I was making analog synthesizers as a hobby back in the 80s while studying in the University. For this kind of circuitry I would reduce temperature drift by en

I was making analog synthesizers as a hobby back in the 80s while studying in the University. For this kind of circuitry I would reduce temperature drift by enclosing it into a heated thermostat kept well above room temperature. This way after initial warm up period there is very little drift.