6CG7/6FQ7 Not In Tube Lore?

[GerryE123]

Hi:

I couldn't find 6CG7 or 6FQ7 in Tube Lore. Any guesses as to why they are
not in there? Does anyone know what year the 6CG7 was released? Thanks.

Gerry

[[email protected]]

GerryE123 wrote:
> I couldn't find 6CG7 or 6FQ7 in Tube Lore. Any guesses as to why they are
> not in there?

In the lorish scene, the 6CG7 was one of many variants in the 9-pin
dual triode categories. Hurting its lorishness, it was originally sold
as a TV deflection oscillator, and only later did it find its way into
some hi-fi amps. In some people's minds, if it's in a Marantz then it
must have lore behind it, in other people's minds it's a TV tube and
therefore uninteresting.

Contrast this with the "grandaddy" dual triodes (6SN7 and bazillion
variants and manufacturers) which are quite lorish (the 6SN7 even has
its own website!). Even though the 6CG7 is electrically equivalent and
standard equipment in some interesting hi-fi stuff, it just doesn't
seem to cut the snuff with at least one big-name hobnobber!

> Does anyone know what year the 6CG7 was released? Thanks.

It first appears in mid-50's ARRL basing charts, along with a metric
buttload of other 9-pin dual triodes.

In fact www.6sn7.com says the 6CG7 came out in 1954 :-).

Tim.

[GerryE123]

> wrote in message
ups.com...
> In the lorish scene, the 6CG7 was one of many variants in the 9-pin
> dual triode categories. Hurting its lorishness, it was originally sold
> as a TV deflection oscillator, and only later did it find its way into
> some hi-fi amps. In some people's minds, if it's in a Marantz then it
> must have lore behind it, in other people's minds it's a TV tube and
> therefore uninteresting.
>
> Contrast this with the "grandaddy" dual triodes (6SN7 and bazillion
> variants and manufacturers) which are quite lorish (the 6SN7 even has
> its own website!). Even though the 6CG7 is electrically equivalent and
> standard equipment in some interesting hi-fi stuff, it just doesn't
> seem to cut the snuff with at least one big-name hobnobber!
>
>> Does anyone know what year the 6CG7 was released? Thanks.
>
> It first appears in mid-50's ARRL basing charts, along with a metric
> buttload of other 9-pin dual triodes.
>
> In fact www.6sn7.com says the 6CG7 came out in 1954 :-).
>
> Tim.

Thanks for the humor and good info Tim! There was a thread on the Tube
Asylum about replacing the 12AU7 phase inverter in McIntosh amps (ex. MC-60)
with a 6CG7. It was suggested as a "superb" mod.

I was curious as to why Mac didn't use the 6CG7 in the first place. My
guess was that the 6CG7 had yet to be released at the time the MC-60 was
developed. It's close, the MC-60 came out in 1955.

RAT's own Steve O summed up the situation in Asylum thread. The thread can
be viewed here:

http://www.audioasylum.com/scripts/t.pl?f=tubes&m=184886

Gerry

[Patrick Turner]

wrote:

> GerryE123 wrote:
> > I couldn't find 6CG7 or 6FQ7 in Tube Lore. Any guesses as to why they are
> > not in there?
>
> In the lorish scene, the 6CG7 was one of many variants in the 9-pin
> dual triode categories. Hurting its lorishness, it was originally sold
> as a TV deflection oscillator, and only later did it find its way into
> some hi-fi amps. In some people's minds, if it's in a Marantz then it
> must have lore behind it, in other people's minds it's a TV tube and
> therefore uninteresting.
>
> Contrast this with the "grandaddy" dual triodes (6SN7 and bazillion
> variants and manufacturers) which are quite lorish (the 6SN7 even has
> its own website!). Even though the 6CG7 is electrically equivalent and
> standard equipment in some interesting hi-fi stuff, it just doesn't
> seem to cut the snuff with at least one big-name hobnobber!

The samples of 6CG7 made here in Oz had exactly the same internal
structure of the 6SN7; the 6CG7 IS a 6SN7 crammed into a 9 pin package,
and apart from a slight power derating there IS NO electronic difference.

Many top name amp makers used 6CG7 including ARC.

The 6CG7 therefore is equal in sonic and electronic performance to the 6SN7.
So are a pair of 6J5.
Quite few different varieties of 6CG7 seemed to spring up such as the Seimans
6CG7
with smaller anodes but very close to original specs, maybe µ was 22 instead of
20.

I don't care what might be in Tube Lore and I don't care if they
say cruel things about tubes used in TV sets, telephone repeaters, radars, TV
stations,
transmitters, or bleeding guitar amps, if they sound well and measure OK and are
reliable and quiet
then they can be used by fussy ppl.

Patrick Turner.

>
>
> > Does anyone know what year the 6CG7 was released? Thanks.
>
> It first appears in mid-50's ARRL basing charts, along with a metric
> buttload of other 9-pin dual triodes.
>
> In fact www.6sn7.com says the 6CG7 came out in 1954 :-).
>
> Tim.

[Tom Schlangen]

Hi Patrick,

> The samples of 6CG7 made here in Oz had exactly the same
> internal structure of the 6SN7; the 6CG7 IS a 6SN7 crammed
> into a 9 pin package,

Also it is known that at the end of NOS 6SN7 production 6CG7
systems were retrofitted into octal envelopes (by GE and RCA,
IIRC)

Tom

--
Live is too short to be taken seriously.
- Oscar Wilde

[Sander deWaal]

Tom Schlangen > said:


>> The samples of 6CG7 made here in Oz had exactly the same
>> internal structure of the 6SN7; the 6CG7 IS a 6SN7 crammed
>> into a 9 pin package,


>Also it is known that at the end of NOS 6SN7 production 6CG7
>systems were retrofitted into octal envelopes (by GE and RCA,
>IIRC)


Maybe some of you may be able to clear up something for me:
The 6FQ7 is often said to be a direct replacement for the 6CG7.
Other sources tell me it's a different tube, and the better
replacement would be a 12BH7.

Now when browsing through my tube books, I fond that 6FQ7 and 6CG7 are
often called similar or even equal, while the 12BH7 seems to be a
totally different kind of animal.

I use 6SN7 a lot, but I'm looking for a good Noval replacement because
sometimes, physical restrictions prevent me from using an Octal tube.

How do they compare in say a Cathodyne phase splitter or driver?

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Tom Schlangen]

Hi Sander,

> Maybe some of you may be able to clear up something for me:
> The 6FQ7 is often said to be a direct replacement for the 6CG7.
> Other sources tell me it's a different tube, and the better
> replacement would be a 12BH7.

I have several NOS/NIB RCA side getter ones in the drawer
(a complete 5-pack and a few more) which say on the sleeve:

6FQ7
6CG7

Also, on the tubes itselves, it is mentioned twice, once
in red lettering, once etched in glass like this (use
monospaced font to view):

/------\
| 6FQ7 |
| 6CG7 |
\------/

I think we can trust RCA when they obviously consider them
to be the same tube.

Hope it helps,

Tom

--
Anyone who considers protocol unimportant has
never dealt with a cat. - R. Heinlein

[robert casey]

>
> Maybe some of you may be able to clear up something for me:
> The 6FQ7 is often said to be a direct replacement for the 6CG7.
> Other sources tell me it's a different tube, and the better
> replacement would be a 12BH7.
>

The 6CG7 has an internal shield between the triode sections. The 6FQ7
doesn't. That's the only difference.

[Sander deWaal]

robert casey > said:


>> Maybe some of you may be able to clear up something for me:
>> The 6FQ7 is often said to be a direct replacement for the 6CG7.
>> Other sources tell me it's a different tube, and the better
>> replacement would be a 12BH7.


>The 6CG7 has an internal shield between the triode sections. The 6FQ7
>doesn't. That's the only difference.


Thank you, Robert and Tom .

Due to an unexpected hospital admission I wasn't able to respond
earlier.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[maxhifi]

"GerryE123" > wrote in message
...
> Hi:
>
> I couldn't find 6CG7 or 6FQ7 in Tube Lore. Any guesses as to why they are
> not in there? Does anyone know what year the 6CG7 was released? Thanks.
>
> Gerry
>
I think there's something in the forward of tube lore to the effect that
tubes designed after 1950 are not included, unless they're famous for some
reason. I think it's probably an oversight, as the 6CG7 is reasonably
famous.

Also notably (to me) absent are some of the pentodes used in portable record
players - well, maybe not a big deal, but I'd like to see info on tubes like
the 25EH5, etc.