Boss - Metal Zone MT2 mods

[astrobass]

IC1 and IC2 are in the active tone stack. They're probably not contributing a noticeable level of noise but they are in the signal path so if you replace them with quieter devices you might notice a small difference. It's probably not entirely worth the effort though.

Here's a demo my buddy did of his MT-2 after I modded it: http://soundcloud.com/rdforsyth/mt2-mod-before-after

I just did the Bogner mod, as it addressed the things he found most problematic with the stock pedal (the highs, the hissing).

[Shawnee]

Thanks astrobass- That's pretty much what I suspected. It's not really that noisy since I changed IC3 and 4 so I'll probably leave well enough alone. Your mod sounded great.

[skylark44]

Anyone know if either IN34 germaniums, or BAT46 diodes would be good sounding clipping diodes, in my Rocktron Metsl Planet? Also, can I do the same mods to it?

[skylark44]

I just built a 12-position rotary switch, with different clipping diodes...this should work, instead of just swapping out D3, right? I don't want to drill a hole in the pedal, if it won't work. I might also add a toggle switch...to go between different diodes, for the other clipping diode (D4). Does it make a difference which one I put the rotary switch in (D3, or D4)?

[skylark44]

Bump...any ideas?

[astrobass]

No, it doesn't matter at all.

If one pad from D3 goes to the switch, and all of the leads coming off the switch are collected and wired together to the other pad for D3, whichever one you have selected will function as D3.

However, pay close attention to orientation, particular vs. D4. The two must be oriented opposite from each other.

[skylark44]

Thanx...that's what I did...and it works perfectly. Now I can experiment with any combos I want...I might even make another similar switch for the other diode (D4), now that I know the first one works. I might even do this with all of my distortion/overdrive pedals.

[astrobass]

Thanx...that's what I did...and it works perfectly. Now I can experiment with any combos I want...I might even make another similar switch for the other diode (D4), now that I know the first one works. I might even do this with all of my distortion/overdrive pedals.

This is how it starts

A good trick is to buy sockets. You can get rows of socket pins on ebay for a couple bucks, clip off one with your wire cutters, and solder that into the board in place of one end of the diode. So you need 4 to replace two diodes, but then you can swap one diode after another.

1N914/1N4148, 1N60, 1N4001 and 2N7000 MOSFETs wired as diodes all sit +/-50 of 650 mV, and the 1N34a usually sits around 300-350 mV. LEDs will sit up around 1.6-1.8 V usually. What I find usually works best is either:

A) Mixing types at about the same voltage drop, so a 1N60 and a 1N914, or a 1N4001 and a 2N7000, etc. The 1N4001 doesn't sound as much like the 1N914 as most Si diodes do, it's slower acting and has similarities to Ge diodes. Combining a "fast" or "bright" sounding diode with a slow one results in one side of the wave being clipped differently from the other, and this can add pleasing complexities to the distortion.

or

B) Mixing voltage drop-offs so that one side is about double the other. So a 1N34a and a 1N914, or a 2N7000 and an LED. It'll seem to have additional harmonic content that way. I find the effect isn't very pronounced until you get to having about a 2:1 ratio between the two opposing diodes.

I've landed on a small handful of options that I like and try first when modding a pedal.

[skylark44]

Thanx for all of the help & ideas...I'll probably just make another 12, or 6-position rotary switch for it.
That way, I can try any combo I can think of. Merry Christmas!

[astrobass]

Thanx for all of the help & ideas...I'll probably just make another 12, or 6-position rotary switch for it.
That way, I can try any combo I can think of. Merry Christmas!

No problem, you too!

[Meddled]

Hello all,

I had to hunt through my email list to find my log in details.

Are there any surefire mods for this pedal that would make it work on bass? I understand the Keeley mod makes it more bassy, but I presume this is 'guitar bassy' not 'bass bassy'. I guess that increasing the input and output cap values to 1uF is a regular mod for guitar-to-bass pedals. However I imagine the pedal would work best for bass if it had quite a wide Q on the bass control and didn't filter away anything below 100hz or so, as most circuits usually do.

Many thanks in advance.

[Thomas Verbeeck]

Does anybody knows something about modding the electro harmonix metal muff? I've heard that the schematic was super close to that of the boss mt2.

[skylark44]

I built a second rotary switch, for d4 (6-way)...but it doesn't seem to alter the sound of the distortion much...any ideas why? I also added a switch to turn on/off the "harsh" (disabling c35 & c25)...and that works.

[astrobass]

Make sure that the diodes connected to your D4 switch are in opposite orientation to those connected to your D3 switch.

[skylark44]

I'll double check everything, but I'm pretty sure they are. Thanx

[skylark44]

It's wired up correctly...any thoughts why it's not working?

[astrobass]

It's wired up correctly...any thoughts why it's not working?

Sorry for the late reply.

I have no idea.

Good photos would help. A few other things to test:
Disconnect the D4 switch completely. This should result in a noticeable change to the sound.
List which diodes you have in switch positions 1-4 for D3 and D4.
List which positions you feel don't result in much difference.

When you're comparing two diodes of relatively similar forward voltage drop, you'll find the differences to be much more subtle. A 1N4001, 1N60 and 1N914 all sound fairly close to each other. The 1N914 will sound noticeably brighter than the other two, but it's not nearly as profound as comparing it to a 1N34A or an LED.

[davizerrat]

hi guys,

New ideas about the triple switch modification have emerged? I am researching on how this mysterious system clipping and seems more a secret temple of Dendera.



I keep thinking about how to achieve that sound but I can not figure out how to decipher.

[davizerrat]

Sorry!

I take this opportunity to introduce myself I'm new here. my name is david and I'm from barcelona spain.

Thanks, thanks and thanks guys.

[davizerrat]

Guys ! This schematic is a good idea to do... Its running in my mt-2 3 types clipping !!

Thanks