti Kan does a pretty good job maintaining the ground's integrity, so the result should be similar to star grounding. 4 layer PCB helps in some of the designs. An example of bad ground plane, is the knock off Beta22 sold on ebay. The ground is diced up like onion. My lungs will explode if I look at it more than 10 seconds. On the other hand, Ti Kan's circuit design is truly amazing. It took me 4 years of education and countless nights to fully understand every bits in Beta22 and Sigma22. I wouldn't know this much about analog circuits without Ti Kan generously publishing his design on the website.

    In the end, it's really not worth it to pick up a fight between Gamma2 and ODAC, both are pretty much wire-the-chips-up kind of design. It's more meaningful to compare their way of handling people and things, then Ti Kan undoubtedly wins this. There's a curse within every young man, time and retrospection are the only cure.
     
  8. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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  9. Azimuth

    Azimuth FKA rtaylor76, Friend

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    It looks like the boards are still available from AMB:

    https://www.amb.org/audio/gamma2/

    They even will sell you a WM8501GED/V for the Gamma 1 board needed. Although you have to supply your own WM8741, WM8742 or WM8740 DAC chips.

    Looks like an interesting project, but too much SMD chip soldering for me. I still signed up on the loaner.
     
  10. Clemmaster

    Clemmaster Friend

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    Do you have an oven? :D
     
  11. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Yes, although I have never attempted wave soldering. I fried a Macbook motherboard trying to reflow some solder because the GPU died. I believe the same thing happens to the original Xbox.

    I did hand solder one SMD part...a resistor that fixed my Vali 2, lol.
     
  12. itsikhefez

    itsikhefez Acquaintance

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    I love AMB projects. I've built multiple Sigma's, Gamma2 (board only), alpha10 preamp (used in my main system), CK2III ...
    Ti Kan provides the best support for DIYers.
    The Gamma2 was incorporated into a Raspberry Pi streamer I built. I had never soldered SMD beforehand either, but it didn't turn out to be extremely difficult.

    I really enjoyed the Gamma2 sound, and will admit that some of those posts deterred me from building it at first.
    One slight issue with the Gamma2 is that the output stage only outputs 1.2V. This is likely not a problem with any high-gain amp, but in my particular system both the preamp and power amp are relatively low gain.

    [​IMG]

    [​IMG]
     
  13. E_Schaaf

    E_Schaaf MOT: E.T.A Headphones

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    Loaner impressions...

    I've got this DAC running via AES Coax from Lynx E22 in my desktop build. I really like the sound of it. And the I/O Flexibility is pretty impressive for such a tiny box.

    I haven't heard many Wolfson implementations in the past, just a phone I once had and the Lumin D2. Both were kind of soft and smoothed-over sounding. This DAC is neither of those things.

    I'd definitely say the technical performance exceeds the Modi-class products I've heard from Schiit (a few 2U's, Modi 3 DS). It's not especially forward or laid back sounding.

    Next to my EAD DSP 9000 III, it sounds a little bit dry in the highs and lean the low mids, but not by much.
    Next to my Monarchy M22B, it sounds slightly damped in the bass and leaner overall, but the top octave is rendered with a bit more clarity of texture.
    Next to the Theta Progeny, it sounds slightly less 'opaque', imparting less of a gloss and color on the sound. I'd say it's a step up from the Progeny in terms of transient behavior as well.

    I'd say the stage is slightly narrower than the above three, but the imaging clarity is comparable. The bottom octave doesn't quite have the rumble of the others, but I don't really notice on my speakers, and honestly I don't feel like it's lacking in this respect in general.

    Still, no sense of glare or digititus. It doesn't stand out as a black sheep next to my R2R DACs, so on that front I'll say the tonal density and timbral smoothness are excellent for an older delta-sig.

    I can't really put my finger on the difference between the digital filter options (A, B, or C), but found myself preferring A for whatever reason. The Anti-clipping toggle makes an audible improvement with loudness-wars style smashed tracks, giving a bit less glare to high frequency transients.

    At the end of the day, I have to admit if someone swapped this DAC in for one of my others while I was sleeping, I probably wouldn't notice for several tracks, at which point I'd probably bump up my sub 1dB or roll some tubes and continue on with life.

    I will say that I like the sound of it better with tubes somewhere in the signal path, but that's the case with most sources I've heard, so that doesn't really feel like a caveat.

    Thanks @rhythmdevils for providing a glimpse into what could have been for me had I gotten into the hobby 5 or 10 years earlier. With reasonably priced DACs, seems like things really haven't come all that far after all.
     
    Last edited: Jan 20, 2021
  14. Azimuth

    Azimuth FKA rtaylor76, Friend

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    It is too bad Wolfson got swallowed up by Cirrus Logic for that coveted Apple contract. This D/S DAC is a real winner. It gets some stuff right, and for a budget DAC, right up there with some of the others. They have a certain "likeable" quality to them.

    Loaner thoughts:

    Source: Metrum Ambre, Schiit Etir
    Amps: Cavalli Liquid Carbon X, Gilmore Lite clone (Dynalo)
    Headphones: HD600, HD650, D2000, T50 modded

    Comparatively I have the Theta DS Pro Basic II, which I would put up against a BF2 or Gungnir A1.

    From right off the bat, the Gamma 2 has a pleasing sound. Very reminicient of my old iPod, but more refined. The first thing I noticed was the space and width. Not super congested. The mids are ever so recessed, and no digititus at all. Where's the grain?

    It is a warmer DAC, almost warmer than the Theta. It does not have the thunderous lows that rattle your pants like the Theta, but it has a lower mid tilt to it. The extra bottom end I agree with @E_Schaaf that it is tight, almost muted quality to it. Not much texture here, but not one-note like the newer Modi DAC's. The top en d can be sligtly dry and will show some some actual harsh top end on some tracks, but certainly not extremely distracting. Only those upper cymbals would I say, "haha D/S...I got you!".

    The next thing I notice is the space between instruments. Lots of blackness and space for everything. Although I can tell I am missing some details, but only if I switch back to the Theta. Presentation is strange like my iPod...dynamic, but soft. Meaning it does not have hard slam, but has plenty of microdynamics. Macrodynamically might be somewhat softer, which actually means less fatigue and also helps reduce this digititus or whatever you want to call it, but still sounds dynamic.

    The filters A, B, C...A is the linear phase brickwall, B is minimum phase, C is the slow minimum phase. I also preferred the A setting and B made it dark and mushy, and C was kind of in-between 1 and 2.

    The Anti-Clipping is like a brickwall limiter with no makeup gain. With as compressed as music already is, not sure I need this except if I was watching a movie or maybe wanted to listen at real low volume. Sure it can smooth out those harsh tracks, but it just makes them sound more flat with even less dynamics.

    One complaint...it does not match the gain of modern DAC's. Even my SMSL 10th had more gain. So not sure what the Voltage out on this is, but might be 1.3 or 1.5 (now I see above that is indeed 1.2V) instead of 2V RMS. @atomicbob, I am sure you will be able to tell us in a heartbeat when you put this on your bench. But really, other than that, that is my only complaint.

    I mean, compared to the SMSL, the AMB was more spacious, natural and more textures and involved. The SMSL just sounded flatter and more aggressive. I would say this AMB Gamma is somewhere between a Modi 3+ and a Modi MB. It has all the traits of an MB regarding space, timbre, depth...just that tinge of glare every now and again.

    Good; pleasant timbre, non-fatiguing (for the most part), spacious and depth (yes for D/S), soft yet dynamic.

    Bad; not normal (low) desktop output.

    PS - I wonder if the low gain output has something to do with the good numbers here. I doubt it would have any affect on jitter. Just wondering about the rest of it. There are probably some resistors to change the output gain to bump it up to full 2V, but that would have to be done by the DIY'er.

    Thanks @rhythmdevils!
     
    Last edited: Feb 2, 2021
  15. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Yes...he borrowed heavily from the Bheringer U-Control UCA202 USB interface. Talk about copying the copy masters.

    Anyway, I remember he used that for the basis of the ODAC in designing his own...without the input of course.
     
  16. atomicbob

    atomicbob dScope Yoda

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    For those of you who listened to the gamma 2 using spdif input and the external Jameco power supply there is a transient, intermittent issue that occurs after approximately an hour of power on time. The power supply develops serious ripple. But again, it is intermittent, transient and variable. It took considerable hours to track down and capture this data. Not something easily captured with the analyzer. It takes an oscilloscope to capture these events. Here is an animation of several events after a period of two hours.
    20210623 Jameco 150mA load 100mV div 5mS div 1MHz fltr animation.gif
    Anywhere from 10 to 100 mV of mains ripple contaminating the gamma 2.

    Replacing the Jameco with an iFi iPower X solved the problem both for measurements and listening.
     
    Last edited: Jun 23, 2021
  17. Armaegis

    Armaegis Friend

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    Any idea what was happening with the Jameco that was causing this ripple?
     
  18. atomicbob

    atomicbob dScope Yoda

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    My first guess would be a bad capacitor. But any circuit component could be suspected. Without tearing apart and probing the circuit I am only guessing.
     

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