Twice now in as many weeks I've received a couple AA5 radios that have both had a 12SG7 in place of the 12SK7.

Seems to work alright... but when I look up any tube chart on these two tubes they do not indicate that they are substitutes for each other. .. one is a "remote cut off" the other is a "semi-remote cut off"

So what gives?

Peter

The sub usually works. 12SG7 has higher gain than 12SK7. There is another difference that can be a problem, basing isn't the same. Check a data book. In most radios pins 3 and 5 are tied together.

Norm

:Twice now in as many weeks I've received a couple AA5 radios that have both had a 12SG7 in place of the 12SK7.
:
:Seems to work alright... but when I look up any tube chart on these two tubes they do not indicate that they are substitutes for each other. .. one is a "remote cut off" the other is a "semi-remote cut off"
:
:So what gives?
:

Hi Peter, Below is a link about hot rodding a AA5 I've long forgotten. Never did try any of the suggestions preferring to keep things original. Mentions the tube substitute of your posting. Richard

http://www.geocities.com/wa2ise/radios/12ba7.html