18v Help

[Kinski]

Would like to build a spring reverb unit. It's recommended to use 18v. Requires both a + and - connection. Anyone know how to get -18v in addition to the stock +18v.

Reverb here, scroll down:
http://www.diystompboxes.com/smfforum/index.php?topic=99803.msg881659#msg881659

[dexxyy]

I could be wrong but I think what you need is +9v & -9v to get your 18v. I think you need  this and continue the +9v to the +v spot on the board.

[Kinski]

Ah, perhaps you are right. I'll look into it. Thanks.

[Freppo]

Yup, Dexxxy is right.

A negative voltage inverter from 9v is what I have been using with my springreverbs.
I've been using the same layout.

Dwell pot really need to be a C50K and the lug are numbered wrong.
Also, none of the pots should go to ground as it says on the layout.
Other then that it works fine and sounds nice (depending on the tank). :)

cheers
/ Fredrik

[Kinski]

Hmmm...glad to hear you got it working. I so far have had no success with this layout.

So no pot lugs go to ground at all?  The RCA Jacks on the reverb tank should be grounded though, yes?

[Kinski]

Also, what reverb tank do you find works the best. I'm temporarily using a tank that has 190ohm impedance, which I believe is a bit low.

I hope to get this circuit working....

[Kinski]

The pots work with or with out the ground connections.

I can hear my unaffected guitar. If I hit the springs, I can hear them faintly.

If I wire nothing to the REVERB TANKs out jack, and wire the BOARD TANK OUT to REVERB TANK Input, I get my clean guitar, no reverb. But if I touch the springs, they are ring loud and clear. So My tank is working then, right?

I don't know what I'm doing wrong...

[Kinski]

Hmmm....plugged it into a different reverb pan from another amp. Reverb sounds really awesome. Except that its reverb is really distorted. So could all of these problems just be an impedance issue?

[Freppo]

You should connect the "board tank out" to the output of the reverb just as it says and same with the input. That is working for me. And yes, the tank needs to be grounded (the rca connections)

For me, without connecting the ground of the RCA connectors, the circuits sounds like a massive LOUD higain distortion.. try connection the board tank in directy to the board tank out and see if you get effect. Otherwise there might be something else that is the problem

I have no idea what impedance my springs reverbs are.. can't remember the model, gonna see if I can find the reciept. :)

Good luck
cheers! / Fredrik

[Freppo]

oh, probably an impendece issue then.

However, it does get a bit distorted for me aswell with the dwell knob on max..
Did you see my other thread?

http://guitar-fx-layouts.42897.x6.nabble.com/Can-you-build-a-spring-reverb-in-a-stompbox-td5758.html

I have a link there to some samples of my mini-spring reverb.

[Freppo]

I did omit the mix knob completly.. Just removed the mix wires so that the reverb is 100% wet.
I added this simple buffer/splitter circuits inside my reverbs insted:


Makes and more usable sweep, for fully off to fully wet :)

Just connect it like this:
output 1 of the buffer to a 50K log pot lug 1
output 2 of the buffer to the reverb input
and the reverb output to the 50K pot lug 3
pot lug 2 to output

Would probably be easier to first breadboard the stage center reverb and modify it. But I didn't bother.. Been using that splitter in alot of different builds. Doesn't take much extra space. :)

[Kinski]

I have everything wired up exactly like the layout, except neither pot goes to ground.

The pan im using now that sounds "great" bu really distorted has an 8ohm impedance. The tanks that I can't get really much sound out of has a 190ohm impedance. Documents say a 310ohm impedance is best...

[Freppo]

That's too bad.

The reverbtanks i'm using is a Accutronics Reverb Tank 8EB2C1B.
And the small one I found, which I don't know anything about..

cheers /Fredrik

[Kinski]

Cool. That 8EB2C1B is 800ohm impedance.

Maybe I'll try to buy the correct reverb tank.

Quick question, when you use this reverb, do you notice any volume boost or volume loss? I'm hoping that when I add this to my signal chain, I would have about the same volume as if it were out of my signal chain.

[Freppo]

With the 8EB2C1B the volume is just about the same.
It does get alittle bit louder and a bit distorted with the dwell pot on max.
But I didn't even bother adding a volume pot on the rackreverb.

With the small reverbtank I found it does have a small volume loss with the reverb at about 50% wet and the dwell down. But it's fine anyway. I can add upp the lost volume by increasing the dwell. I regret adding a volume pot for the small reverb though.. It just stays maxed... :P