Dumble type bias check on a different amp

[gary sanders]

I think it would be good to have the bias check outlets on my carvin like the ods has.Its an EL34 amp and the only way I know to check bias on it as it is is through the standby switch and if youve seen where these switches are on the old X amps,its a pain in the ass.

So would I just run a 1 ohm to ground as on the 6L6s or is there something different I should do.

[mbeldyga]

Just add 1ohm from cathode o ground. Of course you need fixed bias, no cathode bias.

[Structo]

EL34s are a little different.
On the 6L6 there is nothing connected to pin 1.

On a EL34 pin 1 is a suppressor grid.

Usually pins 1 & 8 are connected to each other on EL34 amps.

So yeah, just connect a low tolerance 1 ohm resistor from there to ground.

I use the Vishay/ Dale 1% resistors from Mouser.

The lower the tolerance the better.

Then you just measure the voltage drop across the 1 ohm resistor, sine it converts amps to volts due to Ohm's law.

Does that amp have a bias adjust pot?
Is it accessible from the outside?

If not, that would be a good mod, then have external test lead jacks on the outside so you can measure and set the bias without pulling the chassis.

[FUCHSAUDIO]

Does that amp have a bias adjust pot?
Is it accessible from the outside ? If not, that would be a good mod, then have external test lead jacks on the outside so you can measure and set the bias without pulling the chassis.

Punch the chassis for an 8-pin socket. Gives you ground and 7 other test points. Don't thank me, thank Dynaco. I put a few into Fenders, in place of power plugs.

[gary sanders]

I put a bias pot on it but its on the inside.going to relocate it when i do this mod