The Parasound Halo A31 is a high-current 3-channel power amplifier designed for serious home theatre and high-performance audio systems. Designed by John Curl, it delivers 250 watts x 3 into 8 ohms and 400 watts x 3 into 4 ohms, with high-bias Class A/AB operation, balanced XLR and RCA inputs, and THX Ultra2 certification for powerful, controlled, and refined performance.
Key Features
- 250 watts x 3 into 8 ohms
- 400 watts x 3 into 4 ohms
- Designed by John Curl
- High-bias Class A/AB operation
- First ~7 watts in pure Class A
- Balanced XLR and unbalanced RCA inputs
- THX Ultra2 certified
- 1.5 kVA encapsulated toroidal transformer
- 98,400 µF power supply filter capacitance
- Direct-coupled signal path
- Auto turn-on by 12V trigger or audio signal
- Rack-mount capable 4U chassis with carry handles and rack adapter included
Warranty:
1-year manufacturer's warranty
The Parasound Halo A31 is built for listeners who want real authority, scale, and control from their front soundstage. Drop it into your system and the presentation tightens up immediately — dialogue feels more anchored, bass gains impact without sounding bloated, and demanding movie passages are delivered with far greater ease and composure. This is the kind of amplifier upgrade that transforms both music and movies.
Designed by legendary audio engineer John Curl, the A31 operates in high-bias Class A/AB, with the first approximately 7 watts in pure Class A. Parasound also uses a direct-coupled signal path, meaning there are no capacitors or inductors in the signal path, helping preserve clarity and control. A massive 1.5 kVA toroidal transformer and 98,400 µF of power supply filter capacitance ensure the amplifier can deliver clean current on demand when your system needs it most.
With 250W x 3 into 8 ohms, 400W x 3 into 4 ohms, balanced XLR and unbalanced RCA inputs, heavy-duty gold-plated speaker terminals, and THX Ultra2 certification, the Halo A31 is ideal for premium AV receiver upgrades, dedicated power amplification for LCR channels, and serious home theatre installations
Awards & Recognition
- Stereophile — Recommended Components (2012, Surround-Sound Components)
- SoundStage! Access — Reviewers’ Choice (2015)
- Secrets of Home Theater & High Fidelity — Best of 2012: Best Multichannel Amplifier
Technical Specifications
| Product Type |
3-Channel Power Amplifier |
| Amplifier Design |
High-bias Class A/AB |
| Pure Class A Operation |
First ~7 watts |
| Power Output (8 Ohms, 20Hz–20kHz, All Channels Driven) |
250 watts RMS x 3 |
| Power Output (4 Ohms, 20Hz–20kHz, All Channels Driven) |
400 watts RMS x 3 |
| Current Capacity |
60 amperes peak per channel |
| Power Bandwidth |
5Hz – 100kHz, +0/-3dB at 1 watt |
| Total Harmonic Distortion |
< 0.2% at full power |
| IM Distortion (Balanced 16V RMS) |
< 0.04% |
| Slew Rate |
> 130 V/µsecond |
| Dynamic Headroom |
> 1.5dB |
| Interchannel Crosstalk |
> 78dB at 1kHz; > 63dB at 20kHz |
| Input Sensitivity |
1V for 28.28V (THX Reference) |
| Input Impedance |
47kΩ unbalanced; 94kΩ balanced |
| Signal-to-Noise Ratio |
112dB, input shorted, IHF A-weighted |
| Damping Factor |
> 1100 at 20Hz |
| Inputs |
Unbalanced RCA, Balanced XLR |
| Gain Adjustment |
Adjustable gain up to +6dB over THX Reference level |
| Driver/Input Stage |
Complementary MOSFET driver stage and JFET input stage |
| Output Devices |
24 beta-matched 15 amp, 60 MHz bipolar output transistors |
| Power Transformer |
1.5 kVA encapsulated toroid with independent secondary windings for each channel |
| Power Supply Filter Capacitance |
98,400 µF |
| Protection Circuits |
DC Servo and relay protection circuits |
| Indicators |
AC present, channel status, high temperature |
| Speaker Terminals |
Heavy-duty 24k gold-plated 5-way binding posts |
| Certification |
THX Ultra2 |
| Auto Turn-On |
12V trigger or audio signal |
| Chassis |
4U chassis, carry handles, rack mounting adapter included |
| Dimensions |
17-1/2" W x 7-5/8" H x 20" D |
| Height Without Feet |
7" |
| Net Weight |
65 lb |
| Shipping Weight |
79 lb |
