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previous: Charles Thanks Doc, for the reply.R... -- 11/17/1997 4:39 PM

Re: EL84 in a CHAMP?

11/18/1997 8:06 AM
Doc	Re: EL84 in a CHAMP? Charles: In your amp, from the data provided, the 6V6 is dissipating in the range of 15 watts. (360 volts plate supply, minus 45ma through the 470 ohm cathode resistor, about -21 volts, or 339v X .045=15.3) You can run the EL84 in the same area. Try a cathode resistor around 250-300 ohms. This should put you in the range of grid bias & plate current resulting in 15w of heat. The manufacturer's design rating for 6BQ5 is 12 watts plate dissipation, but that's for long life/reliable service, not guitar amps & tone. Just be sure that the plate structure isn't getting too hot (reddened color in dark background lighting), or the plate voltage (or idling current) will have to be reduced as you've suggested. I have read that EL84's sound better for guitar when the plate voltage is around 275-300 volts.

11/18/1997 8:06 AM

Doc

Re: EL84 in a CHAMP?

Charles:

In your amp, from the data provided, the 6V6 is dissipating in the range of 15 watts. (360 volts plate supply, minus 45ma through the 470 ohm cathode resistor, about -21 volts, or 339v X .045=15.3)

You can run the EL84 in the same area. Try a cathode resistor around 250-300 ohms. This should put you in the range of grid bias & plate current resulting in 15w of heat.

The manufacturer's design rating for 6BQ5 is 12 watts plate dissipation, but that's for long life/reliable service, not guitar amps & tone.

Just be sure that the plate structure isn't getting too hot (reddened color in dark background lighting), or the plate voltage (or idling current) will have to be reduced as you've suggested. I have read that EL84's sound better for guitar when the plate voltage is around 275-300 volts.

Replies:

Charles Yes, about 15 watts is what I came ... -- 11/18/1997 8:14 PM