"CyaD" wrote:
"Dave Plowman (News)" wrote in message
...
Anyone know of such a thing at a reasonable cost? I realise Vellerman do a
VCA type, but the actual audio quality isn't good, and it defaults to zero
if powered down. A kit without case and PS would be fine as it will be
built in. Or a complete unit if cheap enough.
Milford Instruments sells an IR decoder which can be used to switch power to
a motorised pot. It also learns the codes from any common remote.
http://www.milinst.com/index.htm
part # 1-933 at £29
I have used one of these in the past to make a remote switch box , with the
decoder driving relays - worked perfectly.
This is exactly what I used in my home-brew pre-amp, driving an ALPS
motorised pot. Maplin used to sell this module, but don't seem to
any more. I removed the IR detector from the PCB and mounted it on
the front panel of the case. I used a couple of switching transistors
and relays to drive the pot - possibly not the most elegant solution
but there's no chance of getting 'up' and 'down' at the same time
(with unfortunate consequences on the PSU!). I also used a buffer amp
on the output to avoid any impedance problems.
It works fine - the volume control isn't the most responsive in the
world (i.e. it's hard to achieve very small changes in level and
there's a certain lag between pressing the remote button and any
volume change). I used the other outputs from the IR module to switch
inputs and for a mute.
It can sound good too - indistinguishable to my ears from plugging my
cd player (with output level lowered) straight into the power amp.
Alternatively, I seem to remember that Creek did some simple
"pre-amps" that had IR control - they may not be what you call cheap
enough though :-)
Good luck and BRs,
Martin