"I expected the A51 to sound good. What I wasn't prepared for was how good it sounded right out of the box. Its midrange was totally seductive, its soundstage and imaging capabilities in the same league as some of the best gear I've ever heard at any price." - Barry Willis, Stereophile Guide to Home Theater, "Recommended Components," March/April, 2004
Raw Power Meets Elegant Circuit Design
Barry Willis praises the Parasound A51 for its "harmonic rightness" in Stereophile Guide to Home Theater for October 2003. "Its midrange was totally seductive, its soundstaging and imaging abilities in the same league as some of the best gear I've ever heard at any price... With music, the A51 radiated sweetness and light. With action films, it rained thunder and lightning. There aren't many amplifiers that can so effortlessly cover both ends of the sonic spectrum."
The Jan / Feb. 2004 Top Choice Awards issue of DVD ETC. magazine praises the Halo A51 multichannel amp and the Halo C2 surround sound processor for their "sonic performance, auto calibration, complete feature set, programmability and upgradeability."
Uncompromising Audiophile Performance
Parasound's five-channel Halo A51 power amplifier combines raw power with elegant circuit design. Designed by legendary audio guru John Curl in collaboration with CTC Builders, the Halo brings uncompromising audiophile performance to home theater.
THX Ultra 2 certification ensures movie-house quality sonics, but the Halo surpasses this critical benchmark by delivering Parasound-quality sound derived from the ultra-high-end Parasound JC-1 400-watt mono amp. Matched JFET inputs, MOSFET drivers, and high-current bipolar outputs contribute to its exceptional performance.
Class A / AB Operation and Impressive Firepower
The A51 boasts balanced inputs with discrete circuits and XLR connectors. Beautifully implemented high-bias Class A / AB operation makes the most of an impressive 250-watt-per-channel power output at 8 ohms and 400-watts-per-channel at 4 ohms. The 2.2 kVA encapsulated toroidal power transformer with independent secondary windings for each channel and 164,000 ÂµF power supply filter capacitance delivers an impressive current capacity of 60 amps per channel. The direct-coupled design uses no capacitors or inductors in signal path. The complementary MOSFET driver stage relies on the firepower of 40 beta-matched 15 amp, 60 MHz bipolar output transistors and works in combination with a JFET input stage.
"Instant" Warm-up Feature
Like all the other amps in the Halo product series, the A51 has Parasound's exclusive bias circuit, which permits the amplifier to sound perfect from the instant it's turned on, rather than having to wait for bias to gradually build up as the amp warms up over time. Very high bias allows greater Class operating range than others. Even Halo's implementation of its automatic turn-on feature is exceptional. Special relays bypass the AC "soft start" circuitry after it's done its job for the purest AC and the purest sound.
And That's Not Allâ¦
AC present, channel status, and high temperature indicators team up with DC Servo and relay protection circuits to keep this powerhouse running safely at peak performance for years of reliable service. Auto turn-on by 12-volt trigger or audio signal simplifies home theater and multi-room operation. Other features include heavy-duty 24k gold-plated 5-way speaker terminals, gold-plated RCA input jacks, and a rear-panel ground lift switch.
Circuitry designed by legendary John Curl THX Ultra2 certified High bias Class A/AB operation Balanced inputs with discrete circuits and XLR connectors Direct Coupled - no capacitors or inductors in signal path Complementary MOSFET driver stage and JFET input stage 40 beta-matched 15 amp, 60 MHz bipolar output transistors 2.2 kVA encapsulated toroid power transformer with independent secondary windings for each channel 164,000 ÂµF power supply filter capacitance DC Servo and relay protection circuits AC present, channel status, high temperature indicators Heavy-duty 24k gold-plated 5-way speaker terminals Gold-plated RCA input jacks; ground lift switch Auto turn-on by 12v trigger or audio signal 4u Chassis, carry handles, rack mounting adapter included Parasound 5 year parts, 5 years labor warranty (For USA and Canada purchases only)
HomeTheaterReview.com When it comes to high-performance, high-value power amplifiers, few do it better than Parasound. The A51, which is part of Parasound's Halo line of cost-no-object products designed in tandem with audio legend John Curl, has benchmark levels of performance, yet costs a reasonable $4,500. Cost no object, huh? If every manufacturer built sub-$5,000 cost-no-object products, the audiophile landscape would be vastly different.
Audioholics, October 2004 "The A 21 and A 51 amplifiers are both loaded with usable features above and beyond most other amplifiers in todayâs market." "The Parasound A 51 is more than capable of driving any speaker load in even the most demanding home theater systems." "The linearity of this amplifier is excellent at any power level it is operating in, and its freedom from audible noise and distortion makes it a true winner!" "The Parasound Halo A 21 and A 51 are top rate amplifiers at a great value. Parasound seems to have attended to every aspect of their design including the excellent build quality internally and externally matched with great looks." Overall Rating: 5/5 Stars - Ken Stein and Steve Dellasala
Home Cinema Choice (UK), October 2004 "The processor (C 1) offers enveloping surround sound processing, and the power amplifier is muscular. It has a hint of warmth, but nothing that suggests overhang, and the treble is unusually refined." "Indeed, Iâd rate the A 51 as one of the most transparent power amplifiers in its class. It has genuine power and authority, and delivers the kind of visceral kick that makes action films swing along with panache." Five Stars - Alvin Gold
Revue Du Son & Du Home Cinema (France), March 2004 4 Stars
Stereophile Guide to Home Theater, March 2004 AAA Recommended Component - "I expected the A 51 to sound good. What I wasn't prepared for was how good it sounded right out of the box. Its midrange was totally seductive, its soundstaging and imaging abilities in the same league as some of the best gear I've ever heard at any price."
Video (Germany), January 2004 "Mit souverÃ¤ner Kraft und perfekter Harmonie fÃ¼hrt die edle Vor-/Endstufen-Kombi von Parasound direkt ins akustische Nirvana."
"With precise force and perfect harmony the noble preamp/amplifier combination from Parasound takes you directly to acoustic Nirvana." - JÃ¼rgen SchrÃ¶der
Home Theater Buyers Guide, 2004 Featured component in Stepping Up Your System article. "Sky is the limit" system.
Image Home Entertainment (Germany), November 2003 "...als echtes Ãberraschungspaket muss Ã¼brigens die FÃ¼nfkanal-Endstufe gleten: Sie begeistert mit durchweg audiophiler KlangqualitÃ¤t, gepaart mit unerbittlicher Power..." "...lÃ¤utet der Parasound C 1 eine ganz neue Generation von AV-Controllern ein..." "...Feinheiten im Setup zeugen von Liebe zum Detail und enormer Surround-Erfahrung..." "...Fazit: Hier waren zweifellos KÃ¶nner am Werk..." "...das Teamwork mit der A 51 befÃ¶rdert den C 1 in die klanglich erste Riege..." "...der vom legendÃ¤ren Audio-Enwickler John Curl gezeichneten Endstufe..." "...diese eng beschriebene Dokument ist perfekt gemacht, leicht verstÃ¤ndlich, liefert obendrein jede Menge HintergrunderklÃ¤rungen, beschreibt das GerÃ¤t absolute vollstÃ¤ndig und kann sogar mit Internet-Hinweisen, Stichwortverzeichnis sowie ausfÃ¼hrlichen Grafiken aufwarten. Kompliment!" - Roland Kraft
"...the output stage with 5 channels must be considered as a real surprise-package: it enthuses with audiophile sound-quality without exception, joined by inexorable power..." "... the Parasound C 1 rings in a totally new generation of AV controllers..." "...refinements in the setup show the love for details and an enormous know-how for surround..." "...to sum it up: here doubtlessly experts were at work..." "... the teamwork with the A 51 promotes the C 1 to the A-grade squad in sound..." "... the output stage, drawn by legendary audio-developer John Curl..." "... this document in narrow letters is made perfectly, easy to understand, supplies furthermore a lot of background information, describes the set absolutely utterly and even offers internet-links, index and ample graphics. Congratulations!" - Roland Kraft
Stereophile Guide to Home Theater, October 2003 "If that 2-channel test drive had me thinking about buying the A 51, the multichannel experience made me want to slap down my Visa card." "With music, the A 51 radiated sweetness and light. With action films, it rained thunder and lightning. There aren't many amplifiers that can so effortlessly cover both ends of the sonic spectrum." "Beautifully designed and skillfully executed, Parasound's Halo A 51 is all the amp anyone could need..." - Barry Willis
Widescreen Review, September 2003 "From the outset, I have to say that the Parasound A 51 multichannel amplifier delivered impressively clean, effortless, detailed sound." "The Parasound Halo A 51 multichannel amplifier, with its top-notch performance for movies and music, deserves a very strong recommendation for anyone serious about quality home theatre and surround music sound." - Perry Sun
T 3 (UK), September 2003 "The A 51 has so much grunt, grip and grace, you have to restrain yourself from cranking up the volume until the walls start to ripple Matrix style." "Its high price pitches it against formidable opposition, but the C 1/A 51 pairing more than holds its own, with a combination of massive power, killer dynamics, fine transparency and user flexibility." T 3 Five Star Gold Award - David Vivian
AudioVision (Germany), August 2003 "Parasound hat mit der Kombination C 1/A 51 eine echte Alternative zu den Boliden von Lexicon und Tag McLaren geschaffen..." "Insgesamt also eine fantastische Vorstellun." - Michael Nothnagel
Hi-Fi Choice (UK), July 2003 "Robust engineering rather than radical technology sees the THX Ultra 2-specified A 51 power amplifier through the day." "...the Parasound duet (C 1/A 51) allows the most substantial loudspeakers to melt from the scene." "...rest assured that the performance of the C 1 and A 51 is as flexible and impressive as you could hope for." Editor's Choice - Paul Miller
Son & Image (Canada), June 2003
DVD Etc., May 2003 "The bass extension is simply wonderful: copious, deep, taut, and rhythmic." "The experience is so strong, that I found myself in musical nirvana..." "It is a superlative performer in the $4,000, multi-channel amp category..." Rating 98 - Manoj Motwani, M.D.
c't Kino Daheim - special (Germany), April 2003 "Ein nochmals souverÃ¤neres, prÃ¤ziseres Klangbild mit unglaublichem Bass und fantastischer RÃ¤umlichkeit" - Ulrich von LÃ¶hneysen
"And once again more sovereign (confident), more exact sound characteristic, with unbelievable bass and fantastic accommodation" - Ulrich von LÃ¶hneysen
What Hi-Fi (Russia), April 2003
"All sounds - from leaves rustling and rain, to rifles and a train's roar - are reproduced very plausibly, without any tint or digital "dirt" from compressed audio formats such as Dolby Digital. Soundtracks sound excellent, regardless of genre. Voices of actors, their emotions - all sound very plausible, giving true pleasure to any film fan. Special sound effects so loved by mystery and thriller creators are magnificent. During 'The Call' the viewer remains literally chained to the armchair. Creaks, leaves rustling, steps - all so realistic that it forces even people with nerves of steel to shudder. In a word, an outstanding set. Listen to it - you will not regret."