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Subject: Re: [motm] Re: MOTM 300 VCO help

From: A S <synthasaurus@...>
Date: 2012-11-15

 I have a similar situation with my 300. If the FM1 switches are set to AC and LIN, the FM1 input CV has an unexpected result. It does modulate the freq., just not in a way that I would expect.

 I also noticed if either FM1 toggle is set to the up position (to EXP or AC), the freq. increases maybe a half step. This happens even if I remove all CV input cables, and only have one of the outputs connected.

 Also, like with your 300, the sine output is also at a very high level.




On Wed, Nov 14, 2012 at 4:35 PM, gooboworks <andy@...> wrote:
 

Ok, I have more information.

It appears that the 1v/octave and the FM2 inputs and their respective pots are working correctly.

I have more info on the problem. Whenever the EXP/LIN switch is in the EXP position, the FM1 pots has no affect along with the FM1 input voltage.

I noticed another issue. The SINE wave sounded harsh and it is hot, it measures +14v to -14v. Definitely something wrong there.

Any thoughts appreciated.

Thanks
Andy Miller



--- In motm@yahoogroups.com, Richard Brewster <pugix@...> wrote:
>
> Obvious question: Do the 1V/octave and FM2 inputs work as expected? If
> so, then it's just a problem with the FM1 Exp. If those other
> exponential inputs don't work, the problem is more central.
>
> Richard Brewster
> http://pugix.com
>
> On 11/13/12 12:37 PM, gooboworks wrote:
> > Folks, I just finished building a MOTM 300 VCO. I have a problem. the EXP/LIN switch is not acting correctly. When I have a LFO control voltage in FM1 the oscillator appears to work fine when the switch is in the LIN position. When I switch it to EXP, the oscillator will does not react, the oscillator acts as if nothing is inserted into the FM1 jack.
> >
> > I am an experienced builder and I have built MOTM 300's before. I know I can email Paul S. on this, but I wanted to hit the list first to see if anyone had any tips on where I might look for an issue.
> >
> > Any thoughts on what might be the problem and where I can look?
> >
> > Thanks
> > Andy Miller
> >
> >
> >
> >
>