EL34 Bias current High!!!

[grtamp]

Hi , I power on my #183 D-clone and I seems the bias current is too high!

plate voltage 465V
Bias voltage -46V
current pin 1-8 42mA

Thanks

[David Root]

You may have got a hard set of tubes ie that draw higher than average current.

I did that with some 6L6s, got a set that was 8 on a scale of 1 - 10, had to change the bias supply setup to go out to -62V to get the cathode current in line. You might have to do the same.

[ToneMerc]

Hi , I power on my #183 D-clone and I seems the bias current is too high!

plate voltage 465V
Bias voltage -46V
current pin 1-8 42mA

Thanks

If you originally setup the bias safety resistor up with a 22K, change it to an 18K. That should get you pointed towards the mid 30's at least.

I installed Gold Lion KT77's in mine and I had to change the tail resistor as well.

TM