Replacing tube rectifier with solid state plug

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by mightypudge, Sep 28, 2003.

  1. mightypudge

    mightypudge Member

    May 20, 2002
    Huntingdon Valley, PA
    I recently purchased a Seymour Duncan Convertible 100-watt combo with a tube (5U4G) rectifier circuit. I was surfing the Groove Tubes web site and noticed they have a little plug that replaces tube rectifiers with solid state.

    What affect, if any, will this have over the overall tonality of the amp? The web site alleges that a solid state rectifier increases power and dynamics, and never wears out. Sounds good, but what are the negatives?

  2. WrapAround

    WrapAround Member

    Sep 4, 2003
    i have replaced a 5AR4 with a SS plugin from GT in one of my amps. it did give me more headroom and a little more volume. since i missed that sag, the SS plugin didn't stay in there too long. overall i'm pretty happy with either a Mullard 5AR4 or a WeberVST coppercap.
  3. VaughnC

    VaughnC Supporting Member

    Jan 4, 2002
    Overall, with a ss rectifier, an amp will tend to feel tighter and stiffer with not as much bass flab. Whether it's better or worse though is very subjective. However, Weber has a ss rectifier (called the copper cap) that simulates the tube rectifier sag to a degree. But, you must keep in mind that a ss rectifier raises the amps voltages, so you will need to check the bias on your output tubes if you change to a different type of rectifier.
  4. John Phillips

    John Phillips Member

    Mar 17, 2002
    The GT one has no added resistance, so it will both raise the internal voltages and give a 'SS rec' sound - bolder and tighter with no sag. My guess is that the SD, being a fairly modern design, will cope with the extra voltages but it would be wise to check - you don't want to blow a filter cap for example.

    Weber Coppercaps are available in lots of different specs (including 'no sag') to simulate different tube types. If you want sag or need lower voltages, I'd go with one of these.

    Especially on that amp, with the 'power control', you're probably not utilising power supply sag very much, so the extra potential unreliability of a tube isn't really worth it, IMO.

    The only fault that my friend's SD Convertible has ever had is a blown rectifier tube, BTW - although it's worked for years with the replacement.
  5. jzucker

    jzucker Supporting Member

    May 20, 2003
    Some of the early convertable amps ran really hot. I suspect they'd run even hotter with an SS plug. I know folks who's modules actually "melted" from the heat.
  6. roknfnrol

    roknfnrol Silver Supporting Member

    Oct 10, 2003
    Louisville, KY
    I too was thinking about putting a SS rect in place of my GZ34 in my Vox/Matchless clone. Can I just switch them out? I never run my amp on 10, just usually around 5 to get a little wamth and bite then use an overdrive.-Mike
  7. myles111

    myles111 Member

    Nov 19, 2003
    Los Angeles CA

    jzucker .............

    This is because with the SS rectifier you have more (higher) B+ (plate) voltage, and it sounds like the bias was not readjusted for the increased voltage. This made a lot more heat.

    If properly biased in the output set, the amp will actually run cooler with a SS rectifier as there is less load on the power supply and no heat from the rectifier tube.

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