Boss Metal Zone MT-2 Mod

Photo 14-08-2016, 9 51 53 PMAh, this infamous Metal Zone! The pedal everyone loves to hate.

As much as everyone bad-talks the Metal Zone, it probably has one of the most sophisticated EQ sections of any Boss pedal – probably why it’s so easy to get a shitty sound, which it has (unfairly) become famous for.

My good mate Bob asked me if it’s possible to mod his MT2 to be more suitable for bass guitar. I did some research and came up with two ideas: one to smooth out the EQ and remove some top-end fizz, and one to blend the clean signal with the distorted one.

To smooth the EQ and remove the top end fizz, I did the following:

  • C35: Removed
  • C34: Replaced with a 0.047uF (stock was 0.027uF)
  • C25: Removed

Here is a quick demo on bass guitar. Bypassed, then Stock, and then Modded.

I’ll record some better quality ones later – and some on guitar too.

As you can tell, there is a massive difference.

The next thing was the “blend” control. With some help from the guys at DIY Stompboxes, I ended up with this:


C1 is 10uF, and the pot is 50k. Here’s where it got tricky. There’s not much spare space inside the Metal Zone, so getting the extra pot to fit was a challenge. After drilling holes and hacksawing the enclosure, it all squeezed in.

So now it has a glorious knob sticking out of the side like a bolt on Frankenstein’s neck.

Photo 14-08-2016, 11 26 19 PM Photo 14-08-2016, 11 26 32 PM Photo 14-08-2016, 11 26 40 PM

I believe these mods have improved the pedal a great deal. With smoother, less harsh EQ it’s even possible to get some nice blues tones with the gain down low. The blend knob works great, and will be awesome on bass.

If you want a really good technical explanation of the MT2, check out

For reference, here is the schematic and board layout:

boss-mt2-metal-zone-schematic  mt2_05