Another worrying development has occurred in envelope 2, when I set the alt trigger to middle mode (manual only I think) and press the trigger button the vcf is affected even with the depth turned all the way down. It's holding envelope one open, is this normal?
not sure about this, trying to picture it, I'll check later tonight.
Also when I set envelope 2 to affect vco and set the depth to high it sometimes causes the output to go quiet.
yes, this is normal. I left for an extreme amount of modulation that if you have VCO2 tuned really high then you crank up the ENV2-to-VCO knob it kicks it out of range until you lower the VCO2 tune control back to a lower setting. I believe there's a note about this in the crappy preliminary users manual.
Two questions, when I set TM404 to give the same pitch across the full range of slide times I can fix it one for one note but when I try another an octave or two away I get a slight difference in pitch. Is this normal?
yes this can happen because the VCO width is not perfect. It should only be a few cents worst case but can happen. This is probably the most sensitive trim setting, you can get it perfect for one session and then the next section you may find the tune is off a few cents again throughout the range of the slide time control. Not nearly as bad as when it's uncompensated though.
is it normal for an increase in the depth of vcf/vco to affect the vcf (pushes it down)
yes! I'm glad that you're giving it a good workout and using it. These are all great questions. The ENV2-to-VCF circuit is setup similar to ENV MOD, where with increased amount (depth) the minimum cutoff freq is lowered. This gives it more range for corresponding higher modulation amount. It works very well this way. If you want the minimum cutoff frequency to stay the same when ENV2 is used simply increase the CUTOFF control to offset the cutoff frequency.
is it normal for an increase in the depth of the pitch (goes up until turned to mid depth then back down close to again original pitch at full depth) without the envelope actually being triggered?
yes. this one was unavoidable having to do with a design limitation. You can trim it so that the VCO frequencies are the same at the minimum setting. but as you increase the ENV2 to VCO DEPTH control the fundamental pitch will increase.