12AY7 8 pin equivalent

[TIMBO]

Hi guys, Is there an 8pin equivalent to the 12AY7 in the 6S_7GT tube.

[jazbo8]

6N7 is pretty close but it has a common cathode.

[PRR]

12AY7 is unique.

6SL7 is as close as you are likely to find.

[kagliostro]

As PI instead of 6j6 (that is a 7 pin tube) tube a friend used a 12ay7





But 6j6 and 12ay7 are close only in gain (38 vs 40)

K

[TIMBO]

Thanks for the info guys, The reason I am asking is I acquired a ~1940's preamp that has the 6SJ7GT tubes in it.
I'm still a bit IFFY on what to do with it, as it has a bit of local history attached to it, but I can't find any info that will verify it.
The circuit is simple with NO power supply of its own.
It has 6 OCTAL sockets but only 3 are used.
My first thought was to add a small transformer that I took out of an old record player that should have enough to power the HT and heaters and just use it as is and see what its good for.
OR do a TUBENIT no it and do this http://el34world.com/Forum/index.php?topic=17920.0 and sub two of the 6SJ7s with either the 6SL7 or 6SN7.
JUST spitball'in it.

[kagliostro]

Ciao TIMBO

I've no idea on how to use the circuit as is (I've seen the schematic at AGGH)

however Gibson used the 6SJ7 tube in a lot of their amps

give a look here for some inspiration

http://el34world.com/charts/Schematics/files/gibson/Gibson%20Amp%20Master%20Service%20Book.zip

Franco

[TIMBO]

Hi K, Just not sure I want to go that way.
I was even thinking a vintage OVERDRIVE pedal, this way I can keep the circuit pretty much as is, add the power supply and plug it straight into an amp 

[kagliostro]

That is an idea, but 3 tubes seems too much ...... or not ???

a 6SJ7 is like an EF86 .... may be having a low value plate resistor .....    

I mean less than those in this Mullard preamp



---

A posible use ..... an Herzog ?

you can arrange two tubes as preamp (parallel or series ??) and the third as output stage



this is SILVERGUN's version



http://el34world.com/Forum/index.php?topic=17218.msg172218#msg172218

---

Or one tube as pre and two in PP configuration (to obtain an Herzog insipired effect)

this circuit uses 1 ef86 as V1 and 2 ef86 as Power Tubes (you must add a tube or go self split PP)



Franco

[jazbo8]

I like Timbo's overdrive pedal idea, just add a small PT/PSU on the chassis. The mike input tubes have a ton of gain, and need to be dialed way back, or you will end up with a fuzz box and probably not a good one at that. You can also consider converting one of the mike inputs to triode-connected, so you get a two-channel overdrive via a footswitch.

[kagliostro]

Only because there is a 6SJ7 tube employed (and this Tone Control is odd) 



The absence of a cathode resistor + bypass capacitor and the 75k plate resistor suggests this stage has a low gain

more there is the Tone Control that I think will lower furtherly the signal

Franco

[kagliostro]

Ciao Pete

if I try to click on the link you posted appear a window as I was inserting a replay and this warning

Warning - while you were reading a new reply has been posted. You may wish to review your post.

????

is this the tread you wanted to link ?

http://el34world.com/Forum/index.php?topic=17300.0

Franco

[DummyLoad]

Ciao Pete

if I try to click on the link you posted appear a window as I was inserting a replay and this warning

Warning - while you were reading a new reply has been posted. You may wish to review your post.

????
is this the tread you wanted to link ?
http://el34world.com/Forum/index.php?topic=17300.0

Franco

yes...

another example of cascaded pentodes attached.

--pete

[tubeswell]

6SJ7 amps? - lest we forget


http://el34world.com/charts/Schematics/files/fender/Fender_champ_5c1_schem.pdf

[kagliostro]

Seems that TIMBO is thinking to use it for a circuit that allow the original tubes (and may be part of the original schematic) to be used


K

[TIMBO]

Thanks guys, Some great ideas to pounder over.