[LAU] [Slightly OT] 312.5Hz

[Folderol]

On Sat, 15 Nov 2008 14:06:51 +1030
Matthew Smith <matt at smiffytech.com> wrote:

> Quoth James Cameron at 2008-11-15 13:30...
> 
> > What you describe reminds me of a very low frequency RF oscillator with
> > an audio tone added in.  I'd like to see a photograph of the wiggly
> > line, as I suspect it is not a simple sine wave, 
> 
> Here are the photos so far, per Plutek's request:
> <http://www.flickr.com/photos/msmiffy/sets/72157609086659400/>
> 
> I might pull the rotor off completely once I've put penetrating oil on 
> all the rusty bits - then I'll get a close-up of the entire rotor.
> 
> I'm pretty sure that the way that the line is marked would mean that the 
> tone would run as a sweep between the lower and upper frequencies - and 
> 25 times per second at that.  Should be an interesting noise - 
> especially once it's been fed into a synth ;-)
> 
> > Does it start slowly?
> That I can't tell as I haven't powered it yet.  Think I might replace 
> the capacitor first - don't know what will happen if I energise a 40 
> year old capacitor, but don't want my office full of shrapnel.
> 
> Rotor spins very freely so I'd guess that it would get to full speed 
> quite quickly.
> 
> Cheers
> 
> M
> 

Fascinating bit of kit. I'd be inclined to try to keep it as complete
and original as possible. I doubt you'd have a problem with the
capacitor. I know someone with a WW2 communications set that still has
almost all it's 'dry' caps, and only half the electrolytics have been
changed.

-- 
Will J Godfrey
http://www.musically.me.uk