[sdiy] 3046 vco help?

[Dave Magnuson]

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of KA4HJH
Sent: Thursday, August 18, 2011 5:25 PM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] 3046 vco help?

As I hazily recall the heater took longer to stabilize and a tempco was much
simpler. Tom had them in stock, too, so the choice was easy.

I'm sure I have the entire conversation about it in my email
archive--somewhere.

>Tempcos might be hard to get and cost more...
>Heater uses much more power, excess heat might make other components
drift...
>
>(I use tempcos epoxied to dual transistors, usually...)
>
>H^) harry

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"
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Terry is exactly right.  I have EFM VCO-4D with the heater, and they take 5
to 10 minutes to warm up.   My other tempco-based VCOs are nearly instantly
in tune.   

I think I recall Tom G saying this design was based on the Moog Sonic V,
although it's no doubt similar to the Rogue as someone else mentioned.   The
EFM VCO-4D is quite similar (from memory) with some additional waveshapers.

Dave Magnuson