Input Selection Board

The Input Selection Board

The Relay board will have the following features:

Each Input Selection Board will have 4 differential input channels.
Two of these boards can be stacked together for an 8 input system.(3 boards for 12, etc..)
Home Theater Bypass mode will completely bypass the external pre-amp and volume controls.
If desired, unselected inputs can be connected to ground through resistors or wires. This will help properly load down any unused equipment if desired.
The grounds are kept separate throughout.
The output of the input relays can be directed to a preamp or directly to the volume board via hardwiring.
Fully passive design uses high quality signal relays (Omron G5V 50mOhm).
4 XLR(Fully Differential) or RCA(single ended) Left and Right channel inputs.
All 4 channels have XLR (Neutrik NC3 die-cast) connectors directly on the board. However for single ended systems, it is also very easy to hardwire in RCA style connectors in place of the XLR
Three DPDT relays are used to completely switch out each channel and its corresponding gnds, it also shorts the inputs to their corresponding gnds via a resistor (or short or open as needed). This insures that all input equipment is properly loaded, and that there are no ground loop problems between equipment
NOTE: If you decide to make an input single ended. You would jump the negative lead to the incoming signals gnd(before the relays). When this channel is switched in, The negative line will then be grounded, so existing differential input pre-amps can still be used.
1 fully differential or single ended Left and Right Channel outputs.
On board microcontroller contols all relays via commands from I2C bus.
Schematics now available! NOTE: These schematics may be subject to change!

Here are the new schematics!

This schematic was added on June 18th,2003.
Click here to Download the APOX-IS1 REV. 2 input select board schematics in Adobe Acrobat pdf format

Revision 1 of this board had the XLR connector sex swapped for the inputs and outputs. This error was fixed in the latest rev. 2. The schematic has been left here for users of the older board. But the new schematic above may contain some helpful notes for the Rev. 1. users.
Click here to Download the older APOX-IS1 REV. 1 input select board schematics in Adobe Acrobat pdf format
pics New pictures coming soon!
Assembly instructions Assembly Instructions in WORD format.
P.S. Please feel free to update this document with any mistakes you may find. email it to support@apoxcontrols.com and we will post your changes.

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