Upgrade your MesaBoogie V-twin (TM) version 1 with clean gain adjustment for increasing or decreasing the volume (gain) when your pedal is in clean mode.
This is my contribution to anyone who wants to upgrade their Mesa Vtwin version 1 with clean gain adjustment. You don't have to buy this potentiometer from me to complete this mod although I have made it available for your convenience, this is a fairly easy modification for someone with soldering skills and willing to dissemble their v-twin; it should take about an hour. I don't currently provide full instructions for disassembly and all that because it's fairly self explanatory.
The pictures attached show where to locate the potentiometer, that part is free. This purchase is for the actual potentiometer which is a standard IC component I have purchased in bulk and made available to anyone else who would like to add this feature. I was not able to integrate the toggle switch for modes which is present on the version 2 V-twins.
These are fairly generic guidelines for adding clean gain to an early v-twin floor pedal. It is assumed the person adding clean gain will have mechanical and electronics aptitude. Adding a 1 meg ohm variable resistor (potentiometer) in place of the factory installed 330k fixed resistor will exactly duplicate the clean gain adjustment similar to the version 2 V-Twin pedals.
Remove thumbscrews over tubes, tubes, knobs from Pots, locknuts from pots, 4-screws from housing. NOTE: the headphone selector switch must be de-soldered to get the top half of the case off, you may want to mark which wire goes to the front/rear terminal so you get it hooked back up correctly when re-assembling. Remove board from bottom half of housing.
Installing Clean Gain Pot
Install pot as shown in the provided images. For anyone who doesn't fully understand electronics, you are removing a resistor (which is located on the other side of the board directly behind where I show the new blue potentiometer) and replacing it with a variable value resistor, also called a potentiometer.
Locate and remove the factory installed 330k resistor paying attention to where it was connected to the circuit board. In the images I provide, the new potentiometer is placed exactly where the resistor was but on the opposing side of the circuit board. Notice that I did not use the exact two holes where the resistor was removed from; I did use the lower hole for the center leg of the potentiometer but rather than using the upper hole, there is a visible trace on the board that routes just below and to the left of where I've located the potentiometer. This is effectively the same electrical point as the open hole which remains directly above the potentiometer and is easier/cleaner to connect to. As seen in the image, I have routed the left output leg of the potentiometer over to this alternate connection point and also placed a piece of shrink tubing on the leg to electrically insulate it. The right leg of the potentiometer is simply cut off and not used.
After installing, measure physical location on the board and use dimensions for drilling an access hole in the lower housing (sorry, I no longer have the exact drilling coordinates.)
Alternative concept: You could also use a 1 meg potentiometer of your choice and mount it anywhere you prefer such as the top panel for easier access, then use jumper wires to connect the potentiometer to these same locations on the circuit board after removing the fixed 330k resistor.
I get quite a few hits on this modification, I'd love to hear from you if you find this free information useful! Rock on!!!