6DX8/ECL84/6F3P as a reverb driver.

[LeftyStrat]

I've seen mention of people using these as a reverb driver. For those not familiar with this tube, it is a pentode (4w) and a triode (12at7-ish) in a single bottle. These are plentiful and cheap on eBay from the former Soviet block states as 6F3P.

Jeff (10thtx) has done some great work using these as PI/Power tubes.

I found a couple of posts from Gingertube who had used them successfully as a reverb driver, and I recently came across this article:

http://www.channelroadamps.com/articles/reverb_driver/

Which uses a different pentode/triode with good results (check the clip at the end) using a 600R tank.

I've also heard that an Australian amp mfg 'Maton' used this tube as well as a reverb driver.

Does anyone have any info/schematics/advice on using this as a reverb driver?

I'm trying to come up with something to drive a 300R tank that was in a small combo that I gutted to rebuild as a half power Reverb Rocket for my daughter using the SMPS from another thread. It originally used a solid state driver, but I'd like to keep everything tubular.

The tank was probably the nicest part from the combo (Electar 30R). It's a made in the US Accutronics (8DB2C1B).

[10thTx]

Several posts on the Hoffman forum regarding this:

http://www.el34world.com/Forum/index.php?topic=14306.0

& some info by Heinz in this thread using a pentode/triode (diff tube):

http://www.el34world.com/Forum/index.php?topic=7957.0

With respect, 10thtx

[tubeswell]

More links on pentode/triode reverb circuits;

ECL82

http://ampgarage.com/forum/viewtopic.php?t=1569

http://ampgarage.com/forum/viewtopic.php?t=1573

ECL86

http://ampgarage.com/forum/viewtopic.php?t=1806

[LeftyStrat]

Thanks guys, unfortunately all those use a transformer. In the link I posted he uses a higher impedance tank with no transformer. I may need to go back and have another look at the Ampeg reverb.

[darryl_h]

There is a minor error in the first post - the Soviet era valve which is equivalent to the 6DX8 is the 6F4P.

The 6F3P is equivalent to a 6BM8.

One vintage Australian amplifier which used the 6DX8 as a reverb driver/recovery valve was the Moody GA40: http://www.ozvalveamps.org/moody/moodyga40reverbcct.gif

[LeftyStrat]

There is a minor error in the first post - the Soviet era valve which is equivalent to the 6DX8 is the 6F4P.

The 6F3P is equivalent to a 6BM8.

One vintage Australian amplifier which used the 6DX8 as a reverb driver/recovery valve was the Moody GA40: http://www.ozvalveamps.org/moody/moodyga40reverbcct.gif

Thanks! This was the circuit I was looking for.

I guess I'm getting old 'Moody' instead of 'Maton', and '6F4P' instead of '6F3P'.

[VacuumVoodoo]

http://www.channelroadamps.com/articles/reverb_driver/

Which uses a different pentode/triode with good results (check the clip at the end) using a 600R tank.

I like it. Sounds good and makes a saving in components cost.

[gingertube]

Been away for a month.
The 6DX8 was used by Moody Model GA40 but used a high impedance reverb spring unit.
The schemo trace is here:
http://www.ozvalveamps.org/moody.htm
Cheers,
Ian

[Kagliostro]

3 FBT (old italian amps) using pentode reverb drive without transformer

K

p.s.: Note the EL503 final tubes, very rare (and expensive) today

[renshen1957]

Been away for a month.
The 6DX8 was used by Moody Model GA40 but used a high impedance reverb spring unit.
The schemo trace is here:
http://www.ozvalveamps.org/moody.htm
Cheers,
Ian

Hi Ian,

Thank you for the link on the Australian/New Zealand amps. Brilliant! A ton of ideas, many that Gar Gillies of Garnet Amps mentioned in his book in passing, here are real world circuits.

It is wonderful to see non US approaches to the same goals (successful or not).

Best Regards,

Steve (aka Renshen1957

[gingertube]

Steve,
No Worries Mate as we say in Oz.
I like that site myself and whenever I have some vintage Oz Amp referred to me for work I always do a circuit trace and provide it to Rolly Roper the guy who runs it.

That Moody was a case in point. Just finished restoration of a little suitcase style amp that is a home brew from Radio TV and Hobbies Magazine from 1942. It runs 2 x 6J7 (one of them triode strapped), Cathode biased 6V6 SE Output, 80 rectifier tube and an 8" field coil speaker and sounds just stunning. That should be on the site before too long. I would copy it here but don't have it handy, away from home (in Cairns) for 4 weeks filling in as a maintainer for the Oz Navy's Laser Airborne Depth Sounder System, since I was the senior design eng for the system they figured I should be able to maintain it,(the only tube in the whole thing is the photomultiplier tube in the laser receiver).

Cheers,
Ian