Moog Music Forum

So I sprung for the CV out mod for my Little Phatty when I had to send it in for a repair.
I just got around to really digging into it when I noticed something right off the bat. Its out of tune!
I ran an unbalanced 1/4" from the Gate CV output to the KB CV input on my sub37 and everything sounded fine, I hit C and it was intune. However when I plugged the pitch CV out from the phatty to the sub37 pitch cv in it went out of tune. So I tuned the SUB37 up with the tune knob, now its in tune. Is this normal?
Can someone please shed a little light on whats going on here? Am I doing something wrong?

Isn't it necessary to set the reference pitch on the receiving synth? I would test that: before controlling the Sub37's pitch with the LP, hit the leftmost C key on the Sub37.

Hope this helps :/

Okay maybe I'm confused about the purpose of controlling via Control Voltages?
I thought that if I patch my gate and pitch output into another synth's gate and pitch input that Id have control of the receiving synth from the transmitting synth, isn't this how its supposed to work?

stiiiiiiive wrote:Isn't it necessary to set the referecne pitch on the receiving synth? I would test that: before controlling the Sub37's pitch with the LP, hit the leftmost C key on the Sub37.

Hope this helps :/

I found something kind of funny going on when I tested what Stiiiiiive suggested. When I did what he said I got it in tune for that one C key only, as I started playing higher it started going out of tune as I ascended the keyboard.
Im pretty confused as to whats going on.

Ok, let me sort things up

Yes, you can control another synth with the connections you described.
But it's not like MIDI: MIDI (generally) sends an absolute note number and a trig through a "NOTE ON" message. No reference needed here.

CV does not work the same as it basically consists of a voltage. The destination oscillator (for example) is controlled with a given scale; here, increasing the pitch control voltage 1 Volt increase the pitch by 1 octave, hence the commonly read "1V/Oct". This is true for the CV input as well as for the internal keyboard.
If the pitch CV input does not bypass the connection of the keyboard, the voltage sent by the later gets added to whatever you send in through the CV input. That's why I suggested you "set the reference", i.e. the voltage sent by the keyboard, just in case it works that way.

NOW, it's really weird that you get a C in tune only. This does not seems normal. When you play the major scale from the C in tune, when do you feel it's starting to get out of tune?

stiiiiiiive wrote:NOW, it's really weird that you get a C in tune only. This does not seems normal. When you play the major scale from the C in tune, when do you feel it's starting to get out of tune?

WOW okay this is getting weird.
when i don't patch anything in and i use two hands to play the LP and sub37 everything is in tune.
Before patching, i press the lowest C note without any octave changes on the sub37. When i patch the two CVs thats when it gets weird.
Then i hit the lowest C note without any octave changes on the LP and i hear the sub37 and the LP and they're in tune. i toggle the output on the LP and the mute on the sub37 and i can tell its in tune. this seems right to me.

So when i press the D key it should stay in tune correct? D on the LP should also play D on the sub37 via CV?
Well thats not whats happening, when i press D on the LP it still playing C on the sub37 until i press D on the sub37 and then its in tune D on both synths.
Then i move on to E and do the same series of steps and get the same result but moving on to F it gets even more messed up!

When i move on to F id assume both synths should be playing F from the lP if i follow the steps above but thats where it gets completely out of tune. I don't have a tuner at the moment to find out how far out of tune it is but its obviously out of tune. ready for more confusion?

If i follow the steps above and i press C on the sub37 then C on the LP its in tune, but say if i move up a note to D on the lp without pressing D on the sub37 first, the sub37 hangs on to the C note and the LP plays a D, and so on to E and at F again it gets weird.

So i "reset' by pressing C on the sub37 and then C on the lp everything is fine. now when i turn the output off on the lp i notice something else.
if i press c on the lp (but its muted so i only hear the sub37) i hear the proper C note, when i press D on the lp guess what happens? IT PLAYS C ON THE SUB37 STILL! When i move to E its more C! Then when i play F its a different note but because i don't have a tuner i can't figure out what pitch it is (i assume its D) because i can't press a key on the sub37 or ill lose it all. After F i obviously move to G and the pitch of the sub37 increases like it should but turning the output back on on the lp proves that its still out of tune.
My head is in knots right now...Im sorry if its rubbing off on you but at the moment your my only hope Obi W....eh.

Ahem, ok.
This is weird indeed.
My advice: make a quick video of it, and send a link to the Moogmusic technical support. It may come from one or the other synth...

Hope this will get sorted out soon mate. Keep us informed.

Well... I'm not sure the problem is related, but after i had my CV OUT mod installed, i had a similar problem. Not quite the same, but similar (and worse). The upper notes (i think it was the last 8 keys) all gave the same pitch. It also ran the auto tuning process VERY slow.

Turned out, one of the small, errr, chips (edit: resistor) on the mainboard had gone bust. I had the mod installed by a friend (ingeneer) not Moog. He opened it up again, ran some tests and replaced the resistor. Problem was gone afterwards.

Not sure it's related, but i'm just throwing it out there.

EDIT: you can read about it here (later posts): http://forum.moogmusic.com/viewtopic.php?t=10859
EDIT2: seems like my problem was worse than i remembered. I think it played one note at first, and after running the tuning process, it played most notes, except for the upper notes.