6V6 Blackbird question

[Perry D.]

I want to put a set of nos 6V6s in my 20 watt Blackbird. Where should I set the milliamps? What should the plate voltage be?


Thanks,
Perry

[Blue Strat]

Originally Posted by Perry D.

I want to put a set of nos 6V6s in my 20 watt Blackbird. Where should I set the milliamps? What should the plate voltage be?


Thanks,
Perry

The plate voltage is inherent to the amp design and cannot be varied unless you change rectifier tube types (assuming there IS a tube rectifier in the amp). Check with Fargen, but 400 volts is probably a safe bet for calculations.

20mA should be about right for 6V6s.

[Perry D.]

Thanks for the reply Mike. The amp has a GZ34 rectifier. Would you say that 20mA for this amp is about 'middle of the road'?

[Blue Strat]

Originally Posted by Perry D.

Thanks for the reply Mike. The amp has a GZ34 rectifier. Would you say that 20mA for this amp is about 'middle of the road'?

Without knowing the plate voltage, I'd say that 20mA is maximum.

[Seegs]

when I run 6V6s in my Fargen Dual Classic...which is essentially a BB with a Tweed bassman ckt. added to it..I have to change rectifier tubes to a 5Y3GT...

I set my bias to 20mv...

Chow,
Seegs

[pula58]

Funny,
I was just asking Ben F. about this. He said 25mA-30mA for 6V6's in my 30W (it has four 6V6 tubes) Blackbird. Using my " compubias" device I measured 432V on the plates. But, your 20W version might not necessarily have the same plate voltage. Why don't you email Ben I am sure he'll tell you what the correct values are. Bens customer service is really good!

For my amp, 25mA and 432V means each 6V6 is burning 10.8 Watts in its resting state.

I always thought that as long as the tubes maximum plate voltage is not exceeded that it is the POWER that is the relevant bias target. Since we can only easily tweak the current (not the plate voltage) we measure and tweak the current BUT we should set the current so that in conjunction with the plate voltage the POWER is correct.

Blue strat, isn't this the way to go on these matters?.

P.

[Blue Strat]

Originally Posted by pula58

Funny,
I was just asking Ben F. about this. He said 25mA-30mA for 6V6's in my 30W (4 6V6 tubes) Blackbird. Using my " compubias" device I measured 432V on the plates. But, your 20W version might not necessarily have the same plate voltage. Why don't you email Ben I am sure he'll tell you what the correct values are. Bens customer service is really good!

For my amp, 25mA and 432V means each 6V6 is burning 10.8 Watts in its resting state.

P.

30mA at 400 volts is 12 watts, the maximum rating of 6v6GTs. It's not usuallly recommended to run anything at it's maximum.

[Perry D.]

I'd like to thank you guys for your input. TGP is such a great site! :AOK I took your advice and emailed Ben my questions and I'll post his response when it comes.

Perry