Cockpit Audio wiring (hyjacked from "gear warning")

"Mike the Strike" wrote in message
oups.com...
This is probably one of the best suggestions I've heard in a long time
on RAS - feeding the vario audio to the radio intercom input so that
it's squelched when transmitting. It would be a lot easier for my old
ears to have the speaker behind my head double for this function rather
than the wimpy vario speaker in the panel.

Mike


Been RTFMs again.

The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

Bill Daniels

In article , Bill Daniels
writes

Been RTFMs again.

The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

Bill Daniels

I'm not a sparkie, but if you have an 8 ohm speaker it will have
about 0.5 volts of audio across it when sounding. At this low impedance
that will be enough for the radio. It wouldn't work if you fed a high
impedance output into a low impedance input, but its fine this way
round.

My calculation suggests for full output from the music input
you'd need getting on for 8 volts of AC but I expect that'd be enough
volume for a disco.
--
Mike Lindsay

In article ,
"Bill Daniels" wrote:
The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

If the B50 provided an unbalanced output (one side of the speaker is
returned to ground, just hook them up. It will work fine.

If the B50 puts out a balanced output (speaker floats, not connected to
ground), go by your neighborhood Radio Shack ("You have questions, we
have blank stares") and get a 273-1380 audio output transformer. Hook
the 8 ohm side to the B50 and one-half the 1K ohm side to the M760.

What an excellent thread.
Mark's Radio Crap transformer and a couple of resistors, and you're
laughing!
The vario automute function has a side benefit of keeping us off the
radio until we have the thermal centered at 14 knots, allowing
concentration on silly things like not hitting anybody else on entry.
Alle ist wunderbar in segelflugland.
Jim