{"product_id":"parasound-halo-a21-stereo-power-amplifier-in-silver-demo","title":"Parasound Halo A21+ Stereo Power Amplifier in Silver (Demo)","description":"\u003c!-- ======================================================\n     Parasound Halo A21+ Stereo Power Amplifier in Silver (Demo) — AL (bh-*) HTML\n     Two-Column Layout (Overview left \/ Specifications right)\n     Long-tail keyword used 5×: “Parasound Halo A21+ Stereo Power Amplifier in Silver (Demo)”\n     ====================================================== --\u003e\n\u003cstyle\u003e\n  .bh-wrap{max-width:1100px;margin:0 auto;padding:1rem 1.25rem;line-height:1.6}\n  .bh-title{font-size:3rem;margin:.25rem 0 1rem}\n  .bh-sub{font-style:italic;margin:0 0 1.25rem}\n  .bh-grid{display:grid;gap:1.25rem}\n  @media(min-width:900px){.bh-grid{grid-template-columns:1.3fr .7fr;align-items:start}}\n  .bh-section{margin:2rem 0}\n  .bh-section h2{margin-top:0}\n  .bh-bullets{list-style:disc;padding-left:1.25rem;margin:.5rem 0 0}\n  .bh-specs{width:100%;border-collapse:collapse}\n  .bh-specs th,.bh-specs td{border:1px solid #e5e7eb;padding:.65rem;vertical-align:top}\n  .bh-specs th{width:42%;background:#f8fafc;text-align:left}\n  .bh-badge{display:inline-block;border:1px solid #e5e7eb;border-radius:999px;padding:.2rem .6rem;margin:.15rem .3rem 0 0;font-size:.85rem}\n  .bh-badges{margin-top:.5rem}\n  .bh-faq details{border:1px solid #e5e7eb;border-radius:.5rem;padding:.75rem 1rem;margin:.5rem 0;background:#fafafa}\n  .bh-faq summary{font-weight:600;cursor:pointer}\n  .bh-note{font-size:.95rem;opacity:.9}\n  .bh-condition{display:inline-block;border:1px solid #e5e7eb;border-radius:999px;padding:.3rem .75rem;margin:.5rem 0 0;font-size:.85rem}\n\u003c\/style\u003e\n\u003cdiv class=\"bh-wrap\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Product\"\u003e\n\u003ch1 class=\"bh-title\" itemprop=\"name\"\u003eParasound Halo A21+ Stereo Power Amplifier in Silver (Demo)\u003c\/h1\u003e\n\u003cp class=\"bh-sub\"\u003eShowroom demo high-current Class A\/AB stereo power amplifier • John Curl circuit topology • 300W x 2 into 8Ω \/ 500W x 2 into 4Ω \/ 1,000W bridged mono into 8Ω • 60 amps peak current per channel • 1.3 kVA encapsulated toroid power transformer with 108,000 µF filter capacitance • JFET input stage, MOSFET driver stage, \u0026amp; 16 beta-matched bipolar output transistors • balanced XLR \u0026amp; unbalanced RCA inputs with loop outputs • heavy-duty 24k gold-plated 5-way speaker terminals • brushed silver aluminum chassis with 4U rack-mount kit • showroom verified\u003c\/p\u003e\n\u003cdiv class=\"bh-condition\"\u003eCondition: Authorized Showroom Demo • Bench-Tested, Original Packaging, Full Manufacturer Warranty\u003c\/div\u003e\n\u003cp\u003eThe \u003cstrong\u003eParasound Halo A21+ Stereo Power Amplifier in Silver (Demo)\u003c\/strong\u003e delivers monumental high-current amplification, rich Class A warmth, and iron-fisted bass authority at an exceptional showroom-demo value. Designed by legendary circuit engineer John Curl, this flagship Halo Series two-channel power amplifier outputs a conservative 300 watts per channel into 8 ohms, 500 watts per channel into 4 ohms, and 1,000 watts in bridged mono mode, backed by 60 amps of peak current per channel. Built around a massive 1.3 kVA shielded toroidal transformer with independent secondary windings and 108,000 µF of filter capacitance, this brushed-silver demo unit has been gently auditioned in our climate-controlled reference showroom, thoroughly bench-tested, and includes all original accessories and full Parasound manufacturer warranty protection.\u003c\/p\u003e\n\u003cdiv class=\"bh-grid\"\u003e\n\u003cdiv\u003e\n\u003csection id=\"features-and-tech\" class=\"bh-section\"\u003e\n\u003ch2\u003eKey Features \u0026amp; Innovations\u003c\/h2\u003e\n\u003cul class=\"bh-bullets\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eJohn Curl High-Bias Class A\/AB Circuitry\u003c\/strong\u003e — the \u003cstrong\u003eParasound Halo A21+ Stereo Power Amplifier in Silver (Demo)\u003c\/strong\u003e combines matched JFET input stages and MOSFET driver stages with 16 beta-matched 15-amp, 60 MHz bipolar output transistors, operating in pure Class A at normal listening levels before transitioning seamlessly into high-current Class AB.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e300W \/ 500W Stereo \u0026amp; 1,000W Bridged Mono Power\u003c\/strong\u003e — delivers 300 watts RMS per channel into 8 ohms and 500 watts RMS per channel into 4 ohms with both channels driven, effortlessly controlling low-impedance, difficult-to-drive reference floorstanding loudspeakers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMassive 1.3 kVA Toroidal Power Supply \u0026amp; 60A Peak Current\u003c\/strong\u003e — anchored by a heavy-duty encapsulated 1.3 kVA toroid transformer with separate windings for each channel and 108,000 µF of power supply filter capacitance, generating 60 amps of instantaneous peak current per channel for explosive orchestral and cinematic transients.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirect-Coupled Signal Path \u0026amp; Balanced XLR \/ RCA Loop-Outs\u003c\/strong\u003e — eliminates capacitors and inductors from the audio signal path for uncolored harmonic accuracy, offering discrete balanced XLR and gold-plated RCA inputs alongside loop outputs for bi-amping or daisy-chaining multiple amplifiers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4U Heavy-Duty Brushed Silver Chassis \u0026amp; Custom Protection\u003c\/strong\u003e — finished in classic Parasound brushed silver anodized aluminum with heavy-duty rear carrying handles, custom 5-way speaker binding posts accepting up to 7 AWG wire, DC servo protection, and 12V trigger automation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection id=\"faq\" class=\"bh-section bh-faq\"\u003e\n\u003ch2\u003eFAQ — Parasound Halo A21+ Silver (Demo)\u003c\/h2\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat is the condition and warranty coverage of the Parasound Halo A21+ Stereo Power Amplifier in Silver (Demo)?\u003c\/summary\u003e\n\u003cp\u003eThe \u003cstrong\u003eParasound Halo A21+ Stereo Power Amplifier in Silver (Demo)\u003c\/strong\u003e is a gently auditioned showroom display model in pristine cosmetic and electrical condition; it has passed full bench testing by our technicians, ships in its original double-boxed factory packaging with all accessories, and carries the full Parasound manufacturer warranty.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan the Halo A21+ drive demanding 4-ohm or electrostatic speakers without strain?\u003c\/summary\u003e\n\u003cp\u003eYes. With 500 watts RMS per channel into 4 ohms, 60 amps of peak current capability per channel, and a damping factor exceeding 1,100 at 20 Hz, the A21+ maintains total control over complex impedance dips in flagship loudspeakers from Bowers \u0026amp; Wilkins, MartinLogan, Magnepan, and Focal.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I bridge the A21+ into a 1,000-watt monoblock amplifier?\u003c\/summary\u003e\n\u003cp\u003eYes. A rear-panel Stereo \/ Bridged Mono switch configures the A21+ as a single 1,000-watt RMS monoblock amplifier into an 8-ohm load, allowing you to pair two units for ultimate dual-mono reference systems.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eDoes the amplifier include rack-mount hardware?\u003c\/summary\u003e\n\u003cp\u003eYes. Detachable 4U rack-mount ears and hardware are included in the box for custom equipment rack installations, or it can be placed on a standard audio shelf using its vibration-damping isolation feet.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003c\/section\u003e\n\u003csection id=\"why-buy\" class=\"bh-section\"\u003e\n\u003ch2\u003eWhy Buy From Us\u003c\/h2\u003e\n\u003cul class=\"bh-bullets\"\u003e\n\u003cli\u003eAuthorized Parasound reference dealer verifying every showroom demo component for pristine condition and backing it with full factory warranty protection\u003c\/li\u003e\n\u003cli\u003eExperienced two-channel and home theater specialists available to advise on preamplifier gain matching, balanced XLR cabling, and speaker load pairing\u003c\/li\u003e\n\u003cli\u003eDedicated post-purchase technical support for bridged mono configuration, bi-amping setups, and 12V trigger automation\u003c\/li\u003e\n\u003cli\u003eWhite-glove, fully insured freight delivery in reinforced heavy-duty double-boxed Parasound packaging on every order\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection id=\"related\" class=\"bh-section\"\u003e\n\u003ch2\u003eRelated \u0026amp; System Matches\u003c\/h2\u003e\n\u003cul class=\"bh-bullets\"\u003e\n\u003cli\u003eParasound P6 HALO 2.1 Channel Pre-amplifier with Built-in DAC\u003c\/li\u003e\n\u003cli\u003eBowers \u0026amp; Wilkins 802 D5, 804 D5, or Magnepan 2.7x reference loudspeakers\u003c\/li\u003e\n\u003cli\u003eParasound JC3+ Phono Preamplifier in Black\u003c\/li\u003e\n\u003cli\u003eWireworld MES Mini Eclipse 10 Speaker Cable Pair\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003c\/div\u003e\n\u003c!-- RIGHT COLUMN --\u003e\n\u003caside\u003e\n\u003csection id=\"specs\" class=\"bh-section\"\u003e\n\u003ch2\u003eHalo A21+ Specs\u003c\/h2\u003e\n\u003ctable class=\"bh-specs\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eCondition\u003c\/th\u003e\n\u003ctd\u003eAuthorized Showroom Demo (Bench-Tested, Original Box, Full Warranty)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eHigh-Current Class A\/AB Stereo \/ Bridged Mono Power Amplifier\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eContinuous Power (Stereo, 8 Ω)\u003c\/th\u003e\n\u003ctd\u003e300 Watts RMS x 2 (20 Hz – 20 kHz, \u0026lt; 0.1% THD, Both Channels Driven)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eContinuous Power (Stereo, 4 Ω)\u003c\/th\u003e\n\u003ctd\u003e500 Watts RMS x 2 (20 Hz – 20 kHz, \u0026lt; 0.1% THD, Both Channels Driven)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBridged Mono Power (8 Ω)\u003c\/th\u003e\n\u003ctd\u003e1,000 Watts RMS x 1 (20 Hz – 20 kHz, \u0026lt; 0.1% THD)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCurrent Capacity\u003c\/th\u003e\n\u003ctd\u003e60 Amps Peak per channel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSlew Rate\u003c\/th\u003e\n\u003ctd\u003e\u0026gt; 130 Volts per microsecond\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFrequency Response\u003c\/th\u003e\n\u003ctd\u003e5 Hz – 100 kHz (+0 \/ -3 dB) | 20 Hz – 20 kHz (+0 \/ -0.25 dB)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTotal Harmonic Distortion (THD)\u003c\/th\u003e\n\u003ctd\u003e\u0026lt; 0.1% at full power | \u0026lt; 0.03% at typical listening levels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSignal-to-Noise Ratio (SNR)\u003c\/th\u003e\n\u003ctd\u003e\u0026gt; 115 dB (Input Shorted, IHF A-Weighted)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDamping Factor\u003c\/th\u003e\n\u003ctd\u003e\u0026gt; 1,100 at 20 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eInput Sensitivity\u003c\/th\u003e\n\u003ctd\u003e1.0 V for 28.28 V Output (THX Reference Level) | Gain: 29 dB (Adjustable Trim)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAudio Inputs\u003c\/th\u003e\n\u003ctd\u003e1x Pair Balanced XLR (Pin 2 Hot), 1x Pair Unbalanced Gold-Plated RCA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eLoop Outputs\u003c\/th\u003e\n\u003ctd\u003e1x Pair Balanced XLR Loop Out, 1x Pair Unbalanced RCA Loop Out\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePower Supply\u003c\/th\u003e\n\u003ctd\u003e1.3 kVA Encapsulated Toroid Transformer with 108,000 µF Filter Capacitance\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDimensions (W x H x D)\u003c\/th\u003e\n\u003ctd\u003e17.25\" x 7.75\" x 19.75\" (437 x 197 x 502 mm) with feet \u0026amp; handles\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eNet Weight\u003c\/th\u003e\n\u003ctd\u003e71.0 lbs (32.2 kg)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp class=\"bh-note\"\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003c\/section\u003e\n\u003csection id=\"whats-in-the-box\" class=\"bh-section\"\u003e\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul class=\"bh-bullets\"\u003e\n\u003cli\u003eParasound Halo A21+ Stereo Power Amplifier in Silver (Demo unit)\u003c\/li\u003e\n\u003cli\u003eDetachable 4U heavy-duty rack-mount ears and hardware\u003c\/li\u003e\n\u003cli\u003eHeavy-duty 12 AWG detachable IEC AC power cord\u003c\/li\u003e\n\u003cli\u003e12V trigger interconnect cable\u003c\/li\u003e\n\u003cli\u003eOwner's manual and official Parasound manufacturer warranty documentation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003c!-- No purchase\/CTA section --\u003e\u003c\/aside\u003e\n\u003c\/div\u003e\n\u003cmeta itemprop=\"brand\" content=\"Parasound\"\u003e \u003cmeta itemprop=\"category\" content=\"Power Amplifiers, Stereo Amplifiers, Demo Audio Gear, High-End Audio Components\"\u003e\n\u003c\/div\u003e","brand":"Parasound","offers":[{"title":"Default Title","offer_id":53799477576046,"sku":"PARA21PLUSBLKDEMO","price":3999.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0583\/1537\/4703\/files\/Parasound-Halo-A21_-Stereo-Power-Amplifier-in-Silver-_Demo_-See-Pricing-at-Tent-Sale.webp?v=1780503137","url":"https:\/\/audiolab.com\/products\/parasound-halo-a21-stereo-power-amplifier-in-silver-demo","provider":"Audiolab","version":"1.0","type":"link"}