Hi Tom;
 RL> I don't know if a KT66 is a drop-in replacement for a 6L6 or not.
 TS> That's what the Torres catalog says. "The Holy Grail! The best 6L6
   > ever made." Probably a relabled 6L6.
The KT66 is similar to a 6L6, I can't for the life of me remember if 
the bases are the same, I don't think they are.  Pin 1 is connected 
internally on the KT66 while pin 1 has no connection on the 6L6 and is 
typically used as a tie point in Fender amps.  If you find a KT66 that 
looks like a 6L6GC it IS relabeled as KT66's are a completely different 
shape.
 RL> The bias sets your actual potential difference between the plate and the
 RL> cathode.  If the potential is too high, the tube will arc internally.
If you increase the bias ( Make it more negative ) the tube will be 
more cut off and will draw less current reducing output wattage. This 
is biasing towards class B operation.  Biasing lower ( less negative ) 
will shift the operating mode towards class A but will put more strain 
on the iron as the tubes will draw more current.  What Rich says above 
is true but at the -30 to -50 volt levels usually encountered in a 
guitar amp you should have no problem.
     Take care ...
            Paul
 * 1st 2.00 #1346s * How to slow a guitarist down? Put charts in front of 
m!
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