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Running SVT-VR at lower wattage??

Discussion in 'Amps and Cabs [BG]' started by pig, May 10, 2011.


  1. pig

    pig

    Jul 18, 2009
    Halifax, Nova Scotia
    Hey all, I'm wondering if it is possible to just remove a pair or power tubes and run the amp at a lower wattage? Any info would be great.
     
  2. No if you do you'll have some issues and the fault protection circuit won't let you take it out of standby. I would imagine you'd damage the output transformer too which is expensive to replace
     
  3. okcrum

    okcrum in your chest

    Oct 5, 2009
    Verde Valley, AZ
    RIP Dark Horse strings
    I've done this with my CL without problems. The output impedances available will change to 3 and 6 ohms (from 2 and 4) which is close enough for using 4 or 8 ohm cabs, respectively. You'll get a little under 200 watts.
     
  4. pig

    pig

    Jul 18, 2009
    Halifax, Nova Scotia
    Hmmm conflicting answers, anybody know where I could find more info on this. I definitely don't want to screw up my head.
     
  5. mrkreuzschlitz

    mrkreuzschlitz

    Jun 30, 2008
    Dacula, GA
    Look for a 300 watt power soaker/ attenuator.
     
  6. erock0138

    erock0138

    Feb 4, 2011
    Cincinnati
    Power soaker will burn your tubes up really fast, you're not giving them the voltage they need. So you'll be changing them a LOT more frequently. Many people say that's how they get their sound, but unless you can afford a retube frequently, i wouldn't.
     
  7. pig

    pig

    Jul 18, 2009
    Halifax, Nova Scotia
    Yeah I looked in here for info on power soak stuff but I think I read that they don't make 300 watt attenuators. Maybe I'm wrong but I'm sure the last time I looked thats what I came across.
     
  8. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    they don't make them.
     
  9. Pig, I have a VR, but I don't know if it will operate without all three pairs in the power section. I would suggest there are other ways to get at what you're trying to do. How low do you want the wattage to go? Turning down isn't getting the sustain that you're looking for? You could put an EBS compression pedal in front of the amp to compensate for the low volume. You could get a less efficient cab (don't know what you're running, but for instance, if you went from a 4 ohm 810 to an 8 ohm 15 on the 4 ohm tap, you'd effectively make your amp much quieter at the same spot on the volume knob.)

    Just tossing out ideas.
     
  10. You'd also run the risk of damaging your power tubes and output transformer by doing that too. Running a single 8ohm cab on the svts isn't a good idea, it will produce sound but it will seriously kill the life of both your output power transformer and output tubes. Its kinda hit or miss. Imo I don't think its worth the risk
     
  11. bluesdogblues

    bluesdogblues

    Nov 13, 2007
    IMO Don't do it man!
     
  12. fu22ba55

    fu22ba55 Supporting Member

    Apr 16, 2009
    Here's the last time I asked the question:

    http://www.talkbass.com/forum/f15/200-watt-svt-how-do-690298/

    Lots more info than you'll EVER need.

    The short answer? Don't do it.

    The SVT is definitely over-engineered to take a fair amount of abuse, so it CAN run with just 4 power tubes, but long term, it's a bad idea.

    Attenuators == bad idea. You can buy two THD Hot Plates (max rating of 185 each) and figure out some way to parallel things up so all the impedance matches, but it's a bad idea long term. Bad for your amp.

    An SVT is a 300 Watt amp. That's what it's designed to do.

    Buy a 200 watter. Finding the right 200 watter, however, is no easy task. I've been looking for about 10 years. Now I'm broke.
     
  13. Fair Warning

    Fair Warning Deliverin' the Goods! Supporting Member

    Just turn the volume knob up to "2"....

    Also...those tube are not pairs......they are triplets....

    Why the heck would you do that anyway?
     
  14. Duke21

    Duke21

    Nov 14, 2010
    Narvik, Norway
    Orange AD200 is a 200w amp.

    But, dude you have a dream amp, if you want to keep the full sound of your Ampeg in low wattage, just run a Sansamp VT or BDDI in front of it. Isn't it what JimmyM does?
     
  15. 1n3

    1n3

    Sep 13, 2007
    USA
    V4B?
     
  16. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    i do, and it's darn good. but i can dig the purist approach as well. i'd rather use a low wattage amp like a b-15 or v4b than an svt because the b-15 cranked usually won't get you fired (unless you play with bowzer ;) ). but i'm quite happy to use the vt deluxe, especially in live situations where i go from clean to dirty...it's rather unwieldy and tough for the soundman to mix when you go from clean to dirty using the amp.
     
  17. Hi.

    ^This.


    Easy enough to DIY, but a bit on the expensive side if done correctly. Very cheap if done by just using power resistors.

    Going the MusicMan route, ie. SS pre/tone shaping with a tube power amp turned down is an option if one wants to lose almost completely the one thing that makes a tube amp what it is, the power sections contribution to the sound when pushed hard.

    If one goes the emulation route, it makes little or no sense to use the device to drive an amp that weighs a ton and doesn't quite do anything special sonically, unless one has roadies who do the lifting/setup/teardown.

    Absolutely nothing wrong with emulation or even modelling route, but it always makes me chuckle when people use (or need to use) SS devices to get that TUBE sound :).

    Regards
    Sam
     
  18. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    sam, can't tell you how much i disagree that the only thing a tube amp is good for is pushing the power section. i still greatly prefer the clean tones from a tube amp vs the clean tones from an ss amp. the power section makes a difference in clean sounds, too.
     
  19. Alex1984

    Alex1984

    Jan 16, 2010
    Vancouver
    +100, and I'm sure JimmyM'd approve!
     
  20. Hi.

    Jimmy, I do know what You're saying, but if that was the OP's case, the only thing he'd have to do would be to turn the volume down. And If You did read my sentence as You describe, I wasn't being clear enough ;).
    I prefer tube power section behaviour to SS behaviour as well, regardless of the amount of intentional or unintentional signal distortion, but my point was that once one introduces SS components to the signal chain, one (in the audience) must have very good ears to tell the difference on the power amp section.

    As soon as the ~5W OT's drop to the price of the eqvivalent PT's and the class D gets the acceptance it deserves in MI use and the prices drop, we will see plenty of amps that use a true low power tube amp circuit, combined with a class D power sections.
    For an affordable price that is ;).

    Regards
    Sam
     

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