Moog Music Forum

Hi this is my first post, anyway I have a question about the MF-101
that I couldn't find a reference to with the forum search tools.

I bought a 101 & 102 in the last few weeks and I am very very happy with them
to say the least.

Now my query relates to the CV on the filter cutoff on the 101.
It seem to me that the cutoff frequency can only be manipulated
as far as 25% or so of the center frequency selected.

ie: setting of 500hz will have a filter sweep of 125hz to 2khz.

Apart from doing this by hand is there another way to get the full
20hz-12khz

Will the CP 251 do it?
Can I apply more than +-5v in either direction and still be ok?

Cheers
A

I can't remember exactly off the top of my head, but the lfo out on the 102 only goes +/- 1.5 volts (or something like that and the carrier out is that or less). So if you're using that to sweep the 101's cutoff freq then that's why you're getting a limited response.

The 251's lfo is +/- 2.5 volts so it will sweep the whole range of a pedal's parameter as long as you manually set the knob at 50%.

As for applying more than 5 volts, I don't know if it will mess up the electronics in any way. You don't need to do so to get the full sweep though.

ok that makes sense.
Too bad the "amount" control doesn't work externally.

Looks like the 251 is on my shopping list.

Cheers
A

The 251 is great and will add a lot with the 101 and 102. It took me a while to realize this, but the amount control is basically a vca. Moog doesn't make a vca, but there's equipment out there you can use as a "voltage controlled attenuator"

Tell me more!
I understand synth signal flow though have only really been using
VA's (aside from a Juno 6 I had) but as far as single analogue modules
I'm a but clueless as to what is avalable commercially.

I'm just waiting for a few things to sell on "the bay" then
I intend to pickup another Fooger. Probably the Murf & the CP 251.

Ok, I'm not very technically orientated (I know others like OysterRock have actual engineering/physics backgrounds, I do not at all). But attenuating a cv signal is analogous to putting an audio signal through a volume control (like a volume pedal or a voltage controlled amplifier/vca). So both attenuators and vca's work in the same way, except we typically use attenuators with cv and vca's with audio. Both can be used to process either signal though (since they're essentially the same thing, except the cv frequencies are below what we can hear).

Since the amount control can be voltaged controlled, it's essentially a voltage controlled amplifier/attenuator. I might be missing some crucial distinction here though...

Any modular company will make a vca module (dot com, doepfer, etc), but once you start going down that route you're getting way beyond what the Moog MF line offers (currently).

yeah I think thats getting a little beyond what I want to do.
just a bit of automation for my fx really.

Getting fantastic results with my guitars & Yamaha AN1X.

especially as a stereo tremolo effect witha delay and vibrato in the
signal chain.

asd wrote:But attenuating a cv signal is analogous to putting an audio signal through a volume control (like a volume pedal or a voltage controlled amplifier/vca). So both attenuators and vca's work in the same way, except we typically use attenuators with cv and vca's with audio. Both can be used to process either signal though (since they're essentially the same thing, except the cv frequencies are below what we can hear).

Since the amount control can be voltaged controlled, it's essentially a voltage controlled amplifier/attenuator. I might be missing some crucial distinction here though...

You pretty much got it, they're basically the same thing. The only difference between an attenuator and an amplifier is that usually an attenuator can only decrease the amplitude of a signal while and amplifier can increase or decrease the amplitude of the signal. In other words, an attenuator is an amplifier with a maximum gain of one, therefore it can be made of passive components (no power needed).

A VCA is just an amplifier (or attenuator) whose gain is voltage controlled. Tremelo pedals are VCAs; a square or sine wave controls the gain of the amplifier. The VCAs on your synths are just amplifiers being controlled by an envelope.

ok now I've got my CP-251
and I've run out of patch leads already!

is there a way to make the lfo slow right down?
i want to be able to do really slow long sweeps

so if i understand this correctly, the CP can make the sweep wider?

Spank wrote:so if i understand this correctly, the CP can make the sweep wider?

thats right.
and if a pedal is patched in via the attenuator
you get to extend the sweep time!

Cheers
A