Flashing lights of the 100M

Continuing with some stuff from my ongoing silly giant-sized clone 100M – here is the flashing lights bit from the VCA and VCF circuits in action.

It’s unlikely it’ll be of any use to anyone, ‘cos it uses a (possibly unregulated) 22V power line from the 100M PSU, but, just in case – here’s the layout:

Roland System 100M level indicator stripboard

The lights on the 100M are meant to be useful, telling you when signal is coming out of the output, and if you’re pushing the level too hard. In practice, the overdriving seems to kick in slightly before the red light comes on.

It’s lot of effort for some pretty lights, but the whole thing has been a ridiculous endeavour so far anyway; so in for a penny, in for a pound.

The 100M level detector works more reliably than I’ve so far managed with the System 700 equivalent, which seemed to need very specific transistors, and even then occasionally gets stuck.


  1. 9th December 2017Rob at AMSynths says:

    I recently built the SH7 version of the red level detector as part of the HPF and VCF circuit but it doesnt work, maybe because I didnt use the old 2SA826 transistors…the filter sounds fantastic though

    I will try this circuit which omits a diode and has a few other small changes. I think it will work from a +15v rail.

  2. 9th December 2017ua726 says:

    Dunno why I didn’t think of trying it from +15V, it’d be easy enough for me to give that a go – I’ll see if I’ve got time tonight.

    Never thought about doing the SH-7 VCF for some reason, now that’s got me interested 🙂 Tempting to do a second clone 100M cabinet and fill it with different stuff – now he’s up for another run of the boards maybe including a couple of ryk’s 185 sequencers, plus a bank of SH-5 bandpass filters and some other things.

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