I've installed a Sony "Source Switching Relay" XA-39 II this afternoon and thought I would post some information on this.
What this is:
The XA-39 II is a small relay that senses the amp remote lines from two head units and switches the RCA's accordingly.
Why use this?
To be able to listen to a slave unit (ie CD tuner) when the empeg is not present.
Where to get one?
Where else? Crutchfield
http://www.crutchfield.com/cgi-bin/S-O9cBJQ0oJQH/ProdView.asp?s=0&c=3&g=52700&I=158XA39II&o=&a=
Install notes:
The unit is a small brick approximately 5"x3"x2. Inputs are:
*Front & Rear RCA & amp sense line for sources 1 & 2.
*Switched power in.
*Ground wire (w/ring terminal attached).
Outputs are:
*Amp turn on wire (has fitting that accepts two bullet connectors if you two amps).
*Front & Rear RCA outputs.
You will need:
*RCA patch cables (up to four depending on your setup)
*Male & female bullet connectors
*The usual tools: stripper/crimper or soldering rig, multimeter, etc...
The installation is pretty straightforward. I started out thinking I'd leave the CD (slave) with inputs into the empeg as well as the switcher, but this turns out not to work because of the way the XA-39 handles the switching between the two.
The main piece of information I could not find in any of the sales literature was how the switch decided which of the two inputs to use.
The first thing I did was determine which (if any) of the inputs were passed when the switch was not powered. Source 2 passes RCA & amp lead when the switch is not powered. This meant that I'd have to use the empeg as source 2 if I wanted to use it when I had the key out of the car.
The logic of the switching is as follows:
S1=Source 1, S2=Source 2, +/- = Amp out line on/off
________S1 On_____S1 Off
S2 On___ 1+________ 2+
S2 Off___ 1+________ 2-
This information is also not present in the installation sheet which comes with the unit.
I decided to wire the switch per the installation sheet with empeg as source 2. I didn't want to install any toggle switches, so I am not able to listen to the CD when the key is out as this removes my acc power which runs the Sony switch. I can however listen to the empeg just fine with the key out.
I have the line outs from both the empeg & CD running straight into the switch and left the empeg aux inputs hanging out in the passenger wheel well in case I wanted to use a walkman for tapes (or perhaps my cell phone).
If I want to listen to the empeg the CD tuner must be off. When it is turned on, it becomes the source and the empeg continues playing (but is not heard). When I turn the CD/tuner off the empeg's output becomes active again. I suppose I could wire the CD's amp switch line into the Cell Phone sense line on the empeg and then it would pause, but I just thought of that now. Next time.
The hardest part was finding a suitable location for the switch, as it takes up a good deal of space as inputs are on one side and outputs on the other. I ended up jamming mine into an area above my accelerator. The switch comes with mounting holes and four screws, but I didn't use mine and seem to have suffered no ill effects.
Well, I hope this is useful to those of you who want tunes when the empeg is elsewhere & don't want to use the empeg as a slave unit for whatever reason (my reason was that my head unit has no inputs).
-Zeke
just say you weren't paying much attention...
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