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Tantalum bypass caps?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Frostbite Slim, Jan 6, 2008.

  1. Frostbite Slim

    Frostbite Slim Member

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    It seems all I've ever read is that Tantalum caps sound HORRIBLE in audio circuits. I know of a couple "boutique" amp builders who use Tantalum for bypass caps.

    Would anyone with experience care to comment on tantalum caps? I was hoping to use some in a super reverb project.

    TIA
     
  2. jawjatek

    jawjatek Member

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    Expensive. When they fail they usually fail shorted. I would never use them in an amp. YMMV
     
  3. Frostbite Slim

    Frostbite Slim Member

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    Hmmm...so is it a reliability issue that makes them undesirable, or do they impact the TONE of a guitar amp in a negative way?
     
  4. hasserl

    hasserl Member

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    I have used them in the past for cathode bypass, and I really liked the results, until I had a few that were really noisy. I didn't like wasting time chasing down noise problems and replacing caps, and especially since I package and sell quite a few parts kits, I dropped using them a while back. Electrolytics work just fine, so I stick with them now.
     
  5. drfrankencopter

    drfrankencopter Member

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    Tantalums, and other polar electrolytics have non-symetrical responses in forward and reverse bias, thats why they are not typically used in coupling applications except when there is enough bias to keep the signal entirely positive (or negative). When used is a good design they can sound just fine....proof is old Neve mixing consoles with the 1073 modules..they're loaded with Tantalums, but are revered for their great sound.

    Tantalums tend to fail short circuited....thats something to be aware of too. Probably not the best choice as a power supply decoupling cap (though I think that is a common app for them...but not in tube amps).

    There's lots of different flavours in caps available for guitar amps...generally, there's no real space concerns, so you can try polyprop caps all the way through to paper and oil...no real need to get the space saving advantage of tantalum IMO.

    Cheers

    Kris
     
  6. AdmiralB

    AdmiralB Silver Supporting Member

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    Mesa uses them in cathode bypass applications in most of their designs. The Mark series EQ modules use them too.
     
  7. TubeAmpNut

    TubeAmpNut Member

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    They're fine as bypass caps on the cathode of common cathode tube stages. I've tone tested them with electrolytics and film types and struggle to hear much difference (although I prefer film). I use tants when space is a concern. -I'm assuming a cap value under 4.7uF.

    If you're building a super reverb, just use electrolytics. If you're building a 4 channel 7 tube switch monster, tants buy you some real estate.

    BK
     
  8. Frostbite Slim

    Frostbite Slim Member

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    Thanks everyone. I think I've heard enough to make me stick with electrolytics.
     

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