Does anyone use a variac with their Marshall nvm amp ?

Discussion in 'Marshall Amps' started by Ufoscorpion, Dec 20, 2020.

  1. Ufoscorpion

    Ufoscorpion Well-Known Member

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    Watched on YouTube a recent interview by Fluff of riffs and beards with Mike Soldano and he was basically talking about the three SLO’s he sold to Eddie Van Halen which was interesting. But the thing that was most interesting was him saying about Eddie getting him to take away ‘the amp ‘to retube . To Soldano’s surprise it was bone stock and how even after the retube it sounded nothing like ‘Eddie’ just a good stock supelead . Remembering Eddie telling him about the variac Soldano experimented by gradually turning the voltage down to 88volts and bam there it was , instant Eddie and considerably lower volume , according to Soldanos estimates the amp was running at 20-30 watts . This has got me thinking , 1987x with a variac or even studio vintage with variac ???????
     
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  2. South Park

    South Park Well-Known Member

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    Do at your own risk . You don’t want to go to low on the variac
     
  3. steveb63

    steveb63 Well-Known Member

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    Don't forget you'll have to re-bias to run at that voltage.

    Kinda locks you into always having to use it.
     
  4. Ufoscorpion

    Ufoscorpion Well-Known Member

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    I thought this , but Mike Soldano said that the power tubes would be under much less stress doing this so it wasn’t a problem. I don’t know I’m no expert , if anyone else watches the interview you will see what I mean .
     
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  5. wakjob

    wakjob Well-Known Member

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    Some people re-bias, some people don't...

    Remember, Ed always said he RAISED the voltage. Everyone thought he was saying this to throw people of his trail...but in reality, he might of had his amps power switch on the back of the amp set to 240v...in which all the math works out. It's still actually lowering the amps internal power.
     
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  6. K2JLX

    K2JLX Well-Known Member Gold Supporting Member

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    I just use the variac switch on the bogner LaGrange into an 800 or SV20H. It works pretty well in my application.
     
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  7. jchrisf

    jchrisf Well-Known Member

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    Wonder if this is the same effect with the so-called "power starved" EL34s of the Studio amps?
     
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  8. Ufoscorpion

    Ufoscorpion Well-Known Member

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    The Suhr sl68 has the variac built in to take the voltage down with a flick of the switch . I’m not sure if it alters the bias aswell .
     
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  9. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    Yeah I use one here and there. Bit different in feel more than anything. My wall voltage is 119v



     
  10. wakjob

    wakjob Well-Known Member

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    It does... and I think the SL68 and the new Badger amps do too.
     
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  11. junk notes

    junk notes Well-Known Member

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    I periodically post about variacs and posted about the AmpRX BrownBox videos (which would be a good read for @steveb63 / @South Park) and the vid that @solarburnDSL50 previously posted.

    Anyway, this is how I basically have mine setup. As mentioned in the Smithsonian vid, your range is from 60-100 volts. Places like Gazzarri's, Ed would run at 60 volts; and in the studio, the sweetspot that he liked was 89 volts. (with my gear 88v-92v.)

    Very much recommend variacs for the newer SV users.

    [​IMG]
    Rock on!
     
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  12. junk notes

    junk notes Well-Known Member

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    Badgers are power scaling. Another take on London Power. The other is a dual voltage tranny. Both stages are biased and requires a dual voltage 3PDT switch.
     
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  13. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    Yes you should rebias . My amp is cathode biased. I'm on a leash bias whys. Beyond its range ? Well. You guys are sharp.
     
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  14. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    for years, Suhr was on London Power's list of official LP installers...
     
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  15. Biff Maloy

    Biff Maloy Well-Known Member

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    AmpRX Brownbox is on my short list of next gadgets. I'm considering the rack version. No experience with anything like that in my past but theoretically it makes sense to me to give the amp what it wants power wise.
     
  16. JP2036

    JP2036 Well-Known Member

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    Fluff is an idiot and anyone that believes anything Fluff sez is an idiot too relatively speaking.
    Same goes for the 98% of EVH fairytales floating on the internet.
     
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  17. Buzzard

    Buzzard Well-Known Member

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    My variacs are built into my amps,suhr sl 68 , Mesa stilleto deuce stage 1. But I’m still wanting to try one with a 50w plexi.
     
  18. South Park

    South Park Well-Known Member

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    Tubes are set up on a load line you have positive and negative DC for them to work if it drops to much power can not go to ground and tubes burn up. What you want to do is keep the bias the same and drop the plate voltage and for a starve plate distortion . You can do this on the preamp or power tubes .
     
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  19. johan.b

    johan.b Well-Known Member

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    ..sv20 is running the tubes at 280 volt ... but keeps the heaters at 6.3 volt where they belong... just saying...
    J
     
  20. Ufoscorpion

    Ufoscorpion Well-Known Member

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    Was coming from Mike Soldano not Fluff actually.
     
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