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'72 Ampeg SVT question

Discussion in 'Amps and Cabs [BG]' started by Rickenbackerman, May 16, 2001.


  1. Rickenbackerman

    Rickenbackerman

    Apr 17, 2001
    Laurel MD
    Hi people! I got my SVT back from the shop the other day (bought it and took it to get it checked out before I cranked it up), plugged in my 4001 (with bartolinis) and turned it up. It sounds fairly distorted, even at relatively low volume (9 O'clock on the volume, all tone controls flat). I'm playing through two 8-ohm Eden 410XLT's with the tweeters at around 10 O'clock.

    The tech that checked it out has a very good rep, and he said nothing was wrong with it; he even played through it for an hour or two. He just looked it over and biased it up, said it was good to go.

    So I figure the barts in my Rick are overdriving the preamp, does this sound like a fair assumption? The only thing that seems strange is that I have to turn the volume on the bass WAY down to get a clean sound. I didn't think these old Ampegs had such a high preamp gain? Don't get me wrong, I love a good SVT overdrive, but I like the overdrive to come from the power tubes, know whatta mean? Advice?
     
  2. rickbass

    rickbass Supporting Member

    I know of people having to compensate for their Basslines pups with their onboard volume (turning it down). Maybe your Barts are too hot to handle, too, although I've not heard it before.
     
  3. yur pickups seem quite hot...turn down the volume!
     
  4. Rickenbackerman

    Rickenbackerman

    Apr 17, 2001
    Laurel MD
    The thing is I have to turn the volume on the bass down a whole lot to get the sound to be clean (like 50% on both volumes), and even then, I can still some hear some dirt in there. I don't think the bartolinis are 'that' hot. I've heard these old Ampegs should be very clean until you get to around 11 O'clock on the volume knob...

    Anybody else out there have any thoughts on this?
     
  5. Rock City

    Rock City

    Apr 8, 2001
    Boston,Ma
    rickenbackerman.....I don't think your problem lies in your pickups. SVT's typically don't like ported cabinets, especially EDEN and SWR. I know, I've tried! My '71 sounds amazing through it's own 810, but I can't say it's ever CLEAN. I think with time you'll realize and appreciate that. As for power amp distortion, I doubt you'll ever play the amp loud enough, but if you do......WEAR HEARING PROTECTION!!!!!!!!!!!!!!
     
  6. Jeez, that's odd, because my SVT ('76) sounds great through my Goliath III. I know the original SVT thing was the sealed box 810 but I don't think the amp will perform worse with a vented box (based on much experimentation with cabinets). The sealed 810 thing is a classic sound though... The "quintessential" SVT sound so to speak. Mine begins to overdrive at about 11:00 with my jazz bass, and at that point it's louder than hell. Basses with really hot pickups can certainly overdrive preamp circuits. Although I haven't known Barts to be exceedingly hot.... Try a different bass, something passive like a P bass. If it goes away it's probably the pickups if not it's the amp. FYI, different makes of power tubes begin to break up at different gains. For example a 6550 A will have more clean gain than just a plain 6550. A Groove tube might have more clean gian than a Sovtek, etc.
     
  7. Rickenbackerman

    Rickenbackerman

    Apr 17, 2001
    Laurel MD
    Hey guys, thanks for the replies... I played a gig with it on friday nite (with my two eden cabs) and it did sound a lot better than it did in the practice room for some reason. It didn't sound as muddy, although it was still nowhere near clean. I had the volume up around 10 O'clock, tone controls flat, and it was definitely way into overdrive territory. I just wish i knew if it was preamp or power amp overdrive...

    Also friday was the first time i've ever been asked to turn down. :) This thing is way louder than my 400+! Not as much low end tho.

    For what it's worth the barts in my Rick are passive, and my SVT has old GE 6550's in it.
    I'm going to try a few combinations of things - I do have an original 70's 8x10, and I've also got a '66 Jazz...

    My 400+ definitely sounded better through the edens, but maybe the SVT likes the 8x10 better.
    I'll try it...
     
  8. Rickenbackerman

    Rickenbackerman

    Apr 17, 2001
    Laurel MD
    Thanks for the info PBG! I'll try using the brite input as well...
    Do you by any chance have any input on the using the SVT 8x10 versus two eden 410XLT's (or any other ported "flat response" type cab) with these old beasts?
     
  9. Rock City

    Rock City

    Apr 8, 2001
    Boston,Ma
    RICKENBACKERMAN...........Sorry I can't agree with P.B.G on the ported cabinet thing!!! On another subject though......make sure that you still have 12DW7 preamp tubes in your amp. If they are 12AX7, take it to a tech and make sure the proper conversion has been done! If someone just subbed the 12AX7's with no mod your preamp will be WAY too gainy!!!!