Weber Copper Cap Rectifier vs GZ34???

Discussion in 'Amps and Cabs' started by Chazguitar, Nov 10, 2010.

  1. Chazguitar

    Chazguitar Member

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    Am I crazy... or can a hear a difference in my 67 Super Reverb between a Weber Copper Cap Rectifier and a good old GZ34 Rectifier Tube? I've been running my SR with the copper cap because according to Weber in runs my original OT at a lower voltage and extends it's life. I've had it in for months now and all has been well. However, just out of curiosity, I popped the GZ34 back it tonight and man the amp sounds so much better (to my ears). Anyone???
     
  2. wizard333

    wizard333 Member

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    Different B+ is going to sound different. I've never liked silicon replacements for rectifier tubes.
     
  3. hippiebob

    hippiebob Supporting Member

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    Glass sounds better in my 5E3. I tried a Copper Cap to no avail.
     
  4. Cirrus

    Cirrus Member

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    I've used a copper cap in both my AC30's and yes, it does sound different to a valve rectifier. I find the bass and treble to be tighter at high volume, whereas a gz34 will smooth out the bass and treble, particularly round the pick attack.
     
  5. MikeyG

    MikeyG Supporting Member

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    Tightness is the difference. It should only be a feel/response difference.
     
  6. mark norwine

    mark norwine Supporting Member

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    Take a coppercap apart. Go for it.

    Hot resistors in very close proximity to diodes, shoved inside plumbing fittings. High voltages in close proximity to the [ungrounded] metal enclosure.

    I'll take a "tube" anyday over that.
     
  7. Truxton Spangler

    Truxton Spangler Member

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    SS rectifiers usually have alot less sag than tube rectifiers
    changes the feel.. soundwise SS compress less and seem to remove midbumps
     
  8. mark norwine

    mark norwine Supporting Member

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    Copper Caps aren't *just* ss rectifiers. They have big resistors which mimic the forward Vdrop (i.e. "sag") of the rectifier tube they're designed to replace.

    That said, I still wouldn't use one & can't recommend anyone else does, either.
     
  9. goneracin

    goneracin Member

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    I have to 2nd Mark. Ive seen a few of them fail, more than one had the potential to cause a serious injury. the resistor got hot enough to melt the solder holding it in, since the copper part helps it shed heat :bonk
    on 1 of them, 1 leg of the resistor was still in, but the other leg dropped. The others had parts laying in the bottom of the cap.

    you couldnt force me to use one at gun point.
     
  10. Timbre Wolf

    Timbre Wolf GoldMember Support Group Gold Supporting Member

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    Wow!!

    So... No UL listing on Copper Caps, then? :eeks

    - Thom
     
  11. justonwo

    justonwo Supporting Member

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    I just want to go on the record stating - if you held me at gunpoint - I would use one. Bob, you are a very principled builder. ;)

    I used a copper cap in a Double Deluxe and Halle I built from Weber. Neither of these amps has the particular tightness I associate with a standard solid-state rectified amp, but they weren't particularly spongy either. I didn't realize the design was so flawed and potentially dangerous, however.
     
  12. mark norwine

    mark norwine Supporting Member

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    as a component, it wouldn't get a UL "listing"...it would get a "recognition"

    That detail aside, no....coppercaps have no UL (or any other NRTL) rating whatsoever.

    Again, a copper cap is more than just "standard solid-state" rectification. They're designed to mimic the Vdrop {sag} of a tube rectifier. That's what the internal resistors do. So, no, they won't sound like a "standard SS rec amp".

    Either way, I would say, if asked, "don't use them."
     
  13. Timbre Wolf

    Timbre Wolf GoldMember Support Group Gold Supporting Member

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    Ah - an even finer point; thanks!

    In all seriousness, this sounds like a real safety concern. Have any of you with experience contacted TA Weber? I'm certain he would appreciate the feedback, and act accordingly.


    - Thom
     
  14. mark norwine

    mark norwine Supporting Member

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    I have considerable experience with Weber.

    I'll say this: :tapedshut:tapedshut:tapedshut:tapedshut:tapedshut:tapedshut:tapedshut:tapedshut:tapedshut:tapedshut
     
  15. justonwo

    justonwo Supporting Member

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    Yes, I read and understood your post the first time around. My comment was meant to support yours . . . that they don't have the response I associate with a standard solid state rectifier. Rectification inside the copper cap IS solid state but, as you mentioned, resistors are added to simulate the sag effects of a tube rectifier. And they do achieve this goal to a certain extent.

    Next time, I will try to "be clearer" when I post so I can avoid any "confusion" that might be "generated" from my "comments." :)
     
  16. mark norwine

    mark norwine Supporting Member

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    'tis all good, my friend.

    It's the limitations of "text without inflection". Happens all the time.

    My apologies....
     
  17. hasserl

    hasserl Member

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    Hyperbolate much?

    I've used them in the past and found they perform fine electrically, but I've also had a couple of them fail on me as you described, so I no longer use them either. However, in a pinch I wouldn't hesitate to stick one in one of my amps and use it temporarily while I get the correct tube rectifier to replace it with.
     
  18. Atmospheric

    Atmospheric Member

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    This issue used to set Brian Gerhard off big time.

    He originally used a GZ34 in the original Club Royales (I have one). But he found (and the math bears it out) that the amp never pulled enough current through the recto to cause any sag whatsoever. You need to get into the 30w class and larger territory before a tube recto makes any difference.

    Brian eventually started using SS rectification in THCRs but had to go back to using a tube recto simply because customers demanded it. He was convinced that there was no difference whatsoever in an 18w amp.

    So I use a copper cap in my THCR. I recently loaned it to a friend who tried a Mullard GZ34 in it and he couldn't not tell any difference between the copper cap and the NOS recto.

    This same friend owns several trainwreck clones (which he built) and absolutely swears that BRANDS of tube rectos absolutely make a noticeable difference in both tone and feel in higher wattage higher gain circuits.

    I believe him on all counts. This guy has great ears.

    Anyway, that's what I think I know about your question.
     
  19. Mattbedrock

    Mattbedrock Supporting Member

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    I built a Weber %E3 kit and used the copper cap when I initially fired it up. Even withe the copper and cheap chinese tubes it sounde good. I changed it over to some nice NOS Sylvania 6V6's and a Sylvania brown base 5YGTA. It was definitely better, but it's hard to say how much was the power tubes vs the rectifier.

    [​IMG]
     
  20. Chazguitar

    Chazguitar Member

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    Thanks to everyone for the input. I'm sticking with the GZ34. Sounds way cooler in my Super Reverb!
     

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