Introduction: Thank you for choosing this Adastra 1U amplifier This product has been designed to offer reliable, high quality amplification for various installation and PA applications. In order to gain the best results from this equipment and avoid damage through misuse, please read and follow these instructions and retain for future reference.
24. Cooling Fans Phantom power switch (32V) Connection The Adastra A-series mixer-amps and S-series slaves can drive EITHER 100V line OR 4-16Ω speakers. Both types of speaker should NOT be connected together to the same amplifier. 100V Line Speakers 100V line speakers must be connected using the “100V” and “COM” screw terminals (23) on the rear panel.
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Low Impedance Speakers If standard low impedance (4Ω, 8Ω or 16Ω) speakers are being used, these should be connected to the 6.3mm output sockets on the rear panel using quality speaker jack leads. Both of these outputs are fed from the same amplifier section, which is mono.
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Inputs – Slave amplifiers The S121 and S251 slave amplifiers accept a LINE IN via 2 x RCA connectors at the rear and the same signal can be sent out to further amplifiers from the LINE OUT pair of RCA connectors. Since the amplifier is mono, all stereo inputs are summed together.
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For MIC channels priority, increasing the VOX control will cause the level of playback through the LINE or USB/FM/AUX channels will be reduced when speaking into MIC1 or MIC2. Adjust this control to achieve the required amount of “ducking” of the other channels when MIC channels are used. SPECIFICATIONS Model A121 A251 S121 S251 Power supply Switchable 110/240Vac, 50/60Hz (IEC) Output: RMS @ 4Ω...