SP out of tune at high/low octaves

The Moog Forum Little Phatty & Slim Phatty Forum
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Hi guys, I recently got a slim phatty, and I’m totally impressed by its sound. However, I noticed some tuning issues.

Basically, the slim phatty can reach the stable tuning on middle C rather quickly, about 5-10 minutes and I can get middle C to be within 2 cents of the reference.

However, if I play across different octaves, the tuning starts to drift, the lower/higher I go, the more out of tune. This would still be the case after I let the slim phatty to warm up for more half an hour.

I have tried the calibration option a few times and it worked, but it seems to be working only for that day… After I turned the slim phatty off, and come back to it the next day, and warming up for 30-60 minutes, the notes on low/high octaves drifted again, sometimes 10cents off. (Middle C is still solid tho)

I’m just wondering if this is a normal behavior of the synth? I do understand that slim phatty can be quite temperature sensitive, and with the hot weathers lately (hence the A/C going on and off, and the temperature inside my studio can fluctuate) doesn’t do it any favor. So maybe it’s due to the ambient temperature?

Thanks in advance for your inputs!

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Hi hhuang and congrats on your new Slim Phatty!

The Slim is indeed sensitive to temperature; depending on the later, the synth can take as long as 45-50 minutes to warm up. I’ve had 3-4 of them over the years and some took that long.
Running the calibration routine was a good idea. However, it shoud be run once the Slim is steady, i.e. after the aforementioned time. Is it what you did?

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Thank you for the reply. Yes, I later found out that my slim phatty is kind of slow to warm up. Once I give it an hour or so, I was able to get much more stable tuning. I also did another calibration after the unit has been warmed up for two hours, so everything works fine now!

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Great! :slight_smile: