Guitar VCF.?

[Strategy]

Haven't had time to make clips, will try and bang something out!
Strategy

[deadastronaut]

cheers man..

[deadastronaut]

new clips: using last schemo:  (but with added diodes) lfo is uneven, but i'll sort that..

https://dl.dropboxusercontent.com/u/7464107/vcfs.mp3

https://dl.dropboxusercontent.com/u/7464107/vcfspacey.mp3

lo filter then high...then both mixed.


this is using single coil pup on neck..it doesn't seem to like a humbucker bridge...hmmmm

[deadastronaut]

just discovered 2 seperate hp/lp using the lm13700n 0n 9v...

going to try those...and probably lift a bit of stuff from ricks multi mode filter too..

[deadastronaut]

ok ive breadboarded this top one twice, with 3 different lm13700n's...no joy.

will this top one work ?...



vr=2.54

1  1.09
2  0.00
3  2.54
4  2.53
5  1.09
6  0.00
7  1.09
8  0.30
9  0.36
10  1.07
11  9.08
12  1.06
13  2.53
14  2.52
15  0.00
16  1.07

i take it pins 1+5+7 are joined together..
and  12/16/10 too....

[nick d]

   Nooooo.... 1 and 16 are the Iabc control inputs . 5 connects to 7 , 12 to 10 .

[deadastronaut]

ahhh cheers nick...i haven't messed with these OTA's much at all really...(as you can tell)

Iabc?...whats that?. freq control?..

edit: have sound now!!!

[nick d]

    It's the input for the control current I abc  . In a filter , the current controls the filter frequency .

[deadastronaut]

ahhh ive learnt something today ..cheers man.

[deadastronaut]

next thing , how to get rid of distortion on this?..

[mth5044]

The LM136(7)00 Iabc can't go over 2mA total, so no more than 1mA to each, I guess. Don't go over! With your 100k current resistors and frequency all the way down (max current), you'll only be getting 0.09mA. If you use a 1M pot, you can go down to 0.01mA. Maybe if you don't get enough... whatever it is this gives you, a 10k resistor might be useful!

I don't know a lot about OTA's either, but I've been messing around with Ricks' Funky MF too.

[bluebunny]

You turning to the Dark Side, Rob?

[deadastronaut]

^ lol..no, not yet anyway..

i want this for guitar, but going by  it not really being happy with humbuckers going into it i doubt i'll ever get it clean enough

to use with lfo to have the filter sweep really slowly up n down...bit of a juggling act ..hmmmm...