Boss - HM-2 Heavy Metal [schematic]

[slammer88]

For those BOYS iniciants that want to made this his 1º pedal here´s the conections of my layout:


For this new layout, exactly the old, this new have the adaptations ACA/PSA; IN DC in the PCB, the pins identicaly of the original, thats all!!

I have made this version, which includes PSA conversion in it

[slammer88]

It is done, pictures incoming

[slammer88]

Here are the pictures. Its finally working stable, no cold solders, no short circuits etc. The 2 problems that i have are LED is still not bright enough (changed the 2k2 into a 1k, didnt work!), and the distortion character is not that "chainsaw" enough. I've ordered both 4558 and 5218 to be able to try both of them. As far as i could notice, 5218 is a little more bassy while 4558 is a little more loud and treble. So i've mixed them

By the way, i need some help of GodSaveMetal. I've ordered all of the trannies and IC's again with some sockets just to be sure they are not broken. Yet There are 3 transistors, which doesnt affect the circuit. By this i mean, when i remove them from their sockets one at a time, the sound goes away completely. BUT, the ones i've marked with "O" doesnt do that. I can play just fine with or without them. I think there is a problem with their connections on the circuit. I'm sure there are no short circuits around, else it would not work, just like it did at first

Looking for your help. Other than these, its great, it gives the basic character of that saw sound, but as you can hear, its not enough. I've used LePou Hybrid, which is a Marshall VST, in JCM Mode, all at 12 except Contour is full. And for cabinet, i've used Catharsis C1 IR. No pre-post eq at all..Guitar is Ibanez RG7321 with S.Duncan Blackout's..

https://soundcloud.com/baranismen/diy-hm-2-trial

[slammer88]

Forgot to add..Trial begins with all full settingsi then I've decreased the Bass to half, then max'ed, then played with Treble, Volume and Gain..

[slammer88]

Made some changes..

- Changed the LED Resistor to 330R, its much bright now, gonna try with 150r as well..
- Added MID Mod by lifting the C27's - lug and connecting it into an external 10k pot, it has more sound variation now..

[GodSaveMetal]

I don´t see your "O" tranie!!! cuze ther will be a trouble around there!!!!

[slammer88]

The trannies i've mentioned are the ones that i've circled. But i've discovered that, when by-passed, if i remove these 3, the sound goes away..

[slammer88]

By the way, i used AA119 as replacement for 1N34A. Shall i change them?

[slammer88]

Well, its quite ok now! I'm always using "Normal" Input of my POD UX2 to while playing guitars. But there's also another input called "Pad", which gives like -15db input gain/volume w/e. After connecting via Pad, it worked quite well, otherwise it was way too boomy, clippy etc. Now it sounds quite relaxed

https://soundcloud.com/baranismen/r3r3

First, its on Pad input, Gain and Mid at 12, rest are full, goes to LePou Hybrid in JCM Mode, all at 12' clock, one Mesa OverSized with SM57 IR; second in Normal input with very same settings!

[GodSaveMetal]

Well, its quite ok now! I'm always using "Normal" Input of my POD UX2 to while playing guitars. But there's also another input called "Pad", which gives like -15db input gain/volume w/e. After connecting via Pad, it worked quite well, otherwise it was way too boomy, clippy etc. Now it sounds quite relaxed

https://soundcloud.com/baranismen/r3r3

First, its on Pad input, Gain and Mid at 12, rest are full, goes to LePou Hybrid in JCM Mode, all at 12' clock, one Mesa OverSized with SM57 IR; second in Normal input with very same settings!

woooooowwwwwwwwwwwwwwwwwwwwwwww!!!!! thats the CHAIN SAW METAL SOUND!!!!! it sound like the beast!!!!!!!!!!!! PROVED LAYOUT!!!!!!!!!!!!!!!!!!!

[slammer88]

Well, its quite ok now! I'm always using "Normal" Input of my POD UX2 to while playing guitars. But there's also another input called "Pad", which gives like -15db input gain/volume w/e. After connecting via Pad, it worked quite well, otherwise it was way too boomy, clippy etc. Now it sounds quite relaxed

https://soundcloud.com/baranismen/r3r3

First, its on Pad input, Gain and Mid at 12, rest are full, goes to LePou Hybrid in JCM Mode, all at 12' clock, one Mesa OverSized with SM57 IR; second in Normal input with very same settings!

woooooowwwwwwwwwwwwwwwwwwwwwwww!!!!! thats the CHAIN SAW METAL SOUND!!!!! it sound like the beast!!!!!!!!!!!! PROVED LAYOUT!!!!!!!!!!!!!!!!!!!

Yeah! Only thing is, LED is still not bright enough.

[GodSaveMetal]

Yeah! Only thing is, LED is still not bright enough.

What zener you used????

[slammer88]

it is 5v1 as mentioned in project

[GodSaveMetal]

it is 5v1 as mentioned in project

It blow very well!!!! you prove with the ultra bright ones???

[Groovenut]

You might consider this solution to the LED issue.

viewtopic.php?f=10&t=15973&p=212590#p212398

[BuryMeInSmoke]

Anyone interested in seeing the guts of an HM-2?

I have a broken one on my desk that I've opened up for inspection, I'm happy to take pictures if anyone wants to see them.

[GodSaveMetal]

Anyone interested in seeing the guts of an HM-2?

I have a broken one on my desk that I've opened up for inspection, I'm happy to take pictures if anyone wants to see them.

What happens to your HM2???? I have cloned one by photos of the original plus the layout!!!! perhaps I would help you!!

[denimglen]

What happens to your HM2???? I have cloned one by photos of the original plus the layout!!!! perhaps I would help you!!

Thanks. Currently it's got a few broken wires so nothing major. I haven't used this pedal much since I bought it. I used it once about two years ago and it didn't sound 'right' (the last time I used it was about a year prior to that). I can't remember the exact details but if I remember correctly it seemed to be a lot less tone and less clear than it was when I originally got it so I'm guessing a cap somewhere might have died out...

Also thanks for posting that schematic/PCB, I've been looking over it and will likely make it after I've finished my current builds. I've pulled your PCB diagram into Illustrator, traced it, and re-drawn the pot/led daughter board so it's all one board now. I've still got a few more hours of work to go on it though. I'll post it up here when I've finished.

[BuryMeInSmoke]

What happens to your HM2???? I have cloned one by photos of the original plus the layout!!!! perhaps I would help you!!

Thanks. Currently it's got a few broken wires so nothing major. I haven't used this pedal much since I bought it. I used it once about two years ago and it didn't sound 'right' (the last time I used it was about a year prior to that). I can't remember the exact details but if I remember correctly it seemed to be a lot less tone and less clear than it was when I originally got it so I'm guessing a cap somewhere might have died out...

Also thanks for posting that schematic/PCB, I've been looking over it and will likely make it after I've finished my current builds. I've pulled your PCB diagram into Illustrator, traced it, and re-drawn the pot/led daughter board so it's all one board now. I've still got a few more hours of work to go on it though. I'll post it up here when I've finished.

Sorry, the above message was from me, I was using a friends computer and didn't realise he was still logged in.

[GodSaveMetal]

What happens to your HM2???? I have cloned one by photos of the original plus the layout!!!! perhaps I would help you!!

Thanks. Currently it's got a few broken wires so nothing major. I haven't used this pedal much since I bought it. I used it once about two years ago and it didn't sound 'right' (the last time I used it was about a year prior to that). I can't remember the exact details but if I remember correctly it seemed to be a lot less tone and less clear than it was when I originally got it so I'm guessing a cap somewhere might have died out...

Also thanks for posting that schematic/PCB, I've been looking over it and will likely make it after I've finished my current builds. I've pulled your PCB diagram into Illustrator, traced it, and re-drawn the pot/led daughter board so it's all one board now. I've still got a few more hours of work to go on it though. I'll post it up here when I've finished.

Sorry, the above message was from me, I was using a friends computer and didn't realise he was still logged in.

OK no matter man!!! If you want to make my layout PCB go ahead it´s verified!!!!!!!!!!