waggled my clocks

[anotherjim]

To get same roll-off with 2k2 instead of 220k, C1 will be 1uF. It's about 70Hz. It's up over 7Khz with 10n.
If your Tri LFO was at, say, 10Hz, its 3rd, 5th & 7th harmonics will survive a roll-off at 70hz, which should keep it from turning into a sine.
..But, if having any C at all there is stopping modulation, well, I don't have much of a clue at the moment. Could be that if C1 is small, then it's getting discharged too much when Q101 switches on?

[duck_arse]

had my last go at observations of this today (it has since left the building breadboard).

I can only see the shape of the mod-wave tri at the osc highest speed, but then I need to lowest speed look at the way the clock outputs, just to see the swing. the C1 cap as 10nF tends to turn the straight-lined triangle more boob shaped at R5//R101, curved to and from the teat tip, but not at dip. and the clock outs have a definate rhythm to them that looks not like a straight line, but at low osc speed where it should be more triangle.

so, as Vic Reeves said when asked how it works, "I dunno - but it does!" when it come time to build, i'll just use these values and it should work.

[anotherjim]

Ok, I trust you didn't fall in to the trap of scoping slow waves with the CRO AC coupled? I have spent many hours wondering why my wave was wrong until I switched to DC coupling.

[duck_arse]

weellllllll, a casual glance over my shoulder shows ...... nah, I was looking at something ELSE AC coupled, something after the clok waggle. I can't prove otherwise, but that's my story, and I'm sticking to it!