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12AX7 "doubler" device?

Posted: Fri Dec 18, 2020 12:57 pm
by glasshand
I saw a mention of this a while back, but now I can't remember what it was or find it. Basically, it was a device to allow easily adding another preamp tube: it was a kind of adapter that plugged into the spot where a 12AX7 would go, and two 12AX7s plugged into the top of it, giving you another gain stage (technically another two, I guess) without requiring any other mods. Anybody seen anything like that or remember what it was called?

Re: 12AX7 "doubler" device?

Posted: Fri Dec 18, 2020 1:51 pm
by golem
Never seen such a thing. I'm curious.

Re: 12AX7 "doubler" device?

Posted: Fri Dec 18, 2020 3:31 pm
by mozz
Yeah i have seen them, let me scan the memory banks.

Found one,
https://legendarytones.com/hot-mod-v2-t ... on-module/

There was another from years back. It used a 6C10 tube, which is like 3 high gain triodes instead of the 2 in a 12ax7. The thing is the 6C10 tube is very hard to find, used in a few Ampegs and Gibson amps back in the day. Also in a Fender Super Champ? And why yes, they are expensive at about $40 each if you can find them.

Edit: Soldano Hot Mod

Re: 12AX7 "doubler" device?

Posted: Fri Dec 18, 2020 4:32 pm
by mickey
mozz wrote: Fri Dec 18, 2020 3:31 pm Yeah i have seen them, let me scan the memory banks.

Found one,
https://legendarytones.com/hot-mod-v2-t ... on-module/

There was another from years back. It used a 6C10 tube, which is like 3 high gain triodes instead of the 2 in a 12ax7. The thing is the 6C10 tube is very hard to find, used in a few Ampegs and Gibson amps back in the day. Also in a Fender Super Champ? And why yes, they are expensive at about $40 each if you can find them.

Edit: Soldano Hot Mod
I bought a new Super Champ in 1980-2 (somewhere in there) for $206 including sales tax.
By 2000 the 6C10 had become made of unobtainium so I ran the Super Champ on eBay.
It sold for a bit over $1000.
Since then somebody came out with a small circuit board that let you replace the 6C10 with two 12AX7's.
Had that been available back in 2000 I would still have the Super Champ.

Of course, that eBay sale has more than paid for every amp purchase I've made since 2000. :D

Re: 12AX7 "doubler" device?

Posted: Fri Dec 18, 2020 4:51 pm
by glasshand
mozz wrote: Fri Dec 18, 2020 3:31 pm Yeah i have seen them, let me scan the memory banks.

Found one,
https://legendarytones.com/hot-mod-v2-t ... on-module/

There was another from years back. It used a 6C10 tube, which is like 3 high gain triodes instead of the 2 in a 12ax7. The thing is the 6C10 tube is very hard to find, used in a few Ampegs and Gibson amps back in the day. Also in a Fender Super Champ? And why yes, they are expensive at about $40 each if you can find them.

Edit: Soldano Hot Mod
That's the one! Thanks for finding that! I wonder how generally applicable they would be, especially given that there are already two different versions for different Marshalls.

Re: 12AX7 "doubler" device?

Posted: Sat Dec 19, 2020 3:43 am
by LancerTheGreat
Hmmm MOAR GAIN, you say?
Seems like a neat thing to give a try, my interest is peaked(peekt/peeked/piqued?).

Try it out and let me know if I should get 2 or 3 so I can go wild lol.

Re: 12AX7 "doubler" device?

Posted: Sun Dec 20, 2020 12:21 pm
by andrewsrea
Anyone considering this, be aware: this device is specifically for an amp circuit, to which pins 1 thru 3 follow the tone stack or a pre-amp and pins 6 thru 8 are a cathode-follower. So I would not suggest trying this in the V1 stage of a Fender Champ, etc.

Also, the 'fit' aspect is oriented to the Marshall 2203, 2204, 2205 pin orientation. So, you have to consider how this would fit next to your other tubes if not applying this to one of those amps.

It is a pretty cool alternative to the extra tube for cascaded mod for Marshalls, without having to drill extra chassis holes, etc.