So I knew a guy who had torn apart a Marshall amplifier, which have nice Accutronics spring reverbs mounted within them. They have that very cliché spring reverb sound, that kinda fake-ish but serviceable reverb. In my infinite wisdom I decided to try and backwards engineer the reverb tank into a send from my mixer, so i can send whatever I want through it.
This is an Accutronics type 8 spring reverb, it is the bane of my existence. I started by finding out its specs on the Amplified Parts website.
After some research, I ended up finding this website, apparently i’m not the first person to try and do this. My utmost thanks to Rod Elliot at ESP.
so lets get to the actual development process, making this bad mf in KiCad and creating a custom PCB to make it actually work! here was my process:
So duplicating and recreating the diagram wasnt actually that hard, it was more tedious, and working my way through the errors. KiCad’s interface is confusing, but luckily the internet was on my side! With enough help from forums and diy sites i got my prototype working theoretically.
Next up was finding suitable elements for everything, like resistors, capacitors and inputs/outputs, TInytronics was my saviour in this, and i shall never forget what they did for me. The IC’s were easy enough, it just that the voltage convertyer on its own was like 15 euros off amazon and that did sting a little.
Designing the PCB was very fun, it was a lot of creative problem solving within specific bounds and i got to put some fun deisgns on it as well. i did run into some errors when it came to space, as teh RCA outputs are pretty sizeable, but i managed to get it all to fit.
Ordering was pretty simple, I got it in purple because why not, and then waited for like a week. I got five copies, all exactly the same and hermetically sealed, all in all the print went well, no rounding errors.
Then one day later i spengt like six hours soldering and cursing and I had the working thing in my hands, it was pretty exhilerating to see the fruits of my labor, the spring sounded a little smaller than i remembered, but with some gaining and compression it sounded exactly like how you’d expect an accutronics type 8 spring to sound.