Push/pull reverb driver

[Esquirefreak]

Anyone here tried driving a reverb tank with a dual triode tube in push pull - rather than parallel SE like in Fender amps? Thinking that hum rejection would probably be better? Any direct down sides?

Just thinking out loud here.

/Max

[tubeswell]

You’ll need to think about how you achieve phase inversion - self-split vs another stage for PI etc. And the PP xformer. Go for your life.

[sluckey]

The Silvertone 1484 used a twin triode push/pull cap coupled reverb driver in it's cheesy circuit.

Not exactly what you asked for but probably worth a look/see. The Ampeg Echo Twin used a foldback reverb circuit. The reverb tank was driven from the push/pull output transformer.

[pullshocks]

Kevin O’Connor has a push/pull reverb kit on his London Power web site.
I don’t know if this is covered in any of his TUT books

[Esquirefreak]

Maybe a solid state phase inverter would do the trick? Like a cathodyne mosfet? To clarify, I'm not aiming to build anything (yet). Just thinking about alternative ideas. Might be unnecessesarily complicated, though.

Thanks everyone!

[Willabe]

Kevin O’Connor has a push/pull reverb kit on his London Power web site.
I don’t know if this is covered in any of his TUT books

Yes, it's in his books.

[HotBluePlates]

... Thinking that hum rejection would probably be better? ...

Most people don't turn their Reverb control full-up.  That implies there is plenty (too much?) reverb available if wanted.

"Hum Rejection" would only be hum present in the power supply when thinking SE vs PP.
   - We could simply feed the reverb transformer from a different, more-filtered point in the power supply.
   - We would reduce total supply-voltage available at the reverb transformer, which could limit how hard the tank is driven.
   - However, the observation earlier suggests we don't need as much reverb-drive as we have, so some reduction would be acceptable.


The challenge of a push-pull reverb transformer is that London Power seems to be the one source (though I suppose one could buy over-capable transformers from other places).

[Esquirefreak]

I was thinking maybe the Hammond 125B would be a good choice? 5w push pull with a multiple primary impedance alternatives. 22,5ΚΩ for one.

[sluckey]

Maybe steal some ideas from the Firefly...

[Esquirefreak]

Cool! Thanks!

[Merlin]

Yes you can use a push-pull driver, and yes it is more immune to PSU hum and magnetic hum from the PT. The Vox AC30TBR used a push-pull driver for a 600 ohm tank.
Note that KOC's push-pull driver seems to have a drawing error in it; the tail resistor is way too small.
Here's a push-pull driver I have used, the OT is a small power transformer. An SRPP is also a push-pull driver, technically speaking!

[Esquirefreak]

That looks awesome, thank you!

/Max