This isn't a dumble but seeing how few people read the Plexi board and how many people asked about a reverb on the dumble I decided to post it here.
The story goes that I want some kind of a reverb, I was looking around for digital reverb pedals but they were expensive, like more than your average distortion pedal in fact. I seen too many tube amps with spring reverb but nothing Nik or anyone else for that matters offers a kit that has built in reverb, so I decided to find a schematic and do it myself. I got this schematic from the gallery section from rjgtr on 18watt.com. Anyways here is the schematic...
I figured the diagram and schematic is simple enough that I could do this. The problem is there isn't enough space inside the 50 watt plexi for another circuit board because everything is crammed inside just right and with the PPIMV and unbuffered loop it's about as much as I can put in it. So I used an electrical junction box for the tube as well as circuit board because the hole on top is just perfect fit for a ceramic preamp tube socket. I am really pushing it however some of the caps are kinda large in size. I used a small breadboard for all the parts and had to somehow manipulate the leads to get things stuck on the board. Just follow the schematic and connect the proper leads to wherever it asks for. pin 4,5 and 9 are heaters. Just connect them to those pins on your amp's preamp tube. Pin 6 goes to preamp B+ which means where the preamp tube pin 6 is connected to before the 100k resistor. Pin 1 is connected to the blue wire on the reverb transformer and the red wire goes to the output tube screen supply. Yes there are 400+ volts but trust me it works, I done it on my plexi (395 volts at pin 4 of output tube) and it makes the reverb more live. If you can't figure out where it goes on your dumble just wherever the screens are hooked to or wherever the choke is connected to.
Use tank type 4,8,9ABXXXXX you can use whatever you like but make sure it has an input impedance of 8 or 10 ohms. I used 8AB2A1B or whatever they used in the mesa boogie...
Finished project. I decided to place the tank on top of the cab because its crammed inside. The overtone special is really crammed though so maybe ask nik if you can get a larger chassis or something to make space for the extra tube and parts.
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