[R-390] 390A audio

[Tim Shoppa]

> Rasputin Novgorod <priapulus at yahoo.com> writes:
> These useful things should be available surplus and cheap.
> I'd forgotten I'd had it. I'd actually bought it for
> the audio oscillator. These old fashioned CL oscillators
> are suppose to be much cleaner than modern synthesized
> oscillators, and I wanted to pair it with my distortion analyzer.
> When I bought it, I didn't see any use for the patch bay,
> and I had better meters; I'm glad I kept and restored it all.
>
> Google shows Fair Radio with one. It's too expensive, but 
> nice photo:
> <http://www.fairradio.com/catalog.php?mode=view&categoryid=187>

Those sorts of test sets are a bargain at any price!

For super-low-distortion oscillators look at Jim Williams' Linear Technologies
app notes. Wien bridge oscillators engineered down to 0.001% distortion
- very very good stuff.

But putting "390A audio" and "0.001% distortion" in the same E-mail
message seems like comparing a firehose with a syringe or a micropipette:-)

Tim.