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    Yes, you *can* make a preamp sound good, and...

    Yes, you *can* make a preamp sound good, and thereīs lots of examples, but youīll have to work harder, itīs not "automatic" just because you throw some tubes in there.

    As just one example, for...
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    Justb thinking aloud: 1) death caps are never...

    Justb thinking aloud:

    1) death caps are never never ever used in Europe while they were all over the place in USA.
    Notice Peavey/Fender/Randall schematics where the 120V version has them, and...
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    See for yourself what an extension cord with...

    See for yourself what an extension cord with inverted hot-neutral can do:


    https://www.youtube.com/watch?v=vqMehAA2Fso

    FWIW, the kid survived grabbing guitar strings with one hand, microphone...
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    Preamps all by themselves are in general buzzy...

    Preamps all by themselves are in general buzzy fizzy, they NEED the waveshaping, EQ and compression provided by an overdriven power stage.
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    You can indeed get real 100W RMS out of 4x 6L6 or...

    You can indeed get real 100W RMS out of 4x 6L6 or EL34 BUT you need scary 520/530V +V to do so , plus feed screens not more than 400/420V so they survive or tie them to Ultralinear taps so when plate...
  6. Problem is not so much the pot itself, but the...

    Problem is not so much the pot itself, but the long threaded neck which allows it to be placed some 5 or 6 mm further than front panel than normal, and which is not an over the counter component....
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    Then by all means do NOT use that much NFB. ...

    Then by all means do NOT use that much NFB.

    Back it down to 12dB so you have better than 6dB stability margin.

    Donīt band-aid a poor design choice.

    In any case, why do you need so much NFB...
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    But you used the wrong (resistance) scale. Which...

    But you used the wrong (resistance) scale.
    Which is shown by your stating you measured 15K




    Let me give you an analogy:
    "testing components" is the endless and uncertain job of fully...
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    Suggested listening :)

    Was impressed by what this guy shows (besides him being a gifted piano player)


    https://www.youtube.com/watch?v=sAfmDnkJD60

    despite apparently going down in flames, Music still goes forward,...
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    "15 k????" You donīt use a resistance scale to...

    "15 k????"
    You donīt use a resistance scale to check transistors, but the diode one (guess why :))
    IF you find a short, meaning a low voltage drop, say,less than 500mV (which is what the diode...
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    Iīd call that "accomodation to Reality"...

    Iīd call that "accomodation to Reality" :thumbsup:
    You use whatīs available, period, and if "inferior", add as many as needed to keep performance. :thumbsup:

    Glad they adapted and kept the...
  12. Have you at least tried the simple solution I...

    Have you at least tried the simple solution I suggested? ;)
  13. Why do you ask for solutions to your problems,...

    Why do you ask for solutions to your problems, make us WASTE time and then despise advice? :mad:

    Iīm OUT.
  14. Sorry but neither JB Weld nor fish paper are up...

    Sorry but neither JB Weld nor fish paper are up to the task.
    The first one will first become so weak as to crumble if subject to pressure or vibration, the second will plain catch fire.

    Maybe you...
  15. Did-you-use-the-.1uF-coupling-cap-as-suggested? ...

    Did-you-use-the-.1uF-coupling-cap-as-suggested?

    As of what LMNC built, maybe it works, sort of but then it is NOT what he showed in the schematic. Period

    +/-12V tube VCA?

    Build an SS one...
  16. Thereīs at least 8 (if not 12) different versions...

    Thereīs at least 8 (if not 12) different versions of Peavey Bandit, some very similar, some drastically different.

    Post whatever labels are stamped or etched in your board, that might help getting...
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    Me neither, it clicked when I was closing...

    Me neither, it clicked when I was closing notebook cover so I had to add it on EDIT.
    Oh well.
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    Yes. Bootstrapping was necessary (so popular) in...

    Yes.
    Bootstrapping was necessary (so popular) in simple bipolar transistor gain stages.
    Base impedance could be made *relatively* high value, think 470k or so, but biasing resistors were typically...
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    Cool :) In general, when house numbers are...

    Cool :)

    In general, when house numbers are involved I straight play the parameter match game, or "what itīs suppossed to do".

    Contrary to tubes or ICs, transistors are widely compatible, and in...
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    Itīs confusing because itīs "upside down". Itīs...

    Itīs confusing because itīs "upside down".
    Itīs fed from -19V and its "+V" is Gnd/0V but otherwise, voltages must keep standard relationship between each other.
    Meaning Source a couple V more...
  21. Enzo points at the problem that some extreme...

    Enzo points at the problem that some extreme tests can not realistically be made at a Service Shop.
    Can they drive amp and speaker full blast and beyond for 1 hour?
    Because although you say problem...
  22. You have 2 multi pin elements shown in your...

    You have 2 multi pin elements shown in your schematic: 9 pin 12AX7 and 8 pin TL071 , BOTH have pin 4 and 5 , so what are you talking abut?

    * on 12AX7 pins 4 and 5 are 12V filament, inverting them...
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    Too sleepy but basically: 1) you are mixing very...

    Too sleepy but basically:
    1) you are mixing very different gain stages, differentb inherent/"built in" impedances.
    2) we are not talking the stage *on/internal* input impedance by itself 8which as...
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    I would bypass the relay with an NTC thermistor...

    I would bypass the relay with an NTC thermistor and check whether it now turns on.

    Use an inrush current limiting thermistor pulled from an old unused PS smps.
    This is just for testing, you may...
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    You may have a shorted OT :sad: Search for...

    You may have a shorted OT :sad:

    Search for (RGīs???) ringing neon transformer tester.
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    Strong suspect is instability/oscillation, caused...

    Strong suspect is instability/oscillation, caused by poor layout/grounding/shielding.
    The thump/pop at certain pot positions shows the start/stop of oscillation, and "hiss" means itīs present.
    We...
  27. Maybe they had to use a conventional over the...

    Maybe they had to use a conventional over the counter part in this design, for whatever reason (space? ... availability? ...) instead of their usual custom ordered by the millions ones, and just to...
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    Thanks to all of you. :)

    Thanks to all of you. :)
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