MOTM

Hi Mark,

Thanks for confirming this for me. I had the same idea about the  
unused CMOS switches. I put that IC in a socket so I might mod mine  
to use one of those to control the bypass LED more accurately.

For those keeping score at home, my rough plan was to disconnect Q1  
from the bypass circuitry (by removing R6); use the unused NC switch,  
leave one end attached to Ground, and hook the other end to the base  
of Q1 (in the Q1-side hole left by R6), also put a 10K resistor  
between +V and the base of Q1, then connect the NC switch's control  
pin to the other control pins of the CMOS switch. Then. This should  
probably do the trick.

Maybe just lowering the value of R6 would work as well, instead of  
all the rewiring I just mentioned? What is R6's purpose?

I can't say that I'll get around to trying this any time soon. I  
still have a few more modules to build, and for me it's more fun to  
get new ones working than to tweak ones that already work fine.

-Chris

On May 1, 2006, at 4:44 PM, Mark wrote:

> On 4/29/06, xamboldt put forth:
>> Thanks, guys. I got it completed and it does work with voltages,
>> although it actually doesn't specify that in the docs as far as I
>> could tell.
>
> I don't think does either...
>
>> One small possible non-issue - when I hook the bypass jack up to a CV
>> source that is only positive-going (800 EG, for example), the lag is
>> bypassed when the voltage goes below a certain threshold, but the
>> Bypass LED does not light up. The only time the Bypass LED lights up
>> is when the voltage goes negative (or if I touch the tip of the patch
>> cord to ground). The functionality is fine in this case, but the LED
>> doesn't necessarily show the status of the bypass - is this normal?
>
> Yes, when controlling it with a jack, the LED does not necessarily
> show the status of the bypass function -- the effect can be bypassed
> and the LED can be off at the same time.  Notice the base of Q1 and
> the control input to the MUX are on opposite sides of a resistor.
> While it doesn't require a negative voltage to function properly, the
> bypass input needs to "see" a low enough impedance in order to turn
> off Q1.  When connected to an MOTM-800 it sees 2K.  Although, I don't
> know why the bypass LED doesn't use one of the two unused switches on
> the MUX.
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