Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Oddvar on August 17, 2016, 07:10:42 am

Title: EL34 in Bassman?
Post by: Oddvar on August 17, 2016, 07:10:42 am

Hi.  Is it enough to change the 470 ohm resistor to 1,5 k 3 or 5 watt resistor on the output tubesockets and do the redo the bias, jump the 1 and 8 pin to use El34 in the Bassman 59?

Could you leave the 470 ohm in there, maybe make it into 5 watt?

Title: Re: EL34 in Bassman?
Post by: kagliostro on August 17, 2016, 07:14:30 am

Do you remember that the 6L6 requires 900mA each for filament and EL34 1.5A each ?


Franco

Title: Re: EL34 in Bassman?
Post by: HotBluePlates on August 17, 2016, 07:26:07 am

Bias will probably come up differently, as the EL34 has more Gm than the 6L6. So you'll want the adjustable bias circuit to have enough range.

In a related issue, because the EL34 has higher Gm it won't take as much drive signal to get full output and into distortion. But you probably wanted that.  :icon_biggrin:

The suppressor of the EL34 is not internally connected to the cathode. So you'll need a wire running from pin 1 to pin 8.