High pitched blip on noise modulation. Bug in Firmware?

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andybutler
Posts: 32
Joined: Fri Sep 16, 2011 1:31 pm

High pitched blip on noise modulation. Bug in Firmware?

Post by andybutler » Sat Jan 27, 2018 8:29 am

Noticed the following.
I have a patch where noise is routed to VCO2 pitch, creates a fairly good "noise" output.
Every so often there's a brief high pitched blip in the output.
Sounds like the noise signal just becomes a tone for a fraction of a second.

Slim Fatty
Firmware 3.12 Build 680

andybutler
Posts: 32
Joined: Fri Sep 16, 2011 1:31 pm

Re: High pitched blip on noise modulation. Bug in Firmware?

Post by andybutler » Mon Aug 13, 2018 4:44 pm

Eventually someone at Moog was kind enough to send me a calibration procedure.
Useful doc, I'm glad to have it.

Don't know if it would fix the problem though, guy who sent it me reckoned that the noise signal was coming out a DAC, so calibrating that DC might fix.
I don't know, but it's a complex procedure involving disassembly of the Slim to do it.
Calibration is usually about setting the levels accurately, so it all sounds like guesswork to me, it didn't feel like talking to an engineer.


This bug sound more like a software interrupt preventing the noise signal from updating it's value.
After more experiments I found that the blip occurs afters using the controls on the front panel.
I'd say that's evidence enough for the 'interupt' theory to be true, Phatty is saving the current values to memory, and while it does it forgets
it should be keeping the noise going.

Problem solved with the purchase of a CP-251. Better Analog noise that can be routed into the Phatty in a more flexible fashion.

To be honest, I don't imagine this will ever be fixed. Moog tech support didn't spend 5 minutes to set up the sound and hear it themselves,
no-one else has noticed it, it's not a key feature. Also, I suspect it's going to be hard to fix.

As there's that delay between adjusting the front panel and hearing the blip I wonder if this is a known issue. Don't update to memory continuously while a knob is still being turned because that would disrupt the noise (and possibly other functions) noticeably, leave it a few seconds so you only have to update once .

electronicpoison
Posts: 68
Joined: Thu Feb 10, 2011 6:24 pm
Location: Hamburg

Re: High pitched blip on noise modulation. Bug in Firmware?

Post by electronicpoison » Wed Aug 29, 2018 3:07 pm

hai ,i think i have the same problem ,after i update to vers.3.21 691/32. ithe lights around the knobs running very slowly or tremle when you rotate the knobs...after i make a factory restore every thing works now as before.

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