[Ron Ramirez]

My two cents' worth:

I fully believe that the IBAM mod is both valid and beneficial to the set.

I also believe that adding 10 ohm resistors from the cathodes of each 7591A tube to ground is likewise valid and beneficial (and necessary for IBAM).

There is another mod for Fisher receivers using 7591A outputs which involves changing resistors and caps to different values, but I can't find it at the moment.

I have IBAM in my Fisher TA-600 and it sounds great. And I know the bias has been set to a point (34-35 mA) where the Soviet military surplus 6П14П-EB (replacements for 7189) will not self-destruct.