[R-390] Break In

[sdaitch at mor.ibb.gov]

Modify the contacts so they are make before break
physically, so the input of the external amplifier
is transferred to a load or ground.

I'd have to go dig out some old broadcast audio
console diagrams and see how they did channel
switching.  Most consoles were high level mixing
and fairly low impedance on the mixing bus, and
I also can't remember if the channel switching is
before or after the level control on the console.

I don't remember a lot of problems with audio 
popping in consoles where channels were switched 
off and on. 

73
Sheldon



> Once 
> you get that taken care of you then have to consider how badly the 
> audio pops 
> as the relay goes from passing audio, to open circuit, to grounded 
> input as the 
> relay switches. There will be another pop as the relay comes out 
> of break-in. 
> Many audio circuit things to think about as you make improvements 
> to you 
> stations operation.
> 
>