921 tempco

analogmonster · October 20, 2015, 3:23pm

Hi,

which type of tempco is used for the 921 VCO, and how is it mounted?

Thanks

MC1 · October 20, 2015, 9:37pm

1K tempco in feedback loop of IC502 combined with SG3821 transistor array. The schematic shows the tempco to be thermally coupled (dashed line) to the SG3821.

http://experimentalistsanonymous.com/diy/Schematics/Oscillators%20LFOs%20and%20Signal%20Generators/Moog%20921.jpg

analogmonster · October 21, 2015, 5:26am

Great, thanks, MC.

mgrainger · December 1, 2015, 1:31am

In the early production models I believe it was mounted below the I. C. Device covered in heat sink compound.

MC1 · December 4, 2015, 5:59am

Nope.

It was a modification designed later. Was never implemented in production.