reverb help

DDR4LYF · 2013-04-17T15:39:57+00:00

I am building a spring reverb with a spring tank that can get built into a pedal board. I bought a spring tank and found a circuit call the stage centre reverb. I built the reverb and now it mostly does what it's supposed to, but there is a crazy ringing sound that is being created over the sound of the guitar and reverb. It uses a charge pump to get the +9V and the -9V. Could that be the culprit? The reverb sound is a very saturated sound, which makes me feel like it is driving the springs a bit hard and so there is this awesome thick wash of reverb under the horrible ringing whine that is coming out. Cool, but there has to be a more subtle setting as well, I think. I suspect that the ringing and 'over-driven' sound might be related, but I don't really know. I also have the wrong pots on, which will get changed soon. I don't think they would do any damage, but again, I'm just a circuit copier at the moment. I get the concepts, but can't do any real calculations... Any help would be so much appreciated!!! schematic my circuit Up close top left is the charge pump and at the bottom is the reverb circuit. The charge pump chip is not the exact one specified, but has the same outputs and leg names, is there something I have to be aware of with swapping chips? As for the tank, the input impedance is 310 ohm output impedance is 2575 ohm Input insulated, output grounded. Not sure if anyone can tell anything from the pictures, but any advice on what to check would also be appreciated.

Johnny-B

DDR4LYF wrote "Holy rusted metal Batman, the reverb works!"

The chip was wrong! I just got the new one today and it works! I don't have time to test it properly right now, but that will come in time!

Thanks so much to Attila Barath, TomCat, Alan Ratcliffe and especially Johnny B. I would never have figured this out myself! You guys rock!

Well done, Sean. It was a pleasure to help and I learned some things too. By the way, the TTT boards have been reshipped. I'm expecting them in about 2 weeks time.

DDR4LYF

Johnny B wrote Well done, Sean. It was a pleasure to help and I learned some things too. By the way, the TTT boards have been reshipped. I'm expecting them in about 2 weeks time.

That is AWESOME! Thanks Johnny!

Attila

Thanks for the mention .....but kudos goes You and "Johnny the Pedal dude " ..... well done gents

kevjones

Post a pic and a sound clip. Maybe some guys here might buy one or two from you.

DDR4LYF

kevjones wrote Post a pic and a sound clip. Maybe some guys here might buy one or two from you.

Ha ha! Maybe yeah... I will post pictures when I have it inside an enclosure of some kind. right now it just looks like any other circuit board, just messier... (I deliberately put longer wires on so that it can be built into a pedal board easier.)

Anyway, the pedal works, but there is a distinct volume boost when engaged. Should I try change one of the opamp stages' volume output with a trimpot or just stick a volume control on the end like a guitar's volume control? I have other pedals to do the volume boost thing, so this one should just stay at a unity volume. Anyone with a bit of input on this idea?

DDR4LYF

Update! So the volume was a bit high when the effect was engaged and I didn't want to just stick a volume control on the end cause of the dreaded tone suck that haunts the EB VP users. (Maybe not haunts... maybe mildly annoys...)

Thanks to my awesome little brother, he showed me which resistor changes the last opamp stages volume. So I had some random pot with an odd resistance value, which happened to be just in the range I was after. I placed the pot in as a variable resistor in the opamp feedback loop and voila! A volume "dimming" control (can't go to zero). Now it is set to a unity volume and will then be sealed inside the enclosure when I eventually get around to building it. It's in the pipe lines guys!

I really hope to get some pics and a sound clip for you guys to give me some feedback on. It is quite a wet washing kind of sound, which I like a lot! Can't wait for this to be a part of my pedal setup! For now, it's just sitting on my project shelf like an orphan waiting for a home to play in and make joyful sounds to any who will listen.

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