news from parasound backgrounder photo library


For immediate release:

CES Booth:  Venetian Ballrooms
Level 2 - Veronese 2501A


Parasound Introduces a 250-Watt Three-channel
Home Theater Power Amplifier in its High-end Halo Series.


A 31 A 31
Parasound Halo A 31 Power Amplifier (Click any photo on this page for a large 300 dpi view)

San Francisco (1/9/12)  -- Parasound has added a powerful new three-channel power amplifier to its premium Halo product family. The THX Ultra2 certified Parasound Halo A 31, which is rated at 250 RMS watts per channel, is sonically identical to the company's renowned five channel Halo A 51 and two channel Halo A 21 amplifiers.

The A 31 was developed for Parasound customers who want their surround systems to include uncompromised reproduction of stereo music.  The A 31 is ideal for this because it also provides matched amplification for the center channel speaker.

Here are some of the practical applications for the A 31:

  • Powering the C, LS, and RS channel speakers when a separate two-channel amplifier (or pair of monoblocks) is used for the L and R channel speakers.
  • For L, C and R “one wall” theater systems without surround speakers.
  • Powering the LS, RS and single back channel speaker in a 6.1 system.

"It’s interesting how history repeats itself," said Parasound's president, Richard Schram. "In the earliest days of 5.1 home theater, we built two very popular three-channel amplifiers called the HCA-1203 and HCA-2003 that enabled people to repurpose their existing stereo systems for home theater surround sound. With today’s renewed interest in high end two channel the A 31 offers a uniquely  practical way to get the best of both worlds.”  

The Parasound Halo A 31 provides high-bias Class A/AB operation with pure Class A operation up to 7 watts per channel.  It easily delivers 250 watts per channel into 8 ohms and 400 watts into 4 ohms, all channels driven. Exceptional sound quality is maintained with XLR balanced inputs as a step-up alternative to the RCA single-ended inputs. Parasound's traditional Halo topology employs matched pairs of complementary JFETs for its input-pre-driver stages, matched pairs of complementary MOSFETs in its driver stages and 8 beta-matched 15 amp, 60 MHz bipolar output transistors for each channel.

The A 31 is direct coupled, and uses no capacitors or inductors in signal path with full power output down to 5 Hz. The loudspeakers are connected via heavy-duty 24k gold-plated five-way speaker terminals, and each is relay protected. 

The power supply consists of a 1.35kVA encapsulated toroid power transformer with independent secondary windings for each channel.  Power stability is maintained by four premium power-supply filter capacitors per channel totaling 94,000µF, and protected by DC servos and relay protection circuits.

The Parasound A 31 provides a gain control for each channel offering ±6db relative to THX reference level.  This enables the A 31 to play louder in very large rooms and facilitates level matching with other amplifiers. Other features include: auto turn-on options by an audio signal with a threshold adjust or a 12v trigger with input and loop out jacks plus indicators for AC power, channel status, and high temperature. The heavy-duty 4u chassis has rear carry handles, and an included rack-mounting adaptor. The front panel is anodized aluminum.

The Parasound Halo A 31 will be available in April with a manufacturer's suggested retail price of $3,000.

About Parasound:  Founded in 1981, Parasound Products, Inc., is a privately owned U.S. company that specializes in providing affordable audio and home theater components to the critical listener. Parasound's products are available from quality audio/video retailers, and select custom installation specialists in over 50 countries. For more information, visit or call 415-397-7100.

#  #  # 

Full specifications below


        Continuous power output:
        250 watts RMS x 3, 20 Hz - 20 kHz, 8 Ω, all channels driven
        400 watts RMS x 3, 20 Hz - 20 kHz, 4 Ω, all channels driven

        Current capacity:
        60 amperes peak per channel

        Power bandwidth:
        5 Hz - 100 kHz, +0/-3 dB at 1 watt

        Total harmonic distortion:
        < 0.2 % at full power

        IM distortion: balanced 16 V rms
        < 0.04 %

        Slew rate:
        > 130 V/µsecond

        Dynamic headroom:
        > 1.5 dB 

        Interchannel crosstalk:
        > 78 dB at 1 kHz;
        > 63 dB at 20 kHz

        Input sensitivity:
        1 V for 28.28 V (THX Reference)

        Input impedance:
        47 k Ω unbalanced; 94 k Ω balanced

        S/N ratio:
        112 dB, input shorted, IHF A-weighted

        Damping factor:
        > 1100 at 20 Hz

        17-1/4" w x 7-5/8" h x 19-1/8" d, 7" h without feet

        Net weight: 65 lb.

        Shipping weight: 79 lb.







Press Contact:

Gordon Sell   

908 788-0700


Gordon Sell
Public Relations

Parasound Products, Inc.
McKinnon Ave.
San Francisco CA   94124

(415) 397-7100

Gordon Sell Public Relations
63 Main Street
Flemington, NJ 08822

(908) 788-0700