[Boatanchors] 6SG7 VS 717A tubes?

[Bob Kulow]

The 717A is basically an octal-based 6AK5, a sharp-cutoff pentode.
If that IF stage has AGC applied, the 717A isn't a good replacement.
Also, I believe the 717A has lower maximum plate and screen 
voltages.

73
Bob WA2UEH

p.s. The 717A's nickname is "Doorknob tube".
 
> I have a National NC-183R setting on the work table, and one of the 
> first things I noticed about this set is that there is a Western 
> Electric 717A tube in the 2nd IF stage instead of the specified 6SG7.
> 
<snip>
> 
> It's neither in my tube substitution book NOR the Hickock 800A tube roll 
> chart.  My suspicions lead me to believe that this is NOT a suitable 
> substitute for a 6SG7.  Thoughts?
> 
> 73 de Phil  KO6BB