[Ian Bell[_2_]]

The 6SN7 is said to be a good tube for audio and the 6CG7 is apparently
its B9A direct equivalent. Looking for sources of the 6CG7 on the
internet I found more examples of its supposed equivalent the 6FQ7 than
of the 6CG7 itself. Looking at the data sheets the two seem extremely
similar and the 6FQ7 even has slightly less plate to grid capacitance.

So, is the 6FQ7 a worthy alternative to the 6CG7? Are there any real
differences between the two? Presumably there must be some difference
else why have a different number.

Cheers

Ian