Boss - Metal Zone MT2 mods

[ebuprofen]

What is the value of r46? You say to increase value to increase distortion but I accidentally soldered it off when I was trying to remove c35 and it is gone

2k2

[Proco]

Is there any way to get the Keeley mods for the MT-2? I've been digging around the Internet for about 3 hours and nothing concrete... kinda obscure and mysterious mod it is...
The user that posted the mod on the first page... dunno but I think he's wrong, as the Keeley has a 3 way switch and the described doesn't.

Any help will be very much apreciated.

[claytushaywood]

What is the value of r46? You say to increase value to increase distortion but I accidentally soldered it off when I was trying to remove c35 and it is gone

2k2

Thank you very much for your time and effort! you've made my life a lot easier!
Cheers!

[claytushaywood]

hi, some mods :
Diezel mod:

C35 : remove
C34 .047uF
C25 : remove
these three mods remove harsh

C42 1uf
D3 DEL
D4 1n4001
------ make the sound more dynamic and full
C36 .1uf----- EQ more usefull

Boogie/Bogner mod:

C35 a enlever
C34 .047uF
C36 1uF
D3 led
D4 1n4001

EN PLUS:
R46 increase values, more pre-distortion + mids
R41 reduce value you obtain more distortion (470ohms to start)


Mods don't have the same sound of diezel amp or Bogner amp, but it can be better tant the stock sound.



Keeley mod:

C20 .22uf
c42 .1uf
c37 , c39 , c17 , c11 1uf
c8 .22uf
c9 .1uf
c20 .22uf
d3 , d4 LED

Do you have sound clips of any of these mods?

[gkoerselman]

Here is a Youtube demo of the Diezel mod:
http://www.youtube.com/watch?v=v6U3e4V-T3A

and here of the Boogie mod:
http://www.youtube.com/watch?v=qBbfkcWc-I0

[MoonWatcher]

Diezel mod:

C35 : remove
C34 .047uF
C25 : remove
these three mods remove harsh

C42 1uf
D3 DEL
D4 1n4001
------ make the sound more dynamic and full

To give just a hint more mids, try 39nF for C34. But it typically requires that you balance it out by increasing C24 to 47nF, to pull some of the "tin steel treble" off of things.

I also prefer diode combinations that conduct at approximately 8600mV and 9300mV, in an asymmetrical fashion. Gives enough top end detail without blurring/fuzzing things too much, either. Use whatever combos of that you prefer to hit those numbers. I suppose that you could probably offset them to around 8000mV/1500mV with great results as well, but it's so subjective.

Someone mentioned 33nF for C33, and that's a nice touch as well. If you are going to borrow that from the Fab Tone, you may want to try 47n for C23, and either reduce R31, or add a jumper.

[inkwell101]

So in the d3 spot you put in an actual light? why? is that the light that shows above the knobs? I don't think it is. I'm really new to this so would appreciate the help. Other mods to MT2 I don't see them putting a light in this spot. Yes, I'm clueless and I apologize. I just want to do this mod right.

Thanks

[dfer]

Hi guys,

I'm in the process of ordering some components for the keely mod and i can't seem to find any info on the capacitor that replaces D3, from the pedal gut shot pic i was able to read the last two digits "21" but i can't make out what the first digit is? Does anyone have any info, or can someone make an educated guess?


Any help would be greatly appreciated.


Gut pic - http://smg.photobucket.com/albums/v733/ ... 280007.jpg



I'm guessing that's a 220 pf cap on D3, correct?

[AureEntulava]

...i can't seem to find any info on the capacitor that replaces D3, from the pedal gut shot pic i was able to read the last two digits "21" but i can't make out what the first digit is? Does anyone have any info, or can someone make an educated guess?
...
'm guessing that's a 220 pf cap on D3, correct?

Dfer, your guess is correct: that photo does show a 220pF capacitor in place of D3. The digits are 221. (I suggest downloading the full-size photo from the website where you found it. You can zoom in fairly close without it getting too blurry; I was able to read all of the visible component captions in this way)

There also appears to be an additional (non-light-emitting) diode underneath that heat-shrink tubing on the right hole of the D4 spot. Based on my experience with his DS-1 "Ultra Mod" and a quick look at my MT-2, it seems, from a quick glance, that this part of the mod is similar to his DS-1, in that flipping the switch to "Triple Diode" mode places the second LED in series with this diode, and switching away from it removes it from the circuit. To my ears, this part of the "Ultra Mod" alters the sound by increasing bass response, adding some "saturation" to the overdrive sound, and giving the pedal a bit more dynamic range (or "pick sensitivity"). This is just my assumption, however; don't take it as the gospel truth, as I've never seen the inside of one of Mr. Keeley's pedals aside from the photo in your link, which, unfortunately, doesn't show his mysterious 3-way switching wiring.

I'm not sure on where you stand with respect to reading capacitor codes, but just in case you (or anybody else) might find it useful, this site contains a free online tool that calculates capacitance from the numeric code on the case (and vice-versa):

http://www.electronics2000.co.uk/calc/c ... ulator.php

[dfer]

...i can't seem to find any info on the capacitor that replaces D3, from the pedal gut shot pic i was able to read the last two digits "21" but i can't make out what the first digit is? Does anyone have any info, or can someone make an educated guess?
...
'm guessing that's a 220 pf cap on D3, correct?

Dfer, your guess is correct: that photo does show a 220pF capacitor in place of D3. The digits are 221. (I suggest downloading the full-size photo from the website where you found it. You can zoom in fairly close without it getting too blurry; I was able to read all of the visible component captions in this way)

There also appears to be an additional (non-light-emitting) diode underneath that heat-shrink tubing on the right hole of the D4 spot. Based on my experience with his DS-1 "Ultra Mod" and a quick look at my MT-2, it seems, from a quick glance, that this part of the mod is similar to his DS-1, in that flipping the switch to "Triple Diode" mode places the second LED in series with this diode, and switching away from it removes it from the circuit. To my ears, this part of the "Ultra Mod" alters the sound by increasing bass response, adding some "saturation" to the overdrive sound, and giving the pedal a bit more dynamic range (or "pick sensitivity"). This is just my assumption, however; don't take it as the gospel truth, as I've never seen the inside of one of Mr. Keeley's pedals aside from the photo in your link, which, unfortunately, doesn't show his mysterious 3-way switching wiring.

I'm not sure on where you stand with respect to reading capacitor codes, but just in case you (or anybody else) might find it useful, this site contains a free online tool that calculates capacitance from the numeric code on the case (and vice-versa):

http://www.electronics2000.co.uk/calc/c ... ulator.php

Hi AureEntulava,

Your in luck in regards to the mysterious 3 way switch! Read all the 3 pages here - http://indyguitarist.com/forum/index.ph ... ic=1768.30

If you find out anymore info about the value of the hidden diode under the heatshrink please let us know



Thanks,

Dfer

[darthnormand]

MT2 ON/OFF non true bipass help

I am working on an interesting project. Essentially I am installing the Boss MT2 in an oversized tremelo cavity of an Ibanez Destroyer. Don't worry the guitar is beyond value way before I started tinkering with it.
Essentially I want to simply switch the "pedal" on and off. I have simply replaced the boss switch an on/off toggle. It works, however, I have to cycle through the on off to make it turn on and off.
For example down = off.
To turn it on, I have to flip it up, then back down to turn it on.
To turn it back off, (again) I have to flip it up, then back down to turn it off.
It seems like it would be easy to fix, I have experience with the soldering a bit and have had success using jumpers so the board fits in the cavity.
I just do not know where to start. I do not want to put in a true bypass footpedal style switch because I intend this to be used for fast toggling effect.

[gkoerselman]

Boss uses a momentary switch for the FET switching circuit and you have installed a toggle switch.

A toggle switch could be used but then you have to bypass the fet switching sections (remove Q3 and replace Q2 and Q9 with a DPDT switch just like a 3PDT foot pedal switch but without the LED, or bypass 2 and Q9 with wire and hook up the pedal in and out to the DPDT switch if you don't want the buffers to be in the signal path all the time).

[Diego]

Hi everybody, first post in here.

I'd like to improve the Diezel mod, one step further.
You see, I think the mod really hits the nail on the head when it comes to the EQ, which is dreadful in the stock Metal Zone.

The mids and bass sound much fatter and natural, it feels warmer and less like a transistorized toy, and the highs are fine,
but there's two things that could still be improved:

1) TOO. MUCH. GAIN! Nobody needs the amount of gain this pedal puts out. And I do mean nobody.
Anything past 10:00 it's too much, I usually play it between 8:30 and 10:00 but it's too sensitive,
what do I have to do to make it have less gain on tap? So I can adjust it with more freedom and maybe sound a bit cleaner too.

2) Clarity. I think the Diezel mod still lacks a bit of transparency; the pedal has so much gain that too much of the original guitar sound is lost, it needs to be more natural.
I've tried it with low output humbuckers, high output humbuckers and vintage single coils, so my guitars are not the problem.
I guess it needs a bit of a Hi-Fi treatment, to put it somehow.
I usually compensate this with the high knob and with less gain, but it reaches a point where it's too piercing,
and I wouldn't have to do that if the output was clearer to begin with.

So in short, how can I make my Diezel-modded Metal Zone have less gain, and what can I do to make it more transparent sounding, clearer, tighter?
Or I'm just asking too much from this cheap pedal? I'm not really looking for a super heavy Slipknot or Deftones sound here,
I'm more after a 90's Marshall, Soldano kind of sound. Crunchy, but warm and transparent, with a bit of a clean sound always in place behind the distortion, know what I mean?
The Diezel mod took it closer to this kind of tone, but it's not quite there yet and I think it can be done. It's close!

Thanks in advance! This forum has been a Godsend to me.

[dorothegreat]

So in short, how can I make my Diezel-modded Metal Zone have less gain...

IIRC, reducing R41 increases its distortion. so maybe increasing it shall decrease its distortion.

[zoki]

Hey Diego,

I've been playing around with a bunch of these mods myself and have run into the same problem with too much gain - I finally went a ahead and increased R41 to 22k (just cause it's what I had around) and expected it too be to big but what it gave the pedal is a great almost JCM800ish gain range. You lose a bit of that over the top gain and also volume boost the pedal really sounds fantastic now. I later found a 10 k that I threw in parallel to lower the value there but preferred cleaner range at the lower end of the gain to the extra shred at the top of the dial. I can't say enough about the character of the tone with this pedal now - no it doesn't shred any longer but on the front of a clean tube amp it's classic JCM 800...

Just for the record my other mods on this pedal are as follows..

C35 Removed
C25 on a bypass switch - does remove some of the mids but mids are are big part of that Marshall tone I like and though it's nice it is sometimes a bit too much depend on how I have the tone dialed
Tried the 1 uf C36 mod but found that while it does put more on tap for the EQ boost and cut (dangerously so for stage use imho) it also shifts the freq. response lower and you loose the upper end of the range (2k to 5kish) that can be used like a presence knob so I undid that..
Also tried c34 and 35 mods but undid..

After trying all these I think for those that have had the MT-2 around since the old days (like me) and have grown into more classic and indie type tones I'd say removing C35 and changing R41 to 10k or 22k (depending on whether you want say about a JCM900 or 800ish gain stage) will put this pedal back in rotation!

I may try switch D3 and 4 to LED's later if someone chimes in that it will take the pedal further down this road but for now I love it (again!)

Happy Modding!

[gnognofasciani]

Does anybody tried lowering R44 value to, let's say, 22k (1/10th of the original) instead of removing C34 or C35?? That should do the trick without changing too much the character...
Lowering C30 as well should give a tighter distortion with less low end fuzz...

I'd like to try those mods but I have a brand new (birthday present still in warranty) SMD metal muff and no smd skill...

[Diego]

Well, thank you guys!

The stock value of R41 is 1k I think? I went ahead and put a 3k resistor in there instead.
The gain knob is much more flexible now, and it can still go over the top if I wanted it to. Not that I do.

However, I still have three BIG gripes with my Diezel MT2 that I'm not sure that can be fixed.

It's still not transparent enough. It doesn't have much high end by itself; you really have to push it in the EQ and by that point it sounds very unnatural.
It really needs more of the natural sound of the guitar coming through; you can tell it falls flat on this when setting the gain real low. It doesn't crunch at all, it's just mud. And it should crunch. My BD2 crunches like a mofo with low gain.

Also, the dynamics are very flat. Compared to my modded BD2 it doesn't feel like it moves any air, it just sounds tiny.
In fact I prefer my BD2 (I followed the Keeley mod, plus some extra mods in the BD2 thread) with the gain around 7-8 for heavy sounds.

And I just realized that the EQ got all mushy after the mod.
It feels like the EQ stage is pre-gain, not post-gain so increasing the bass makes it sound all fuzzy and muddy in the mids and highs.
That didn't happen before the mod, I'm sure of it.

So I'm wondering if it's even worth it to keep modding this pedal, or if I should just buy another BD2 and mod it too.
It sounds heavier than anything with "Metal" on it's name that I've ever tried!

And BTW, thank you all guys! This place is fantastic, you made me dare to open my BD2 and MT2 and put a soldering iron to it, and the learning experience has been great. I'd never tried something like that without all the information here!

[Razvan S.]

After reading a heap-load of mods and stuff, I finally decided to redo some of the mods(almost all), but i did them on the Rocktron Metal Planet!!(which is almost identical to the MT-2, even in part numbering!)
I once had the MT-2 just with the diezel mod, but i had to give it away

So far, i have sockets in most places, and experimented, this is my final mod in my pedal, a cumulative mod (of all you folks that made this possible! some i can remember on the spot: laurie, moonwatcher, indiguitarist,mark hammer, and other several users from other forums that have posted and done trial and error jobs on the MT-2 schematic! thank you very much you have my undying respect )

The same part numbering is in the MT-2, so everything that is in red, can be done exactly like this in the Boss pedal.
Maybe i will try other stuff, but for now, this is ok for me anyway(i didn't have a chance to play at high volume yet,so i'm pretty sure i will modify some things, but not drastically).

C42 and C36 ---> 0.1uf for both sounds best,1 uf is too muddy (or even 0.068 can be tried)

Metal Planet (mt-2) cumulative mod.jpg

[Razvan S.]

Tried the pedal at high volume, the only thing i lowered is R46(put back 2k2 stock),and also i'm fiddling with the diodes...i actually don't like the led that much with the 1n4007. Tried a DZ308 old Romanian zener diode in a Ge style black capsule. Did not try mosfets yet(I ordered some, very curious )

[sault]

I've come across this thread a half-dozen times now as I've been researching how to mod my Metal Zone. A good chunk of the mods focus on modifying the pedal's gyrator filters. Well, I figured I'd try the Diezel mod, and turned out that I wasn't much of a fan - it added too much noise. Now, I could have spent a few hours tweaking cap values, but I began to realize very quickly that changing one component changed the response of the whole filter. Why not write up a program that would tell me what would happen if I changed this value or that value?

Jack Orman already has a gyrator calculator, true, but I wanted to see the frequency response graphically and especially see how it changed in real-time as I shifted component values. As an added bonus I also show how the frequency response changes when you lift C2 or short C1 (which is a mod that you never hear about with this pedal!), and included preset buttons for the Metal Zone stock values and the Diezel mod values.


This is my little blurb about it.

http://awasteofsalt.com/online-gyrator-frequency-calculator/

This is the direct link.

http://awasteofsalt.com/gyrator/


I hope it can be of some benefit to you.



Saul T