Video demo of a Boss HM-2 I modified and am selling via eBay, auction ending May 29, 2012. I had another earlier version of this pedal, the Japanese-made edition. I found the main performance difference compared with this Taiwanese-made edition, is the ("inferior") Taiwanese has about 25% more output.
Text from my Facebook page album of it:
"The operational amplifier is where a lot of the pedal's tone is shaped, especially for distortion units. Boss uses Mitsubishi M5218L Inline Format Op Amps as stock in several of their pedals, such as the DS-1 Distortion, MT-2 Metal Zone, GE-7 EQ and the CE-3 Compressor. Sounds okay, but can sound a little muddy in the upper or lower midrange. If you swap out this op amp with a higher quality one such as the Burr Brown OPA2134PA, the frequency range opens up a lot more. I was curious to see if the HM-2 used the same chip, and they do. So I used some mod PCBs meant for MT-2s and installed them into this pair of HM-2s— making these THE ONLY TWO OP AMP MODDED HM-2s IN THE WORLD! ...For now."
