Parasound Halo P 7 Multichannel Preamplifier, A 51 Multichannel Amplifier & JC 1 Single-Channel Amplifier
One of the few lessons that was ingrained into me during my time in the Navy was, “Keep it simple.” I admit it wasn’t phrased quite so politically correctly, but the point is still the same. It’s a motto I apply to just about everything I do in my daily life, and when I received the Parasound Halo P 7 multichannel preamplifier ($2,000) for review, it appeared that Parasound sticks to the same philosophy. The strictly analog preamp shrugs off digitaldecoding duties to your source components, shunning any dirty digital processing while providing a high-end, multichannel, analog preamp stage to feed into your amps. With the right front-end source components, this makes for a spectacular two-channel and multichannel listening experience.
The Clean Halo Line
For this review, I received not only the P 7, but a few other Halo amplifiers as well. Since I was going to be performing a full seven-channel setup, and in honor of this issue’s high-performance editorial focus, Parasound provided the Halo A 51 five-channel amplifier ($4,500) for the center and surround speakers and a pair of magnificent Halo JC 1 monoblock amplifiers ($4,500 each) for the mains. The A 51 is a THX Ultra2-certified, multichannel amp rated at 250 watts of power with all channels driven into 8-ohm loads. It was designed by renowned electronics designer John Curl, who has served as a consultant for Parasound since 1988. We reviewed the A 51 amp back in 2003 when Parasound released the Halo C 2 audio processor, but this amp is anything but long in the tooth, and I thought it would be fun to tell new readers just how great it is. The JC 1 is an entirely different animal. Each monoblock features hand-selected parts throughout; it was a pet project of Curl (and his CTC Builders team of the late Bob Crump and Carl Thompson) and Parasound to deliver a no-compromise, monoblock amplifier that could compete with anything, at any price. The pair are rated to each deliver a staggering 400 watts each into an 8-ohm load and double down into a 4-ohm load. Because the P 7 is geared toward those looking for an improved analog-preamp stage compared to what you’ll typically find in even a high-end receiver or A/V processor, it also made sense that Parasound would send along a pair of reference-quality amps. The Halo A 21 two-channel amplifier ($2,300) may make a bit more sense if you’re looking to stay in the same price range as the P 7, but I certainly wasn’t going to balk at the chance to audition the JC 1s.
The Halos sport a very clean aesthetic that is continuous across the entire line, with silver, machined-aluminum faceplates and the glowing “P” badges. The P 7 has a modest display on the front panel that allows you to set up and configure the preamp to your own desire. Because the P 7 is a fully analog design, there are no processing modes to contend with nor elaborate menus to negotiate. You can set up the preamp via the multifunction, front-panel knob or from the included remote. The remote was surprisingly basic compared with what I would have expected from a Halo-line accessory, but it got the job done. The P 7 menus are easy to navigate and there are only a few selections available for tweaking each input, all of which can be renamed to your preference. Each input has its own memory, so it’s a set-it-and-forget-it kind of deal. There are also settings for triggers and volume limiting. Parasound has discontinued its Zhd HDMI selector, but any similar device can be used to switch the video from multiple HDMI sources to a display, while keeping the video signal away from the P 7 as it pristinely handles the analog-audio duties.
The P 7’s back panel has a clean layout with a mix of RCA and XLR inputs and outputs. The preamp sports a balanced stereo XLR input and a seven-channel, balanced XLR output. There are also seven RCA stereo inputs and two seven-channel RCA inputs for connecting to a multichannel device such as a DVD or Blu-ray Disc player. Because the P 7 doesn’t perform digital decoding, you’ll need to make sure your source device is capable of decoding the audio formats and has an analog output for each channel—and the higher quality they are, the better.
For this review, I turned to my reference Blu-ray Disc player, the Oppo BDP-95. This is Oppo’s flagship universal player that offers full audio decoding with an analog-output stage designed around ESS’s top-of-the-line SABRE32 DACs. Oppo also included a fully differential, balanced, stereo XLR output. Using a player like this covers all of the bases when it comes to playing back the key disc formats on the market today. The BDP-95 also supports audio files found on a home network or attached hard drive, making it a great piece to center your system around.
Of course, if you have other digital sources that may require decoding, the P 7 has you covered. The dual, multichannel inputs feature a theater-bypass mode that provides a pure passthrough for the source device. This means you can keep your existing receiver with preamp outputs or A/V processor and use it as a digital decoder; the P 7 simply passes the analog output of the outboard processor through to the amps, allowing it to handle decoding and multichannel volume of your digital sources without going through any additional gain stage in the P7. I know several people who use a configuration just like this for their two-channel playback, allowing for a higher-end, analog preamp for stereo playback and a full passthrough for surround sources. Parasound has this same feature on its reference-design Halo JC 2 preamp.
When you look at the Halo A 51 and JC 1 amps, you can see how Parasound has gone out of its way to keep the regal look of the series intact across the whole line. The pair are almost identical from the front, with the A 51 getting five LED channel indicators to the JC 1’s zero. The back panels are where you see the main differences. If I had to find a fault with the A 51, it was here. There is a large heat sink that takes up most of the panel. On either side, you’ll find the speaker connections and XLR and RCA input jacks. Because they’re all cramped together, connecting the rest of your gear can be a bit of a pain, especially if you’re using larger speaker wires or connectors. (Parasound does supply gold-plated banana plugs, at least.)
The JC 1 is the polar opposite and has real estate to spare. Each monoblock features both single-ended RCA and balanced XLR inputs. Parasound has also included dual-speaker binding posts to make biwiring easier for the user. All of the Halo amps have trigger inputs and can be turned on via a 12-volt trigger signal or, if you prefer, from automatically sensing an audio signal. Both amps are class A/AB designs, but they are said to feature higher biasing toward Class A than other amps at this price point. The A 51 is biased to operate in Class-A mode for the first 8 watts, before transitioning to Class A/B as more output is required. The JC 1 has a selectable bias switch that can run in Class-A mode at up to 10 watts in low bias or up to 25 watts in the high-bias setting. Pure Class-A amps run extremely hot, and even limiting Class-A operation to the first 25 watts, the JC 1 gets hot to the touch.
Setting up for this review was easy. Connections from the Oppo to the P 7 were made with AudioQuest Columbia XLR and RCA cables for both the seven-channel input and twochannel, balanced input. I also used Columbia XLR cables to mate the P 7 to the JC 1s later on and AudioQuest’s NRG-4 power cords for the amps and preamp.
Because all the channel trims and time delays for the P 7’s multichannel input were performed in the Oppo, the P 7 didn’t require much adjusting. I did find the trim levels for the sub a bit hard to get right in the BDP-95’s menus, but the P 7 supports trim levels for the sub channel to help. Critically, the P 7 has dedicated sub level adjustments for both the multichannel and stereo inputs. This is a feature my Anthem Statement D2V has that I find missing in many other preamps. I like to kick the sub up a notch or two with two-channel playback, and having the ability to have different trims makes this a breeze.
The P 7 does provide some bass management in the analog domain if your source components don’t provide it. The preamp provides a high-pass filter for smaller speakers and a low-pass filter for the sub. You can set the crossover to full range, 80 Hz, or 50 Hz. It can also add your sub into the mix even if you want to run your mains in full range. It simply combines the front left/right channels and then mirrors the low-bass, full-range signal to the sub for some extra oomph. It’s a very nice touch for a device with an all-analog signal path.