Little Phatty CV in.

The Moog Forum Little Phatty & Slim Phatty Forum
1

Hi

I’m using my LP with great pleasure.
I have a question though, something bothers me.

I also own a mf-101/102 and came up with an idea for a nice effect. I thought a tremelo effect would be cool so I tried to hook up the LFO/carrier from the 102 to the volume CV in of my LP.
This works of course, but I noticed that it doesn’t open the volume (or filter/pitch) entirely. Why not?

Same with the 101, I wanted to use the envelope to control the volume or filter of my LP. But it doesn’t open it entirely.

Could somebody explain me why?
I thought it’s both -5V/+5V?


Thanks! :slight_smile:

2

If you check the voltage out of the 102, you’ll read that it’s only around 2.5-3V so with the LP considering 5V ‘full’, you’ll only get 50-60% volume. I have no idea what the negative voltage will do to the LP’s CV in, likely nothing.

When you mention 101, I suppose you are talking about the envelope follower output? Same story possibly. Best to measure it with a good multimeter and a quick acting analog multimeter (if you don’t have a scope or O’tool module) is best; digital mm’s sample at rates which may only be a few times a second and you’ll miss the peak.

3

Hi EMwhite,

Thanks for your reply, I get it now.
Why is it only 2.5-3V? Is there a way to get the ‘full’ range?

Yes I was talking about the envelope follower output, I guess it will be the same.


Thanks again,


Jack

4

You can get the full range with the cp-251s mixer module. I do this with my Sub Phatty, as most of its CV inputs are only 0 to 5V. So I use the offset knob to raise the voltage that I want to use. I`m not sure about the CV inputs of the Little Phatty though… But the cp-251 is a great companion to a 101 and a 102 anyway :bulb: :smiley:

Cheers, radioland

5

You sir.. are you trying to empty my wallet? :mrgreen:

Totally forgot about the CP-251, it’s perfect haha. Let’s think, re-think and consider.

Thanks!

6

You sir.. are you trying to empty my wallet? > :mrgreen: >

Yes. :imp:

But later you will see and realize that it was for your own good. :laughing:

Happy considerings - you will love it. :sunglasses:

Cheers, radioland

7

I don’t have a CP so don’t know but maybe the offset only pushes 5V total range (2.5V in either direction) and Moog didn’t want somebody to take an LFO from the Ring Mod and shift it too far possibly damaging gear? Most Opamps and other circuits are rated at well over 12V, even so, not convinced that is the issue.

My Voyager, which is just > a year old runs it’s triangle LFO up to 1.9V, while square wave from 0…3V; for reference, my Modwheel goes up to 4.9v. I’m measuring this on a nixie-tube based voltmeter that my Uncle built while he was in the Army back in the day so I may be off by .1V easy. I’ll try and get my scope module hooked up later in the week but I think you might have your answer by now.