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preamp vs master volume settings

Discussion in 'Amps and Cabs [BG]' started by unatratnag, Sep 20, 2005.

  1. So I recently obtained a GK 1001RBH-II. I was looking through the manual on all the knobs and it was saying it always recommended the master volume on 12-3 o'clock and use preamp to control the overall volume.

    While I guess I realize the preamp volume controls how loud the initial volume is being pumped into the head, and the master volume controls the overall volume going out (at least that's what i thought was happening...) I don't know how they work in conjunction with each other. Manual says master volume below 12 will cause distortion. Can anyone explain this to me as to why?

    On my old SWR, I usually used master volume for overall and left pre-amp(gain) at 12 to 3 o'clock all the time and never had an issue with distortion or anything.....maybe the dif companies work differently but in any case, can someone maybe explain this a little better as to how they work together especially in terms of headroom and clipping...
  2. KJung

    KJung Supporting Member

    I'll look forward to the responses on this thread. I've seen a number of manuals state the same thing. It doesn't make sense to me. My thought was to always set the preamp volume to the optimum setting (which would be just before clip on a transistor preamp, and to how much grit you wanted in your sound on a tube preamp) and then control the volume with the post gain 'master'.
  3. Quality


    May 7, 2003
    Long Beach, CA
    I have a GK combo. While it's not the same exact head, I believe it has the same architecture. It's the 300 watt head.
    My manual says that you shouldn't run the Pre-amp above 1 o'clock unless you want some distortion and the master should be used overall. The pre-amp is there to get the maximum headroom out of the power amp. Normal settings from 12 - 3 o'clock on the master but crank it if you need the extra volume.
  4. Quality


    May 7, 2003
    Long Beach, CA
    I've also had questiond for GK and could usually get a very experienced person on the phone with very little waiting.
    Just another option.
  5. Jack


    Sep 6, 2003
    Newcastle, UK
    Also, try PMing Tb'er Daniel Elliott.

    Im not sure what exactly he does at GK (sales rep?) but he's in there and if he doesnt know, he'll know someone who does.
  6. If the preamp has post-gain master volume (not to be confused with a pre-gain "gain" knob) I set the power up at full and use the preamp to control it's overall volume.

    If the preamp doesn't have a post-gain master volume, I use the power amp's master volume to control the overall volume.
  7. Thanks for the info...can you explain why? and do you just know this by looking at manual for how it's wired?

    I just spoke with a guy named Gene I think at GK.

    We apparently have 3 knobs on the 1001rb-II, the input volume (pre as i call it), master volume (also labled woofer), and the boost which I hadn't really messed around with much.

    Gene was saying that the master controls the headroom of the amp. Pretty much recommended what the manual said to put it at 3 and boost at 12 and that you usually don't want to put your pre/boost higher than your master volume. Also says that overall, none of these should really go beyond 3 o'clock. Not sure that really helped explain much though....
  8. Quality


    May 7, 2003
    Long Beach, CA
    The Boost is the GK growl Circuit.
    That just ads a bit of even order harmonic distortion. Yeah, You don't want to run that highter than the master or it gets a bit mudded out.
    The boost is actually a really cool thing if you like that kind of thing in your tone. GK is kinda famous for that growl.
  9. Never read the manual, just past experience with other pre/power amp setups.

    Essentially, the master volume of a preamp and the master volume of a power amp control the same part of the circuit....that is, they both control how much signal is hitting the power tubes.

    Since they're both controlling the same part of the circuit, you're best off maxing one and relying on the other simply from an ease of use standpoint.

    So, keeping in mind what you've been told. I'd max the power amp master and keep the preamp master at or below 3:00.
  10. syciprider

    syciprider Banned

    May 27, 2005
    Inland Empire
    Tweak the knob that gives you less hiss at high settings.

    Or if I really must max one knob I'd rather clip my preamp than my power stage. If nothing else at least I don't ruin my cabs.