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Deluxe Reverb Snubber Cap question

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by mxvin, May 17, 2011.

  1. mxvin

    mxvin Member

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    1978 DR with the 1200pF snubber caps acroos the power tubes. My question is does this give the amp more gain in anyway.:huh:huh
    I know clipping them helps to get the Fender "chime" back but the amp actually sound like it has less headroom too. Not necessarily a problem I am just wondering. The other owrk on this amp was just filter caps 22/500 and clipping the bright cap.
     
  2. 1guitarslinger

    1guitarslinger Member

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    Those caps are there to suppress parasitic oscillations. They have nothing to do with gain, and they rob the amp of harmonics.

    They were a "band-aid" fix that allowed for sloppy lead dress which sped up production.

    Clip those bad boys, check the lead dress, and change a few components and it will be blackfaced. And you'll probably say "there it is!" to the positive changes.
     
  3. mxvin

    mxvin Member

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    thanks for the info and I knew what they were there for just wonder what the overall tonal effect was. I have read that they did bleed of some highs and "deaden" the tone a bit...
     
  4. 1guitarslinger

    1guitarslinger Member

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    I think Gerald Weber said years ago that "they suck tone." Difficult to say it any better than that.
     
  5. TweeDLX

    TweeDLX Member

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    Easy enought to reverse if you try it and don't like it, but I'm betting you will. I removed a few snubbers from the pre-amp tubes of my '82 Concert II, and actually replaced one of them with a lower value cap. Seems to be a good compromise.
     
  6. mxvin

    mxvin Member

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    Thanks...actuallly I have done it on several amps. I usually notice a better tone...I guess. But this particular DR seem to loose a bit of headroom. Maybe its just me. No worries and thanks for the input guys...
     
  7. wizard333

    wizard333 Member

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    If its losing headroom, that could be a perception of:

    1) higher harmonics early in the breakup phase become more apparent, giving you the impression that it breaks up sooner,

    2) there is parasitic oscillation and the amp is wasting power trying to produce frequencies you can't hear with those removed, in that case, check lead dress etc as noted above.
     
  8. mxvin

    mxvin Member

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    Cool....sounds reasonable. I have heard the term parasitic oscillations som many times regarding this issue. I always wondered, as a no engineer and as an amp hobbiest, what do parasitic oscillations sound like and can you even hear them?? I guess you can hear the "result" of them being there or not being there.
    Mind you I like the bit of grind in this amp...but its not may amp....:) All of my Fenders definitely grind sooner rather than later on the volume dial.
    Of course DRs themselves aren't really a clean machine its just soemthing I noticed before and after clipping out the snubbers....:aok
     
  9. donnyjaguar

    donnyjaguar Member

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    Parasitics can be audible, subaudible or ultrasonic. An oscilloscope is your friend here.
     

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