Riptide Reverb - very little effect until power cycle, or spring crash!

[Toy Sun]

I've built 2 of these, here is the Riptide info:
https://scientificguitarist.wixsite.com/home/riptide-spring-reverb

Both work great (except for cannot get rid of charge pump whine).

The first one used the super tiny tank:
https://www.tubesandmore.com/products/reverb-tank-accutronics-amc2bf-2-spring
Input Impedance: 150Ω
Output Impedance: 1500Ω


2nd one uses:
https://www.tubesandmore.com/products/reverb-tank-mod-mn-8bb2c1b-medium-decay-3-spring-mini
Input: 190 Ω
Output: 2,575 Ω

Note that I am using an Incandeza Bypass for the 2nd one. Both wired to NOT have tails.

I have the strangest issue with the 2nd one. There will be very little effect (output level is fine, just not much 'verb) until I either:
Power cycle (unplug, replug DC) or crash the springs pretty hard. That then brings back the effect, for a while. I'm thinking this has something to do with a capacitor and grounding, but that's the extend of my ability to analyze.

Any ideas?

Thanks,
John

[Rob Strand]

Probably a bad connection on or inside the tank.   Try wiggling and checking the connections.

If you have a small transformer-based (ie. unregulated, non-switchmode) wall-wart you might be able to place it near the reverb spring output coil to create some hum.  If the hum changes when in working and non-working state that will possibly narrow the problem to the tank output signal path.

[PRR]

> until I either: Power cycle (unplug, replug DC) or crash the springs pretty hard.

Yeah, tarnish in plug or joint. Same reason you sometimes have to wiggle the plug in the guitar or the amp.

[Toy Sun]

I assumed bad connection and have re-done those - the unit doesn't move at all, I use it in desktop. If we consider the two solutions, it seems that one rules out the other: Bad connection in the tank wouldn't be fixed by power cycling...

It really seems to be some kind of lock up - I know it seems strange. Maybe it's with the Incandeza Bypass? Relay issue?

[Rob Strand]

I assumed bad connection and have re-done those - the unit doesn't move at all, I use it in desktop. If we consider the two solutions, it seems that one rules out the other: Bad connection in the tank wouldn't be fixed by power cycling...

It really seems to be some kind of lock up - I know it seems strange. Maybe it's with the Incandeza Bypass? Relay issue?

If the relay circuit is wired as true-bypass then it can't explain why the reverb part only is weak.

Maybe try measuring the DC voltages on the opamps and see if any of the voltages are different when the unit is working and not working.

Having the reverb come back when you crash the springs is a weird behaviour.   (At first I'd be thinking bad connections, bad pot, bad cap, then after that a small possibility of oscillation.)

[duck_arse]

In addition to component selection, Riptide further taps into the vintage tone profile by using a JFET preamp that gives some great color. It's essentially the Dunlop EP101 Echorec Preamp with a fixed gain ....

check that the gate resistor is really there and connecting to ground. I dunno what an Incandeza Bypass is. or does.