Tim Escobedo 9V MS20 / Sallen-Key filter- Layouts?

[Strategy]

suggestions for pot values on this one?

[hoyager]

I think its 100k's. I've just built one based on the layout posted

http://img401.imageshack.us/img401/9132/ms20lpvcf.gif

and using this to wire it up (layout above has 2 extra resistors and uses 100nf input and output caps rather than 1uf on the one below)

http://i644.photobucket.com/albums/uu167/iloophao/2.png

I had some bit crushing effect with what sounded like the correct operation of freq and res controls, more signal passed when input level boosted alot, but still bit crushing sound until I found pin 1 of the ic had a solder bridge to the line above, after which nothing was happening at all.

Does anyone know or can confirm if the layout is good? I'm sure I've done everything correctly and on second look has no errors.

Andy

[hoyager]

I've rebuilt this and have it working now, mixed up 2 of the caps on the last one i think...

As far as wiring goes res 1 is attached to h 19 (Vr?) and freq 1 goes to ground with freq 3 to the 9v line a

I also have the dc jack ground going to both grounds, not sure if that needs to be the case or not, but it works as it is.

I've changed the input and output caps to 220n and 470n, seems to have more bottom end, would that do it? Also changed the 2 100ks from pin 1 & 16 to 56k. Would that allow more bottom end as well as high end?

Andy

[mthibeau]

Hate to dig up an old thread, but I have a question about this effect.

I built it a few days ago, and works great (thanks to those in the thread who answered where all the pot wiring goes?).

My question is about CV in? I don't see CV in anywhere in the schematic, but I am new at these things so I may be overlooking it.

The Q&D filter scem and layouts had a CV in that worked great, would like to try to get the same with this MS20 filter.

I did try putting my CV source on a switch (to switch between the pot controlling Freq and the LFO), that works fine, but isn't what I wanted, I want CV to work like it did with the Q&D, where the Freq knob works with the LFO (changing the base freq of the LFO sweep).

Using the above Vero layout, any idea where I could pump in CV and still have the freq pot work?



- MikeT

[daverdave]

I'd say use a summing amp to mix the voltage divider signal ( the frequency CV from lug two of the frequency pot) and your external CV from your LFO.

[mthibeau]

I'd say use a summing amp to mix the voltage divider signal ( the frequency CV from lug two of the frequency pot) and your external CV from your LFO.

That sounds like what I am looking for, but I am kind of a beginner at all of this, have a link to an example circuit of a summing amp I could look at?

- Thanks

[artifus]

toptop added cv in to tim e's idiot wah with a transistor and a couple of pots: http://oi56.tinypic.com/2r7qyh0.jpg. you could try adding a transistor between the freq pot and ground in a similar manner.

[PRR]

[mthibeau]

Thank you, that worked great!