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Discussion in 'Amps and Cabs [BG]' started by jbass67, Mar 29, 2004.

  1. jbass67


    Nov 17, 2003
    i have chance to purchase a stewart pa-1800 power amp
    & would like to know if it would be suitable as an amp for my bass rig. i believe it has no volume (gain) controls so it's wide
    open. would it be compatable with my ivp preamp that has
    gain & master on it? also i would like to use it with a 2x12
    & a 2x10 but i wouldn't be able to balance speaker volume.
    would this amp be a drawback since it has limited flexibility?
    opinions & suggestions needed.
  2. http://www.stewartaudio.com/pa1800.html
    Do you mean SVP-pre-amp? It should work just fine with that pre. In order to balance your speaker output, add a small line mixer to one channel between the pre and the power-amp. This will allow you to turn one channel up and down in order to balance it with the other. ART makes several nice ones.
  3. pjhandlin

    pjhandlin Gold Supporting Member

    Sep 17, 2002
    Grand Rapids, MI

    I have a Stewart PA 1200 amp, it supposedly has similar specs to the current World 1.2, although my amp has a fan and is two rack spaces instead of one.

    On my amp, there are two very small gain attenuators that essentially sit flush with the back panel. They are located between the input 1/4" jack and the output binding posts. They have slots in them and I think the idea is that you set the gain level with a screwdriver then vary your input gain with you preamp stage(s). I've done the .. set it and forget it.. thing with good results. Basically just opened them up to 80-90% with hardly any increase in noise and left them there.

    One thing to consider though: I just called Stewart customer service to get a schematic for the amp because one side has been giving me some problems and they informed me that no schematic was available. Furthermore, this person commented that components used for my model are no longer available and that they would not take the amp in for service. So unless I figure something else out, I'm SOL!

    It has been a great amp for the four years that I have owned it, but I think now there seems to be a growing number of decent alternatives (inexpensive amps new) that I might recommend something other than an old stewart amp right now because it might not be able to be serviced if anything does go wrong.

    Good luck!
  4. jbass67


    Nov 17, 2003
    thanks pjhandlin for the firsthand experience involving
    obsolescence but it would depend on how much i can
    move the price. 1400 watts bridged & lightweight is kinda
    expensive these days. also greybeard, it's an
    intersound (ivp) preamp. vintage phil lesh tones from
    the 80's.
  5. yodedude2

    yodedude2 Supporting Member

    Nov 19, 2005
    san antonio, texas
    bumping this old thread for a related question: i have one of these amps and it works fine. however, i have always used it in stereo mode in the past. i now want to use it as a subwoofer amp. i moved the back panel switch from stereo to mono. my question:

    to run the amp in 'bridge' mode, do i need to run a banana plug across the positive terminals of both channel outputs, leaving the negative terminals unused?

    (i apologize if my question seems obvious, but i can't take any chances and there is zero customer support for this amp. thanks for helping, talkbass!)
  6. yodedude2

    yodedude2 Supporting Member

    Nov 19, 2005
    san antonio, texas
    bridge question bump

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