Need help with Ampeg SVT-4.. please!

Discussion in 'Amps and Cabs [BG]' started by skankinrabbit, Sep 30, 2003.

  1. skankinrabbit


    Aug 26, 2000
    My Dad is a pretty successful guy, and he's the type of guy that gets excited about stuff and has the money to indulge himself when he gets excited. Anyways, he saw my band a couple of nights ago, and I guess he liked us, because he heard me say something about how I wasn't really happy with my bass amp (i'm using a yamaha powered mixer...).... so he buys me a freaking Ampeg SVT-4.


    Anyways, I'm not sure it's working completely right.... My cabinet is an 8 ohm Avatar B410, and after reading through the reader's manual a couple of times, I got the impression that an 8 ohm cab was safe to use with this amp. Well, for one thing, i haven't been able to get it to work when I use the speakon cable that came with the amp. It turns on and everything, but no sound. I tried it out with just a regular old 1/4" plug, and it seemed to be working fine, but then it kept just cutting out with the little red peak light next to the gain knob lighting up. I had it at very low volumes - at first i figured it was my bass, because I had had problems with it having a crackly connection (I bent the input connecter closed a little bit and it hasn't been as much of a problem), so I figured that was the problem, BUT when I unplugged the bass it kept doing it - even if I unplugged the cord from the amp altogether, the little red light was still turning on and off sporadically. I tried it with another bass and had similar results. No obvious damage signs like... smoke or a hum or anything. I just turned it off and then turned it back on without anything plugged in at all and the peak light isn't turning on or anything, but I'm afraid to plug anything in because I don't want to damage it. Anyways - what's going on? Is there something wrong with the amp, or am I connecting something wrong? Any feedback would be GREATLY appreciated.
  2. skankinrabbit


    Aug 26, 2000
    I tried plugging my bass in again, and it had the same effect (worked alright for a bit, and then started cutting out), and although it did keep flashing the limiter, it stopped after a bit.... someone please help - I really hope there's nothing wrong with the amp.
  3. Sonds like the 1/4 inch jack in your bass is not making good contact therefore it's setting off your limiter. Your cable could be bad to.

    I use the Ampeg SVT400T it's close to your SVT pro head.

    Have you turned on the amp and plugged just a guitar cable into it to see what happens? Give it a try.

    ;) Treena
  4. BillyB_from_LZ


    Sep 7, 2000
    Is the amp brand new? If so, take it back!!!!

    If not, it sounds like something isn't right. If the amp is used, it could have microphonic preamp tubes...if this is the problem, you need to replace them. If the amp is new you could be having a tube problem's possible.

    As for problems with the speakon cable... Are you using the in the bridged mode? If so, the amp end of the cable needs to specially wired for bridging (uses 1+ and 2+ instead of 1+ and 1-). If you're not bridging and the cable is set up for it, I'm not sure what you'd get. Since you have an Avatar cabinet I assume that it has 1/4 in. jacks...correct?

    Another common Ampeg problem is with the switching jack on the effects loop. Take a short instrument cable (make sure it's a shielded instrument cable, not a speaker cable) and jumper the effects send to effects return...or press the effects bypass switch.

    Good luck!!!!
  5. skankinrabbit


    Aug 26, 2000
    I'm not having problems with it clipping out anymore - I had to turn the gain knob down to about 10 - 11 o 'clock to get rid of it though - is that normal? Also, the speakon connector (that came with the amp) seems to be labelled for use in the bridge connection, but it still doesn't seem to be working - you're right in that it does have a 1/4" connector on it. Am I doing something wrong still?

    BTW it is a new amp, so i guess if worst comes to worst I can send it back.
  6. atldeadhead


    Jun 17, 2002
    You might want to narrow the problem down to make sure it's the amplifier. If you think your bass might be the problem or part of the problem I'd suggest borrowing a friends bass and see it you have the same issues. If you don't, then you know it's your bass and not the amp. I'd also suggest that you try different cords all the way around. Just to make sure you don't have a bad cable.

    As for the gain knob...check the manual that came with the amp. It should have some recommended settings for the amp. Usually you want to turn the gain knob up so that the limiter light barely flashes when you play most aggressively. At that point turn the gain knob back just a tad. Then adjust the volume knob to the desired level.

    Hope this helps.
  7. jawzzz


    May 23, 2003
    Denver Colorado
    If you are using the cable that came with it, the amp should be bridged for it to work properly. If you don't want that much power, then you will have to use a speakon cable labeled NL2 or a 1/4 inch speaker cable hooked up to only one side of the amp (amp A or amp B).

    The clipping could be because you have the gain, eq, or your tone controls (bass,mid,treb) set too high.:)
  8. skankinrabbit


    Aug 26, 2000
    Thanks so much for all of your help so far - the problem with it clipping is gone, and it was a combination of a problem with a bad connection on my bass and the gain knob set too high.

    The only thing I still haven't figured out is why the mono bridge speakon connection still isn't working. Is there like... a button or something I have to press to make it send sound out of that connection? I read the users manual a couple of times and there's a button that's supposed to set it from stereo to mono bridge that I have been using, but it's still not making any noise, and I checked to make sure the speakon/1/4" cable is the right kind or whatever (1+/2+), but when I plug it in, it just makes absolutely no noise at all. If anyone knows what I'm doing wrong, or if this sounds like a problem with either the cable or the amp, your input is VERY much appreciated... I guess I'll just keep fooling around with it and hopefully something obvious will pop out at me.
  9. jawzzz


    May 23, 2003
    Denver Colorado
    When using the bridge mode(speakon in the center),the button below it that says stero/mono, should be pushed in for it to bridge the amps. All other speaker outs on the amp "A" and amp "B" should not have anything plugged in to them in bridge mode. I would also try another cable(NL4 of course) and see if it works. Also make sure you don't have the mute switch engaged on the front.
  10. skankinrabbit


    Aug 26, 2000
    Well, I made sure that the button was in the mono position, I tried it with a new cord, and I made sure the mute button was not on.

    Still no sound.

    I guess this is when I start calling Musician's Friend to get it replaced.

    Thanks for all your help guys.
  11. jawzzz


    May 23, 2003
    Denver Colorado
    Bummer. At least you can get it replaced.
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