{"product_id":"parasound-halo-a21-power-amplifier","title":"Parasound Halo A21+ Power Amplifier","description":"\u003cdiv class=\"woocommerce-product-details__short-description\"\u003e\n\u003cp\u003eParasound's A21+ power amplifier is 71 pounds and \u003cmeta charset=\"utf-8\"\u003edelivers a whopping 300 watts per channel of clean power thanks to its \u003cmeta charset=\"utf-8\"\u003elarge toroidal transformer inside. This amplifier represents a new unparalleled value in amplifier performance. \u003cmeta charset=\"utf-8\"\u003eStable enough to drive just about any speakers you might care to hook up. This amp is an improvement upon the company’s original Halo A21, which was a popular choice among audiophiles during its own 15-year run. This newer “plus” version has a refined new look, and offers more power and improved specs almost across the board. Details like soundstage depth, focus, and texture is where the A 21+ puts real distance from the A 21. The A 21+ is exceptional and provides an awe-striking feel.\u003c\/p\u003e\n\u003cp\u003eIn bridged mode, the A21+ really turns on the firehose, putting out an amazing 1,000 watts into a single channel. All that power comes from a beefy toroidal transformer and a high-bias Class A\/AB amplifier design that help your system reproduce music with stunning clarity and accuracy. On the back panel are balanced XLR and unbalanced RCA inputs for each channel, and each has its own individual gain control knob and loop output. There are also binding posts for connecting a pair of speakers. The amp can be rack mounted using the included ears.\u003c\/p\u003e\n\u003cp\u003eThe A 21+ features circuitry designed by John Curl, a legend in audio engineering. He started his career in the 1970s, designing tape and video recorders at Ampex, and he had a hand in building the Grateful Dead’s famous Wall of Sound. Curl has worked with Parasound since 1989, designing all of their high-power amplifiers and more. The power supply, transistors, capacitors and other parts in the A 21+ were chosen to offer high performance at a reasonable price.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch4\u003eFeatures \u0026amp; Specifications:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ch5\u003eChanges from the original A 21→A 21+\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli\u003e250 → 300 Watts (8Ω)\u003c\/li\u003e\n\u003cli\u003e400 → 500 Watts (4Ω)\u003c\/li\u003e\n\u003cli\u003e750 → 1000 Watts (bridged)\u003c\/li\u003e\n\u003cli\u003eFilter cap: 88,000 uF → 108,000 uF\u003c\/li\u003e\n\u003cli\u003eS\/N: 112dB → 115 dB\u003c\/li\u003e\n\u003cli\u003eTHD (at full power): 0.2% → 0.1%\u003c\/li\u003e\n\u003cli\u003eCrosstalk (20kHz): 63dB → 70dB\u003c\/li\u003e\n\u003cli\u003eTransformer size: 1.2 kVA → 1.3 kVA\u003c\/li\u003e\n\u003cli\u003eWeight: 60 LB → 71 LB\u003c\/li\u003e\n\u003cli\u003eRefined Halo cosmetic with aluminum end caps \u0026amp; gold highlights\u003c\/li\u003e\n\u003cli\u003eUpdated rear panel with heavy duty speaker terminals from JC 5\u003c\/li\u003e\n\u003cli\u003eUpgraded internal gold on gold audio connections\u003c\/li\u003e\n\u003cli\u003eUpdated auto turn on circuit\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eAll Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e300 watts x 2 @ 8 Ω RMS, both channels driven\u003c\/li\u003e\n\u003cli\u003e500 watts x 2 @ 4 Ω RMS, both channels driven\u003c\/li\u003e\n\u003cli\u003e1000 watts x 1 @ 8 Ω, in bridged mode\u003c\/li\u003e\n\u003cli\u003eCircuitry designed by legendary John Curl\u003c\/li\u003e\n\u003cli\u003eHigh bias Class A\/AB operation\u003c\/li\u003e\n\u003cli\u003e60 amperes peak current per channel\u003c\/li\u003e\n\u003cli\u003eStable with speaker impedance dips to 1.5 Ω\u003c\/li\u003e\n\u003cli\u003eBalanced inputs with discrete circuits\u003c\/li\u003e\n\u003cli\u003eCHK Infinium, custom 5-way speaker binding posts\u003c\/li\u003e\n\u003cli\u003eGold-plated RCA input \u0026amp; loop output jacks\u003c\/li\u003e\n\u003cli\u003eDirect-coupled signal path, no capacitors or inductors\u003c\/li\u003e\n\u003cli\u003eDC Servo and relay protection circuits\u003c\/li\u003e\n\u003cli\u003eAC turn-on inrush surge protection with relay bypass\u003c\/li\u003e\n\u003cli\u003eJFET input stage, MOSFET driver stage\u003c\/li\u003e\n\u003cli\u003e16 beta-matched 15 ampere, 60 MHz bipolar output transistors\u003c\/li\u003e\n\u003cli\u003e1.3 kVA shielded toroid transformer w\/ independent windings for each channel\u003c\/li\u003e\n\u003cli\u003eIndependent power supplies for input stage, driver stage and output stage\u003c\/li\u003e\n\u003cli\u003e108,000 µF filter capacitors for output stages\u003c\/li\u003e\n\u003cli\u003eFull power is rated all the way down to 5Hz for unrestricted low-end bass\u003c\/li\u003e\n\u003cli\u003eHarris hyper-fast soft-recovery bridge diode rectifiers\u003c\/li\u003e\n\u003cli\u003eAutomatic turn-on by 12 V trigger or audio sensing\u003c\/li\u003e\n\u003cli\u003e4 rack space chassis with rear carry handles\u003c\/li\u003e\n\u003cli\u003eRack mount hardware is included\u003c\/li\u003e\n\u003cli\u003eAvailable in silver or black\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePower Output – Stereo Mode (0.1% THD)\u003c\/b\u003e\u003cbr\u003e300 watts x 2, 8 Ω both channels driven\u003cbr\u003e500 watts x 2, 4 Ω both channels driven\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePower Output – Bridged Mode (0.1% THD)\u003c\/b\u003e\u003cbr\u003e1000 watts x 1, 8 Ω\u003cbr\u003eBridged 4 Ω operation is not recommendedPower measurement are at 120 VAC:\u003cbr\u003e0.1% THD, RMS continuous power,\u003cbr\u003efull audio band (20 Hz – 20 kHz)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eCurrent Capacity\u003c\/b\u003e\u003cbr\u003e60 amps peak, per channel\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSlew Rate\u003c\/b\u003e\u003cbr\u003e\u0026gt; 130 volts per microsecond\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFrequency Response\u003c\/b\u003e\u003cbr\u003e5 Hz – 100 kHz, +0\/-3 dB\u003cbr\u003e20 Hz – 20 kHz, +0\/-0.25 dB\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eTotal Harmonic Distortion (THD)\u003c\/b\u003e\u003cbr\u003e\u0026lt; 0.1 % at full power\u003cbr\u003e\u0026lt; 0.03 % at typical listening levels\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eIM Distortion\u003c\/b\u003e\u003cbr\u003e\u0026lt; 0.04 %\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eTIM\u003c\/b\u003e\u003cbr\u003eUnmeasurable\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eInter-channel Crosstalk\u003c\/b\u003e\u003cbr\u003e\u0026gt; 80 dB at 1 kHz\u003cbr\u003e\u0026gt; 70 dB at 20 kHz\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eInput Impedance\u003c\/b\u003e\u003cbr\u003eUnbalanced: 33 kΩ\u003cbr\u003eBalanced: 66 kΩ,(33 kΩ per leg)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eTotal Gain\u003c\/b\u003e\u003cbr\u003e29 dB\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eInput Sensitivity for 28.28 V Output into 8 Ω\u003c\/b\u003e\u003cbr\u003eUnbalanced: 1 V\u003cbr\u003eBalanced: 1 V per leg\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eS\/N Ratio\u003c\/b\u003e\u003cbr\u003e\u0026gt; 115 dB, input shorted, IHF A-weighted\u003cbr\u003e\u0026gt; 110 dB, input shorted, unweighted\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eDamping Factor\u003c\/b\u003e\u003cbr\u003e\u0026gt; 1100 at 20 Hz\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eDC Trigger Requirements\u003c\/b\u003e\u003cbr\u003e+9 Vdc to +12 Vdc, 5 mA\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAudio Trigger Requirements\u003c\/b\u003e\u003cbr\u003e2 mV – 10 mV\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eXLR Pin Identification\u003c\/b\u003e\u003cbr\u003e1 = Ground (Shield)\u003cbr\u003e2 = Positive\u003cbr\u003e3 = Negative (Return)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eDimensions\u003c\/b\u003e\u003cbr\u003eWidth: 17-5\/8″ (448 mm)\u003cbr\u003eHeight without feet: 7-1\/8″ (181 mm)\u003cbr\u003eHeight with feet: 7-3\/4″ ” (197 mm)\u003cbr\u003eDepth: 20″ (508 mm)\u003cbr\u003eDepth with cables: 21-1\/2″ (546 mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eNet Weight\u003c\/b\u003e\u003cbr\u003e71 lb. (32.2 kg)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eShipping Weight\u003c\/b\u003e\u003cbr\u003e88 lb. (39.9 kg)\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePower Requirement\u003c\/b\u003e\u003cbr\u003eStandby: 1 Watt\u003cbr\u003eIdle (no music playing): 160 Watts\u003cbr\u003eTypical Listening levels: 300 Watts\u003cbr\u003eMaximum: 1400 Watts\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Parasound","offers":[{"title":"Default Title","offer_id":47816335425777,"sku":null,"price":7350.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0942\/5024\/files\/Parasound-HaloA21_-front-noteworthyaudio-1000x.jpg?v=1771516196","url":"https:\/\/www.noteworthyaudio.com\/products\/parasound-halo-a21-power-amplifier","provider":"Noteworthy Audio","version":"1.0","type":"link"}