5F6-A reverb idea/question

[Luthierwnc]

I'm toying with the winter project and was thinking of a '59 Bassman. Reverb helps. I've got some schematics with different out and insertion points but was wondering how folks here think a passive loop after the treble pot would work with my Neunaber Wet. It's a nice sounding device in an active loop and would save a lot of effort if it would work with just the line level signal. I could put it in front of the amp too but I like time-based effects to be on the outward-bound side of the tone stack.

Thanks, Skip

[Stevem]

well you would be driving the out board effect with the needed low impeadance off of the cathode, but I am not sure how the tone will be?

[Luthierwnc]

The one-tube reverb circuits on the Dumble side work a bit like that.

Attached is another possibility, Thanks, sh

[10thTx]

Skip,

I've done quite a few one tube reverbs and I've gotten to where I prefer an active FX loop. I've done this type of arrangement on 4 different amps and have liked it.

The V2a CF and tone stack acts as the FX send and the V2b acts as the FX return. Makes for a nice master volume also. I have this exact arrangement on my current D'Mars ODS 5879 for the clean channel.

Just and idea to consider along with others.

With respect, 10thtx

[pdf64]

10thTx, a 22k load on the 5F6A tonestack seems to have a big effect on tone control ranges (try it in TSC)? A dropper resistor before the 22k would help a lot, eg 470k - 22k potential divider.

[Luthierwnc]

I see the possibilities. Hope you're well, BTW. Is the Send pot a trimmer? That's where I'd put the Neunaber. AT 12 VDC it handles line-levels. If it bogs down I might put the trimmer on the send entrance and run it straight into the recovery with a 220k grid-leak.

This will be a head serving either 8 or 4 ohm cabs so I made a couple changes for the configuration. Bias will depend on whether the PT has a dedicated tap.

Looks like the little caps on either side of V2b are knocking down some hash. I used the stock 270p's on "D" amps but never experimented past that. I've thrown a 1meg resistor across single volume versions of 2-pot CF entrances to replicate the ground reference of the originals. Sometimes dimed is too hot but the 5751 might fix that.

I threw a "Purist" switch in as a 3PDT mini but there is probably a better way if I think about it more. Not sure it won't pop wickedly with the phase change but I've certainly had more expensive failures -- and then I still have a switch -- maybe a 10 uf bypass cap on V1b K.

Also attached is my version of the T-Lite 5879 OD we kicked around a couple years ago.

Cheers, sh

[10thTx]

There isn't really a send pot per say just a 22k resistor to ground. Originally I had a 250ka pot there where the 22k now is but found this simpler and more to my liking tone wise. And I found I wasn't adjusting the 250k send pot using the delays and reverb pedals.

It has a return pot and level pot.

With respect, 10thtx

[pdf64]

OK, but as Luthierwnc has added a true bypass switch, it should be bourne in mind that the frequency response from the tone stack may be rather different, fx loop bypassed cf fx loop engaged.

[Luthierwnc]

Has anyone tried pulling the signal off one of the plates and fed it back in at the PI with a blend pot (like the Hoffman tweed reverb circuit except further upstream)?

Here's an old musing on the cathodyne Fenders of yore but with the dual pentode/triode circuit in my first schematic. It's mostly on here to show how the circuit bleeds back into the mix early in the circuit. sh

[10thTx]

I like that idea of the blend pot with the reverb! That's a cool idea.

with respect, 10thtx

[Luthierwnc]

Maybe something like this, sh