Gibbs Model 6520 tank replacement help

[davohilts]

Hello,
I'm working on a Harmony H440 combo amp that has a gibbs short tank inside a cardboard box mounted vertically on the side of the amp cab. The H440 schematic is found here: harmony h440 amplifier schematic Download page :: Schematics Unlimited And the reverb is tube driven without a transformer. The input dc resistance reads 268 ohms and the output dc resistance reads 254 ohms.
Is there a way to determine what replacement tank to use?
Thanks for any help.
Dave

[Enzo]

Yes, recognize it is not rocket surgery and find what is close. In the Accutronics number system, which everyone seems to use, you would probably best use an FB type pan, though an EB might work.

[davohilts]

Yes, recognize it is not rocket surgery and find what is close. In the Accutronics number system, which everyone seems to use, you would probably best use an FB type pan, though an EB might work.

Thanks Enzo! So because the amp doesn't use a transformer, a high impedance tank is needed?

[jpfamps]

This article on Rod Elliot's excellent site gives the DC resistances of the various Accutronics tanks:

Spring Reverb

Your tank would appear to be an F input (1475 ohm) and B output (2k2).

This is logical given the schematic where the tank is driven from the plate of a valve.

[davohilts]

jpfamps,
Thanks for the link! and help.
I'll check it out. Really appreciate it.
Dave

[52 Bill]

Agree with everyone about the FB tank. I'll add that the 6520 is a manufacturing date code.