Parasound HALO A23+ Power Amp

The Halo A 23+ power amplifier combines exceptional power and performance. With two channels delivering 125 watts per channel into 8 Ω, it offers a compelling audio experience. The high bias Class A/AB operation ensures accurate and detailed sound reproduction. Its stable operation into 2 Ω loads provides flexibility for various speaker configurations. The direct-coupled design, free from capacitors in the signal path, maintains signal purity and enhances transparency. With balanced XLR and unbalanced RCA inputs and A/B speaker terminals, it offers versatility and compatibility. Experience exceptional power and performance with the Halo A 23+ power amplifier.

 

Two channels @ 125 watts per channel @ 8 Ω
- High bias Class A/AB operation
- Stable into 2 Ω loads
- Direct-coupled without capacitors in the signal path
- Balanced XLR and unbalanced RCA inputs
- A/B speaker terminals

Changes from the original A 23→A 23+

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

Features

160 watts x 2 @ 8 Ω RMS, both channels driven

240 watts x 2 @ 4 Ω RMS, both channels driven

500 watts x 1 @ 8 Ω, in bridged mode

Circuitry designed by legendary John Curl

High bias Class A/AB operation

45 amperes peak current per channel

Stable with speaker impedance dips below 2 Ω

Balanced inputs with discrete circuits

Heavy-duty 24k gold-plated 5-way speaker binding posts

Gold-plated RCA input & loop output jacks

Direct-coupled signal path, no capacitors or inductors

DC Servo and relay protection circuits

AC turn-on inrush surge protection with relay bypass

JFET input stage, MOSFET driver stage

12 beta-matched 15 ampere, 60 MHz bipolar output transistors

1.1 kVA shielded toroid transformer w/ independent windings for each channel

Independent power supplies for input stage, driver stage and output stage

54,400 µF filter capacitors for output stages

Full power is rated all the way down to 5Hz for unrestricted low-end bass

Harris hyper-fast soft-recovery bridge diode rectifiers

Automatic turn-on by 12 V trigger or audio sensing

2 rack space chassis with rear carry handles

Rack mount hardware available separately

Specs

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