Minimoog tuning goes slightly sharp during amp release

Tips and techniques for Minimoog Analog Synthesizers
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2pulse
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Minimoog tuning goes slightly sharp during amp release

Post by 2pulse » Sun Oct 20, 2019 2:00 am

I've noticed my original Minimoog's notes go sharp by a few cents during the release stage of the amp envelope. Has anyone encountered this or know what would be the cause? No modulation is active. It happens to all oscillators uniformly and it occurs when playing the physical keyboard as well as when controlling it with S-trig and CV... sort of like not enough voltage is getting to the pitch circuit when the gate is being triggered. Appreciate any insight!

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till
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Re: Minimoog tuning goes slightly sharp during amp release

Post by till » Mon Oct 21, 2019 8:51 am

Is it also happening when you switch the VCO modulation to the left of the VCOs off?
If yes, it appears to be a hardware error.
If not, check the most left switch in the lower controller section: is is set to filter envelope modulation?

The modwheel zero position might no shut-off all modulation in its zery position. This happened on older Minimoogs too sometimes.
keep on turning these Moog knobs

Sequence:
Prodigy * Minimoog (1979) * Voyager * MF102 * MF103 * MF104z * MP201 * Taurus 3 * Minitaur * Sub Phatty * MF105 * Minimoog reissues with MUSEs * One

2pulse
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Re: Minimoog tuning goes slightly sharp during amp release

Post by 2pulse » Mon Oct 21, 2019 11:06 am

Yes, both Oscillator Modulation and Filter Modulation switches are off, and the problem persists. I'm assuming it's a hardware fault, hoping it's something someone has encountered before. It's barely noticeable by itself, but in a mix it's brutal.

2pulse
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Re: Minimoog tuning goes slightly sharp during amp release

Post by 2pulse » Sun Dec 01, 2019 12:05 am

So, slight correction to my initial assessment of the problem. While the release still goes sharp when playing the keyboard, the pitch is actually fine when being controlled *properly* by CV... It was a random coincidence that my DC-coupled audio converters used for control voltage from Silent Way Voice Controller seem to lose voltage when the trigger and pitch CV were both engaged. Don't know why, but that has nothing to do with the synth. I connected a separate audio interface via ADAT strictly for the trigger signal, and now the pitch is fine. Interestingly, my Roland SH5 has the opposite problem when CV and trigger are sent from the same interface... the pitch goes *flat* during the release. Maybe it has something to do with the way that the Minimoog's S-trig and the SH5's V-trig load the converters.

Now that the issues seems to be specific to the keyboard, any thoughts on what would cause the sharp release?

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till
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Re: Minimoog tuning goes slightly sharp during amp release

Post by till » Sun Dec 01, 2019 9:52 am

Glad to hear, your Minimoog is fully working and not damaged.
keep on turning these Moog knobs

Sequence:
Prodigy * Minimoog (1979) * Voyager * MF102 * MF103 * MF104z * MP201 * Taurus 3 * Minitaur * Sub Phatty * MF105 * Minimoog reissues with MUSEs * One

2pulse
Posts: 4
Joined: Sun Oct 20, 2019 1:30 am

Re: Minimoog tuning goes slightly sharp during amp release

Post by 2pulse » Sun Dec 01, 2019 2:53 pm

Sort of. The problem is still there when playing the Minimoog's keybaord, in case anyone stumbles on this thread with a known diagnosis. At least I have a kludgy workaround for the moment, which is a MIDI master controller -> DAW running Silent Way Voice Controller -> two separate DC audio interfaces (one for pitch, one for trig) -> Minimoog.

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Analog Prophet
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Re: Minimoog tuning goes slightly sharp during amp release

Post by Analog Prophet » Mon Dec 02, 2019 2:06 am

Try to clean the metallic rod and connectors below the keys - it can cause pitch related issues.
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