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Low OD gain on Ampeg SVT-4 Pro

Discussion in 'Amps and Cabs [BG]' started by exiii, Jan 9, 2012.

  1. I just bought a used Ampeg SVT-4 Pro.

    My problem isn't volume, as has been discussed several times before. It has more to do with over-driving this thing. Using various basses, including an active Washburn Force 4, I need to crank the gain to max, use a pick, and drive those strings for all they're worth to even start to get the grrrrrrr sound I love so much. It's just too damn clean.

    With my Marshall 4210 combo, 1/4 gain rides pretty clean, with a nice increase at 1/2, and full sweep giving me off-the-chart distortion. These two amps seem to be polar opposites in the drive dept, and I'm looking for something in-between.

    So I'm wondering what my options are using the Ampeg:

    • replace the preamp tubes with something gnarlier, and if so, which ones.
    • add a boost box before the input.
    • or just get the OD box(es) of my choice - currently digging the SansAmp Oxford.
    • other ideas?

  2. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Occasionally I've seen that with the 4 Pro. Different basses will trigger the grind in the gain differently...hot basses will trigger it more, quieter basses will not trigger it at all. But usually you can get some out of it, although it can require some gain cranking. I've heard tubes can help with that, but I don't know which ones. Also, don't know if you're using an active bass with the active switch on, but if you are, run it passive and that will add about 15db of gain.

    But really, for live work, I think a pedal is the way to go, especially if you switch between clean and dirty. If you don't, then it's fine to use the gain to get some crank. Another thing you can try is turning the graphic EQ on and boosting the level. That should work and it's free ;)
  3. Active bass, -15db pad off.

    I'll try out the EQ tip and see what that does. So the EQ sits before the preamp?

    I haven't played with this thing quite enough yet. I do have a good deal of bass and treble EQ boost on the instrument, but there's no mid knob. Being very cautious until I get my cabs built, I've noticed that bumping the those knobs does make up some of the gain difference (it just ruins the usual tone I like). This leads me to believe that a full-range boost might be just what I need.

    Thanks JimmyM!
  4. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    oops...maybe I'm wrong about the EQ being able to help...the EQ is just after the gain and tone controls. Oh well, no harm in trying it, but yeah, I'd agree a boost pedal will work.
  5. Rehearsal last night. A signal boost before the input was exactly what did the trick. I'm still not sure I like the gain knob on the amp, but I'll find the sweet spot I can use with a pedal solution when I have more time.

    Awesome sound last night though. My dry signal ran the amp tubes, with my Prunes & Custard set back a bit in it's own loop. There were some real moments of glory.
  6. i used to have a 4 pro...couldn't od at all. Passive jazz and pbass (gain at full). Then i bought a vt bass :), then a 800rb, and now I'm waiting my V4B to arrive to the country.

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