Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jonas on February 25, 2026, 08:35:49 am

Title: 6GH8A any good?
Post by: Jonas on February 25, 2026, 08:35:49 am

I have a small collection of random tubes, one of which the 6GH8A. This is a 9 pin preamp with a pentode and triode section. 

https://frank.pocnet.net/sheets/135/6/6GH8A.pdf

Would this make for a good preamp? A couple ideas would be pentode -> triode cathode follower, pentode -> triode plate, OR triode plate -> pentode...

What are your thoughts?

Title: Re: 6GH8A any good?
Post by: johnnyreece on February 25, 2026, 09:21:07 am

My notes say it's in several old Univox amps.  Good replacement for a 7199 (with different pinout!), and much cheaper/easier to find. 

Title: Re: 6GH8A any good?
Post by: astronomicum on February 25, 2026, 09:25:31 am

Quote from: johnnyreece on February 25, 2026, 09:21:07 am

My notes say it's in several old Univox amps.

I am not aware of any and would be very interested in knowing which ones?

Title: Re: 6GH8A any good?
Post by: johnnyreece on February 25, 2026, 09:40:02 am

Quote from: astronomicum on February 25, 2026, 09:25:31 am

Quote from: johnnyreece on February 25, 2026, 09:21:07 am

My notes say it's in several old Univox amps.

I am not aware of any and would be very interested in knowing which ones?

Good call!  Looks like my notes were mistaken.  Univox used the similar-but-different 6AN8.  My apologies!