Cgs synth

>Hello All,
>
>I just finished constructing, rather reconstructing (I bought it used from

>-ahem- "interesting" soldering techniques) my first CGS module, a Gated

>running almost 100% correctly, and I spent a few hours last night playing

>cool module.
>
>The only problem I'm having involves the last 4 stages of the shift

>the status of the preceding stage is moved along with each clock pulse, as

>for stages 5-8, they also get moved along, but about 60% of the time, the

>passed (on instead of off, or vice versa). It's a rev 1.1 board with the RC

>halves of the 4015. Any ideas as to why this might be happening?
>
>Thanks, and looking forward to some more CGS modules down the line...
>
>-Chris
>
>
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
>
>
>

On 8/13/05 7:09 PM, "sasami@..." <sasami@...> wrote:

> Sounds like the delay isn't working, or is too short.
>
> Also, if you are using a LM358 as the input processor, switch it to a TL072
> - it may be the the LM358 is too slow, giving a poor clock signal.
>
> Ken
>
>> Hello All,
>>
>> I just finished constructing, rather reconstructing (I bought it used from
> someone who had
>> -ahem- "interesting" soldering techniques) my first CGS module, a Gated
> Comparator. It's
>> running almost 100% correctly, and I spent a few hours last night playing
> with it - very
>> cool module.
>>
>> The only problem I'm having involves the last 4 stages of the shift
> register. For stages 1-4,
>> the status of the preceding stage is moved along with each clock pulse, as
> it should, but
>> for stages 5-8, they also get moved along, but about 60% of the time, the
> wrong value is
>> passed (on instead of off, or vice versa). It's a rev 1.1 board with the RC
> delay between the
>> halves of the 4015. Any ideas as to why this might be happening?
>>
>> Thanks, and looking forward to some more CGS modules down the line...
>>
>> -Chris
>>
>>
>>
>>
>>
>>
>> The CGS Modular Synth home page: http://www.cgs.synth.net/
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>>
> _______________________________________________________________________
> Ken Stone sasami@... or sasami@...
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>
>
>
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
>
> Yahoo! Groups Links
>
>
>
>
>
>

>Thanks, Ken! You nailed it. Actually, both of the things you pointed out
>were wrong. The previous owner had installed a 1uf cap instead of a 1nf cap
>on the RC filter. I changed that, but the problem persisted. So I swapped
>out the LM358 for a TL072 and the problem vanished. I must say I'm amazed at
>your long-distance diagnosis. Thanks again!
>
>-Chris
>
>On 8/13/05 7:09 PM, "sasami@..." <sasami@...> wrote:
>
>
>
>>Sounds like the delay isn't working, or is too short.
>>
>>Also, if you are using a LM358 as the input processor, switch it to a TL072
>>- it may be the the LM358 is too slow, giving a poor clock signal.
>>
>>Ken
>>
>>

>I have substituted the TL072 for the LM358 in many CGS comparator
>circuits with good results. The one place you probably should not do
>this is when the power supply is not dual, i.e. pin 4 is grounded
>instead of -15V. The LM358 handles the single supply better, I believe.
>
>For example, in the Infinite Melody, IC2 can be a TL072, but IC1 cannot.
>
>-Richard Brewster
>
>xamboldt wrote:
>
>>Thanks, Ken! You nailed it. Actually, both of the things you pointed out
>>were wrong. The previous owner had installed a 1uf cap instead of a 1nf cap
>>on the RC filter. I changed that, but the problem persisted. So I swapped
>>out the LM358 for a TL072 and the problem vanished. I must say I'm amazed at
>>your long-distance diagnosis. Thanks again!
>>
>>-Chris
>>
>>On 8/13/05 7:09 PM, "sasami@..." <sasami@...> wrote:
>>
>>
>>
>>>Sounds like the delay isn't working, or is too short.
>>>
>>>Also, if you are using a LM358 as the input processor, switch it to a TL072
>>>- it may be the the LM358 is too slow, giving a poor clock signal.
>>>
>>>Ken
>>>
>>>
>
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
>
>
>