Rock Mania / RockBrain

JTEX

JTEX

Well-known member
I think I'm finally ready to come out of the deep, deep Rockman-related rabbit hole. I'll leave some of my schematics here in case they are of interest to someone. No need to trace my stuff :)

The bulk of my work ended up in the form of modular analog engine that I called RockBrain (formerly Shockman). I built it on a small PCB that can be treated like a large IC. It can be used to build various Rockman-type devices, from basic to pretty involved (such as my Rock Mania pedal).

Here's the engine:

RB_v1.1.png

Here's a very basic circuit that can be built around the RockBrain with just a few passives for testing, experimenting etc:

RB_minimal.png

Here's what the Rock Mania pedal schematic looks like. Note that the Rock Brain is treated as an IC. The ATtiny, relays and momentary stomp switches could be replaced by standard DPDT or 3PDT stomp switches if you use a larger enclosure than I did (1590B).

RM_v2.png
 
It's nice that the compressor looks quite simpler than on Rockman circuits. do you have to do any matching on it, or the average mmbfj201 will work ok? I don't think I've seen a scholz-comp circuit without trimmers or hand-picking jfets before.
 
I'ts a very nice group of schematics! :)

There's just a thing I can't understand. In the distortion section, a pair of caps ends in white triangle that is not ground nor voltage reference (Mid supply, in the schematic). So what?
 
Blackboarcult said:
It's nice that the compressor looks quite simpler than on Rockman circuits. do you have to do any matching on it, or the average mmbfj201 will work ok? I don't think I've seen a scholz-comp circuit without trimmers or hand-picking jfets before.
Click to expand...
I did hand-pick MMBFJ201s. It was easy though: the batch I got were very consistent and roughly in the ballpark for this circuit. YMMV of course. BTW if I had to do something like this again, I'd replace the compressor with something completely different, like a THAT-based design with a proper RMS detector and VCA. JFET/opamp compressors are not that great and too finicky IMO.
 
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Elijah-Baley said:
There's just a thing I can't understand. In the distortion section, a pair of caps ends in white triangle that is not ground nor voltage reference (Mid supply, in the schematic). So what?
Click to expand...
That's probably a leftover symbol from when I was still experimenting with the internal grounding arrangement. Should be a filled triangle (mid-supply), which I actually corrected in a minor revision. (Rev1.1+).
 
BTW, the final-final (I swear!) iteration of the RockBrain is Rev2 (renamed to RockEngine) and you can find it here. It's a little bit more polished and comes with a datasheet:

www.jtex.ca

JTEX Electronics - RockEngine

“Jerry, WOW! That's all I can say! Sounds great, better than the original, and the SMD boards are artwork! We search around for every clone*, and yours was the only one that sounded genuine besides the originals.” – Chris R, New York *Jerry's note: thank you, but it's not really a clone :)
www.jtex.ca www.jtex.ca
 
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