Hi Mike,

Ooooh, analogue.  I remember that.

Possibly still available (I checked the Digikey book without success, but
RS etc. maybe?) would be bucket-brigade delay lines, which were used
extensively for audio effects (delay / spin / reverb etc.) in the olde
days.  Recoton was a manufacturer if memory serves, as I think were
NatSemi, but they've been shedding even less esoteric product than that in
recent years.

They had only so-so noise performance, but their dynamic range would be
plenty good enough for what you're suggesting.  The through delay is
varied by clocking their fixed-length chain of buckets faster or slower.

       73

               Steve        W3EEE  /  G3YDV



Mike Dennison wrote:

I have been playing around with feeding differently derived audio into
the two halves of stereo headphones with some interesting results.
I will report in detail when the tests are complete. In short, it is
certainly possible to improve headphone reception, both in terms of
close-in selectivity and resistance to static.

One question. How do I make an electronic circuit to delay a
broadband audio signal by about one-thousandth of a second,
without resorting to DSP? Any genius out there with a simple
circuit? And yes I do know about the methods (that were originally
used for electric guitar echo) such as connecting the diaphragms of
a loudspeaker and a microphone by using a spring, and also the
tape recorder method.

Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm