Federal AM-864/U Need matched input tubes?

[jwhmca]

Does any body know if the front end on the Federal should be a matched pair?

 

[mjrippe]

Although the manual does not specify it, it would seem advisable.  The 6SK7 are where gain reduction occurs.  In limiters of this type a mis-match can result in thumps or other noises when crossing the threshold.

 

[DerEber]

It should yes. Will reduce thumb and distortion.

 

[DerEber]

But it will work without maching and probbably still sound good (or even fancy) at medium gain reduction.