[sdiy] Active VCO temp compensation

[Luís Marka]

By the way, I see Jim has 2 versions of this VCO: one uses a MAT04 as 
the matched transistor array, while the other uses a CA3046. Is there 
any difference in performance between these? The CA3046 is much easier 
to find (at least, where I live...)

Luis Marka

Simon Brouwer wrote:
> Jim Patchell has some real nice documentation on his VCO that uses this
> approach: http://www.oldcrows.net/~patchell/synthmodules/vco.html
>
>
> George Hearn schreef:
>   
>> I'd like to modify my polysynth design to use active temperature
>> compensation by making the VCO's output a temperature reference voltage
>> that
>> has a TC of 3300ppm/c.  This would then be used to derive the DAC
>> reference
>> voltage in order to compensate for the VCO exponential converter
>> temperature
>> drift.  I would like to do this by using a MAT04 quad matched pair or
>> LM3046, using two transistors to make the exponential converter and
>> somehow
>> use the others to generate a voltage proportional to Vt.  Does anyone have
>> any ideas?  The CEM3374 had this arrangement and it was successfully
>> employed in the Oberheim XPander and Matrix 12.  Regards, George
>>
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