Lectrosonics PA8 8-Channel Power Amplifier

Lectrosonics' PA8 8-Channel Power Amplifier is designed for distributed loudspeaker systems using mix-mminus zoning. The amplifier is typically used with Lectrosonics matrix and DSP processors for sound reinforcement systems in boardrooms, courtrooms and conferencing systems.

Eight separate power amplifiers, each with an output power capability of 10W (4 Ohms) or 6W (8 Ohms) provide amplification for each loudspeaker or zone-grouped loudspeakers in the system. The PA8 is passively cooled, and features full short-circuit and thermal overload protection. The amplifier outputs are also muted at turn-on and turn-off, to eliminate transients.

The front panel includes a power switch and individual level controls for each channel. The rear panel includes a standard 3-pin AC power socket for IEC 60320 C13 cords. Line level audio inputs and speaker level outputs are made via depluggable "Phoenix" connectors.

Two adjacent channels of a PA8 may be bridged to increase the power output. In the bridged mode, the minimum speaker load is 8 Ohms, and maximum power output is 20W at 8 Ohms. The Channel Level controls are set to the same level in this mode.

The input to the PA8 is fully balanced and RF filtered. The level control feeds a monolythic power amplifier. The amplifier has a voltage gain of 26dB (x20). Each power amplifier is internally power limited to protect itself from short circuits, excessively low load impedances, or highly reactive loads. Thermal limiting is also integrated into the power amplifier, with an intelligent shutdown mode that minimizes thermal shock to the device under extreme operation.

The PA8 uses a straightforward, low parts count design for long term reliability. The heart of the power supply of the PA8 is a low radiation toroidal transformer. The toroidal transformer generates less heat than a conventional type and emits considerably less 60 cycle energy. This is particularly important when the PA8 is used in close proximity to microphone preamplifiers.

Any two adjacent channels may be used in the bridged mode for higher power (20W into 8 Ohms or 12W into 16 Ohms).

Lectrosonics PA8 Features:

• 8 separate amplifier channels
• 10 Watts per channel into 4 Ohms in non-bridged mode,20 Watts per channel bridged into 8 Ohms
• Passively cooled
• Full short circuit and thermal overload protection
• No turn-on "thump"

Lectrosonics PA8 Specifications:

• Line Input Type: Electronically balanced and RFfiltered
• Impedance: 20k Ohms, Balanced or Unbalanced
• Rated Output:
  • 10 Watts RMS per channel at 4 Ohms
  • 6 Watts RMS perchannel at 8 Ohms
  • 20 Watts RMS bridged at 8 Ohms
• Input Level for Rated Output:
  • -2dBu (615mVRMS) at maximum level
  • +15dBu (4.36VRMS) at mid level
• Maximum System Gain
  • Line Input to Speaker Out: 20dB
• Signal-to-Noise Ratio: 88dB relative to 10W at 4 Ohms
• System THD: Less than 0.1%, 20Hz to 20kHz (10W into 4Ohms)
• System IMD: Less than 0.1%, 60Hz/7kHz (10W into 4Ohms)
• Slew Rate: 12V/uS
• Power Consumption: 200 Watts max at 120VAC
• Weight: 8 lbs., 9 ozs.
• Dimensions (WxHxD): 19" x 1.75" x 8.25"