Spring Tank Reverb and driver module DIY

DIY STUFF
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There was no thread about driver module for tank reverb, so

i still have 1 tank and projet to make a module driver for my future case 5 (yes i know the future 4 still not finalized but all are adjust, btw there is already not much room left in the implementation of the 5 … on the paper :slight_smile: )

i find some schematics, to compare them …
this one one (from ?)

Spring-Reverb (1)
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and this one that caught my attention because it seems to be able to work with several different tanks (read in article and comments).
TOMBOLA :

schematic-2019-02-27
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tombolaSpringReverb

Link with all infos : https://ua726.co.uk/2012/07/08/tombolas-diy-spring-reverb-driver-circuit/

Does anyone have a tank reverb in their modular ?
and which driver module are you using / building ?

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Oh I’m currently working on something similar, I found a broken lamp that seems quite springy when I hit it:

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I have already glued in place two piezo disks, now I need to do the electronic around it.

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I do not have a tank reverb (yet). But I noticed in the first schematic 2 electrolytic capacitors (elco) which are connected in series with reversed polarization (C2, C3 and C4, C5). That seems unwise to me. I would suggest using one 10 uF a-polar capacitor instead in each case. Elco-s don’t like reverse polarized voltages.

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That’s a common trick to make an non polarized capacitor with two polarized in anti-serie

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I’ve seen this on occasion in schematics (of unverified origin) but that does not mean that it works. Depending on the voltage you use one of them will get a reversed voltage that it will not like. So how is this going to work in actual practice?

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Love this idea, please post a video when you have it going

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That first schematics is from Kassutronics :

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Here is someone that will explain it better than me: https://electronics.stackexchange.com/a/21932/200523
You can also add diodes in parallel to be extra sure.

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Adding those diodes makes sense. But still, it will not be a 1 to 1 replacement of an a-polar capacitor, I think.

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Three DIY Eurorack spring reverb modules, schematics available online:

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I have the music thing module. I should maybe try some other builds, since I have several more tanks lying around.

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I’m keen to contribute the this thread more once I get home from Christmas holidays.

I finally managed to find some of those kids echo mic toys in the local dollar store. I’ve got a piezo pickup with a high-z amp made from a fet from an electret mic and a cheap $1 amp chip driving some tiny speakers as the driver(s)
Seems to work pretty good so far.

I like the lightbulb idea and curious to see if it works. I’m pretty sure I have a fusor bulb from an ink jet printer in my junk box. Might have to sacrifice it. :thinking:

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for experiment spring stuff i post some things here

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Great idea! :slight_smile:
Maybe some basic information (if you don’t already know) that would have saved quite some time in my experiments: spring reverbs are driven by current, hence they are very non-linear when driven by a voltage source. More information is here: http://www.valvewizard.co.uk/reverbdriver.html
I have tried the quick and dirty trick with the small capacitor to manage the non-linearity, but I was never too happy when coupled to a small OP amp like the TL072…
Hence: are you intending to go with a current source? :slight_smile:

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I recently bought a used Reverb Tank on ebay with a low impedance of 8 ohms. I was going to try out the schematics from Spring Reverb as it draws more current than the ones with higher impedance and an op amp is not suitable for it.

Does someone got any experience with this?