I built a linestage with a power pentode. It sounds better than any of the triode circuits I have played with. The pentode is a 6AV5GA. Screen grid is shunt regulated at 75V. The plate load is a 750R resistor. As usual there is a single input and output. B+ runs ~200V, perhaps a bit less due to rectifier drop( depending on 5R4 or 5AR4 and a few inbetween ). It idles at power-amp levels of 55 mA each.
cheers,
Douglas

I'm a big fan of pentode gain stages. Some of my favorite amps(Futterman H3AA, WE91 Clone, power amp section of Dyna SCA35) uses the much maligned pentode. It may not be as accurate as a triode, but there is something in the mid-range and "jump" factor in the music. I was once chastised on technical merit on liking a pentode gain satge... but then again that what they said about SETs.

Thanks for sharing your experiencde on "road less taken".

Quinnling

Would you be willing to share a schematic of this latest sacrelige?

I am sure that many people would be interested in experimenting.

A schematic with a power supply would be nice over in the projects forum?

Norris

Any problems with microphony? Quiet? What kind of gain do you get?

The g2 voltage is 75V, and gm is published for that OP. The bias is ~5.5V established with a 100R cathode resistor. Actual plate V is about 150 as dropped from a B+ of ~200. I may even try a lower value plate load...:)
cheers,
Douglas

Love my 12B4 parafeed pre, but finding non-microphinc 12B4s has been a real pain.

No problem with pentodes/tetrodes here. I run 6CA7's or EL34s single ended in my parafeed 6B4 amp when the material calls for it. They really perked up my disc of "Green Onions" on Saturday!

Working up a 6688 driver for my 300b amp.