Dumblelator with Spring Reverb

[LegendaryCheddar]

Hi Everyone,

I've been trying to incorporate a fender-style spring reverb into a Dumblelator circuit, and would appreciate some help.

I have taken the standard 1x12AX7 Dumblelator, and thought that I could use the first triode as a phase splitter: So the plate of V1A is the reverb driver, with coupling caps and a Dwell control (I 'think' this would be safe from B+ if theres a cap either side...). Then the dry signal goes through a standard 25K-8Ohm reverb transformer (like the Hammond 1750A), through the reverb pan, and back through a standard 0.1uf coupling cap and dropping resistor (I copied the AA1164 mostly), to rejoin the wet signal from the buffered FX loop before the recovery stage of the Dumblelator.

Questions for you legends:

1. Will it work?
2. Is the Dwell control between plate and reverb transformer primary safe if decoupled both sides?
3. Does the phase flip between (V1's plate-to-reverb/cathode-to-fx loop) matter when the reverb pan itself screws around with the signal anyway?
4. Anything massive I have missed?

thanks in advance!

[Richard1001]

Your schematic will most definitely not work for several reasons, but the most important one is that there is no signal on the anode of the first triode since it is directly connected to the B+.

The easy way of adding reverb to a dumblelator would be to use a solid state reverb module from accutronics. I think Fuchs uses those too.

[LegendaryCheddar]

Thanks Richard!

I would put a 220k resistor between the first plate and B+, would that solve that?

Im a beginner so please tell me the other reasons why it wont work!

Im also trying to copy the reverb from a JMP 2144, which is only two triodes of a 12AX7.

[nuke]

Yeah, ditto on that schematic not working.

If you want spring reverb, another approach might be lifting the solid-state op-amp based circuit used in the Fender "Blues" series, like the Blues Junior, Blues Deluxe, Deville.

The circuit is pretty simple, inexpensive and both short and long pans of suitable impedance are readily available. You'll need +/- 15v power supply. But you can get a simple solid-state power module that runs off mains AC voltage to do that. Doesn't need a bunch of current. The circuit is simple enough to build on a "strip board" that resembles the layout of a breadboard, readily available from "maker" suppliers like AdaFruit. The board and power supply would easily fit in a low-profile rack enclosure. Just need a spot for the spring tank.

[FUCHSAUDIO]

Cute circuit, the errors or omissions have already been noted. Just for the record, I don't use the Beltron brick and can't fit a coil inside a Verbrator .
I use the Spin Semiconductor chip (which many people use in pedals and rack stuff and amps). 16-Bit digital and analogue in and out. It's fantastic.
The chip is not cheap and only made in SMD form, but worth the trouble.