The HD-MA35UA is a four input audio mixer amplifier for systems demanding the broadest range of features and the highest energy efficiency. Two output power amplifier zones, 35 watts (Zone 1) and 4 watts (Zone 2), are driven from high-efficiency Class D amplifier stages. The mixer and amplifier sections all normally shut down (standby "sleep" mode) when audio is absent and automatically turn on when needed. The Zone 1 amplifier output level may be VCA controlled using various optional RDL remote controls, or by industry standard 0 to 10 Vdc or 0 to 10k ohm controls. This output provides a constant voltage output (25 V, 70 V or 100 V). The Zone 2 amplifier output drives an 8 ohm speaker and/or 600 ohm telephone equipment.

The HD-MA35UA is engineered, tested and manufactured in the U.S.A. to strict energy conservation standards. The unit consumes less than 1 watt of mains power in standby mode, and meets power amplifier efficiency specifications with analog-filtered Class-D digital output stages for both power amplifier output zones and for the 600 ohm output.

The HD-MA35UA features two mixers. The Zone 1 mixer is located on the front-panel providing user level and tone controls for the 35 watt amplifier output. The tone controls adjust the equalization at the Zone 1 amplifier output and can be switch selected on the rear panel to also adjust the equalization at the line-level output. The Zone 2 mixer on the rear panel provides level trimmers normally set by the installer to provide music-on-hold and/or for background music in a small zone equipped with an 8 ohm speaker. The Zone 2 section includes a 4 watt amplifier, a 600 ohm transformer-balanced MOH output, and an active balanced line-level output that may be used to feed another audio power amplifier.

The HD-MA35UA has four inputs that are common to both mixers. Inputs 1 and 2 accept balanced mic or line level sources. Inputs 3 and 4 accept unbalanced mono or stereo line-level sources.

• Four inputs with individual front-panel volume controls
• Bass and Treble tone controls
• Designed for background music with paging and music-on-hold
• Master volume VCA controlled with remote adjustment capability
• Manual or automatic (VOX) priority ducking
• Balanced inputs and amplified outputs on detachable terminal blocks
• Unbalanced inputs and outputs on RCA jacks
• Includes power supply
• Automatic sleep mode meets strictest energy saving standards

• Amplifier Zones (2): Zone 1 (Main): 35 W RMS, front-panel mixer (user controls); Zone 2: 4 W RMS (8 Ohms), rear-panel mixer (trimmers)
• Audio Inputs (5): 2, balanced, mic or line switch selectable on terminal blocks; 2, unbalanced stereo summing inputs on RCA jacks; 1, unbalanced amp in on RCA jack
• Gain Adjustments (2): Inputs 1 and 2: Rear-panel single-turn trimmer
• Maximum Input Level: Mic Inputs: -9 dBu; Balanced line inputs: + 20 dBu; Unbalanced Inputs: + 5 dBV (+11 dBV, one input); (for 1% THD+N at output)
• Phantom Voltage: 24 Vdc (IEC 1938: 1996-12), switch-selectable for each mic input
• Ducking/Muting Actuation: Automatic (Input 1 VOX: rear-panel adjustable signal threshold with LED indicator) or Manual (contact closure to ground)
• Ducking/Muting Release Delay: Rear-panel single-turn trimmer, adjustable 2 to 6 seconds
• Ducking/Muting: Switch-selectable for inputs 2, 3 and/or 4, 25 dB ducking attenuation, nominal
• Effects Loop: Unbalanced RCA jacks (preamp output from main mixer, input to power amplifier)
• External RDL Module Power Output: 24 Vdc, 100 mA maximum, ground-referenced
• Input level (to cross compressor threshold equaling 23 W amplified output): Mic Inputs: -50 dBu (2.5 mV), (front panel and rear trimmer at max.)
  Balanced line inputs: -21 dBu (70 mV), (front panel and rear trimmer at max.)
  Unbalanced Inputs: -15 dBV (180 mV), (front panel and rear trimmer at max., both inputs driven)
• Noise (line or amplified outputs): Mic or Balanced line inputs: -70 dB (below compressor threshold at max gain); Unbalanced Inputs: <-75 dB (max gain)
• THD+N: < 0.5% (1 kHz at compressor threshold, main amp output); < 0.1% (line output, main)
• CMRR:
• Mic inputs: > 50 dB (50 Hz to 120 Hz); Balanced line inputs: > 80 dB (50 Hz to 120 Hz, transformer-coupled input)
• Compressor: Threshold 2 dB below rated output, automatically adjusting attack and release times
• Frequency Response (mixer): Mic to line output: +/-1.5 dB (40 Hz to 25 kHz); Balanced line input to line output: +/-1 dB (20 Hz to 20 kHz); Unbalanced line input to line output: +/-0.5 dB (20 Hz to 20 kHz)
• Frequency Response (amplifiers): Constant voltage: +/-3 dB (50 Hz to 18 kHz); 4/8 Ohm: +/-1 dB (50 Hz to 20 kHz)
• Tone Controls: +/-10 dB @ 10 kHz, +/-9 dB @ 100 Hz (front-panel) with center detent
• Audio Outputs (2): -10 dBV nominal (316 mV), dual mono unbalanced RCA (main mixer; FLAT or EQUALIZED, switch-selectable on rear panel); 0 dBu nominal balanced, terminal block (zone 2 mixer)
• MOH Output: 0 dBu nominal (775 mV), 600 Ohm transformer-isolated, 16 dB headroom
• Power Amplifier Outputs (2): Zone 1 (main): 35 W RMS (25, 70 or 100 V); Zone 2: 4 W (8 Ohms, on detachable terminal block)
• Indicators (9): Front-panel: Signal present (4; 1 per input, green), Compressor activity (red), Power (bright=on, dim=standby, blue); Rear-panel: dual-LED VU meter (for inputs 1 and 2, green/red), Ducking/muting threshold (yellow)
• VCA: Zone 1 (main) master level (with switch-selectable input 1 bypass), 0 to 10 Vdc control, RJ45 (compatible with RDL VCA wall controls)
• Front-panel controls (7): Zone 1 (main) mixer level controls (4, inputs 1 through 4), EQ (2, bass and treble), Power (momentary pushbutton, toggle on/standby)
• Rear-panel controls (22): Gain trimmers (2, input 1 and 2), Mic/Line switch (2, input 1 and 2), Zone 1 line output pre/post-EQ switch, Effects loop bypass switch, Sleep (standby) mode delay (4 binary switches), Input 1 ducking/muting detector sensitivity trimmer, Phantom voltage switches (2, input 1 and 2), Ducking control switches (3, to duck inputs 2, 3, and/or 4), VCA paging bypass (includes or excludes input 1 from master VCA control), Zone 2 mixer level controls (4, inputs 1 through 4)
• Efficiency Standard: "Energy Star® Program Requirements for Audio/Video" Version 2.0
• Sleep Mode Power Consumption: < 1 W (amplifier and included power supply)
• Sleep Mode Delay: 10 minutes to 2 hours (switch-selectable in 10 minute increments)
• Sleep Mode Disable: Selectable
• Active Mode Delay: 2 seconds (nominal) after input audio detected
• Audio Detector Threshold: -80 dBu mic (at max input gain), -55 d