MF-102, mf-103: 12-15 volts?

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macteacher
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MF-102, mf-103: 12-15 volts?

Post by macteacher » Tue Apr 12, 2016 3:11 pm

The mf-102 manual states: POWER REQUIREMENTS: +9 to +15 volts DC. Nominal current is 100 milliamperes.

The mf-103 manual goes a bit further:

POWER: The MF-103 works satisfactorily on +10 to +15 volts DC and uses about 100 milliamperes of current. Note that most power adaptors that are rated at +9V DC will actually produce +10 to +11 volts, and power adaptors rated at +12V DC will actually produce +13 to +14 volts, when used with the MF-103. For this reason, you can power your MF-103 from virtually any power adaptor which has a nominal rating between +9 volts and +12 volts at a rated current of at least 200 milliamperes, and has the appropriate power connector.
If you use a power source other than that which was supplied with the MF-103, be sure that the voltage never exceeds +15 volts. Power sources with voltages in excess of +15 volts may cause serious damage to the MF-103's circuit.

Is there any advantage to using a higher voltage?

headroom?

Has anyone tried it?

thanks.

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Vsyevolod
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Re: MF-102, mf-103: 12-15 volts?

Post by Vsyevolod » Fri Apr 15, 2016 1:35 pm

Yes, the advantage to using a higher voltage is that you will now have a functional door stop.

Stephen




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stewdio
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Re: MF-102, mf-103: 12-15 volts?

Post by stewdio » Wed Apr 27, 2016 2:40 pm

Vsyevolod wrote:Yes, the advantage to using a higher voltage is that you will now have a functional door stop.

Stephen




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I think they may have meant using a supply that is on the high end of that voltage range (15V) rather than the 9V supplies that ship with moogerfoogers to which I would also be curious to know if headroom will increase or if the foogers are internally regulated to 9V
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Vsyevolod
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Re: MF-102, mf-103: 12-15 volts?

Post by Vsyevolod » Wed Apr 27, 2016 11:53 pm

The Foogers are designed to work within a set range. Too low of a voltage and the components may not work the way they were designed. Too high of a voltage and components will lose their magic smoke. To the best of my understanding, there is no inherent increase of anything by pushing that upper limit. The components will not work better, they will just 'still work the same'. If higher voltage worked better, it would not be wise for Moog to include a lower power PSU with their unit.

Stephen




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latigid on
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Re: MF-102, mf-103: 12-15 volts?

Post by latigid on » Thu Apr 28, 2016 3:54 am

The older 'foogers were completely analogue and didn't require regulated power, and even specified in the manuals that you could use a higher voltage adapter (as you noticed). Add to this there wasn't guaranteed pitch control or temperature tracking on oscillators and such; the original intent was clearly for effects units not synth modules. I remember that at least in the CP-251 there's a kind of voltage doubler/virtual ground chip that generates a bipolar supply from the plug pack, but no regulators I think. 'Foogers are mainly a collection of op amps and transconductance amps (LM136(/7)00). The former won't mind a bit of extra voltage, but you have to be a bit careful driving the latter (although I'm sure there's safety built into the design).

All of the circuits/resistor values are likely optimised for a 9V supply. As a wise MC explained to me 10 years ago(!) "heat is the destructive enemy of electronics" and by increasing that voltage you potentially (no pun intended) decrease the life of the device.

I'm not sure if headroom is really relevant here. The signal goes through a drive circuit at the input so perhaps you get a bit more gain, but in my experience they were designed by Bob Moog to ensure the best signal integrity.

So if you want, you can safely try a higher supply voltage to see if you can notice a sonic difference (maybe GearSlutz would be a more appropriate place to ask), but you run the risk of your beautiful phaser pedal having a shorter lifetime.

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