Parasound Halo A23+ Stereo Power Amplifier

The A23+ builds on the phenomenal performance of the A23.

Features include circuitry designed by legendary John Curl, upgraded power output, transformer, filter capacitance, internal connections, speaker terminals and cosmetics. High bias Class A/AB operation. Direct Coupled. DC Servo and relay protection circuits. 2 x XLR inputs. 2 x RCA inputs (with loop output). Independent gain controls for each channel. Ground lift controls. Input selector controls (XLR/RCA). Bridged/Stereo switch. Audio sensing on/off (withsensitivity controls). 12V trigger input & output. Power output (Stereo): 160 watts RMS x 2 at 8 Ω. 240 watts RMS x 2 at 4 Ω. Bridged Mode: 400-500 watts at 8 Ω. Heavyduty 24k gold-plated 5-way speaker binding posts. Gold-plated RCA input/output jacks. 2U Chassis, carry handles, rack mountable with HRA2 (sold separately).

Improvements from a23:

• 125 → 160 Watts (8Ω)
• 225 → 240 Watts (4Ω)
• 400 → 500 Watts (bridged)
• Filter cap: 40,000 uF →54,400 uF
• Crosstalk (20kHz): 63dB → 70dB
• Transformer size: 1.0 kVA → 1.1 kVA
• Refined Halo cosmetic with aluminum end caps & gold highlights
• Updated rear panel with heavy duty speaker terminals from HINT 6
• Upgraded internal gold on gold audio connections
• Updated auto turn on circuit

Power Output – Stereo Mode (0.06% THD)
160 watts x 2, 8 Ω both channels driven
240 watts x 2, 4 Ω both channels driven

Power Output – Stereo Mode (0.9% THD)
210 watts x 2, 8 Ω both channels driven
300 watts x 2, 4 Ω both channels driven

Power Output – Bridged Mode (0.06% THD)
500 watts x 1, 8 Ω
Bridged 4 Ω operation is not recommended

Power Output – Bridged Mode (0.9% THD)
600 watts x 1, 8 Ω
Bridged 4 Ω operation is not recommended 

*All Power measurement are at 120 VAC,
RMS continuous power, full audio band (20 Hz - 20 kHz)

Current Capacity
45 amps peak, per channel

Slew Rate
> 130 volts per microsecond

Frequency Response
5 Hz - 100 kHz, +0/-3 dB
20 Hz - 20 kHz, +0/-0.25 dB

Total Harmonic Distortion (THD)
< 0.06 % at full power
< 0.03 % at typical listening levels

IM Distortion
< 0.04 %

TIM
Unmeasurable

Inter-channel Crosstalk
> 85 dB at 1 kHz
> 70 dB at 20 kHz

Input Impedance
Unbalanced: 33 kΩ 
Balanced: 66 kΩ,(33 kΩ per leg)

Total Gain
29 dB

Input Sensitivity for 28.28 V Out (8 Ω Load)
Unbalanced: 1 V
Balanced: 1 V per leg

S/N Ratio
> 112 dB, input shorted, IHF A-weighted
> 107 dB, input shorted, unweighted

Damping Factor
> 800 at 20 Hz

DC Trigger Requirements
+9 Vdc to +12 Vdc, 5 mA

Audio Trigger Requirements
2 mV - 10 mV

XLR Pin Identification
1 = Ground (Shield)
2 = Positive
3 = Negative (Return)

Dimensions
Width: 17-1/4" (437 mm)
Depth: 15"-1/4" (388 mm)
Depth, with cables 17" (432 mm)
Height, with feet: 4-1/8" (105 mm)
Height, without feet: 3-1/2" (89 mm), 2U

Net Weight
27 lb. (12.2 kg)

Shipping Weight
34 lb. (14.4 kg)

Power Requirement
Standby: <1 Watt 
Idle (no music playing): 75 Watts 
Typical Listening levels: 125 Watts
Maximum: 800 Watts
110-125 VAC 60 Hz or 220-250 VAC 50 Hz
AC mains voltage is set on rear panel