Parasound HALO P 3 Two-Channel Solid State Preamplifier October, 2002 Sandy Bird
My first experience with the Parasound HALO family was at Good Guys in Sunnyvale, California. I was looking for noise cancellation headphones to help reduce the strain on my ears while flying back to Canada. Upon entering the store, a beautiful looking display consisting of three slim silver components emitting a mild blue glow grabbed my attention. I have to admit I am partial to blue lights on my audio gear, and I can still remember the daunting blue power light on the big old Marantz integrated I had when I was 17. I usually ignore most of the audio gear at mass market stores, but the cosmetics of these units alone warranted further investigation.
To my surprise, I discovered the units were made my Parasound. I have owned Parasound gear in the past. It is good gear with good build quality for the price, especially on the used market. However, in my opinion, the factor Parasound always lacked was in its looks. I tried to audition the components, but everyone was busy. So, I jumped at the chance when I was given the opportunity to review the preamp of this combo in my own environment.
Parasound's goal with the HALO lineup was to build on Parasound's already respected platform, while bringing a new level of performance and visual distinction to the Parasound family. The first in the HALO lineup is the '3' series made up of the P 3 preamplifier, A 23 amplifier, and T 3 tuner. Parasound will be adding additional models to the HALOs which will include monoblocks, a surround processor, multi-channel amplifiers, and disc players. The designer of the '3' series was given the flexibility to choose quality internal parts for power supplies and audio paths, which should give birth to some exceptional products.
As I mentioned, Parasound's build quality has never been a concern to me. Their components are comprised of quality parts and are well built. The HALO P 3 is no different: it weighs 16 pounds, all controls feel solid, and there is no chassis flex when connecting even the tightest interconnects. I was surprised to find the P 3 had both balanced and unbalanced connections. Balanced inputs and output are rare on a unit at this price, especially when it includes a remote control. The P 3 features high quality gold plated RCA connectors for the single-ended Direct 1 input and the single-ended outputs. The balanced inputs and outputs also seem to be excellent build quality.
A few other features found on the P 3 are a headphone amp, external processor loop, +12v triggers, RS-232 control and a phono input. The P 3 has a standard IEC detachable power cable and can run on either 115v or 230v. The word 'Parasound' is embossed on the top cover, and large silver feet fitted with rubber inserts to damp vibration are on the bottom. A purplish-blue glow is emitted from underneath all the buttons, and the 'P' logo glows a brilliant red. The unit is quite striking upon first glance. To keep you informed of operational status, a blue 2-line multi-character display is set in the center of the face.
The direct inputs of the P 3 are said to have to shortest signal path from input to output with the minimal number of components in the way to achieve superior signal quality for your highest quality sources like a CD player or DAC. The direct inputs also have separate selection circuitry composed of hermetically sealed gold contact relays.
The inside of the P 3 is as well built as the outside. The power supply section has a custom wound toroidal transformer and enough capacitance to run a small receiver. The caps are Nichicon, and op-amps are Burr-Brown, which are both quality-name parts. The size of the power supply and caps impressed me, and they account for a good portion of the 16 pounds.
Parasound did take a few shortcuts to keep the cost down. The rest of the single-ended inputs are of the standard gold plated type found on most hi-fi components. The sides of the front aluminum face are fitted with plastic silver plates where the optional rack mount handles would be installed. The face of the unit is an 1/8" piece of aluminum, formed in such a way that it resembles a thicker piece. This deviates from the classic Parasound products, as they usually have a thick piece of metal as the front panel. You have to choose between balanced or single-ended inputs for the Direct 1 source selection with a small toggle switch on the back of the unit. Similarly, you have to choose between a phono input or an AUX input. Even with these two input reductions, the unit should still have ample inputs for most systems. I commend Parasound, as the unit looks very good, and the shortcuts they took are only noticeable upon close inspection.
I was happy to see a rotary volume control on the P 3, as I have always thought you should 'turn the volume up'. The control is not a motorized pot or stepped attenuator but instead a digital controlled analog IC (integrated circuit). These new control circuits perform very well, cost substantially less to implement, and are more reliable than a high quality motorized pot or stepped attenuator. The physics behind the digital controls are reflected in the sound, and I have heard some very good implementations. Parasound claims in their documentation that the 'high-precision analog volume ICs' provide very accurate level matching between channels for both balance and volume.
Balanced connections are common in commercial audio installations and high-end home systems. The reason for this is their exceptional ability to reject common mode noise. Single-ended connections, common to home audio, use one wire for the signal and one for ground. When noise is picked up by the interconnect, noise in the signal with respect to ground gets added. There are many sources of noise that can be picked up by interconnects. Some of these are voltage differential between two components (ground loops), electromagnetic fields (electric motors, power transformers, etc.), or radio frequencies (radio tower or RF remote). In a balanced connection there are three wires, one for the positive signal, one for the inverse of the positive signal (sometimes referred to as the negative), and a separate ground connection. The noise picked up by the balanced interconnect appears in both the positive and the negative connection, but once the final circuit sums the positive signal with an inverted negative signal, the noise is effectively canceled out.
I should mention that the P 3 is a 'quasi-balanced' design. Fully balanced circuits treat the positive and negative signal of the balanced connection separately throughout the internal circuitry. In a quasi-balanced design like the P 3, XLR jacks are at the input and output, but the internal circuits are not balanced. This gives you the benefits of noise rejection in the interconnects, but does not give the benefit of a fully balanced design.
Many of us know that in high-fidelity audio that there can be two high quality components that just don't work well together. In this case, I would eventually find that connecting the P 3 to my Simaudio Celeste 4070se power amplifier using the balanced connections surprisingly yielded poorer results than when I employed the single-ended connections. I figured I would use the highest quality input right from the start, assuming that would be the XLR, and was initially disappointed, then later on, found that the unbalanced RCA connection gave me the best sound because it more properly matched the input sensitivity of the Simaudo power amplifier.
Once everything was connected, I turned the P 3 on. As the preamp powered up, I could hear a hiss in the speakers. I had not expected this as the Simaudio unit is dead quiet with both the balanced and unbalanced inputs. The only time the hiss disappeared was in the volume's lowest position or when mute was engaged, and in both of those cases the speakers became dead quiet. I did try the ground lift switch on the P 3 but it did not make any difference. The hiss is only noticeable a couple of feet from the speakers and should not affect music reproduction at low listening levels or in highly dynamic recordings, unless you were sitting 3 feet from the speakers.
I did not do any critical listening of the unit for the first couple of weeks. This was not intentional, but I had been spending a lot of time with my Home Theater system and did not get around to spending any time with the P 3. My wife and I did however have enough time to discover some usability issues. The P 3 has a volume control that goes from 0 to 80. The numbers are arbitrary and move in 2 step increments, giving you a total of 40 steps of attenuation. During normal listening, we never increased the volume above 18, leaving only 9 steps which were too far apart and made it hard find the right level. Late night listening aggravated the problem as I could only use the first 2 or 3 steps during these sessions. Our living room, where the P 3 was set up, requires some adjustment of the balance depending on where we are sitting. The P 3's balance steps, like the volume, seemed to be too far apart, making it hard to find the right adjustment. The remote control allows for source selection, volume adjustment, and control of the T 3 tuner. However, it does not allow for balance adjustments. Source selection via the remote is made by number, not name, which can also be confusing at first. The last usability issue I will mention is that you cannot turn off the display or the blue lights. The lights on the P 3 can be very bright at night and give the beige walls in my living room a blueish tint.
Well, during the first two weeks of non-critical listening, I was starting to form a conclusion about the sound of the unit, and it was not terribly positive. Music is a part of our daily life, so even though no critical listening had been done, the P 3 already had over 40 hours on it. I found it odd that at no point was my attention caught by the P 3. Several times I looked down and noticed the purplish-blue glow coming from the unit, but never anything exceptional about the sound.
The next weekend arrived, and I decided to do some critical listening. Our living room is oddly shaped, and I usually change the speaker positions when I am going to be listening to music for more than a few hours. This also allows me to avoid having to adjust the balance. My wife does not appreciate this as one speaker ends up sitting in front of the fireplace, and admittedly I usually forget to put them back. After spending some time with the unit and a wide selection of music, I was still not very happy with the sound. All music seemed somewhat unemotional at reasonable volumes, but did seem to improve as the listening level increased. As many of you are aware, music sounds better louder, but this was different. There seemed to be substantially more detail as the volume level approached 16. I knew I would be able to use less attenuation (increase the volume) if I changed from the balanced outputs to single-ended. John Johnson confirmed gain would drop 6 dB by going back to the unbalanced connection. This seemed to do the trick on countless aspects. I now was listening to the unit between settings of 10 and 30 instead of 2 and 18, and the detail and emotion in the music finally reached my expectations of the unit.
I am now happier with the sound of the P 3 and have spent a couple of weeks with the unit connected via the single-ended outputs. To generalize the sound of this preamp, I would have to call it neutral (and that is good). There is no rolloff at either end of the frequency spectrum, and it doesn't sound warm or have a tendency to be bright or harsh. Looking at the bench measurements (below) you can see there is a slightly more than 1/2 dB rolloff at 20 Hz using the single-ended outputs and a flat response using the balanced outputs. The soundstage has good depth and width and even after long listening periods I did not notice any listener's fatigue. (Listener's fatigue is when your ears start to hurt after extended listening sessions, and this plagues me sometimes especially with bright equipment.) My Paradigm Reference speakers can be a little bright when mated with certain amps and preamps, but were perfect with the P 3. The P 3 performed very well with all types of music from jazz to classic rock. It has superb imaging capabilities and a deep soundstage, although the soundstage does not extend much past the edges of the speakers. The only criticism I would make, although very minor, is vocals that should be placed in the front of the soundstage appear too high in placement.
I started my listening sessions with Peter White - "Glow". This is a great instrumental disc and a must have if you are a fan of modern classical guitar. The P 3 achieved everything this disc is about. Right from the first track Chasing the Dawn, the guitar was front and center with all other elements filling out the back of the soundstage. The P 3's performance continued throughout the rest of the disc and provided me with a much needed reminder. When traveling, I carry a mini disc of this album and listen to it through a set of noise cancellation headphones. I had completely forgotten how well this disc was recorded, and listing to it though the P 3 was a great pleasure.
Those of you with CD players or DACs that decode HDCD are probably familiar with the "Practical Magic" Soundtrack. This is a great disc and has musical content for just about every taste, and almost every track is well recorded. I don't have HDCD capabilities anymore, but this is still an exceptional recording, and I thought the P 3 did everything right. I will say the P 3 is not a tubed preamp and does not sound like one. Some tube equipment brings an airy realness to music that is not produced by solid state components like the P 3. This is no fault of the P 3 but instead a property of tubes. I only mention it because I miss it with this particular disc.
I could go on for paragraphs about the enjoyment of listening to a variety of music with the P 3, but in all reality that isn't what you are probably looking for out of this article. To sum up my experiences, the P 3 is a great preamp, and if I were looking for a preamp in this price category I would definitely consider purchasing this unit. It has been in the system in our living room for several months now, and once I converted back to the single-ended input we have been very happy using the P 3 in our daily life.
To compare this preamp with
others at 2 or 3 times the cost doesn't seem appropriate, as it doesn't
quite have the detail of some of the more refined preamps from Sonic
Frontiers or Simaudio (hmmm . . . you would think I was a Canadian).
it does come close. Trying to compare the P 3 to its direct competition
is a difficult task, because finding a two-channel preamp with a remote, phono
stage, balance inputs and outputs for under $1,000 is hard.
The two closest competitors I could think of still in production are
the Rotel RC-1070 ($499) and NAD C160 ($599). These are remote controlled,
two-channel preamps with a phono stage, but they are still a lot of features
short of the P 3. To come up with a unit that did have balanced inputs
and outputs, 12v tigers, RS-232 control, phono circuitry, and remote
control, I ended up having to look in the higher than $1,000 range with
the Rotel RC-1090 at $1,199. As you can tell, the P 3 is a value oriented
product. If you are considering purchasing a preamp in or around any
of the prices mentioned above, you should definitely audition the P 3.
On the Bench (JEJ)
Frequency response test results are shown below. The XLR input has a flatter response than the RCA unbalanced input, with XLR being within 0.5 dB from 20 Hz to 90 kHz, and the unbalanced beginning to drop off below 100 Hz. It is within 1 dB from 20 Hz to 90 kHz. Switching in the tone control circuit added a bump and a steeper high frequency rolloff, even with the tone controls set at flat.
Parasound's claims for distortion are:
Using a 1 kHz sine wave input signal, THD was found to be higher with the RCA input than with the XLR input. This suggests that the XLR input is not simply a "convenience" connection, where pins 1 and 3 are just soldered together.
IMD tones (11 kHz and 12 kHz) showed good results with both types of inputs.
Parasound hit the nail on the head with the P 3. At $800, this is an outstanding preamp. To find a stereo preamp with the same features that will outperform the P 3 by any significant amount you are going to end up paying 2 or 3 times the cost, and you will still be short a few features.
I was disappointed with the P 3 using the balanced connections, but I believe that was a problem specific to my setup. If you have a sensitive amp or efficient speakers the single-ended connections might be a better option for you. Regardless, I highly recommend you try the balanced outputs to see how they perform in your system. I have not tested the matching Parasound A23 with the P 3, but I am sure Parasound has accounted for the sensitivity issue in the design.
As many of you have switched to surround setups over the last 10 years, you may find yourself missing your old two-channel setup. If so, you should check out the Parasound HALO '3' series as I believe it is an affordable way to get back into two-channel audio without breaking the bank.
Sandy Bird -