[sdiy] Ovens for oscillators?

[patchell]

    Yes, it would work.  In fact, some people on the list are more or less
doing that by heating up the CA3046 with an internal transistor.  The
exponential converter is the biggest contributor to temperature drift.  This is
what the Tempco resistor compensates for.  There are, of course, other
sources.  This is where an error annalysis would come in handy, to identify the
sources for temp drift and what can be done to eliminate them.  Ian Fritz has
done a lot of work doing these sort of things.  In general, most of us just
worry about the tempco of the exponential converter.

    There are four ways of dealing with the problem:
    1. Tempco resistor, has the advantage of being simple and very effective.
    2. Temp Control, has the advantage of not needing a tempco, but consumes a
lot of power.
    3. Electronic Compensation, needs no tempco, but is more complicated, and
does introduce some noise.
    4. Ignore it. (This is the Ostritch Solution).

Glen wrote:

> Hi everyone,
>
> I know that some precision quartz crystal oscillators use ovens to keep the
> circuitry's temperature elevated above room temperature by several degrees.
> The exact temperature of the oven is closely regulated, to prevent
> temperature drift affecting the components.
>
> Now I know that this sounds like an extreme measure to suggest for
> home-built synth oscillators, but has anyone tried it? Would it eliminate
> the need for special tempco resistors? I realize that if the oven's power
> failed, the oscillator might indeed need recalibration afterward, or at
> least a long warm up time before use. Unless special mobile power sources
> were employed, it would make the synth less mobile, and probably not suited
> for taking to a live gig. However, for an experimental synth that always
> stayed in one location, and always supplied power to the ovens, might it be
> useful?
>
> Later,
> Glen

--
 -Jim
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