Parasound Halo C 2 Surround Processor and A 51 Multi-Channel Amplifier Reviewed

Published On: April 17, 2003
Last Updated on: October 31, 2020
We May Earn From Purchases Via Links

Parasound Halo C 2 Surround Processor and A 51 Multi-Channel Amplifier Reviewed

Parasound is one of those companies that has been steadily churning out products that have provided intelligent engineering and great value for the money for the better part of two decades. Richard Schram, the owner, enlisted the help of...

Parasound Halo C 2 Surround Processor and A 51 Multi-Channel Amplifier Reviewed

  • The staff at is comprised of experts who are dedicated to helping you make better informed buying decisions.


Parasound is one of those companies that has been steadily churning out products that have provided intelligent engineering and great value for the money for the better part of two decades. Richard Schram, the owner, enlisted the help of renowned audio engineer John Curl a decade ago to help with the design of Parasound's amplifiers. This has resulted in a series of well-received amplifiers that also scored well on the value front.

Additional Resources
Read more Parasound Reviews from here.
Read more high performance HDMI AV Preamp Reviews from Parasound, Lexicon, NAD, Sunfire, Krell, Meridian and many other brands...

Over the past few years, the Parasound lineup has changed very little as work has commenced on their new flagship Halo line of audio products. When the Halo line was first shown last year at CES, there was an enormous amount of attention because the products (which have not been shown in actual operation) were not only very interesting technically, but simply stunning aesthetically. The buzz around the Halo line grew louder over the past year as more details have become available, and crescendoed this past January at CES as they were finally about to be released. Richard Schram has been overwhelmed already with the response to the Halo line, but has been kind enough to send one of the very few C 2/A 51 combinations available for review to DVD ETC. and yours truly.

The Halo lineup has within it two surround sound processors, the $6,000 C 1 and $4,000 C 2. The C 1 has a 5" LCD screen so your television and projector does not need to be turned on to use the menus or preview a disc, and does have a few extra features over the C 2 such as an extra component input. The C 2 is the real value of the pair (even though it is not as sexy as the C 1), as you get pretty much the same audio innards as the C 1 without some of the extras for less money, so we chose to review the C 2.

The $4,000 A 51 amplifier is a John Curl design, and uses the same circuit topology as the JC 1, the flagship monoblock amplifier that has already received critical acclaim since its release. This is an excellent pedigree to be derived from and, although the 5-channel A 51 cannot match the sheer, total grunt of the single channel JC 1, it still does not fare too badly at 250 watts per channel at 8 ohms, and 400 watts at 4 ohms. It also has a peak current output of 60 amps, a significant number for those of you who own difficult-to-drive speakers that crave current as if it's an addiction.

C 2 Processor

Unique Features - When the C 2 processor arrived, I found it very intelligently double boxed. To my greater surprise, I found the processor in a purple velvet drawstring bag instead of just a plastic cover--a very nice, sophisticated touch, which might alone be enough to make me buy it. When removed from the bag, the first words from my mouth were "simply stunning." The C 2 has a curved polished aluminum front panel with a central blue LED display, exit and menu buttons surrounded by blue LEDs to the right, and mute and dimming buttons also lit to the left. Next to the latter is the IR remote window, the headphone jack and the calibration microphone jack. The indented trough that runs along the bottom has the power switch, zone switch, source switch, and surround mode switch. These four buttons are surrounded by a blue "halo" of light that is dim while the unit is in standby, and brightens when powered up (hence, the Halo name). A jewel-like touch is added to the center by a red lit "P" above the Parasound name that also brightens upon power-up. The rest of the metal casing is in a light grey that matches perfectly. Fit, finish, and build quality are beyond reproach, and the overall effect is beautiful, and very elegant. Although some may find the extra lights to look a little busy in comparison to the simplicity of the Krell equipment (a comment by the Lady Jacqueline who rated the C 2 a lofty 9 on the LJAF), I find the aesthetics to be among the best available. In this, Parasound is very much like KEF, as its cosmetics have now gone from dowdy to art deco beautiful.

Parasound continues to impress once the remote box is opened as it contains the excellent Home Theater MX-700 remote system which comes with a small "sidekick" ancillary remote, and a cable to hook it up to your computer for programming. The remote is also in a lovely shade of subtle silver-gray with bluish-teal backlighting. Another box contains the power cord, a bag of RCA-BNC connectors for the component jacks, the calibration microphone, and trigger cords. Even the manual is easy to read and carefully explains the workings of the C 2 in plain English.

Installation/Setup/Ease of Use - Turning to the back of the C 2 reveals a system similar to the Krell Showcase with completely assignable S-video, composite, analog audio, digital audio (Toslink and coaxial), and 12 volt triggers. There are balanced and unbalanced outputs for all channels, one pair of balanced analog inputs, and a 7.1 analog input for SACD/DVD-Audio players. There are outputs for a second zone, and controls are switched for either zone by the front zone button. The component video switching is very wide bandwidth, easily handling even 1080p switching, and consists of two inputs and one output. Both curiously enough, are not in RCA format, but the more stable, higher end BNC connectors. Those with regular RCA cables need not fret, as the conversion connectors are included. Right smack in the middle of the back panel is a small metal plate that is intended as a future expansion port (Firewire, HDMI switching perhaps?), as well as a "Made in Finland" logo. Yes folks, the C 2 was designed and built mainly in Finland, by all of those intelligent engineers that have to spend those cold, long, dark winter days indoors.

The C 2 is fully stocked with all of the latest surround modes including DD EX, Pro Logic II, DTS Neo:6, nix Ultra 2 processing, and Stereo96 which up-samples from 48 kHz to 96 kHz. There are also modes to compress the dynamic range for late night watching, and an EBass mode which feeds bass information from all channels to the subwoofer even if they are set to "large" in the setup menu. This is very handy, as it allows you to switch from the remote whether or not you want deep bass information going to your speakers or not. Speaking of the setup menu, it, too, is logical, easy to use, and very flexible. In fact, I found it overall one of the easier setup menus I have used. The source inputs are initially called video 1-6 and audio 1-4, and they can all be renamed in the setup menu. There is a flexible crossover for the subwoofer that ranges the cutoff from 40 to 140 Hz in 10 Hz increments. There is also Halo Setup software that allows you to set all of the parameters of the C 2 using a computer hooked up with a (yes, again included) serial cable.

In addition to the normal 7.1 setup there are four other channels that can be used. There is an output for an extra subwoofer, and one that provides under 20 Hz signals for a tactile transducer. The other two channels are much more special as they are completely programmable. These two channels can be used to setup speakers pretty much anywhere you want from a "height" speaker placed on the ceiling above the display, to an extra pair of surrounds for a long theater room. The information from these speakers is completely programmable from the 7.1 channels. Let's say you want to create an extra pair of surrounds for a long room. The information can be mixed partially from the surrounds and partially from the fronts. It can also be filtered to remove certain low or high frequencies. By the same virtue height channels can be created by mixing parts of the center, left and right speakers and rolling off the high frequencies so it is not overly prominent. I did not try these programmable channels, as I simply am not equipped with a room that can house all of these extra speakers, but these may be the tweaker's ultimate delight. Think you can do one better than Dolby Labs or THX? Here's your chance to create a 10-channel system.

The auto calibration system is very unique, allowing for proper setup of levels and distances by a microphone connected to the processor and placed in the main listening position. The microphone plugs into the front panel, the auto-calibration sequences are activated, the microphone is held close to the level of your ears. The processor goes through three tests for each channel, and determines distance and level compared to reference level. Thankfully, it does so at moderate noise levels and in short bursts of pink noise, as long exposure to loud pink noise is something I like to avoid if I can. Overall, I found it to be fairly accurate, and I only made a couple of minor tweaks afterwards. Although one can take out the SPL meter and work on this manually, this really makes life a lot simpler for the majority of buyers, and I think it is a real plus in a processor.

The C 2 was set up in my system using AudioQuest Python interconnects between the C 2, the amp, and sources. Digital connections were via AudioQuest Optilink-5 and VSD-4 cables. Video cables used were Tributaries S-video and component. Power conditioning was supplied by a Monster HTPS 7000. AudioQuest Gibraltar speaker cables were used between the amp and KEF Reference 207 fronts, 204c center, and 201 rears. Amps used were the Classé CAV-150, the Parasound A 52, and the Parasound A 51.

Final Take - After assessing all that, and giving the unit appropriate time to break in, it was finally time to start listening to the C 2 and see if it actually lives up sonically to all of the hype. First off was using the Krell DVD Standard as a transport and assessing the sonic signature of the C 2. The midrange is slightly laid back, expansive, and crisp like my reference Krell Showcase processor. The top end is slightly rolled off, but clear and transparent. The bass drive is dynamic, rhythmic and taut. The imaging is excellent, and the soundstage wide--just about as wide as the Krell Showcase. In fact, except for the slightly rolled off top end, the crispness and expansiveness reminded me of the Krell. The overall performance was very good for two-channel.

When tested as an analog pre-amp with the balanced outputs of the Krell DVD Standard, the rhythmic bass drive remained, but the midrange and top end opened up and sparkled even more. It was as if a veil had been lifted off the midrange/tweeter/hypertweeter unit of the 207s. The Krell DVD Standard is designed to give world class two-channel performance, and the C 2 did an impressive job of letting it shine through. In fact, combined with the excellent bass extension of the A 51 when I added that to the system, this performance was absolutely sparkling and never bright; testament to the clarity of the Krell, and the transparency of the C 2 as an analog pre-amp. This is not to take away from the performance of the C 2 as a DSP in two-channel mode, it simply was designed to do multiple things at the $4,000 point, while the Krell was designed to be an all-out 2-channel performer.

Movie processing with the latest processors is uniformly excellent, a result of the excellent digital front ends being constructed today. That said, the C 2 is at the head of the pack in this area with its clarity, steering, and ability to create a cohesive soundfield. THX processing is easy to activate, but often unnecessary due to the smooth sonic top end.

Performance as a 7.1 analog pre-amp for SACD/DVD-Audio was also excellent. I used the Marantz DV-8300 universal player as my source, and the C 2 once again was as transparent as I could ask from a surround processor. There is a separate setting for the 7.1 inputs; they do not have to be assigned to any of the other audio or video inputs.

A 51 Amplifier

Unique Features - The second part of this duo is the A 51 5-channel amplifier. Interestingly enough, when I first received an amp with the C 2, I did not check the model number, and initially did not notice that it was the $2,000 125 watt/channel A 52. As I mentioned at the beginning, the A 51 is rated at a very healthy 250 watts/channel at 8 ohms, and 400 watts/channel at 4 ohms. The A 51 is taller than the A 52, but has the same gorgeous aluminum front with a large lit "P" in the center, a "halo" blue power switch, and 5 small blue lights for each channel in the indented trough. The A 51 also differs cosmetically by having large, silver heatsink fins on each side and on the back. The A 51 runs warm at low levels, as it runs in Class A for the first 6 watts per channel, before switching to Class AB. In fact, I would recommend good ventilation for this unit, as it does function well as a space heater.

Installation/Setup/Ease of Use - None of this was known to me at first, as I just took out the amp, removed my Classé' CAV-150, and put it into my system. Both amps have the ability to be powered on by the front panel, by 12V trigger, or turn on automatically when a signal is detected (very handy). I powered it up and, even during the first couple of hours of break in, was struck by the increase in bass extension with the KEF 207s in comparison to my Classé'. As it broke-in over the next couple of days, I really liked the way it sounded: clean, neutral, but with a top end a little less transparent than my Classé'. Imagine my shock when, upon talking to Richard Schram, I discovered that I had the smaller amp in my system! Parasound immediately shipped me out the A 51.

The A 51 is a bit of a back-breaker at 80 lbs. It really is a gorgeous piece with its silver heat fins, and its massive construction. The Lady Jacqueline gave it a very high LJAF of 9.5. It has balanced and single-ended inputs for all five channels on one side of the rear heat sink, and solid binding posts for the speakers on the other side. I have been told that a 7 channel version is not planned at this point, as keeping the performance the same would entail that the amp would weigh in excess of a 100 lbs. For those that want seven channels, you can mate an A 21 which is essentially a 2-channel A 51, or go all the way with a pair of JC 1s.

Final Take - As nice as the A 52 was and, indeed, it was one of the best $2,000 amps I have heard, the A 51 is simply better in all respects. After appropriate time breaking in, the amp had simply excellent control over the bass drivers of the KEFs, testimonial to its ability to generate lots of current. The bass extension is simply wonderful: copious, deep, taut, and rhythmic. Midrange transparency is also excellent, and the amp has a neutral, clear, crisp character. Top end is very smooth and very neutral. The smoothness of this amp mated very well with the softness of the KEF's midrange to create excellent clarity.

In two-channel mode, there is an enormous amount of effortless power--beyond what I needed. It is this kind of smooth power that allows for total control of a speaker. Micro-dynamics are smooth and well-delineated, and listening to music using the Krell DVD Standard via the analog inputs of the C 2 was a very pleasing, engrossing experience. The experience is so strong, that I found myself in musical nirvana, and started pulling out old CDs from my collection. Although these electronics and the KEF Reference speakers are very revealing, the dynamic energy created by this amp in conjunction with the C 2 and the Krell made even some of my old, poorly recorded CDs sound good. I found that this amp was able to help extract the bass in even heavily compressed recordings, and helped balance the bright, smeared compression artifacts sometimes found in the top end. In fact, with good cables, the combination of the excellent analog bypass in the C 2 and the transparent neutrality of the A 51 really allowed the Krell DVD Standard to show off its ability to resolve enormous amounts of top end information.

Read much more on Page 2


Moving on to multi-channel music, the amp really strutted its stuff. In comparison to the A 52 or the Glasse', the speakers seemed to have much greater dynamic energy, which sewed to make the soundfield even more cohesive. It was as if the energy from each speaker was so strong that a true bubble had been created around me. Combined with the excellent imaging and soundstage of the KEF Reference speakers, the sound-field just extended from speaker to speaker. The A 51's power was able to extract enough bass from the 207s that it often sounded as if I had a subwoofer on when I did not. Explosions and loud, deep noises had significant impact.

Those with greater power needs than what this amp can provide had better look to dedicated mono amps such as the JC 1 or dedicated stereo amps.

C 2 and A 51
As you can probably tell, I have been very impressed by the Halo products. After reading the above, one may rightly point out that there must be some negatives. With the C 2, I really wished for a third component input like the C 1 has. The two-channel performance as a DAC is very good, but perhaps not quite as good as the Krell Showcase. At times, the bass output of the A 51 and the KEFs was so strong, that the midrange almost seemed slightly overwhelmed, but this is really nit-picking here. This was not something present when the C 2 was used as an analog preamp. It would have been nice if the C 2 had an AM/FM tuner, and it would have been really nice if it up-converted composite and S-video

to component. This is not really fair, as the latter is still very rare. The one really annoying problem that popped up was not even the fault of the C 2 at all: it seems the Krell DVD Standard and the C 2 share the same remote control codes. Otherwise, the C 2 was relatively bug free, not even a pop when switching between sources. This is remarkable considering that it is an all-new product, and I had one of the first production versions.

I have almost no negatives to say about the A 51 amp. It is a superlative performer in the $4,000, multi-channel amp category, and one that I strongly recommend people to audition. If I had to complain about anything, I could wish for a back panel that was slightly less crowded, but this seems to be out of necessity for the large heat sinks.

Overall, this is a class leading pair, and I do not say this lightly. The C 2 package with its sonic performance, automatic calibration, complete feature set, excellent remote, programmability, beautiful aesthetics, and hardware/software upgradeability is quite possibly the most complete processor package in the $4,000 arena (one that is extremely competitive at this time), and rightly takes its place at the head of the pack. The A 51 so thoroughly bettered the performance of my Class& amp with the tough-to-drive KEF speakers, that I cannot imagine going back to it. Parasound has totally hit the proverbial home run with the Halo C 2 and A 51, and I very strongly recommend them.

Additional Resources
Read more Parasound Reviews from here.
Read more high performance HDMI AV Preamp Reviews from Parasound, Lexicon, NAD, Sunfire, Krell, Meridian and many other brands...

C 2:
17-1/4" W x 5-7/8" H x16" D
Dolby Digital EX, DTS ES, Pro Logic II, THX Ultra2
Certified with THX Surround EX
7.5 Channel Enhanced Surround
7.1 with 4 programmable outputs
9 balanced outputs, 2 balanced inputs
with XLR connectors
8 digital inputs; 2 digital outputs
7.1 analog input with pure analog path,
bypasses DSP
6 audio/video inputs with composite
and S-video connectors
3 composite video and 3 S-video outputs:
OSD, no OSD, record
2 assignable component/RGB video inputs and
1 output with separate H and V Sync
Calibration microphone with 25' cable included
Dual zone control with analog audio and
composite video outputs
Fully upgradeable and controllable
via 2-way RS-232 port
10 years parts, 5 years labor warranty
MSRP: $4,000

A 51:
250 watts per channel at 8 ohms
400 watts at 4 ohms
17-1/4" W x 7-5/8" H x 20" D
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
Heavy-duty 24k gold-plated,
5-way speaker terminals
S/N ratio: > 112 dB, input shorted,
IHF A-weighted
Damping factor: > 1100 at 20 Hz
MSRP: $4,000

Subscribe To Home Theater Review

Get the latest weekly home theater news, sweepstakes and special offers delivered right to your inbox
Email Subscribe
HomeTheaterReview Rating
Overall Rating: 
© JRW Publishing Company, 2023
As an Amazon Associate we may earn from qualifying purchases.

linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram
Share to...