Elektor Formant

[René Schmitz]

At 16:07 04.10.00 -0700, tomg wrote:
>>Would it be possible to replace the ua726 with a modern
>> equivalent ?
>> 
>> Stephen Gray
>
>I tried to do this several times without sucess. I have never found 
>the magic combination that makes a standard diff-pair act like a 
>726. I can get them to almost work... but not. Oh yeah...I got lots 
>of expo-converters!  The cookbook is full of them.
>
>Take a look at this one. It uses a 3046 heater. 
>http://www.xavax.com/efm/cbook/vco2a.html
>
>But nothing works like a 726. It may not be possible. I'm saying 
>that hopeing that somebody will prove me wrong..;-)
>
>Alternatly the VCO4 series has multipule outputs, is very stable
>and uses common stuff. Damm nice actually..;-)
>

Hi all!

Another alternative which is not to be overlooked is to replace the uA726
with a modern dual transistor (like MAT02, LM394, 2SC1583) and a tempco
resistor. 
Platinum temperature sensors make good tempcos and still can be obtained.
Parts count is low, and the performance of these transistors is way better
than the CA3046s.

You might want to look at the expo primer at my website, it should give you
plenty of alternatives to choose from. You can find a few VCOs there as well.

http://www.uni-bonn.de/~uzs159

Bye,
 René



-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159