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Marshall power reduction

Discussion in 'Pro Audio Equipment' started by crazy_guitar, Apr 29, 2002.

  1. crazy_guitar

    crazy_guitar Guest

    I've been trying to find a cheap way to lower the volume of my 100 watt marshall amps(with 4x12 cabs) when cranked up to 10(JCM800s seem to be WAY louder than normal 100watt amps). there are a lot of level reduction boxes that go between the amp and the cab, but are known for lowering the sound quality too. So an engineer friend told me that some guitarists use voltage reduction boxes (the ones that reduce the voltage coming from the wall), which are cheaper then the previous. It is supossed to work, but I'm wondering if it will damage my amps, and will I still get power tube saturation when I crank it up to 10??????
    thanks
     
  2. daniel_c

    daniel_c Guest

    Yes lowering the votlage going into you amp will work. Eddie Van Halen did that with his Marshall. However , it is VERY VERY DANGEROUS if you try to DIY (like Eddie using a light dimmer!). You can buy professional variacs that can safely lower the voltage down to nothing , but i have a feeling these may be more expensive than say , a Marshall powerbrake. With the valaves supplied with less voltage than normal , their headroom is reduced and distortion is achieved at lower SPL's.
     
  3. RandomGuest

    RandomGuest Guest

    Joined:
    Feb 10, 2001
    Marshall make a thing called the Power Brake... I want one...

    I have a SE100 that can act as speaker load and can reduce the output back out to a cab bu 30% or 60%...

    Interesting topic!

    Be carefull man!

    :)
     
  4. MadMoose

    MadMoose Active Member

    Joined:
    Apr 22, 2001
    A Marshall Power Brake works well. THD makes the Hot Plate. Both of them go between the amp and the cab and do a good job of bringing things down to more managable SPL's.
     
  5. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Joined:
    Jan 4, 2001
    Variac's can lower the volume. Eddie said he was lowering the voltage, which I'd tend to believe based on some subjective experience, but Harry Kolbe thinks he was raising it. Kolbe knows a hell of a lot more than me. Common speculation has it that he was basically using the variac to fine tune the tone, something that is better done with proper biasing. Throwing all the voltages out of design spec, especially upward, can play hell on component life, espescially in something as tempermental and fragile as a Marshall. Eddie switched to Soldannos and Peaveys when he thought his Marshall no longer had it .

    The THD Hotplate is probably the best commercially available product for your needs. All the modifications that I would suggest for power reduction will take the Marshall edge off, with the possible exception of one non invasive one: pulling tubes. Pull the inside or outside pair of power tubes to basically make your amp a 50 watter. You still have the 100 watt output iron for a big thump and good dynamics. Contrary to superstition, their is no necessary impedence adjustment required. You're in a safe zone with the OT enough that you can adjust it to where it sounds good.

    Bear
     
  6. jeronimo

    jeronimo Guest

    Great topic!
     
  7. crazy_guitar

    crazy_guitar Guest

    The power bake takes the edge out of the amp, you still have power tube saturation. I've also pulled tubes out to make it 50 watts, but it sounds like a 50 watt cranked up, not like a 100 watt, which I think is different, plus also at 50watts the amp made a cracking sound very bad at half vulume. So seems like a Variac is the only way to go, for preserving the tone. I know a lot of the tone comes from the speaker distorting a little, but I'll still be loud, it's just that 100watts its too much, but the tone is amazing. well I'm happy to know that with a variac you can still have power tube saturation. I think they cost around $250-$350 like a power brake.
    thanks
     
  8. crazy_guitar

    crazy_guitar Guest

    power brake :mad:
     
  9. plexi

    plexi Guest

    Ok, guys here is my take on this subject.
    I have dealt with this for a few years and have a
    lot of experience with the hot plate , power brake, pulling tubes ect....

    pPwer brake REALLY sucks, kills the dynamics and reduces your tone to a wimpy buzzing.

    Hot plate is a lot better, but you can`t reduce the volume down a to reasonable level without losing the beef of the tone.

    Pulling tubes makes no big difference, you lose punch, but are still just as loud (-3dB)

    I found two solutions, use the hot plate as a load box, run the signal into a poweramp and the into your cab. this works pretty good(this is how Eddie does it)

    But for me the best way was to simply turn my cab
    backwards and I could play as loud as I wanted.
    And my bandmates are pleased. The sound engineer loves it!

    My 68`Super Bass(plexi) sounds extremely good when turning it up to 10. It`s in very good shape, not muddy at all. Gives me a beautiful
    Eric Johnson lead tone.

    Sorry, but there is no way a hot plate or power brake can help you without ruining the sound.

    Amund
     

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