Speaker Connections; Input Connections - Adastra A4 User Manual

Speaker connections

The A4 has 4 speaker output channels (Ch1, Ch2, Ch3, Ch4) which can be assigned as 2 independent stereo
zones – i.e. Left 1 + Right 1 and Left 2 + Right 2 outputs.
For each output, connect "–" to the "–" speaker terminal(s) and "+" to the "+" speaker terminal(s)
Connect speakers with a combined impedance of no lower than 4Ω to each output channel.
• If the speakers being connected are 4Ω, then connect only 1
speaker to each channel.
• If the speakers are 8Ω, you can connect up to 2 speakers in
parallel to each channel.
• If the speakers are 16Ω, you can connect up to 4 speakers in
parallel to each channel.
Some example wiring diagrams are shown opposite with speakers
connected in parallel.
The impedance of the load measured in "Ohms" (Ω) will also
determine the power output. The amplifier delivers its maximum
power output at the minimum impedance rating (4Ω). Higher
impedances result in lower outputs.
The combined load on each output shares the power from the
amplifier. If the amplifier is delivering 200W to 2 speakers
connected in parallel with the same impedance, they must each be
capable of handling 100W.

Input connections

The A4 has 2 microphone inputs and 4 selectable stereo sources (one of which is the internal media player)
Connect wired microphone(s) to the Mic 1 and/or Mic 2 jack inputs (6.3mm) on the front panel (17, 18)
The volume level of these is controlled by the Mic 1 and Mic 2 volume controls (19, 20)
Mic 1 and Mic 2 inputs are always fed to all outputs, whereas stereo inputs are selected independently.
A smart phone, tablet or mp3 player can be connected to the Aux jack (3.5mm) on the front panel (4)
The volume level of this stereo input is controlled by the Aux volume control (5)
To hear this input through the speakers, "AUX" must be selected on the relative input selector (9 or 22)
On the rear panel, there are 2 further stereo line inputs for connecting CD/DVD players, DVB/DAB tuners etc.
Line 1 input has a choice of Left + Right 6.3mm jack (33) or RCA inputs (34)
The volume level of this input is controlled by the Line 1 volume control (7)
To hear this input through the speakers, "LINE 1" must be selected on the relative input selector (9 or 22)
Line 2 has Left + Right RCA inputs (29)
The volume level of this input is controlled by the Line 2 volume control (8)
To hear this input through the speakers, "LINE 2" must be selected on the relative input selector (9 or 22)
The mix of mic/line inputs to Ch1+Ch2 can be fed onto further equipment via the RCA line output (35)
The mix of mic/line inputs to Ch3+Ch4 can be fed onto further equipment via the RCA line output (30)
For good reception of FM radio stations (if needed) in the media player, the A4 has an "F" connector on the
rear panel (28) which can be connected to an external FM antenna (aerial)
Connect the IEC power inlet (38) to the 230Vac mains supply, using the IEC lead provided.
953.404UK User Manual