what's up with my moog slim phatty being out of tune?

[ejlif]

I was playing a layered part and noticed something was wrong. I turned the tuning knob on the slim phatty from the normal 12 o'clock position to almost 1 o'clock and everything was as normal. After a while I had to take it back to 12 to get it sounding right again.

This might be dumb and redundant question but I'm no analog synth expert and I'm guessing this is what guys are talking about when they mention analog synths going out of tune.

If this is the way it is I'll still take it. I have found so much joy in the sound of the Korg Ms 20 and Moog Slim Phatty that even if it fades out of tune it's worth the hassle.

[megamanx]

The little phatty, has an "auto-tune" function in the little phatty, so I am guessing it should be in the slim phatty.

[mute]

Yeah, i thought they had autotune. Even then probably still requires warm up? MS-20 mini's autotuning doesn't..it's pretty much always in tune, but then again.. it's also the reason they used Hz/V back in the day, right..? On a related note, the minibrute def. has to warm up before use.

[meatballfulton]

MS20 has no auto tuning It's just very stable.

Moog's manual suggests something like 30 minutes before tuning is stable.

[moremagic]

the ms-20s linear oscillators warm up real fast and drift way less than exponential oscillators, which is the primary benefit of linear voltage scaling, and i think the mini has digital thermostats or tempcos or something to keep them even more stable
the exponential converter is the most temperature sensitive part of most exponential vcsos as i understand it, and they take a while to warm up. i think modern moog synths have digital tempcos like the ms-20mini, but exponential (v/octave) oscillators will always have a little more drift than linear ones
and half an hout to warm up seems pretty normal if you just moved the synth or something, but i find it takes a lot less time if its kept in a good spot with a steady temp

[redchapterjubilee]

I had a Little Phatty with a bad 2nd VCO. It would never 100% track accurately. Not even a full octave. It was painful to have the oscillators tuned just right at middle C for a little bit of movement between the two then have it go sharp with every half-step beyond that. Moog eventually had to replace that oscillator.

[zaphod betamax]

The MS-20kit most assuredly does not have any autotune. If the Ms-20mini does,that is news to me.

Also, the MS anything compared to the Yamaha CS-xx is no comparsion.
MyCS-40m used to be in tune on turn-on, even at sub 50F temps.

[HideawayStudio]

The MS-20kit most assuredly does not have any autotune. If the Ms-20mini does,that is news to me.

Also, the MS anything compared to the Yamaha CS-xx is no comparsion.
MyCS-40m used to be in tune on turn-on, even at sub 50F temps.

You've got to be kidding.. just lifting an M-Board out of the cage on a CS-50 is enough to throw the thing out of tune as everything cools down slightly on the pcb - it makes tracing calibration issues a nightmare when working on cards in the service position... especially when there is a hulking great big midi retrofit board mounted over the top of them all!... grrrh...

[zaphod betamax]

Well the CS-40m is not a CS-50.
I have now sold my CS-40m, however, I can tell you that it was very good at staying at pitch,
even when cold, and turned on, relative to the deadnuts C reference note of a Waldorf Blofeld keyboard
with an INIT patch.

The MS-20kit takes a bit to tune up even when ambient temp is 68F (20C), but it usually goes in tune quick.
I rarely need to retune my perFOURmer or my Vermona '14.

If you don't believe me, then get a CS-40m and experiment for yourself!

The MS-20kit most assuredly does not have any autotune. If the Ms-20mini does,that is news to me.

Also, the MS anything compared to the Yamaha CS-xx is no comparsion.
MyCS-40m used to be in tune on turn-on, even at sub 50F temps.

You've got to be kidding.. just lifting an M-Board out of the cage on a CS-50 is enough to throw the thing out of tune as everything cools down slightly on the pcb - it makes tracing calibration issues a nightmare when working on cards in the service position... especially when there is a hulking great big midi retrofit board mounted over the top of them all!... grrrh...

[HideawayStudio]

Well the CS-40m is not a CS-50.
I have now sold my CS-40m, however, I can tell you that it was very good at staying at pitch,
even when cold, and turned on, relative to the deadnuts C reference note of a Waldorf Blofeld keyboard
with an INIT patch.

The MS-20kit takes a bit to tune up even when ambient temp is 68F (20C), but it usually goes in tune quick.
I rarely need to retune my perFOURmer or my Vermona '14.

If you don't believe me, then get a CS-40m and experiment for yourself!

The MS-20kit most assuredly does not have any autotune. If the Ms-20mini does,that is news to me.

Also, the MS anything compared to the Yamaha CS-xx is no comparsion.
MyCS-40m used to be in tune on turn-on, even at sub 50F temps.

You've got to be kidding.. just lifting an M-Board out of the cage on a CS-50 is enough to throw the thing out of tune as everything cools down slightly on the pcb - it makes tracing calibration issues a nightmare when working on cards in the service position... especially when there is a hulking great big midi retrofit board mounted over the top of them all!... grrrh...

The CS40m uses the same VCO (and VCF) ICs as the CS50/60/80 but located next to each other on one pcb and not on individual M-Boards and with a totally different pcb layout and architecture to the others. It may be that this improved the warmup time - I've never had a 40m in the workshop - only the bigger polys.

Once warmed up I admit I've never really had an issue with tuning stability on the MS series or CS series... but that is not to say they don't like having parts of themselves cooled off whilst open on the bench which is ok on many analogs but when access is poor such as in the case of the CS50/60/80 it can be a real pain during calibration... and made worse due to the complete lack of auto-tune.