E AC Input Use the included power cord to connect your amplifier to an AC power source. F Master Power Switch Turns the current to the amplifier on or off. NOTE: The picture below is an AT2007 seven-channel model. It differs from the AT3007 only in the extra space on the panel. Other models ranging from two to six channels will only have two to six sets of balanced audio inputs, unbalanced audio inputs and speaker outputs. Input Connections Connecting the amplifier to your source equipment is si

Place lugs between the plastic cap and the back of the terminal. Be sure to observe proper polarity, using the appropriate speaker hook-up icons for your system’s configuration. Using your fingers, tighten to obtain a positive contact. When using banana plugs, connections may be made by simply inserting the jack affixed to your speaker wire into the hole provided on the rear of the colored screw caps on the binding posts. Before using banana type jacks, make certain that the plastic screw caps a

Always start with a low volume level on your controller or preamp to avoid damage to your speakers. Manual On Simply press the front panel power switch to the “up” position. There will be a short pause from the time the power is turned on until power is applied to the speakers. This is intentional, and protects your speakers from damage while the amplifier stabilizes. To turn the unit off, press the Power button downward. The ON indicator light will go out and the STANDBY light will illuminate.

Plug the AC adapter into a switched outlet on the source device that will be activated when you wish to have the amplifier turn on. This may be the switched outlet at the rear of an AC receiver or other audio equipment. Connect the 3.5mm mini- plug from the adapter to the trigger-input jack on the back panel of the amplifier. The amplifier will now turn on and off automatically, based on the status of the controlling device. Power Connection Once all audio and system connections have been made,

No user serviceable parts inside. Refer servicing to qualified service personnel. WARNING: To reduce the risk of fire or electric shock, do not expose this appliance to rain or moisture. The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user to the presence of uninsulated “dangerous voltage” within the product’s enclosure that may be of sufficient magnitude to constitute a risk of electrical shock to persons. The exclamation point within an equilateral

Page 3 Unpacking ............................................... Page 3 Precautions .............................................. Page 4 Safety Instructions .................................... Page 5 Notes On “Hum” ........................................ Page 6 Cooling .................................................... Page 7 Placement ................................................ Page 7 Rack Mounting ......................................... Page 7 Electrical Connections ...............

audio.com DESCRIPTION The SUM100 Summing Amplifier is an inexpensive, high performance amplifier that is designed as a line level stereo to mono summing amplifier. It is also useful as a gain block, and as an impedance converter and summing for IHF (RCA type) signals. The inputs provide balanced 40Kohm bridging impedance for line levels up to +24dBm. The high input impedance allows the SUM100 inputs to also bridge 10dBu (hi-fi, RCA plug) lines without loading. Front panel, screwdriver adjust, fu