EHX Micro Q-Tron + Buff'n'Blend hack

I own an Electro Harmonics Micro Q-Tron, but it always bugged me how the volume increased so much when activating the pedal. To counter that, I ordered a “Buff N´ Blend” (link to Musikding – no affiliation! – originally from GuitarPCB), which allows to mix a dry and wet signal of an effects loop. Originally I wanted to put it into a seperate enclosure, but while building I found out that it does fit directly into the Micro Q-Tron.

Here’s a demo video:

To do so, just replace the original 3PDT switch with the “Buff N´ Blend” switch/PCB. The original switch is connected to the main PCB with a ribbon cable with 6 wires. Unsolder that cable and create connections to the B’n’B as follows (looking at the back of the box, left to right):

• 1) is “Signal in” – connect to “In T” on the B’n’B
• 2) is “FX in” – connect to “Send T” on the B’n’B
• 3) and 4) are used to switch the pedal on and off, with 3 most likely being ground. I soldered those to the middle pin of the B’n’B PDT switch and the right connector of D1. This closes the connection when in “non-bypass mode” and activates the pedal. (It’s also possible to just “short” those, if you’re lazy…)
• 5) is “Signal out” (going to the “Amp” jack) – connect to “Out T” on the B’n’B
• 6) is “FX out” - connect to “Return T” on the B’n’B

Since I always use external power supplies, I got the 9v for the B’n’B from the pedal power input. I soldered GND to the left pad of diode right next to the power jack on the PCB and +9v to a little open pad a little bit above that same diode, also on the right side of the power jack.

I did not use the LED at all, since the one of the Q-Tron still works as expected.

Finally I needed to put C2 on the opposite site of the PCB (where the PDT switch is) and bend Q1 down to make it fit into the Micro Q-Tron enclosure.