[sdiy] Tempco group buy news

[Ian Fritz]

At 11:24 AM 5/29/05, Metrophage wrote:
>Most of the older VCOs I have seen use 2k tempcos, though some specify
>1k. Almost all of the more recent circuits I have seen specify 1k. I
>had no idea why! Of course it figures that people design circuits
>around the components which they have available. The ARP 2500 VCOs used
>100 ohm tempcos, and the later ARP VCOs used 1.87k! What makes 1k or 2k
>better?

With 2k you can put the tempco in the opamp CV summer's feedback loop and 
use a standard 100k input resistance.  The resulting voltage has to be 
attenuated slightly to get to 1 V/Oct.