User manual RANE MA 3

[. . . ] If you are running series or parallel combinations, be sure and check your total load impedance. For constant-voltage distribution, consider using the optional TF 407 (40 W / 70. 7 V) or TF 410 (40 W / 100 V) transformer. Transformers may be installed inside the MA 3 on any number of Output Channels required. If you intend to use constant-voltage distribution transformers, you may want to read RaneNote 136 "Constant-Voltage Audio Distribution Systems" (contained in this booklet). [. . . ] All three Channels have turn-on and turn-off muting to reduce switching transients. Manual-2 REAR PANEL DESCRIPTION IEC cord socket: This connector accepts a standard IEC line cord (included with 120 V domestic units). Plug this into a grounded AC outlet of 120 VAC (or 230 VAC if the MA 3 is internally wired for 230 V operation). OUTPUTS: Connect the speaker(s) to each of the three Channels by means of the Euroblock connectors with 18 to 12 AWG wire. Each Output may have an optional 70. 7V or 100V distribution transformer installed inside the MA 3. These optional transformers are 40 watt devices with 0. 5 dB insertion loss at rated power and a frequency response of 50 Hz to 15 kHz, ±1 dB. The 70. 7 V transformer kit is the TF 407. INPUTS are balanced Euroblock connectors. We recommend the use of at least 18 AWG wire for reliability. Driving the MA 3 from a balanced source is recommended. If you must drive the MA 3 Input with an unbalanced source, we recommend using a cable that has two conductors plus a shield. Connect the (+) or "hot" source to the MA 3 (+) Input, the ground to the MA 3 (­) Input and connect the shield to the MA 3 shield input. Do not connect the shield on the source end. Shield connections go directly to chassis ground and should not be used as signal ground. Shield connection to chassis occurs via the screw found between the Input and Output connectors--keep this screw tight for improved EMI protection. When operating the MA 3 with unbalanced Inputs, be sure to keep cable lengths as short as possible. Refer to RaneNote 110, "Sound System Interconnection" (included in this booklet) for additional information. LEVEL controls adjust the input sensitivity for each of the three Amplifiers. The internal Limiters have maximum operating range (most amount of limiting before input overload) when the LEVEL controls are set to maximum. For best system noise performance, the input sensitivity may be reduced to send a "hotter" signal to the Amplifier. There are always tradeoffs to be made (better overdrive capability or lower system noise). For additional information see RaneNote 135 "Setting Sound System Level Controls" available from our website or upon request from the factory. The NORMAL setting (switch out) allows the MA 3 to deliver full rated continuous average power into 4 ohms, all Channels driven, with ambient room temperature of 22°C. [. . . ] It has the ability to instantaneously monitor the temperature of the power device die, yielding a level of reliability not achievable with discrete designs. 80 Hz Highpass Filters Internal jumpers allow independently selecting 80 Hz, 2nd-order Butterworth Filters for each Channel. These Filters are useful when using small bookshelf speakers or small constant voltage distribution transformers. Optional constant voltage distribution transformers Up to three 70. 7 V or 100 V constant voltage distribution transformers may be mounted inside the MA 3. [. . . ]