Black Widow [Update] - Second round official, 100 amps total, single chassis

Discussion in 'Eddie Current' started by purr1n, Oct 5, 2015.

  1. jexby

    jexby Posole Prince

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    it’s no transformer, but maybe the new iFi Powerstation would fix the issue if it’s ground hum related?

    in USA, DC offset could be solved by using Emotiva CMX-2. unsure about international version.
     
  2. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    Yanked the XLRs to the GoldPoin/Genelecs from the Soekris and the buzz is gone. Annoyingly a set of ground lift XLR adapters doesn't help any.

    A little more testing:

    Unplugging the Genelecs from the power strip makes no difference. So that eliminates a ground loop on that front.
    Soekris-->XLR-->Genelecs causes buzz.
    Soekris-->XLR-->GoldPoint-->Genelecs causes buzz.
    Soekris-->XLR-->GoldPoint causes buzz (with no connection to Genelecs at all). This is pretty weird, it's completely passive. The tone is slightly different though.
    Soekris--XLR is clean as a whistle (nothing connected to the XLRs, just the short leads that go to the GoldPoint)
    Soekris-->No XLR is clean as a whistle of course.

    In all cases of course Soekris-->RCA-->BW2 is connected.

    Maybe Soekris doesn't like both XLR and RCA connected at the same time? It's like any sort of common ground on the connected XLRs causes a buzz, but I know this stuff can be voodoo, though. The GoldPoint does seem to be complicit as well.

    For now I have the Genelecs being driven balanced by GO2A SE and listening to DAC1541-->RCA-->BW2-->HD600. Even my sibilant nemesis track "Bruce Hornsby's "The Western Skyline" doesn't grate on this combo.
     
  3. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    I have a strange behavior with BW2. Using 2 different DACs I get the same issue where the left channel will be weak and distorted or drop out completely. If I mess with it - swap input chanels and swap back, or unplug/replug the output from the source it will come right. Once I've done this, if I leave the amp powered up it seems stable, but power it off and on again and the same thing happens.

    Interestingly the distortion sounds similar to that when you power off teh amp and the last power bleeds out of the caps (I presume). What is weird is it's always the left channel.

    What might this be?
     
  4. jexby

    jexby Posole Prince

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    @Gaspasser might this be similar to the slight left channel distortion we had in our BW2 and you fixed by soldering the...?
     
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  5. JK47

    JK47 The Beer Houdini

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    Bad karma
     
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  6. sheldaze

    sheldaze Friend

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    I never had the issue with my original BW2. The issue first occurred during the summer of 2017, after I purchased a used BW2. I sent it to Craig, who replaced the board. However the next summer, 2018, I encountered the same issue. I sent it to Craig, who tightened up a few pieces. But he was unable to reproduce the issue. He said it was likely due to DC from the source.

    Until I spoke to @Ice-man, who suggested I simply leave my amplifier on 24/7, I was not able to use my BW2 (now with replaced board, and certified 100% functional) for longer than an hour. This is with common DAC sources such as Bifrost, Gungnir, and Yggdrasil. I have no problems once the amplifier has been running for 24-hours (not with a source playing, just sitting idle). And I have also been successful taking it to meets, off for an hour of travel, and immediately back on for the duration of the meet.

    Short story - Craig suggested I sell to someone who has a better source, with no DC offset. Long story - I just power the amplifier on 24-hours before use, or just leave it on. I suspect it has a thermal stability issue, which becomes stable after a day.
     
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  7. Gaspasser

    Gaspasser Flatulence Maestro

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    On that particular BW2, which if I remember correctly is the same one @GoodEnoughGear has now, had a molex connector that must have wiggled loose during shipping. I opened the case (after about 36 hours powered off) and followed the left channel and removed and reconnected the molex connectors for the boards. It was a crackle in the left channel for me that resolved fully after the remove and reconnect. I would try that and hopefully that will resolve your issue. Good luck.
     
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  8. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    Cool, let me check that out. Thanks!
     
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  9. purr1n

    purr1n Finding his inner redneck

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    I've heard of these issues. They seem to amount to when the amp hasn't been used for a while. The distortion occurs when it's cold, but goes away when warmed up. Might also be regional, temperature, humidity.

    50% of the boards were bad from the board house. The culprit was usually solder splash. The components were put so close together, and thus the design is more susceptible to this. I figure board expansion and contraction is the cause of the issues.
     
  10. brencho

    brencho Friend

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  11. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    May be worth having someone local take a look for anything obvious. It doesn't sound like very reassuring o_O but if it's solder splash maybe it can be cleaned up.
     
  12. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    I sent the amp in to a reputable local builder Karel Mars who's seen some solder cracks on some joints and a wonky volume pot. He's resoldering the cracked joints and replacing the pot, and we'll see what we get after that.
     
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