Buchla triggers and gates in eurorack

I recently discovered that Buchla synths use a combined trigger and gate signal. Basically the gate is the same as in eurorack (5V equals on, 0V equals off) but for triggers they simply add a large spike of up to 13V at the beginning of the gate signal. That allows to have notes without any gap in between them, but the gate signal can still retrigger envelopes etc. Because of that voltage spike.

I’m working on some sort of sequencer in VCVRack and what really annoys me is that in eurorack we have to add a short low-period in a gate signal to make envelopes retrigger. That puts me in a situation where I have to guess when the next clock signal will occur so that I can pull the gate signal to 0V briefly before the next clock cycle starts a new note.

Now I’m wondering why the Buchla combined gate and trigger signal appear nowhere in eurorack. As far as I can tell no one uses that system even though it is backwards compatible with the existing gate spec and only adds more freedom to designs. Even the hardware requirements for reading this combined signal are quite low. So why is there no combined gate&trigger signals in eurorack?

But why is it a problem to add small gaps again? Isn’t that the same technique but in the opposite polarity?

Maybe because there wasn’t such a thing in Moog systems?

I would also love single channel clock + reset signals following a similar system (the clock pulses are at +5V, but when the playback is started; or at the beginning of each bar/pattern/cycle; they reach +10V).

No it’s not. You have to add the gap before the note starts, otherwise the actual note will be delayed by the width of the gap. That is exactly my issue.

So why not implement it that way? It would still be backwards compatible. Someone has to make a start, I guess…

I could see this being backwards compatible as a clock / reset output, but not as clock a clock / reset input. Since the voltage of a clock / gate / trigger varies between 5v and 10 / 12v between modules / manufacturers, some clocks would cause a reset on every step.

Yes, I agree. Though it would be easy to add a jumper (or a setting in a menu) to configure how the input is treated. Both the actual hardware and the software can easily be designed to accept both.
Compared to other standards, it would actually be a relatively seamless transition from the current eurorack gate/clock signals to a combined gate&trigger / clock&reset signal.

I made a module within Audulus that I connect to the modular using the ES-8 that just introduces a 1ms gap when two gate signals are mixed together and it works really well. I don’t know if you have the means to do something like this with your set up but it’s a pretty noticeable effect.

I wouldn’t mind 1ms of delay at the beginning of notes. Did you have problems with the gap being too narrow for some modules? In my experience, some modules will not reliably react to pulses smaller than 10ms.