Metal zone MT-2 schematic guide.

[kooroshi60]

Hello guys. I'm going to build up a boss Mt-2 pedal using a true bypass switch so I changed the schematic and eliminated the Mosfet switch circuitry.
I am a bit doubtful about what I have done! I have uploaded both original and tampered schematics. Can you guys take a look at them and tell me if I have done it correctly?

Original :
http://www.8pic.ir/images/85476376198035559975.jpg

Simplified:
http://www.8pic.ir/images/35632204799053161747.jpg


Thankyou

[jblack547]

Nice job. I imagine you are going to completely bypass the input R59 and Q0011 buffer and output buffer Q0001 and R0001 for the true bypass. Those two elements give a very nice high impedance input and a solid low impedance output. In fact, since you aren't actively switching the signal you could probably get rid of those too.

[duck_arse]

you can remove and bridge C039, and remove R052 and R047.

[kooroshi60]

Thank you guys. I eliminated the parts that duck_arse has suggested but I think the input and output transistors shouldn't be omitted. So i'm drawing the schematic in Eagle cad. I'll upload it once finished. Hopefully it will work! This is my 4th DIY pedal. I was pretty much successful with my previous works.
Cheers

[jblack547]

Can't wait to see the build. Are you going to do a youtube demo?

[kooroshi60]

I've just finished the PCB design. It will take a week to build it up completely since I can't work on it full time. Of course I'll upload a video on Youtube when it gets to work properly and will put the final Schematic and PCB here.Ciao!

[onemt2]

I'm hoping I can find help here, I have completed phase two of mods to the Mt-2 metalzone, Somehow I accidentally disconnected the white wire from the foot switch from it's connection. Now, I cannot for the life of me figure out where it originally went. I know the Purple one from switch goes to location #18 on the board, I looked on the schematic it shows a ground, I would think any ground would work. I tried to put it onto the input jack ground terminal, still no luck. I'm hoping someone maybe able to tell me where it originally went, or a picture of the board with the switch wires still connected. Having trouble, I basically just want to connect it back up, then be able to tell if I made a soldering error. Thanks. Jerry

[kingswayguitar]

sorry... can't help
but one question for the knowledgable out there
just what are the transistors doing in the feedback loop of the opamps?

cheers

[R O Tiree]

I've seen that sort of topology in active low-pass filter circuits in old BBD delay circuits, but the caps and resistors are reversed in a low-pass filter. This layout, then, makes them high-pass filters.  I guess, then, that they bleed low frequencies away from the opamp's feedback path.

[FiveseveN]

Yes, they are gyrators used in bandpass filters. See RG's article and Jack's calculator for more info.
In the MT-2, the 1st one (around Q10) provides a mid boost pre-clipping, and the latter boost the lows and (what some find excessive) highs post-clipping. And then come the active tone controls.

[kingswayguitar]

thanks guys