Rocket voltages OK?

[George61]

Since I discovered the input jack problem and my Rocket seems to be working more or less normally I decided to check the voltages. Everything seems to be close except for V3. I have 176.8V on pin 1 and 178.4V on pin 6. The voltage chart list 180V and 159V.

If both plates are fed by B+3 and both plates have a 100K resistor why wouldn't the voltage be the same?

According to the Weber bias calculator I am dissipating 12W on the output tubes at idle. I don't know if that is too high or not. With the volume at max the amp is into 80's chainsaw territory. I like that.

Attached is my voltage chart.

[martin manning]

The PI tube's sections, not to mention the plate and grid resistors on each side, are not identical so you shouldn't expect the voltages to be identical. Whomever filled in the expected voltages on the Rocket voltage chart didn't have a PI that is as well balanced as yours is.

12W is right at 100% Pa max for EL84's. If the plates aren't glowing red you're ok.

[George61]

Thanks for the reply. Using a more accurate method of checking bias, I get a dissipation of 11.5W. I have trouble checking voltages as my line voltage fluctuates a good bit. I am at the junction of three power plants. The York Haven Met-Ed hydro plant, PP&L's Brunner Island plant, and, unfortunately, Three Mile Island.

The amps sounds good to me, so I am calling it a keeper and putting it back in the cabinet. On to my 18W power scaling project.

Solder on,
George