Hey I recently built Tombola’s diy spring reverb and kind of had some success with it, but not exactly. I am able to get a signal through, and the potentiometers work for the most part, but I am not really getting a reverb output. I’m not sure if it’s the tank I’m using which is a Belton, 8EB2C1B, Medium Decay, 3-Spring that has a 800 ohm input and 2,575 ohm output. I even changed the resistor from 100k to 68k on pin 9 and 8 on the Tl074. Even with the blend knob turned all the way down, which I guess is meant for more reverb, it still is a really dry signal. I also tried adding the additional feedback circuit, tapping the input of the circuit to pin 7 of the TL074 then the output from the CGS DC mixer onto the same trace as the audio input. Can anyone help with this?
I think the reverb input must not be grounded to the tanks case. Did you checked that?
In general there might be some adjustments necessary for different input impedances, see Spring Reverb
Here is the original link for reference: Tombola’s DIY spring reverb driver circuit - ua726
When you said reverb input, do you mean like the audio input jack or as in the two rca jacks I used, both of them should not be grounded?
The 8EB2C1B has the input insulated and the output grounded to the metal case
Yeah I just isolated the reverb jack socket that is on the reverb RTN tip trace from ground, and now I can’t even hear the coils when I touch them, but when I put it on ground again, I can hear the coils again. In both cases I still don’t really get reverb
I’m not familiar with the particular circuit, just with reverb tanks.
The side that goes to the reverb return (reverb tank output), should be grounded to the circuit ground. Don’t remove the connection. It is also internally connected to the metal casing so you can mount the tank on rubber shock mounts.
The side that connects to the reverb send (tank input) should not be grounded. It should connect to pins 1 and 2 of the opamp and the resistor and capacitor parallel to it.
Put the blend knob halfway so you are sure there will be wet signal (in case the potentiometer pins are switched around)
Do you get any sound when you touch the springs or move the tank?
If you hear sounds then the recovery circuit is working and you have to check the drive circuit.
If you put signal in the input and the drive circuit is working you should be able to feel and hear the drive coil moving. It will be pretty soft though.
If this is the case then you have to check the recovery circuit
Hey that actually worked and now the reverb sounds amazing! Thank you so much!
Hey nice you’re welcome 