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Super quick question

Discussion in 'Amps [BG]' started by Pills Are Yummy, Dec 30, 2012.


  1. Pills Are Yummy

    Pills Are Yummy

    Joined:
    Dec 6, 2012
    Location:
    Santa Rosa, California
    I have an SVT CL
    I also have an SS poweramp
    Can I run the pre from my CL into the SS power amp?
     
  2. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Yes but you still need a speaker load on the SVT.
     
  3. Pills Are Yummy

    Pills Are Yummy

    Joined:
    Dec 6, 2012
    Location:
    Santa Rosa, California
    On the power section, right?
     
  4. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Yep. But since after the power section is the only place in the chain you can plug in a cab...

    :D
     
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  6. Pills Are Yummy

    Pills Are Yummy

    Joined:
    Dec 6, 2012
    Location:
    Santa Rosa, California
    So I need a cab on the SVT power section and (obviously) the ss power section.

    Thanks bro
     
  7. Got2SadowskyNYC

    Got2SadowskyNYC

    Joined:
    Dec 5, 2012
    Location:
    Nashville, TN
    Disclosures:
    Artist: Sadowsky, Bag End, Visual Sound, Pedaltrain, George L
    You could also get a dummy load for the SVT power section, that way you won't have to tote an extra cab. The trick is finding one that will take the power.

    YOu could also make one with a "Non-Inductive Dummy Load Resistor". Actually several and make sure the master vol. is all the way down.
     
  8. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Dummy loads that size are going to be pretty darn huge and cumbersome, plus you'll likely have to build it yourself. Might as well just bring a cab if you ask me.
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Joined:
    Sep 7, 2000
    Location:
    Chicago
    What if he pulled the power tubes?
     
  10. Got2SadowskyNYC

    Got2SadowskyNYC

    Joined:
    Dec 5, 2012
    Location:
    Nashville, TN
    Disclosures:
    Artist: Sadowsky, Bag End, Visual Sound, Pedaltrain, George L
    If you want to burn the power transformer up.
     
  11. Pills Are Yummy

    Pills Are Yummy

    Joined:
    Dec 6, 2012
    Location:
    Santa Rosa, California
    I really don't.
     
  12. Got2SadowskyNYC

    Got2SadowskyNYC

    Joined:
    Dec 5, 2012
    Location:
    Nashville, TN
    Disclosures:
    Artist: Sadowsky, Bag End, Visual Sound, Pedaltrain, George L
  13. hibachiduck

    hibachiduck

    Joined:
    Aug 31, 2011
    Location:
    Augusta, GA, USA
    Or you can trade me your SVT for my Streamliner 900 and then you have the best of both worlds :)
     
  14. Pills Are Yummy

    Pills Are Yummy

    Joined:
    Dec 6, 2012
    Location:
    Santa Rosa, California
    Ha no.:bassist:
     
  15. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
  16. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Joined:
    Sep 7, 2000
    Location:
    Chicago
    What if he ran the signal from the CL's preamp out, put a shorting plug in the Power Amp Input jack and also insert a shorting plug in the speaker jack?

    Tube amps don't hate short circuits like solid-state amps do and there will be no input signal to the power amp anyway.

    Plausible?
     
  17. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    I built a dummy load out of two of those eight ohm non-inductive resistors that Parts express sells. Below are a few pics of one way to do it.

    Connect to the amp via a speakon, 1/4" jack, or banana plugs. The resistors get a big warm but not too hot. If I were running it as a dummy load for a long time, I'd add a fan to the box which draws the heat off.

    There is another option that hasn't been mentioned. You can add a line out similar to what is shown in the last two pics. You add a pot resistor and a jack to the dummy load to tap off the signal. This allows you to take advantage of having the tone of both the SVT's pre and power amp and feed it into the solid state power amp. You have to be careful how hot the signal going to the SS amp is otherwise it will be quite distorted. I've done this with smaller amps and the distortion and sustain are amazing. Never tried it with an SVT. Similar circuits are found on some Mesa (as in the last pic) as well as other amps. Add a transformer and you can have a 600 ohm balanced line out to go to a mixing board.


    [​IMG]

    [​IMG]

    [​IMG]

    Line out.

    [​IMG]

    [​IMG]

     
  18. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    You can short the out for short periods of time without harming the amp. Some techs do this when working on amps like when setting the bias. It isn't such a good thing to do when playing though. Some amps short the output when a speaker isn't connected. In the short term, it protects the amp till you go "oh no, what have I done" and shut down. As was mentioned above, you can disable the power amp on the SVT by pulling the driver tubes. It isn't good to keep installing and pulling the tubes. No harm in doing it just to see if the pre into the SS amp delivers the goods.

    EDIT: I checked the SVT-CL schematic, if you plug a shorting plug into the power amp in, the pre-amp out will still work and the input to the power amp will be shorted shutting it down. An errant spike in the power amp could cause a problem without a dummy load in place. As Charlie said below, just a little extra insurance to have it in place.
     
  19. Passinwind

    Passinwind Charlie Escher Supporting Member

    Joined:
    Dec 3, 2003
    Location:
    Columbia River Gorge, WA.
    I've done this for many many gigs with one of my old guitar amps. The key part is the input shorting jack at the power amp in, and that input jack being normalled such that it cuts signal when something is plugged in. If the power amp isn't seeing signal it's not going to cook the output transformer. If you want to be really safe, use a dummy load anyway. Doesn't need to be a high power one, and this way the power tubes are not getting unnecessary wear. Of course, you only get the preamp section mojo then though.

    If I owned an SVT I wouldn't mess with any of this, frankly. I'd use it where it worked for me and just use something else the rest of the time.
     
  20. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Ya, really...what's the point of lugging 85 lbs of SVT only to use the preamp? Just get an old SVP-CL if that's what you want. They're $300 or so used and much lighter, and they're the same pre.
     
  21. walterw

    walterw Supportive Fender Gold Supporting Member

    Joined:
    Feb 20, 2009
    yep, worst. preamp. ever.

    if you're gonna lug it out, might as well use its power.
     

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