for those interested in building a spring reverb...

[joelindsey]

...use shielded RCA cables connect reverb tank. Spent the good part of a day hunting down the source of terrible hum and noise, only to find it was my unshielded RCA cables.

My reverb is pretty much this here: http://sound.westhost.com/project34.htm
except I adapted it for use with a single ended supply, cut out the mixing section and added a tone control. Still a fair amount of hum, but it's tolerable. I've been using a 9v supply, however I've noticed if I increase the voltage (no higher than 18V for the LM386's sake) the noise is reduced.

Just figured it was worth posting in case somebody runs into this problem in the future. I'll upload a photo or two tomorrow.

[petey twofinger]

which schomo did you use ?

is it bipolar p.s. ?

i want to do the same thing , have a tank here i want to throw in a mini amp (portable . so 12 volts max .

how noisey is it ?

no mixer , only tone ?

[joelindsey]

which schomo did you use ?

is it bipolar p.s. ?

i want to do the same thing , have a tank here i want to throw in a mini amp (portable . so 12 volts max .

how noisey is it ?

no mixer , only tone ?

I used the third photo from the top. It was made for a bipolar 15v supply, I used a single ended 9v supply. To do this, I added another 100k between the non-inverting input and +9V. I intend to use a 15v supply in the future, simply due to the noise I mentioned above.

I took out the mixer (opamp in the lower right corner of the schematic) because I don't need it. Nothing but the wet reverb sound. The noise is tolerable for now. In the future I'd like to increase the gain of the recovery stage so it may become more of a problem. 

Keep in mind that the efficiency of this circuit largely depends on the reverb tank itself. Mine is an accutronics taken out of a twin reverb with an input impedance of 8 ohms and output of 200 (i think).

[petey twofinger]

i would really like to figure out a simple 9 volt solution to the reverb tank dillema .

[Gurner]

i would really like to figure out a simple 9 volt solution to the reverb tank dillema .

Just use a BTL in lieu of the modest LM386 (you'll need to rejig the circuit a little...but not as lot)....you'll get 4 x the power off the same voltage rail vs an non BTL amp like the LM386  - of the top of my head, something like a  TDA7056.