MS20 filter IS WORKING!

[Keith Winstanley]

Ok everyone, I have got this filter working but still need some advise.

First of all on the schematic there are 47k resistors attached to the emitter of -

the 3906's and earth, on the PCB layout this resistor is shown connected to pin 
1 and pin 16 of the lower LM13600 so these resistors need moving about 45 
degrees up to the earth bus.

Secondly the 3906's I used had the pinout of :

C
B
E

when viewed from the top with the flat on the right hand side,
rather than:

E
C
B

as shown on the component overlay.
I had great fun working out views from the top/bottom, which legs to cross and 
which way round the flat bit should be! In the scans I posted earlier the 3906's -

were the wrong way round!

Thirdly the 100k frequency pot gives much too large a sweep and the audible 
sweep is such a narrow band on the pot. I have substituted a 10k pot and even 
this is too great a range. Does anyone know how to reduce this range? At the 
moment the useful sweep range is about 45' on the pot.

You may also notice on the scans I posted earlier that I had connected the 
frequency pot the wrong way round so that turning the knob clockwise closed the 
filter!

so just a few bits to tidy up and I have a working filter.

Many thanks to :

vco for the circuit
dave909 for sympathy
pfperry for advice
stew for confusion
and to Paul S. for suggesting I buy one of his instead.   :)
(I fully intend to buy some of your kits Paul as soon as money allows)

I will put some pics of the project up on my site soon.

Keith Winstanley
http://dspace.dial.pipex.com/town/street/sl67/