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WIGGLING 'LITE' IN GUEST MODE

Microbrute modding (EDIT: NOW WITH STEPS)
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Microbrute modding (EDIT: NOW WITH STEPS)
AW198
Hi guys, I'm not usually one for DIY but I found this video:Minibrute Mod which made me turn green! screaming goo yo
I'm planning on doing a similar mod for my microbrute - I want to have the waveforms on their individual outputs. However, I read here: Upsetting Comment that essentially if I'm not careful with which test points I use, I'll just end up with the raw waveforms out rather than the ultrasaw-d/pwm-d/metalized waves.
The problem is that the FluxWithIt page says 'TP93= SQUARE VCO, TP94 = SAW VCO, TP102 = SUB VCO, TP124 = TRIANGLE VCO', but looking at the schematics at: Microbrute schematics makes me think that the correct test point for the metalized wave (for example) is TP110. I'm not experienced enough to know which the correct test point is from the schematics, and I'm unwilling to start messing around with my microbrute until I know what my plan is, due to my inexperience.

Can one of you fine people help? seriously, i just don't get it
davestrength
I'm pretty sure the mixed saw is TP119...as they show the RawSAw and SawAnim being mixed here.

A similar circuit is shown for the Metalizer out at TP110.

I'm fairly sure these are the signals showing up at the mixer. But to verify, simply ohm out these TPs to the Pot inputs at the Mixer schematic on the FrontBoard.
AW198
Ok thanks - maybe I should just be a little more confident with taking my MB apart and testing these things!
AW198
Update: I successfully have modded it and now have individual waves out!
eb0687
AW198 wrote:
Update: I successfully have modded it and now have individual waves out!


Can you take pictures to show what you have done exactly? I am interested in modding mine as well.

Thanks.
AW198
eb0687
You'll need:
- Soldering iron + solder
- Wire + wire strippers
- Jack sockets
- Nuts + washers
- Electric handheld drill with an 8mm drill piece
- Oscilloscope (preferably)
You can get some of that stuff from here:
https://www.thonk.co.uk/shop/3-5mm-jacks/
- Thonkiconn jack sockets
- Washers
- Nuts

I'm lucky enough that my brother is a bit of an electronics genius and so had plenty of wire/solder/etc lying around for me to use.

Steps:
1) Unscrew the back of the MB and find the right test points using the schematics I linked above (TP102=Sub, TP119=Saw, TP122=Pulse, TP110=Triangle) - test these with an oscilloscope to make sure they're correct. They are post-waveshaping, so the Metalizer knob etc. will affect the corresponding waveshape.

2) Drill holes along the side of the MB - there are plastic struts inside the case so you will have to make sure the holes are in between them. I found the correct placements to be 2cm from the centre of each hole to the next, and every hole then was between the struts. For the Thonkiconn sockets, 8mm is the correct drill shape.

3) Before soldering, put all the sockets in to check they fit - the nuts will hold them in place. You'll need to unscrew the rear PCB for this.

4) Take them out again, and test with the oscilloscope to see which the ground metal 'tab' is and which the live 'tab' is (I don't know what their actual names are, I'm no good with electronics). In the Thonkiconn's case, the long tab on the outside of the plastic case is the grounding one, and the tab on the opposite side is the one to solder to the test points. I don't know what the use of the middle tab is.

5) Cut your wire to the correct lengths for soldering - remember to leave some extra length for wiggle room.

6) Solder the wire to the sockets and replace the sockets in the case. Don't solder to the PCB before you do this or you won't be able to get the sockets into place after!

7) Solder the wire to the test points (be careful not to press the wires against any nearby components) and screw the whole thing back together. VoilĂ !

8) Enjoy the new wave outputs!

This was my first mod and my first time soldering anything outside of practicing, hence it's not very pretty - the sockets aren't quite on a straight line and one of them has very damaged plastic around the edge from where I made a complete pig's ear of the drilling. I'll probably replace the washers with wider ones to cover it up at some point, and I still need to label the outputs.

Sorry I don't have any better pictures, I didn't take any of the process as I did it, and I don't want to take the entire MB apart again! You can see what it looks like from the outside and how the wires inside are soldered.





AW198
After the surprisingly easy success of this, my next project will be to add a 2-way switch which will change the MB from working normally and working at a much lower frequency, so that I can use the wave outs as complex LFOs.
This should change the MB from being my keyboard + control wheels of my setup to being the main modulation source!
eb0687
AW198 wrote:
After the surprisingly easy success of this, my next project will be to add a 2-way switch which will change the MB from working normally and working at a much lower frequency, so that I can use the wave outs as complex LFOs.
This should change the MB from being my keyboard + control wheels of my setup to being the main modulation source!


Thanks for the detailed response! seems straightforward enough.

Update us with the complex LFO mod when you get around to doing it.
ProgRocket
- What's your experience with this, are there any downsides to this?
- Do any voltages get shared/dimmed by using them simultanoulsy outside of the microbrutes own vco mixer?
- Do the VCOs still track well?
- What happens if you use the line-out in the back as well?
- Are your outs affected by the respective attenuator/overdrive-knobs on the front?

- Are there patchpoints to all those beautiful CV-inputs like this DIY frontpanel on modulargrid suggests? https://www.modulargrid.net/e/other-unknown-microbrute-euro-se
tassie tiger
Hiya,

Leafcutterjohn recommends making connections from MB (mini/micro) using non-inverting buffers. These could be in the MB, or outside.
See http://leafcutterjohn.com/?p=1887

J
AW198
ProgRocket wrote:
- What's your experience with this, are there any downsides to this?
- Do any voltages get shared/dimmed by using them simultanoulsy outside of the microbrutes own vco mixer?
- Do the VCOs still track well?
- What happens if you use the line-out in the back as well?
- Are your outs affected by the respective attenuator/overdrive-knobs on the front?

- Are there patchpoints to all those beautiful CV-inputs like this DIY frontpanel on modulargrid suggests? https://www.modulargrid.net/e/other-unknown-microbrute-euro-se


- My experience is 0, this was the first time I've even used a soldering iron, and I learnt how to read schematics as I went. The only downside is the warranty obviously stops.
- There is a small voltage drop (it goes ~12cents flatter) when 2 outputs are being used rather than 1 - I don't mind this as I like the organic detuning.
- All outputs track well enough, there's a ~8cents difference per octave - again, I don't mind this.
- The line out can be used simultaneously without problem as far as I can tell.
- The outputs are pre-attenuator, so are unaffected by any knobs other than the waveshaping ones (Pulse Width, Metalizer, etc). There is enough output gain that I don't need to use an op-amp or external amplifier before plugging the outputs straight into my Mother 32.
- No, I am unaffiliated with that full-eurorack mod project, and since the correct test points were to one side of the rear PCB, that's where I put my output jacks (opposed to the centre of the front PCB like shown in the picture). Feel free to put the sockets somewhere else if you prefer though!
AW198
tassie tiger wrote:
Hiya,

Leafcutterjohn recommends making connections from MB (mini/micro) using non-inverting buffers. These could be in the MB, or outside.
See http://leafcutterjohn.com/?p=1887

J


Leafcutter seems to be a lot more experienced than I am - if anyone else wants to do this mod, I suggest you look at Leafcutter's pdf tutorial for improvements. I don't know the first thing about making buffers etc and I couldn't be bothered to do anything more complex than basic soldering for this mod, as my first one, so that's why I have tiny voltage drops etc thumbs up
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