I have 3 MOSFET 921 b oscillators and driver but am vague about using the sync function. How exactly are they patched? I know one is a driver the others slaves but unclear about the actual patch cord placements. Ive not seen any diagrams or clear explanation so far. Anyone any advice?
Don’t you mean MOSLAB ?
Oops. Oo er yea Mos Lab. !! I’ve been using MOSFET IC’s in pcb’s …and you know how things are when getting old? So I’ve got 3 Mos Lab 921b’s not 3 IC’s
Yeah, seeing your alias name, I figured it was a rare component indeed !
As for sync, I’m not a Moslab modular owner myself, but from what I understand of synchronizing oscillators, one would take the output of what would be a master, and plug it in the sync input of what would be a slave.
You would have to make sure that the frequency of the master is lower than the slave in order to hear anything. As the master will restart the slave at the master’s frequency, regardless of the slave frequency.
If the master frequency is higher than the slave, then you wouldn’t hear anything (with sync “on”) as the master will restart the slave before it has even finished one cycle !
By setting the frequency of the master one octave lower than the slave, and varying the frequency of that slave over a wide range, then the famous “sync” sound will be heard. More intense with the waveform of the slave set to pulse or square, and only listening to the slave of course. As the master is only used for restarting the slave regardless of the master waveform.
EDIT Have a look at the Moog 15 Instruction Manual, on Kevin Lightner’s Synthfool site here (starting on page 19 of that document, it explains the sync function in detail with illustrations for patching):
http://www.synthfool.com/docs/Moog/modular/
I also wish that I could speak from experience because if I could, that would mean that I had my OWN MOS-LAB OSC setup (a dream)
But the following should be true:
- 921a provides Volt/octave functionality, common frequency base to all 921b’s (via backplane connection), and uniform pulse (rectangular wave) width control. Many people incorrectly interpret the capabilities of the MOS-LAB system to think that if they have 2x 921b, that they can have two voices when in fact it’s quite like a Voyager with a master tune and the opportunity to offset tuning for each OSC by a small range.
- in order to get the SYNC sound that you are after, you’ll need to patch a sharp leading edge wave into the 2nd OSC’s ‘SYNCH.IN’ jack (most modular OSCs work in this way). Sharp leading edge = Square wave or even downward slope ramp.
- then alter the semitone/tune on the slaved oscillator (the one with a cable input into SYNCH.IN jack)
Seb used to have pages on his site which detailed various methods of connecting these, but his web site has changed and sadly they are no longer available. I suggest you contact him directly (I tried the Wayback machine but his site isn’t indexed beyond the home page).
Let us know if this makes sense and/or if it worked.
Many thanks for the above info…its all a lot clearer now and the link to Synthfool is excellent
…great stuff!
What happens when you daisy chain sync multiple oscillators? Chaos?
Hahaha, maybe ?
That’s one of the joys of owning a modular system, you can experiment things like this that would rather be difficult, even impossible, to do with any other conventionnal analog synth.
I’d also be curious to know what happens when daisy chaining multiple synced oscillators ?
Sounds come out when you do that. Hard to explain what happens to it. Kind of like describing what blue is.
Video or sample, anybody?