Parasound Halo A 21 and A 51 Amplifier Review

[steve]

Parasound is a privately-owned San Francisco based company, founded and operated since 1981 by still-acting President Richard Schram. The Parasound mission has been to provide affordable high-end audio components, for the dedicated audiophile, home theater enthusiast and custom audio/video designer. After spending considerable time with the Parasound Halo A 51 (Five Channel Amplifier) and A 21 (Two Channel Amplifier), it was easy to see that Parasound completed their mission. The A 51 / A 21 performed exemplary in our bench tests. Coupled with the Parasound Halo C1 / C2 Processor was a complete package to satiate any audiophile’s desire for high performance home theater and uncompromised two channel audio.

Read the A 51 & A 21 Amplifier Reviews

 

[Diablo]

How much heat do these amps produce, do they have fans, how much space is necessary for proper ventilation?

 

[surveyor]

The Halo amps look great. From the review, I would consider them to be a very good value. I would think there worth every penny!
I'm very envious.
Another excellent review!
Kelly

 

[warnerwh]

How much heat do these amps produce, do they have fans, how much space is necessary for proper ventilation?

Being class A/AB designs they get very warm. It's uncomfortable to put your hand on the heat sinks of my HCA 3500 for a period of time and the new A21 is a very similar design only it runs 8 watts in class A where the 3500 I use runs 15. I live in Oregon so for most of the year this is good. It literally helps warm my room. IOW these amps need to have good ventilation, they have no fans.

 

[Ken]

How much heat do these amps produce, do they have fans, how much space is necessary for proper ventilation?

Warnerwh is correct it is hot to the touch. It does not have any fans but there is an ample amount of heat sink to dissipate the heat. My shelf unit is 2' x 2' with only the back exposed. I removed the shelf above it to give it ample room to breathe. Parasound recommends 3 inches around the sides and 6 inches of clearance above the unit and don't forget that it weighs 60 pounds. Hope this helps.

Ken Stein
Audioholics

 

[Ken]

The Halo amps look great. From the review, I would consider them to be a very good value. I would think there worth every penny!
I'm very envious.
Another excellent review!
Kelly

Thanks Kelly. The Halo is an excellent value, there's a lot of bang for the buck.

Ken Stein
Audioholics

 

[toquemon]

Really impressive, i tought you had to spend a ridiculous amount of money to be a pride owner of a high end system. But, how much would it cost if i put a Parasound preamp?. Should i waste the capabilities of this amp if i connect my Yamaha RX-V1400 as a preamp?. Excuse me, but i have a limited budget.

 

[gene]

Should i waste the capabilities of this amp if i connect my Yamaha RX-V1400 as a preamp?. Excuse me, but i have a limited budget.

Why not try it and see how you like it? I am currently doing an install with a RX-V2500 as preamp to a dedicated 7CH power amp. Good receivers serve well as preamp duties and usually outgun most dedicated processors that cost over 2X more in terms of bass management, features, processing, etc.

Down the road you can always upgrade to a dedicated processor, put the RX-V1400 in a second room and have the best of both worlds.

 

[toquemon]

Well, if i put my Yamaha in another room I still have to spend in a preamp, haven't I?
The thing is that I could buy this amp, but my bank account would be in zero for the next six months. Does it worth it? I mean, if I put my receiver as a preamp with the Parasound, can i expect better sound than if I buy the Yamaha Z-9 or the Denon 5805?. This is the main reason i don't wanna buy an overpriced piece of gear. If i attend to the affirmations of Mr. Mtrycrafts, this effort (buying the Parasound) will be worthless; on the other side, if I attend to the affirmations of Mr. Av_Phile this effort would be my first step to the sonic Nirvana. I'm a little confused here because a few months ago me and my friends performed a test between receivers, on the top line a Nakamichi AV-10 (700 to 1000 bucks) and on the bottom line a Sony-something receiver (300 bucks), well, none of us could hear a difference. I'm very worried about this because it would be very frustrating if I get this Parasound and then happen to hear no difference at all. Another thing, I really think this Nakamichi is overpriced, but if it's not?. If it's correct to buy this Parasound with its premp i can save money for the preamp later, but i need to be sure about this. Here in Mexico the dealers don't borrow the "demo" amps for you to test them; this is an unilateral choice: you buy them or you don't. What do you recomend?

 

[gene]

toquemon;

The law of diminishing returns between flagship receivers vs separates comes rather quickly. Since both products are usually designed excellently, there should be little to no sonic differences in most applications.

To spend more $$$ on electronics without first addressing the following is fruitless IMO:
1) Room acoustics
2) Proper Speaker Placement
3) Proper calibration

I went from a top of the line Aragon powered system with 8008 series amps, even a notch above the Parasound Halo's, to a Yamaha RX-Z9 / Denon AVR-5803 and heard very little difference for my application.

Here are the reasons why however:
1) My speakers are moderately high efficiency > 90dB
2) All of my speakers are crossed over at 80Hz
3) My main speakers have a very flat impedance response curve making them an easy load to drive by any decent amp
4) I have multiple subwoofers in my system (this is where the bulk of power is needed)
5) My room is not the perfect acoustical environment, but its pretty decent and lively
6) My room is moderately sized (20 x 18 x 10) or 3600 cubic feet

Before upgrading your equipment and spending more hard earned $$$, make sure you have first addressed 3 issues I previously mentioned. Many people don't realize just how well you can make a moderately priced system sound if its properly integrated into the room as opposed to spending high $$$ on electronics with poor system integration.

 

[toquemon]

Thanks Gene.

 

[blownrx7]

RE: Parasound A51 Review clarification

I own a Parasound A51 and concur with the reviewer that it sounds great. Imaging, tonal balance, bass tightness etc are incredible. With power to spare and good looks to boot, this will probably be the last multi-channel amp I ever buy (until they come out with Dolby 9.2 ). However, there needs to be some clarification regarding differences in features between the A21 and A51. The A51 does NOT have pass thru connectors or gain controls. Also, the A51 does NOT have any provision for bridging any of the channels. Also, one of the negatives should be how tight the speaker connectors are grouped together. Banana plugs are the way to go or else you risk the distinct possibility of shorting out connections. That being said, I feel the A51 is one of the BEST values in high-end multi-channel amplification. BTW, I use this amp along with a Proceed AMP3 for my AV system (hmm, maybe I should take another look at the A21...).

 

[Ken]

With power to spare and good looks to boot, this will probably be the last multi-channel amp I ever buy (until they come out with Dolby 9.2 ).

Just buy another A51 and you'll be ready for Dolby 10.4.

Ken Stein
Audioholics

 

[mickster1972]

Parasound Halo Amps vs. Integra Research and/or Balanced Audio Tech

Has anyone directly compared the Parasound amps to either the Integra Research or BAT amps? I am considering one of the 3, and can't find any except the Parasound in my area (Sacramento, CA). I would be using an Onkyo TXNR900 as a preprocessor, eventually switching to something like the Integra research with balanced outputs... Thanks!

 

[gene]

Both are good amps and are integrated into our reference systems. The Parasound will deliver more power in low impedance loads than the Integra Research. If you need more power, you may wish to consider the Parasound.

 

[jeffs.]

Damping Factor

Trying to connect the dots between your review of the A21 and the article "Damping Factor: Effects On System Response". In the review, you said "the Parasound had tighter bass [than the Acurus A250] which is probably attributed to a better damping factor." Yet, the other article on Audioholics suggested that changes in damping factor should not be the cause of audible amplifier differences. (http://www.audioholics.com/techtips/audioprinciples/amplifiers/dampingfactor2.php)

So, why cite damping factor as a cause for sonic differences between the two amps?