Using Modules with 12BZ7

I searched the forum and not one hit on 12BZ7. I can't believe I am the only one to ever try 12BZ7 tubes in these modules.

While not convinced yet that tube rolling the same type of tube in these modules makes any difference I can say that using 12BZ7 does. Perhaps not so much in tone but for sure a bit in feel and increasing the amount of gain and even clarity with the gain increase.

Anyone else try?

-Charlie

Although you can try them, I'd be careful. Voltage isn't really at issue, as the 12BZ7 operates at the same voltage as a 12AX7. The 12BZ7 has twice the transconductance, but half the plate resistance of the 12AX7 spec. This still leaves it at roughly the same amplification factor, but the heater draws twice the current. If you blow the heater fuse in the amp, that's the cause.

Thanks for that info Rob.

I ran the experiment in my RM4 with only one module installed. I figured if it could handle a full load of 4 that it could handle just 1 running over spec.

-Charlie

I agree fully sir.