Modular Synth Panels

Sigh... The shame of non-standard spacing. I shed a salty, salty tear  
for standard spacing, Richard. My grey lil' heart breaks.
But I want to see pics and hear sounds and watch your modular grow,  
nonetheless.

Scott Deyo
contact@...
The Bridechamber
www.bridechamber.com
Jealous Edison Record Kompany
www.jealousedison.com




On Mar 18, 2010, at 5:51 PM, Richard Brewster wrote:

> I'm planning to build one of these, but with my own 1U panel.  Yes,  
> 1U.
> It will have three pots, the mode switch, and three jacks per filter
> section.  No spread feature, though.  I'm waiting for Ken's PC board  
> to
> become available again.
>
> Richard Brewster
> http://pugix.com
>
> Scott Deyo wrote:
>>
>>
>> Of course, I didn't think of that, so I asked Ken:
>>
>> "Pin 3 is not a summing node. You can feed a second signal into it  
>> via a
>> second resistor. The two -CV will AVERAGE with each other, not sum.  
>> In
>> other
>> words, stuff will happen, and it will probably be good enough. The - 
>> CV
>> won't
>> be quite as sensitive as on the other unit, though it probably won't
>> be that
>> noticable. It will be in keeping with the general "roughness" of the
>> module
>> though, and that is part of its charm. "
>>
>> You'd think I'd learn to stop doing mods. At least it only effects  
>> one
>> of the filters, and it's not a 1V/oct, precise filter anyway.
>>
>> Scott Deyo
>> contact@... <mailto:contact@...>
>> The Bridechamber
>> www.bridechamber.com <http://www.bridechamber.com>
>> Jealous Edison Record Kompany
>> www.jealousedison.com <http://www.jealousedison.com>
>>
>>
>>
>>
>> On Mar 17, 2010, at 8:38 PM, joshdaigleusa wrote:
>>
>>> I apologize if this is posted twice - I have a difficult time with
>>> Yahoo groups sometimes and finding recent posts. Posting again
>>> because it doesn't seem to have made it through.
>>>
>>> Ok, I'm building this now and am confused. I think Ken has his
>>> schematic wrong for the CV section:
>>>
>>> http://www.cgs.synth.net/modules/pic/schem_cgs49_twf.gif
>>> <http://www.cgs.synth.net/modules/pic/schem_cgs49_twf.gif>
>>>
>>> This schematic shows the CV "+" inputs summing into the non- 
>>> inverting
>>> input, pin 3, and the CV "-" input going into the inverting input,
>>> pin 2. If you look at the traces on the board this is reversed: The
>>> single "CV-" input goes to pin 3, the non-inverting input, and the
>>> summed "+" CV inputs go to the inverting input, pin 2, with the 2K2
>>> resistor in the negative feedback loop between the output and pin 2.
>>>
>>> So, correct me if I'm wrong, please, but I'm going to venture that
>>> this mod will not work as suggested then, right, because we can't
>>> throw another input onto the non-inverting input of the TL072, can
>>> we? If, as suggested, I add a wire, through a 200K resistor, to the
>>> intersection of the 100K input resistor for the CV- input and the  
>>> 2K2
>>> pull-down resistor, ultimately feed into into the non-inverting  
>>> input
>>> summed along with the "CV-" input, this won't work, will it? Am I
>>> off? The way I've understood op-amps is to sum/mix multiple inputs
>>> into an op-amp this has to happen via input resistors which sum into
>>> the inverting input, with the non-inverting input tied to ground.
>>>
>>> So, does this mean we either have to sacrifice the CV Invert switch
>>> or not have the spread functionality?
>>>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>