Over the years, we have received numerous questions
	about setting up the Zone 2 functions on receivers. Zone 2 refers to a
	stereo line-level output on the back of the receiver that can be used to
	drive a power amplifier in a second room so you can have background music at
	a party, for example.Since Zone 2 is most
	often line-level (about 1 Volt or so), you need to have an additional power
	amplifier either right next to the receiver, or in the next room where you
	have the Zone 2 speakers.
	For Zone 2 operation, the main receiver acts as a
	volume control and source selector. Therefore, it is not necessary to waste
	money on an integrated amplifier that has a lot of features you would never
	use.
	We looked around for basic two-channel amplifiers
	that might be used in Zone 2 situations. The AudioSource AMP-100 is our
	first selection for this purpose. In fact, the AMP-100 is designed
	specifically for custom install projects, and has the basic things you would
	need for use in Zone 2, namely, auto-on, auto-switching for two inputs, and
	two sets of speaker outputs (Speaker Set A and Speaker Set B).
	The Design
	The AMP-100 outputs 50 watts per channel into 8
	Ohms. This is perfect for Zone 2 and background music at parties, or for
	just having dinner by yourselves.
	The front panel of the amplifier has an on/off
	switch, buttons for selecting Speaker Set A or B, and a volume control for
	each channel.
	The rear panel has RCA jacks for two sets of stereo
	inputs, as well as a line-out for Input Set 2. This lets you forward the
	signal for Input 2 to another room (Zone 3) if you like. In other words, you
	could then have the receiver send CD music to the den or bedroom, through
	the Input 2 line-out on the AMP-100. Of course, you would need an additional
	power amplifier in Zone 3.
	The back panel also has a slider switch for bridging
	the AMP-100, but I don't think that is of real use in a Zone 2 situation.
	There is a slider for setting the AMP-100 to Manual-On or Auto-On. For Zone
	2, you would probably want to set it to Auto-On so that it turns on when you
	activate the Zone 2 operation from the main receiver.
	There are two sets of speaker binding posts for each
	channel, one set for Speaker Set A and one set for Speaker Set B. Thus, you
	can activate either set. For example, you could have one set in the dining
	room and another in the kitchen. Both sets of speakers can be active at the
	same time.
	The AMP-100 AC power cord is two-conductor, so it is
	unlikely that you will encounter ground loops with typical two-conductor
	power cord receivers.
	The on-board volume controls make it easy to fine
	tune the volume in Zone 2 rather than having to go back to the main
	receiver.
	Auto switching for two inputs means you can use the
	AMP-100 to drive a second source that is not part of the receiver. For
	example, the second input could be used with the line-out from a TV in the
	dining room, when you want to have more volume. The auto-switching gives
	Input 1 priority, so when it is turned off, and Input 2 is active, the
	amplifier switches over to Input 2.
	
	In Use
	I tested the AMP-100 using stereo outputs from
	several of my sources as well as just connecting them to a CD player
	directly.
	The AMP-100 is not designed to compete with high
	powered, expensive two-channel amplifiers. Nevertheless, I was pleasantly
	surprised at how good it does sound. Part of this is due to the fact that
	the AMP-100 is made overseas at manufacturing facilities that produce
	thousands of amplifiers for various OEM contracts all over the world. So,
	you are getting a lot for your money.
	With only 50 watts per channel, the AMP-100 runs out
	of steam as the volume is cranked, but that is not its purpose. At modest
	volume, actually a little higher than one might set it for background music,
	the AudioSource performed well, giving plenty of detail, tight bass, and no
	background hum or noise. If you want to play "Jurassic Lunch" with the 8 Hz
	footsteps, into low impedance, low sensitivity speakers, forget it. But for
	Beethoven, at coffee and dessert SPLs, it's very nice. If you want more
	power in Zone 2, say for dancing, you might go with the
	
	AudioSource AMP-3.
	The built-in volume controls are handy for
	situations where one speaker might be farther away from the dinner table
	than the other, so you can turn up the volume on the farther distance
	speaker.
	Conclusions
	The AudioSource AMP-100 is a nicely featured, good
	performing, two-channel amplifier that is perfect for Zone 2 operation. At
	its price (I saw it for $103 at an Internet store), you simply cannot go wrong.
	 
    - John E. Johnson, Jr. -