PDP-8/A transformer hum

Chuck Guzis cclist at sydex.com
Tue Jun 9 16:36:47 CDT 2020

On 6/9/20 2:10 PM, Josh Dersch via cctalk wrote:
> On Tue, Jun 9, 2020 at 7:44 AM Jon Elson <elson at pico-systems.com> wrote:

> Thanks Jon (and everyone else).  Yes, this is a ferroresonant transformer
> (w/matching motor-run cap), I'd just never heard one in a DEC machine that
> was so very loud.  I'll see if there's anything that needs to be screwed
> down a bit more.

Well, humming isn't always bad--I'd like my transformers to be able to
hum  "Coro a bocca chiusa" from Madame Butterfly... :)

Ferroresonant supplies do work, but make ugliness on the AC line.


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