Tube Amp Archive

Yes -24v, that is correct same as when I measured the 6v6's

Bias was -24 and current was 20mA with the trim pot all the way up

BTW I measured the resistance from B+ to the ot at the tubes, B+ = 397v, the resistance was 45.5 and 44.8

396 pin 3
387 pin 4

No Problem, give me about 30 minutes ,

BTW you said 17millamps was high for idle current, I thought low 30's was idle, or are you referring to something other than the bias current?

Back shortly

Yes, On the actual pin

Thanks for that,
Ok, I don't have another set of el34's , the current I built a pair of sockets from this site http://el34world.com/charts/BiasChecker2.htm and plug in my Multi meter and away I go

Peter

OK, Plate V = 390.8/392
Pin 4 = 356.5/356.5

Cheers Peter

Some pics sorry about the quality

Thanks for the relies,, what pin do I check the plate voltage on.

Yes Both are matched

I did also try a pair of 6V6's, But same problem

Regards Peter

B+ is around 397 volts, EL34's All voltages are with in a couple of volts of the schematic dia, R29 = 150k, negative V is -33.8, Milliamps is around 12 R29 = 220k, negative V is -24, milliamps is around 31. Both of the above readings are with the bias trim pot all the way up. (what are the pin numbe...

High guys/gals, I am having some odd voltage/milliamp readings on my TWEx. Please see attachment, this is the schematic I have used for my build, All voltages are within a couple of volts on average, my bias voltage with R29 150k, is -33.8 the milliamps per tube is about 12 ma with the bias pot turn...

oops

this is the schematic I used for my build

Ok , I know what we are talking about now, I did not know that NFB and Presence was the same thing.............sorry guys my Bad

Hi Geetarpicker,

where in the circuit does that go? I cant recall that,

Peter