EF86 as a later gain stage?

LeftyStrat · Post by **LeftyStrat** » Fri Nov 02, 2012 11:29 pm

I've been trying to find amps that maybe use two triodes of a 12ax7 followed by an EF86. I seem to remember Matchless may have done one but can't remember which model.

I also interested in any other designs that may have one to two stages before a pentode to try to generate pentode distortion in the preamp.

Any suggestions?

Structo · Post by **Structo** » Fri Nov 02, 2012 11:41 pm

Was it the Clubman?

Not EF86 but a 6SH7.

LeftyStrat · Post by **LeftyStrat** » Fri Nov 02, 2012 11:58 pm

Thanks Tom, that was the one I was thinking about. I'm also interested in any other designs.

dartanion · Post by **dartanion** » Sat Nov 03, 2012 12:44 am

I seem to recall a Dukane that used 2 ef86s in series. I also think that the Mullard circuits book has some ef86 preamp designs. I would have to dig through my files to find these though. Might take a while to find.

tubeswell · Post by **tubeswell** » Sat Nov 03, 2012 12:46 am

I've done a thing loosely based on a 6G3, with a switchable parallel/single V1 and EF86 and the tone stack recovery stage and a 5G9 type trem.

Here is the latest folly of it (dubbed '6H3A' heh-heh) with the James TS (which I put in a couple of months ago, and which I really like with this amp). I should do some soundbytes of it. It has rich trem.

[img

725]http://farm9.staticflickr.com/8327/8149 ... 6849_b.jpg[/img]

LeftyStrat · Post by **LeftyStrat** » Sat Nov 03, 2012 1:00 am

Very nice design! I'd love to hear some clips. Are you able to get some decent distortion at lower volume levels?

10thTx · Post by **10thTx** » Sat Nov 03, 2012 1:41 am

I am enjoying this amp that uses a 5879 pentode in the OD section

With respect, 10thtx

LeftyStrat · Post by **LeftyStrat** » Sat Nov 03, 2012 2:24 am

Thanks, these all look great. I just thought it might be more interesting to drive a preamp pentode into distortion later in the preamp than using it on the input. Looks like an area to play with.

Reeltarded · Post by **Reeltarded** » Sat Nov 03, 2012 2:28 am

Selmer Zodiac 30! No scheme here. It is on this forum though!

-boats off to deeper water-

LeftyStrat · Post by **LeftyStrat** » Sat Nov 03, 2012 2:35 am

Reeltarded wrote:Selmer Zodiac 30! No scheme here. It is on this forum though!

-boats off to deeper water-

Interesting, found a sweet clip on youtube:

http://www.youtube.com/watch?v=KdW4z2L5 ... re=related

M Fowler · Post by **M Fowler** » Sat Nov 03, 2012 2:41 am

http://www.vintagehofner.co.uk/selmer/s ... /wire.html

Andy Le Blanc · Post by **Andy Le Blanc** » Sat Nov 03, 2012 3:08 am

put it in front of a split load inverter stage, or nearly any low gain inverter.
you can do the same with any other pentode from 6au6 to 6sj7.
I had a rig I really liked, it was a 6sn7 and 6sj7, half the 6sn7 was pre and the other was a splitload driven by the 6sj7, into kt88's and 50w fender tranny.

fusionbear · Post by **fusionbear** » Sat Nov 03, 2012 4:43 am

I built three of these. Not gainy, but with a few minor tweeks gives a delicious clean tone...

http://taweber.powweb.com/store/6s100_schem.jpg

renshen1957 · Post by **renshen1957** » Sat Nov 03, 2012 6:25 am

dartanion wrote:I seem to recall a Dukane that used 2 ef86s in series. I also think that the Mullard circuits book has some ef86 preamp designs. I would have to dig through my files to find these though. Might take a while to find.

Hi

Most of the Mullard circuits had the EF86 wired as triodes as memory serves me right.

Best Regards,

Steve

bb5000 · Post by **bb5000** » Sat Nov 03, 2012 9:45 am

The Weber 6S100:

https://taweber.powweb.com/store/6s100_schem.jpg

a Sunn 100S-inspired amp with lots of clean headroom, I use it for bass.

oops, there was already a post about this amp

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EF86 as a later gain stage?

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