metal can 6v6's

[ThermionicScott]

I just came across a few NOS RCA/JAN metal 6V6's and popped one in my Champ clone. It sounds great, as good as the best of the GT glass versions, IMO. It seems to be perfectly happy with 410 volts on the plate too, whereas it seems you have to pick through 6V6's in general to find ones that don't mind high B+ voltages. Next amp I build will have lower B+ because I think everything is just better that way - but it's hard to beat the sound of a "Champ in pain"! But I am impressed with how rugged the metal 6V6 is. It just doesn't LOOK as cool as the glass bottle, though!
-Boots

The metal 6V6's carried the same ratings as the glass versions, so it's not *that* surprising. And you can get away with throwing them into Champs/clones, since they don't use pin #1 unless you've modded the circuit.

One downside: you can't see the plates glowing red if the dissipation is excessive. Have you checked the dissipation?

- Scott

[boots]

The metal 6V6's carried the same ratings as the glass versions, so it's not *that* surprising. And you can get away with throwing them into Champs/clones, since they don't use pin #1 unless you've modded the circuit.

One downside: you can't see the plates glowing red if the dissipation is excessive. Have you checked the dissipation?

- Scott

Yes, I checked the dissipation and it is right in the neighborhood of 14W. I changed the cathode resistor from the standard 470 ohms in the 5F3 design to a 680 ohm, which makes the amp much happier. I used a Hammond PT that was touted as the proper replacement for the Champ, but I suspect that PT was to be used with a choke-input B+ supply, which would inherently deliver a lower B+ than a capacitor-input PS. I, of course skipped using a choke, so I think that is why I ended up with a B+ of 410 volts. With the 680 ohm bias resistor and the right hand-picked 6V6, the amp sounds delicious, no red-plating with GT's and probably not with metal tubes either. However, lots of heat as well as that special hot smell. That smell kinda grows on you! Actually, the smell goes away after a while.
-Boots

[ThermionicScott]

I agree -- the smell of that black paint is something that the glass-only folks are missing out on!