SVT-CL Master All The Way Up (Gain Control For Volume)?

Discussion in 'Amps and Cabs [BG]' started by zwish, Jun 10, 2019.

  1. zwish


    Nov 3, 2009
    I've heard tell of running a SVT-CL with the Master all the way up and using the gain knob as a volume control - effectively making it sound more like the SVT-VR. Two questions:

    1) For those that do this, do you dig the results?
    2) Will this shorten the life of your tubes?

    I typically run a preamp into a big, clean SVT, either a Rusty Box or a Darkglass B7K but I'm curious to hear people's thoughts. Thanks a bunch!
  2. bobyoung53

    bobyoung53 Supporting Member

    That is exactly how a non master volume amp works (VR, 70's SVT's etc), preamp gain was called the volume control and they had no master, were always at maximum, all a master does is cut volume, doesn't add. This has nothing to do with your power tubes, this will sound very clean unless you earthquake whatever place you're playing in. I love the sound of SVT's, I've never owned one with a master, not that I wouldn't, just that my 70's heads still run great, I expect them to outlast me.
    Arthur U. Poon likes this.
  3. Wasnex


    Dec 25, 2011
    It really depends on the sound you want. IMHO most tube preamps tend to be a bit more articulate and focused at lower gain settings. As you push the gain, the sound tends to lose a bit of detail and then transition through compression and light OD into distortion. So if you want more of a clean, focused and punchy sound, turn up the master and turn down the pre.

    Whenever you push tubes hard it will cause them to wear more. The volume of the amp is dependent on the position of both the Gain and Master. If you crank both so the amp is distorting, then you will experience increased tube wear. If you crank the Master but run the Gain at a lower level so there is no distortion and the volume remains constant, the wear on the PI, Drivers, and Output tubes will remain constant. You may shift some of the wear and tear around in the preamp a bit because your decreasing gain in the middle of the preamp and making it up at the very end. The difference should be minimal unless your pushing into distortion.

    Since your using OD and Distortion pedals, I would think you might prefer pushing the front end up the amp till it starts to grind a bit, and then running the Gain of the preamp up until you get even more distortion. IMHO running multiple gain stages on the verge of distortion often produce superior results to running one really high gain distortion stage. The distortion is typically more complex and less fizzy IMHO. The only way you can get the front end of the amp to distort is to hit it with a really hot signal, because the Gain control comes later in the preamp.
  4. zwish


    Nov 3, 2009
    Good info! I typically use one of those two preamps, but I'm not not a super distorted guy. Just that typical SVT/SansAmp kind of Mike Dirnt-ish bass tone.
    Wasnex likes this.
  5. beans-on-toast


    Aug 7, 2008
    The master volume on the CL is an ATTENUATOR located between the preamp out and power amp in. Setting it on full many the the preamp signal is not lowered. The gain will set the amp’s level.

    This in now way shortens the life of the tubes, turning the amp up loud does. It was designed to be used this way.
    Wasnex and bobyoung53 like this.
  6. bobyoung53

    bobyoung53 Supporting Member

    Running too much into the preamp is really not good for any amp and is why there are lower level inputs on most newer amps. You want distortion turn up the preamp gain. It's a talkbass myth that OD devices over drive the preamp, they create the distortion themselves and the preamps amplify it cleanly.
  7. Does anyone know if a peavey VB-2 work the same way ? Master volume is an attenuator ?
  8. Wasnex


    Dec 25, 2011
    Maybe @beans-on-toast or @agedhorse will comment, because I don't think this is a myth.

    AFIK It's not difficult or dangerous to push the front end of a tube preamp into saturation with an OD or Clean Boost pedal. A Clean Boost in particular does not distort, but it can push the first triode in the amp to saturation.
    Last edited: Jun 10, 2019
    beans-on-toast likes this.
  9. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    1. Yes
    2. No
  10. beans-on-toast


    Aug 7, 2008
    You have it covered.

    Of course, too much input can blow the first stage. BUT, it won't happen with an overdrive pedal outputting instrument level. Running the speaker output into another amp will damage an amp. Some have actually done this.

    Pushing a tube input stage hard will shorten the tube's service life. Pushing any tube hard takes life out of it faster than conservative levels.

    If the instrument's signal is too hot, the first stage can be overdriven. Using the padded input, typically -15dB, will knock the instrument signal level down enough that it shouldn't cause distortion in the first stage. If the signal is way too hot, a 15dB pad may not be enough.
    Wasnex likes this.