[sdiy] 440hz revisted

[Roy J. Tellason]

On Wednesday 11 January 2006 07:15 pm, Oren Leavitt wrote:
> An LC tuned Hartley (or other) oscillator with a few dividers might also
> be an option...
> LC oscs (with real inductors) are reasonbly stable.

That's what ARP did in the Omni,  as I recall...

> Tom Arnold wrote:
> >>      455*525*30
> >>f   = ---------- = 3579545,454545... Hz
> >> SC    2 * 1.001
> >>
> >>f  = 8192 * 440 = 3604480 Hz
> >> 0
> >>
> >>f  - f   = 24934,545454... Hz
> >> 0    SC
> >>
> >>That would be about 3 Hz below and you need to pull some 20k before
> >> getting it even risking sharp.
> >
> > Forgetting power of 2 and unstead using circuit complexity to use a cheap
> > crystal :
> > 8134 * 440 = 3578960 or a 500hz pull from 3579545, should be able to pull
> > 2khz easily ( 3+ if I put two crystals in parallel, look online for the
> > SuperVXO ) so its well within range although it would be nice to find
> > something that'd pull to  3.604 or 7.208 so I'm still looking...
> >
> >>A 4,4 MHz oscillator divided by 625 followed by a 7-stage binary counter
> >> would supply A1, A2, A3, A4, A5, A6, A7, A8. Simple enought.
> >
> > Would it be overkill to just use a top octave divider and a 1mhz crystal?
> >
> > :-)

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