Hi
I am no expert with MIDI and CV but have managed to get some success with this set up:
Samson MIDI Keyboard MIDI out > Pulse 2 MIDI in> Pulse 2 Gate out and CV out> MG1 Trigger In and CV in.
When I play the Samson keyboard I can get the expected sound from the MG1 and it follows the pitch of the notes played.
The problem is that the Gate doesn’t seem to close, so the note just keeps going after releasing the key, as if I was holding the key down. I have checked the settings on the MG1 itself, by removing the gate and trigger inputs and playing a note on the MG1 keyboard, and the note plays and stops as expected.
Am I right in thinking that either the Samson or the Pulse2 are sending the Gate open signal but not the ‘close’ or ‘note off’ signal? (Sorry if that’s the wrong terminology).
Two bits of information that might help:
1- the Pulse 2 gate setting can be set to either 0 or 3.3V, both described in the manual as with ‘active trigger’. Changing this setting only seems to make the volume louder or quiter.
2-The MG1 Manual says this :“The trigger input is simply a swithcing input- when the hot lead is shorted to ground, it wil trigger the synthesizer”. Does this suggest a particular kind of cable should be used?
There is always also the possibility that the MG1 is a bit broken- it has seen better days and the housing itself isn’t in the best condition, but mostly seems to work as it should.
I tested a bit more and the Gate setting on the Pulse 2 did make a difference after all. Setting it to Low worked - more or less. I can still here some faint ongoing sound so it’s not perfect, but low enough to make it usable.
I’ll leave this here in case anyone can add anything or it’s useful to someone some day.
i thought the moog used S-trig which is different than typical gate signal? i forget the details but i think S-trig is like an inverted gate.
anyway… the gate should just be triggering the envelope and holding it open for only as long as you sustain the gate (hold down the key). unless it has a ‘gate mode’ which means it’s just - on - sustain - off. like opening the VCA the gate directly.
if you dig around on the internet you can probably find specifics for the moog w/details about it’s cv/gate format. i’m not familiar with the MG-1 but many moogs of that era use S-trig.
There is indeed a sustain switch, along with tone settings ‘keyed, contoured and continuos’. There is still some disparity in behaviour when playing the MG1 keyboard vs via the trigger input, which I guess is related to these settings and/or an internal problem with the MG1. But I think I’m on the right track now.
Yeah its a bit of a funky set up with the switch, Its been a long time since I played mine (suspected dead key scanner) but the switch expands the simple AR contour generator.
You can get some classic Moog bass sounds using the contour generator to open the filter with some resonance and the cutoff right down. The release control becomes the decay control from memory?
Great sounding synth but sadly plagues by issues like the keyer IC and that horrible black gloop that needs scraping off everything!
Yes that’s right. There’s a ‘contour cutoff’ control that is applied to both the filter and the volume.
I will make or find a CV-Gate to S-trig cable and see what happens.
Mine is in pretty bad shape, the casing is loose and someone has removed the ‘right output’ (which doesn’t really matter cause it’s effectively mono anyway). I’m surprised it works at all. My brother in law found it on the side of the road in hard rubbish collection!
I always found the headphone output on the front gave the best signal. Have you opened it up? There’s a layer of foam between the front panel and the pcb. It degrades and turns into a sticky gloop. You don’t want that getting in the faders so it’s a wise move to clean it all out.
Thanks all for the knowledge. Next step might be to work up the courage to take @Bunker’s advice and open it up for a clean out. One of the sliders needs repairing too.
Now that I finally have it working I’m excited about how I can get the most out of it.
Ring mod sounds is very useable, as is the organ sound if used to beef up behind the synth part. It’s a cracking little synth, issues aside.
It’s a nasty job but unless someone’s already done it you really need to get that sticky gloop out before it starts to get inside the faders. Disposable gloves, a plastic scraper, isopropyl alcohol and a bit of elbow grease is all that’s required.