Brown Sound and Variac

lenheyvan

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It is well known that Eddie used variac to make Brown Sound.

However, I have one question.

I believe that if you lower the voltage with a variac, you lower the bias current.

Did he use it in this condition?

Or did he use it with the voltage lowered and the bias current adjusted to the proper value?
 

EADGBE

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I don't know how he used it. Or even if he used it at all. Anyway one amp maker said you can use a variac with an amp. But that you can turn it down but never up. As in higher voltage than the amp is designed or set to. Personally from what I have heard an amp sounds better without a variac.
 
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lenheyvan

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I tried a variac with my Marshall clone (JCM800/JTM45 hybrid) in the hope of finding some glorious new sound. Did absolutely nothing for the tone for my rig. Your mileage may vary.

Thanks for the info!

I too was wondering if using a variac would give me a very different sound.
 

playloud

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I tried a variac with my Marshall clone (JCM800/JTM45 hybrid) in the hope of finding some glorious new sound. Did absolutely nothing for the tone for my rig. Your mileage may vary.

At some point, the lower heater voltage will stop the tubes from operating - so that will do something to the tone!

Regarding Van Halen, the details are so opaque around the variac use, there's no chance this level of detail is reliably known.

However, if you use a variac to drop the mains voltage, it's worth rebiasing at the lower voltage. Just be sure to return to the original bias setting before returning to full voltage, otherwise you risk redplating the tubes!
 

lenheyvan

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At some point, the lower heater voltage will stop the tubes from operating - so that will do something to the tone!

Regarding Van Halen, the details are so opaque around the variac use, there's no chance this level of detail is reliably known.

However, if you use a variac to drop the mains voltage, it's worth rebiasing at the lower voltage. Just be sure to return to the original bias setting before returning to full voltage, otherwise you risk redplating the tubes!
Thanks!!!

In a previous interview, Eddie mentioned that he used it like a master volume.

If that is true, it means he didn't change the bias.

But he's very secretive, so I'm not sure if he was telling the truth about that.
 

playloud

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Thanks!!!

In a previous interview, Eddie mentioned that he used it like a master volume.

If that is true, it means he didn't change the bias.

But he's very secretive, so I'm not sure if he was telling the truth about that.

Yes, I would take anything Eddie said with a grain of salt.

Variacs aren't a very effective "master volume". They make the sound fuzzier/less defined perhaps, but not noticeably quieter (until, as mentioned above, the tubes stop working).
 

mAx___

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I use a Variac to keep the heater voltages at 3.15V. Amp runs cooler, sounds better.
 

jmm22

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Thanks for the info!

I too was wondering if using a variac would give me a very different sound.
I should clarify. There was perhaps a minor change in tone, but it was not an improvement. I would imagine different amps could react differently when using a variac.
 
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