[Ian Bell[_2_]]

flipper wrote:
On Mon, 24 Nov 2008 16:20:52 -0800, PhattyMo wrote:

Ian Bell wrote:
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

I have some tubes that are marked as both types on the glass.
They show 6CG7 with 6FQ7 right under it on the next 'line'.

My double marked tubes have 6FQ7 first.

I doubt it matters.

The GE plate curves are identical for the two with pin 9 shield the
only different I see.

The 'normal' plate curves look the same as the 6SN7 but the +ve curves
run slightly higher... but that may be measurement error.


So, on balance it looks like they are identical. Have you noticed any
differences in real applications?

Cheers

Ian