|Parasound - Halo A23 Balanced Amplifier
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"Editors' Choice Award" 2012 - The Absolute Sound Magazine
"Rhythmically Right" THX Ultra 2-Certified Amp
Parasound's Halo A 23 stereo amplifier combines superior technology, incredible sound, advanced features, and attractive industrial design. With high current Class A/AB amplification, smooth sounding MOSFET drivers, and balanced XLR inputs, it will bring out the best in any source material from Franz Schubert to The Avengers
The A 23 won the coveted "Editors' Choice Award" in the October 2007 issue of The Absolute Sound magazine, which calls it "musically involving."
"It was so rhythmically right," marvels Shane Buettner in The Absolute Sound. "The subtlest aspects of musical timing were always apparent..." According to Buettner, "I was impressed with the A23's resolution, which was really quite astonishing."
Auditioning the Halo A23 power amp and the P3 preamp together, Eric Hetherington writes in December 1, 2004 GoodSound! review, "I found the Parasounds’ sonic virtues to be many and their overall value to be greater than their prices. Good value and good sound: a winning combination!" He concludes, "Anyone seeking a new pre-power pair within the GoodSound! price range owes it to him- or herself to check these out."
The A 23 boasts 125 watts of THX Ultra 2 certified power per channel at 8 ohms and includes an adjustable audio sensitivity trigger as well as a 12-volt trigger for ease of operation with other hi-fi and home theater components. At 4 ohms, the Halo delivers 200 watts per channel, and can also be operated in bridged mono for a power delivery of 400 watts.
Advanced John Curl-Designed Circuitry
The circuitry of the A23 was engineered by legendary audio designer John Curl. Its direct-coupled topology uses no capacitors or inductors in the signal path for pure, uncolored sound. Balanced inputs with discrete circuits and XLR connectors yield dead quiet operation. The complementary JFET input stage and MOSFET drive stage incorporates 12 beta-matched 15 amp, 60 MHz bipolar output transistors for pristine sound. The high-bias "Class A"/"Class AB" operation blends best sound with highest efficiency performance.
The A23's custom-made, high-current power supply is specially designed for exceptionally quiet operation along with ample power for climactic music passages. The 785VA encapsulated toroidal power transformer uses independent secondary windings for each channel along with a 48,000 µF power supply filter capacitance. DC servo and relay protection circuits keep operation safe and reliable. And Parasound backs the A23's reliability with an impressive 10-year warranty for parts and five years for service.
No Need for a Remote
The front panel of the A23 looks great even when the unit is turned off. When you switch the Halo on, LEDs display AC-present, channel, and high temperature status. Adjustable signal sensing can be set to automatically power up the A23 when it receives a signal from your preamp or other compatible component (or when it receives a 12-volt trigger command), eliminating the need for yet another wireless remote! The rear panel includes gain controls, heavy-duty 24k gold-plated five-way speaker binding posts, and a ground lift switch that can help eliminate any audible hum caused by the presence of ground loops in your hi-fi or home theater system.
"You'll Have to Spend a Whole Lot More for Better"
"You'll have to spend more money to get better performance, in many cases a lot more," cautions Shane Buettner in The Absolute Sound. "This Halo P3 / A23 combo is the kind of system that should be celebrated as an invitation to participate in high-end audio as a hobby. And it continues Parasound's tradition of giving people more performance for the money than they have any right to expect."
Owner’s Manual (1.5mb PDF)
Parasound products cannot be shipped outside the USA.
- Circuitry designed by legendary John Curl
- Lucasfilm Home THX Ultra 2 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
- 12 beta-matched 15 amp, 60 MHz bipolar output transistors
785 VA encapsulated toroid power transformer with independent secondary windings for each channel
- 48,000 µF power supply filter capacitance
- DC Servo and relay protection circuits
- AC present, channel status, high temperature displays
- Gold-plated RCA input jacks, loop output jacks
- Auto turn-on by 12v trigger or audio signal
- Heavy-duty 24k gold-plated 5-way speaker binding posts
- Rear mounted gain controls, ground lift switch
- Continuous power output:
- 125 watts RMS x 2, 20 Hz - 20 kHz, 8 ohms, both channels driven
- 200 watts RMS x 2, 20 Hz - 20 kHz, 4 ohms, both channels driven
- 400 watts RMS x 1, 20 Hz - 20 kHz, 8 ohms
- Current capacity: 45 amperes peak per channel
- Signal-to-noise ratio: > 112 dB, input shorted, IHF A-weighted
- Total harmonic distortion: < 0.06 % at full power
- IM distortion: < 0.04 %
- Power bandwidth: 5 Hz - 100 kHz, +0/-3 dB at 1 watt
- Slew rate: >130 V/µsecond
- Dynamic headroom: > 1.5 dB
- Interchannel crosstalk: > 80 dB at 1 kHz; > 63 dB at 20 kHz
- Input sensitivity: 1 V for 28.28 V, THX Reference Level
- Input impedance: 33 k_
- Damping factor: > 800 at 20 Hz
- Voltage: Switchable for 110V – 120V or 220V – 240V operation
- Dimensions: 17-1/4" w x 4-1/8" h x 13-1/4" d, 3-5/8" h without feet
- Net weight: 28 lbs.
- Manufacturer’s limited warranty: 5 years parts, 5 years labor
"It was so rhythmically right. The subtlest aspects of musical timing were always apparent with the Halo gear, even with pieces featuring solo piano. Rhythm and pace form one of the foundations of music, and that's the most exciting thing about the Halo combo's presentation: a trait that was best expressed when the two units were paired, as they were designed to be."
"I was impressed with the A23's resolution, which was really quite astonishing."
"You'll have to spend more money to get better performance, in many cases a lot more. This Halo P3 / A23 combo is the kind of system that should be celebrated as an invitation to participate in high-end audio as a hobby. And it continues Parasound's tradition of giving people more performance for the money than they have any right to expect."
- Shane Buettner, The Absolute Sound, 2002
Finalist: Parasound Halo A23 Power Amp -- The Absolute Sound, Power Amplifier of the Year Under $3,000
"What does $850 buy in today's power-amplifier market? Lots of great sound, according to Shane Buettner, who called Parasound's new 125WPC Halo A23 an amazing bargain."
"[The Halo A23] possesses a musical rightness and sense of timing that makes it unusually communicative."
--The Absolute Sound, February/March 2003.
||If your speakers are 90db efficient or better this is the amp for you
|Wadia 381 direct into the A23 driving
Usher Compass X-929 speakers.
All electronics off Furman Reference IT-15i conditioner. I use PS Audio ac cords,
Kimber KS-1121 XLRs cd to amp and DH Labs Q-10 speaker wire.
The A23 is of excellent build quality both parts and layout...and most importantly sounds great.
I wont go in to all the audiophool drooling superlatives but will say this is imo one of the best amps for the money in its power class.
Kudos to John Curl and Richard Schram for bringing high quality products to our hobby as there is surely no lack of stupid-expensive products whose performance rarely dictates the insane asking price.
THANK YOU PARASOUND!!!
When you consider the AA 30 day demo and a 5 year warranty from Parasound youd have to be crazy to spend more money|
|- Eric R, MO|
|I bought a pair to use with a Bryston BP-6: this is a great combination. Bought the BP-6 first, and the A-23’s brought the potential of it to life. The combination brings focus and imaging that get your attention. Timbre on acoustic instruments is a little cold when new, but becomes neutral with break-in. Sounds better over long term. Played ‘Green Carnation’s’ “Light of day, day of Darkness” when had units about 2 weeks, and didn’t really hear anything different: played it after two months of break-in, and heard more subtlety and detail—lots of chances in this song of 1 hour and 6 seconds long. About features: has XLR and RCA inputs, and can be ‘daisy chained’ through a pair of RCA’s. Can go stereo or monoblock, has ‘trigger’, and has a filter for IM noise switchable from back. The lights on front add an unexpected element of cool and flash that were unexpected-the red shield with a “P” is lit, and blue around the switch at all times, with 2 blue power lights when power on. From construction, engineering, sound, and price, a hard unit to beat for people on a budget. Very impressive.|
|- Vernon H, TX|
|Like the previous reviewer, Kevin from WY, I am a committed tube amp advocate. I love the warmth that tubes provide for classical music. My main system includes a Unison Research Unico SE hybrid integrated being fed by a Benchmark DAC1 and in turn feeding Vandersteen 2c Signature speakers with low end help from Velodyne DD-12 and REL Q100 subs. My interest in the Halo A23 was as an alternative to the tube sound for rock, folk, blues, etc., where more accuracy in the frequency extremes can be crucial. I purchased the A23 and it is being driven by my Benchmark DAC1 in preamp mode. Digital source is a Sony 9100ES SACD/CD player.
All I can say is that the A23 is a truly fine solid state amp! Boy, have they come a looong way since I last had one in my system!! My impressions after about ten days are that: 1. You need to allow at least 24 hours of burn-in before you really listen to the A23. It was bright and undernourished and maybe even clinical during the first few hours, but it improved tremendously after that. The mid-range now approaches what I hear from my Unico SE. I have them wired so that I can quickly A/B them and the main difference is that the high end is more apparent and better resolved by the A23. 2. My tests of piano, violin, symphony and Fender bass guitar recordings have been passed with flying colors by the Benchmark/Halo A23 combo -- a match made in heaven! 3. Which brings me to the last point -- component combinations really matter a lot and perhaps the problem Kevin of WY had was not so much with the A23 as with his system combinations along with his desire to have the A23 sound like tubes. Kevin does not identify his sources and speakers, so its hard to say if system mismatches may be part of the issue.
Finally, the A23 is a superb solid state amp that has the ability to bring out the best and also reveal the worst in your records. Thats about all I could want from an amp costing less than $1000. GREAT VALUE!|
|- Dave D, ME|
||A little disappointing
|I bought two of these for bi-amping. Visually, they are beautiful amplifers and are very well built. Sonically, however, they are leaving me wanting.
These are the least expensive comps in my system...by far. My preamp and universal player each cost $5,500, for example. I bought them to try because of the rave reviews. One of the great pleasures in this hobby is to find a bargain.
Yes, these amps do sound OK but, in my system at least, they sound like $850- no more. And, lest you think it unfair of my to judge these in a system with much costlier componenets, I also have an Outlaw RR2150 receiver that has spent a lot of time in my main system. In many ways, the $699 Outlaw sounds better to me-both as a receiver and using the amp-in
connections with my tube preamp.
The most disappointing aspect of the Halo A23 is its clinical sound. A lot of the reviews say neutral and actually praise the midrange. I say it goes beyond neutral to the clinical. There are a lot of midrange harmonics and overtones that are present with my other applification that I do not hear with these amps- or at least to a lot lesser degree. Acoustic guitar and piano are prime examples.
The bass is tight, but lacks some authority and bloom where appropriate. The mids and highs are very detailed, but lack a smooth, liquid character. There is definitely a processed sound to these amps versus a natural feel. The Outlaw receiver has a smoother, liquid mid-range and the bass has more impact, if not as much detail and tightness. The bass with the Halo is, again, more clinical.
The soundstage is wide and has good imaging, but lacks some depth compared to what Im used to- even when compared to the Outlaw. Dynamics are no better than the Outlaw.
I really wanted to like these, but I dont see me keeping them. Thankfully AA offers a 30 day return policy. Who knows-maybe these will be your ticket. Give them a try since you have nothing to lose here with AAs generous satisfaction policy. For me though, theyre going back.|
|- JASON W, WY|