Anyone know how to Bias the Seminar head?

[blumuz123]

I did not attend the seminar.

thanks

 

[guitarslinger]

EDIT: this is assuming you know that even an amp not plugged in can shock the living daylights out of you. Do you know what filter caps are>?

there's a 1 ohm resistor sitting up on a lug terminal when you have the chassis out of the cab..

turn all of the knobs down.

turn the amp on.

put standby in the "play" position

don't fucking touch anything in the amp except for the trim pot with a screwdriver and the terminal lugs with the 1 ohm resistor..

multimeter set to mV. put red probe on one side of 1 ohm resistor, put other probe on other side of resistor. You should get something between zero and 100.00.

Depending on the tubes, it should read around 70 or so. (E34L's in this case)

 

[blumuz123]

EDIT: this is assuming you know that even an amp not plugged in can shock the living daylights out of you. Do you know what filter caps are>?

there's a 1 ohm resistor sitting up on a lug terminal when you have the chassis out of the cab..

turn all of the knobs down.

turn the amp on.

put standby in the "play" position

don't fucking touch anything in the amp except for the trim pot with a screwdriver and the terminal lugs with the 1 ohm resistor..

multimeter set to mV. put red probe on one side of 1 ohm resistor, put other probe on other side of resistor. You should get something between zero and 100.00.

Depending on the tubes, it should read around 70 or so. (E34L's in this case)

Thanks and yes I do understand not to touch anything and that it can be deadly
Can the amp be modified to have the bias settings on the outside of the chasis like the mod 50?


big thanks

 

[Gino]

Can the amp be modified to have the bias settings on the outside of the chasis like the mod 50?

You could run two test points to that resistor and then get a panel mount pot to replace the one on the board I'm sure. That's all based on how comfortable you'd feel doing this yourself though. Perhaps an amp tech in your area could do it for you.

 

[blumuz123]

Can the amp be modified to have the bias settings on the outside of the chasis like the mod 50?

You could run two test points to that resistor and then get a panel mount pot to replace the one on the board I'm sure. That's all based on how comfortable you'd feel doing this yourself though. Perhaps an amp tech in your area could do it for you.

Thanks sounds simple enough

I would have a tech do it