It is probably a construction error cause by missidentified parts - the sort
of thing that would cayse the same mistake to be made twice. Check that you
have the correct transistors in each expo converter. There is an NPN an a
pair of PNP in each. Get one in the wrong spot, and it won't work. Also
check power directly at the chip's power pins. Make sure any CV or pot
change results in a voltage change at Pin 1 of the corresponding TL072.
Check you haven't cooked your LM3080s.
Ken
the trimmers to the minimum setting and still no effect. A saw tooth wave at
the input gives a saw wave at the HP and Notch but nothing at the LP or BP.
The distortion gives the desired effect of turning the saw into a distorted
saw on the scope. The voltages are all good + - 15 and -5 are at all the
correct spots. Both sides of the Dual filter behave the same way?
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
of thing that would cayse the same mistake to be made twice. Check that you
have the correct transistors in each expo converter. There is an NPN an a
pair of PNP in each. Get one in the wrong spot, and it won't work. Also
check power directly at the chip's power pins. Make sure any CV or pot
change results in a voltage change at Pin 1 of the corresponding TL072.
Check you haven't cooked your LM3080s.
Ken
>Hello,the filters has no effect. The CV's input also have no effect. I have set
>
>I am having a problem with the CMOS filter. The frequency pot on either of
the trimmers to the minimum setting and still no effect. A saw tooth wave at
the input gives a saw wave at the HP and Notch but nothing at the LP or BP.
The distortion gives the desired effect of turning the saw into a distorted
saw on the scope. The voltages are all good + - 15 and -5 are at all the
correct spots. Both sides of the Dual filter behave the same way?
>set at O /+15 and -15/+15 doesn't make any difference.
>Any ideas what may be wrong? I have tried the frequency pot (CW and CCW)
>_______________________________________________________________________
>Thanks
>Robert Gerard
>
>
>
>
>
>------------------------------------
>
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Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>