6CG7/6FQ7 questions
Mutantmoose
I've not seen much about this tube, so I thought I'd ask--
Are any of these tubes any good? Are some brands better than others? Are
there any recommended replacements? It look slike a 12AU7 might be good, or
a 12AT7 even, once the heaters are rewired. Of course, in a PC board amp,
that's pretty damn difficult, so are there any other tubes I could slap in
and try? (Amps I'm thinking of are Ampegs and SIlvertones)
--
Mark
mutan...@worldnet.att.net-nospam
you know the routine, remove -nospam to reply
Ned Carlson
"Mutantmoose" <mutantmoose*nospam*@worldnet.att.net> wrote:
>I've not seen much about this tube, so I thought I'd ask--
>Are any of these tubes any good? Are some brands better than others?
For guitar amps? I dunno. For hifi I like Tungsol & RCA the best.
But most old US made 6CG7/6FQ7 are good, it's more a matter of taste
than a mega-difference between brands.
They're not that expensive. The Yugos make 'em, those
I'll sell you for $9.95 each. NOS are a bit more.
> Are
>there any recommended replacements?
A 6GU7 would work, also, *depending* on the circumstances,
a 6BQ7/6BS8/6BZ7 might work. They have a bit more gain.
>It look slike a 12AU7 might be good, or
>a 12AT7 even, once the heaters are rewired. Of course, in a PC board amp,
>that's pretty damn difficult,
Actually, it's not that bad, since only the filament traces have to be
dealt with. But there's a lot of other alternatives, plus the
original, so no need to bother.
The only really similar tube that pins out like 12AU7/12AX7
is a 12BH7, and there no cheaper than 6CG7/6FQ7.
>so are there any other tubes I could slap in
>and try? (Amps I'm thinking of are Ampegs and SIlvertones)
If you have a GE tube manual, look up base code 9AJ,
there's a slew of tubes that pinout the same, but vary in gain
and plate dissipation. What's apropo depends on the situation, but
as far as the Ampeg reverb driver is concerned, I'd stick with
6CG7/6FQ7 or 6GU7.
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
Email catalogs: email our CataBot: cat...@triodeel.com
Mr. James C. Mcshane
I think its a damn good tube. It's basically a small bottle version of
the 6SN7, and is a very linear tube.
Jim McShane
MLJ...@prodigy.com
KentElltt
>Date: Mon, May 4, 1998
Wow, what kind of time warp are you in? Or was my nap longer than I thought.
Seriously, why replace the 6CG7? It's not hard to find, probably less
expensive than NOS 12AX7's, and it works well.
Kent Elliott
Mutantmoose
KentElltt <kent...@aol.com> wrote in article
<19980207052...@ladder03.news.aol.com>...
I guess so, I should actually trust my ears sometimes. : ) I guess after
you spend most of your times working on a few Fenders and Valcos, it's
wierd to see tubes other that 12AX7's and 6L6's, typical tubes.
This question came up because in my two Ampeg GV-22's, there are 6CG7's
driving the reverb, which sounds particulary bad for an Ampeg. It's got a
harsh, brittle tone to it, like a really nasally Fender reverb with the
tone all the way up, a real ear piercing sound. So what I'm wondering is,
where in the circuit should I start looking to change the tone, keeping in
mind that this is a pc board amp? I don't want to go mod crazy, I don't
want to change anything else in the amp, I just want to improve the reverb.
Any suggestions?
Thanks!
Mark