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Is it safe to dime the master vol on a SVT? (And use the 'Gain' as a Master vol)

Discussion in 'Amps and Cabs [BG]' started by DeadbeatLine, May 30, 2017.

  1. DeadbeatLine


    Nov 13, 2013
    Hi all, proud owner of an SVT-2 PRO.

    Got a little tip I saw online somewhere (escapes me where) that suggested diming the master and using the gain as a master volume, supposedly it'll engage the Power amp section and cause tasty meaty power amp distortion over pre amp distortion (which I find a bit underwhelming personally). So i've done this, and it *seemingly* sounds better to me, but I'm wondering if I'm just convincing myself this.

    However the more important question to ask, is it safe? I never crank it super loud or anything as frankly I haven't needed to with the volume it puts out, and a lot of gigs (gigging fairly regularily) it's been mic'ed anyway.

    Any advice is appreciated!

    krkozbassman likes this.
  2. It’s safe. Most of the pre/power set do the same thing putting the power amps faders on full and using the gain for volume. It delivers the loudest cleanest signal that the amp can produce.
    jmlee, Aqualung60, Al Kraft and 4 others like this.
  3. superheavyfunk


    Mar 11, 2013
    This is correct. And conversely, if you wanted the most gain (distortion) your amp could provide, you'd do the opposite: Crank the Gain knob, and inch up the master until you reach the desired volume.
    Joe David, Rattman, Sartori and 2 others like this.
  4. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    If you want the cleanest sound an SVT will do that is how you get it.

    Kind of defeats the purpose of an SVT to me but it's safe.
    handofseven and Killed_by_Death like this.
  5. ^ What they said. This is how I know.

  6. Gain does not equal distortion. If you crank the gain and control the volume with your master, you will always have some pre-amp distortion. I too find this sound underwhelming. Edit: the most distortion your amp can provide is with gain AND master dimed.

    Yes, cranking the master and controling the volume with the gain does render a clean sound up until the point it doesn't - and that's power tube distortion which you will at least find whelming. Edit: the downside is this only happens at extreme loudness unless you have the world's least efficient cabinet.
    mattwear and Steve Dallman like this.
  7. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    I wasn't talking about distortion in the literal sense. My favorite tube amp tone has always been just under gain distortion. But that's me. OP can do what makes him/her grin.
    Runlikegregg likes this.
  8. There's a reason for 50 and 100w tube bass amps.
  9. Korladis

    Korladis Banned Supporting Member

    I actually like the SVT-CL's preamp drive.
  10. 10cc


    Oct 28, 2013
    Hell yeah baby powder!
    eigentone likes this.
  11. InhumanResource


    Dec 28, 2012
    Yeah man, a lot of people run that way. I believe this is the set up on the "volume only" SVT's years ago, you only had gain control and the power amp was always wide open. Someone can correct me if I'm wrong though, likely @JimmyM ;)
    Pbassmanca, bobyoung53 and Bim1959 like this.
  12. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Master volumes didn't even exist on amps until the 1970s. Of course it's safe to dime it. I treat master volumes like mutes, it's either full CCW or full CW.
    bobyoung53 likes this.
  13. Master on full is the only way to run a tube amp.
    gfen and bobyoung53 like this.
  14. DD Gunz

    DD Gunz

    Jun 18, 2015
    No issue at all.
  15. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    The master volume is an attenuator in these amps that sits just after the preamp, before the power amp. Opening it up all the way turns it into a non-master amp.
    bobyoung53 and Seth Miller like this.
  16. I thought you were wearing a white chef's hat on first glance!! :D

    This is a helpful thread btw--I've never tried this but am now!
    dbase and sharkbait130 like this.
  17. Korladis

    Korladis Banned Supporting Member

    BassmanPaul likes this.
  18. Omega Monkey

    Omega Monkey

    Mar 8, 2015
    There's no free lunch. You can't magically get power tube distortion by cranking the master and running the gain low. Like people have said, you'll tend to get a cleaner signal that way because it will be very loud at a given gain amount. If you want power tube breakup on an SVT, you're going to have to push at least 300+ watts into it peak. And it's going to be ungodly loud into any cab that can actually take that kind of power.
  19. Omega Monkey

    Omega Monkey

    Mar 8, 2015
    Actually, now that I think about it, to get the least preamp distortion and most power tube distortion, you would want to set the gain so that the bass is easily clipping the input stage on peaks. Since there's no peak light on an SVT you'd have to do it by ear. Basically when the clipping is obvious, you back it off just until it's not. Then you should have a "full" signal hitting the power amp regardless of what you have the master set at. So as you turn up the master, the point of clipping (and being able to hear it as separate from preamp clipping) is going to happen as early as it possibly could.

  20. That was an outside gig under cover and it was really humid that night. Rained for most of the gig. Cornstarch baby powder worked great.:thumbsup:

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