Headphone Splitting

[Dwaine Hurta]

For headphone splitting, I used a 100 ohm isolation resistor
between the rig and each set of headphones in a "Y" 
configuration for the audio "hot" side, and a common ground
line.  For 4 and 8 ohm headsets, we didn't have any problems.
In one box though, I used a 100 ohm audio "l-pad" to give a variable
level output to one side when/if needed (it's more a problem that
kt5v listens to cw much as if he's on the front row of a rock
concert :-)

If you're trying to mix (or just use) 600 ohm headsets with an 
8 ohm radio (or headset in parallel), Radio Shack  sells a 
1K to 8 ohm audio transformer (center tapped) that works well
either way in the circuit.  Keeping an impedance xfmer box
around for aircraft headsets might be the thing to do...

I know that some people use Dave Clark aircraft headsets in the
shack, but the "head vise" effect must be torture beyond belief.
I use my old "stereo" headsets in the airplane and in the shack.
(I wish wb5vzl could get more Pioneer SE-205's :-)

73, Dwaine

-- 
Dwaine Hurta, N5HD  hurta at apicc.dseg.ti.com (or hurta at lobby.ti.com)
Texas Instruments, Dallas, Texas           480-1338