Spring reverb driver

[cnspedalbuilder]

Hello, I have had an unbranded 4DB2C1D reverb tank sitting around and at some point would like to make it work, probably as a standalone, or perhaps in a small amp build. 

But assuming I do it in a standalone, can you suggest a good circuit to drive it with? I just need simple, solid state, minimal pots...i.e., a quick and easy build, ok if its a little lo-fi.

Thanks!

[cnspedalbuilder]

Just wanted to bump this. Here are the details on the tank:

Type: Long (2 Spring) tank
Decay: medium decay
Input: 250 Ω
Output: 2,250 Ω
Connectors: Input insulated/output grounded

Also, I found a PCB from OP-Electronics that claims to work for this tank, but they are in Europe. Also, it has a few more bells and whistles than I need. Is there a simpler circuit that should work or should I just go with this one?

[PRR]

http://sound.whsites.net/articles/reverb.htm

[mac]

Nice article.


Laney VC/LC 30 reverb driver circuit is very simple, but  input is grounded.

https://www.diyaudio.com/forums/instruments-and-amps/285055-transformerless-reverb-tank-tube-amps.html

mac

[cnspedalbuilder]

PRR thanks. So basically combining Fig. 5A and Fig 9 would be sufficient? Would it make sense to add an LPB or something to push the input harder?

Also, can we get the +15V and -15V voltages with a straight 9V power supply? My first thought was the 7660 but looking at the datasheet and it looks like it will not be completely straightforward to get that output from a +9V input.

[Peter Snowberg]

PRR thanks. So basically combining Fig. 5A and Fig 9 would be sufficient? Would it make sense to add an LPB or something to push the input harder?

Also, can we get the +15V and -15V voltages with a straight 9V power supply? My first thought was the 7660 but looking at the datasheet and it looks like it will not be completely straightforward to get that output from a +9V input.

Also check out Fender's solution: https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Hot-Rod-Deville-Schematic.pdf

Your problem sounds like it will be driving the tank rather than driving the tank driver. Consider the tank is a mechanical device hooked to a power amp even if it's a small power amp. The 7660 won't have nearly enough current to make it go. Ohm's law says output Power = Voltage^2 / Resistance so if we consider the absolute maximums, a 30 volt swing through 250Ω dissipates 3.6W while a 9 volt swing through the same 250Ω will only dissipate a little over 0.3W. The actuals from the signal here will be much smaller but the relative dissipation remains relative so you can see why there are tanks with 8Ω coils for low voltage use.

The 7660 is a switched capacitor device and inherently quite a bit quieter than a boost converter for light loads provided you use big reservoir caps but they're not made for power applications beyond 10s of milliamps max. and their ripple quickly gets bad as you pull more and more from them. If I were you, I would look into switching converters to derive a true +15/-15 supply with some nice reservoir caps for the tank driver but I would only look at higher frequency devices running between 500KHz and 2 MHz. The higher frequency devices use smaller magnetics and require more expensive fast diodes, but they move the noise well above the audio world. You should still check for and filter out high frequency noise on the outputs to insure you're not messing with oversampling ADCs like you'll find in the majority of digital pedals.

Switching converters are really easy these days and I would recommend LTSpice for design and simulation.

https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

Linear always had more pricey parts, but the performance was there.