Integrated Amplifiers

Harman Kardon HK 990 Integrated Amplifier and HD 990 CD Player

ARTICLE INDEX

Introduction

Most likely recognized in today's market as a purveyor of home theater receivers, desktop/PC speakers, iPod docks, and factory-installed automotive sound systems, Harman Kardon is a name that is also well-recognized in traditional 2-channel audio. While the history of the company is quite interesting (see the "about us" link on the company's webpage), one thing has remained constant at Harman Kardon over the years: they produce an aesthetically pleasing product that delivers the high-sound quality sought after by the brand's customers. The HK 990 integrated amplifier and HD 990 CD player represent the company's firm commitment in delivering a true audiophile experience to the 2-channel crowd.

Specifications

  • HK 990
  • Design: Solid State Stereo Integrated Amplifier
  • Power: 2 x 150 watts RMS into 8 ohms @ 20 Hz - 20 kHz, 2 x 300 Watts into 4 Ohms
  • MFR: 10 Hz – 100 kHz
  • THD: <0.07% at Full Output (8 Ohm Load)
  • Analog Inputs: 7, Plus 1 Phono MC, 1 Phono MM, and 1 Balanced XLR
  • Digital Inputs: 1 HRS-Link, 2 Optical Digital, 2 Coaxial Digital
  • Analog Input Sensitivity/Impedance: 350mV/43k ohms for tuner/CD, 10mV/47k ohms for Phono-MM, 1mV/100k ohms for Phono-MC
  • Digital Input Capability: All Standard Digital Formats
  • Dimensions: 6.4" H x 17.3" W x 17.5" D
  • Weight: 43.2 Pounds
  • MSRP: $2,599 USA
  • HD 990
  • Design: 2-channel, Tray-loading CD player
  • Codecs: Red Book CD, MP3, PCM: 16 to 24 bits, 30 kHz to 96 kHz Sampling
  • Analog Outputs: 1 Balanced XLR, 1 RCA, 1 Headphone (front panel)
  • Digital Outputs: 1-HRS Link, 1 Optical Digital, 1 Coaxial Digital
  • Digital Inputs: 1 Optical Digital, 1 Coaxial Digital
  • Output Voltage: 2.0V RMS (Unbalanced), 4.0V RMS (Balanced), 0.5 V pp/75 ohms (Digital Coaxial)
  • Digital Output Filter: 24-bit/384kHz Asynchronous Sample Rate Converter
  • MFR: 20 Hz – 20 kHz +0/-0.5 dB
  • THD+N: <0.0006% @ 1kHz
  • Dimensions: 2.5" H x 17.3" W x 13.1" D
  • Weight: 8.6 Pounds
  • MSRP: $699 USA
  • Harman Kardon

Design

The HK 990 and HD 990 are certainly befitting products from a company with numerous design awards. The overall look of both components is clean and modern, with sharp lines contrasted by gently rounded corners. While some may find the front panel designs "minimalist," I absolutely loved them and feel that the design theme will age extremely well. In a bit of a contrast to the current all-black (or all-silver) theme most companies have adopted, the units both sport a two-tone design of gloss black top halves with a dark pewter bottom half. While I typically prefer all black myself, I really liked having this bit of extra flash in my equipment rack. As a testament to the beautiful design, numerous houseguests commented that the HK 990/HD 990 looked very expensive. Also drawing numerous "oohs and aahs" were the white lighting on both components when powered up. The volume control knob on the HK 990 is particularly neat, with its white light illuminating the volume knob from within.

My only criticism of the design of both units' centers is the front-panel buttons. Frankly, the labeling is impossible to see in the dark and since all of the buttons are the exact same size and shape, you can't identify them by touch either. Being that most users will typically use the remote control, this is a minor issue, but one I feel I must mention. Speaking of the remotes, the unit included with the HK 990 is an interesting design. The remote is not the most comfortable to hold, but there are buttons for every function I ever needed, including a dedicated button for the "EQ Preset," which I'll cover later. The HK 990's remote can also control the HD 990 and is missing only one button from the HD 990: "source." It can be programmed to control numerous other components as well. The remote for the HD 990 is simpler, but is far more comfortable to hold. It includes everything one would expect from a CD player remote, including dedicated buttons to help you move through folders of MP3s. To be honest, I never even had to use the HD 990 remote as the HK 990's was able to do everything required for both devices. My biggest complaint with both remotes is that they aren't backlit, so they are very hard to use in the dark.

The back panel of the HK 990 is well equipped. There are 7 analog RCA inputs, plus 1 phono Moving Magnet (MM) and 1 phono Moving Coil (MC). There is also a single pair of balanced XLR connectors for use with the CD input only. This is a truly balanced, dual-differential design. The RCA input labeled "Processor" is basically a home theater bypass and passes the incoming signal directly to the HK 990s amplifier section at full strength. There are two subwoofer inputs that can be utilized with the home theater bypass functionality as well. On the digital side of things, there are 2 coaxial digital inputs and 2 optical digital inputs. There is also the proprietary HRS-Link connection, which looks just like a standard Ethernet port. There are RCA pre-outs for the left and right channels as well as two subwoofer channels, which is a very nice touch. The EZSet/EQ can calibrate the system for two subwoofers, which could be very useful for those of you running more than one sub. There is also a coaxial digital output as well as two other RCA record outputs. Rounding out the connections is an RS-232 control, IR in/out, and two 12v subwoofer triggers. The HK 990 can also be used to drive two pairs of speakers via the four sets of well-built binding posts. However, if you wish to run two pairs of speakers make sure that they are both 8 ohm or higher loads; otherwise you could damage the amplifier section. The only things missing are USB (asynchronous), RJ45, and iPod connectivity. I can definitely see some users wishing they could send their computer/network-based audio directly into the HK 990.

The HD 990's back panel has a few more options than most CD players I've used. Besides analog RCA, HRS-Link, coaxial digital, and optical digital outputs there is also a fully balanced XLR output (with dual Diamond Class A output stages) which is rarely seen on a player in this price range. Of further interest are the coaxial digital and optical digital inputs. The HD 990 can take a digital feed from other source components with lesser quality DACs, convert them to analog using its own Analog Devices AD1955 DAC, and then pass them along to the HK 990 or other connected device.

Build quality of both components is excellent. My first surprise of this review came when I went to retrieve the HK 990 from my front porch after it was delivered. I hadn't checked all of the specs on the unit yet, so I was expecting a normal mass-market 25 pound 2-channel "receiver." Well, the shipping weight on the HK 990 is closer to 50 pounds, so the laugh was on me. Wondering if they packed a bit of lead in with the amplifier, I tore the box open and checked things out. No lead could be found, but it was pretty obvious that Harman Kardon hadn't taken any shortcuts with this thing. The HK 990 is beautifully constructed, with absolutely no flex to the chassis whatsoever. Fit and finish is excellent and in line with a product of this price. The center of the chassis contains two large heat sinks/air channels, which keep the amplifier cool.

After removing the top plate of the HK 990, I could see that the internal construction is up to snuff as well. The two toroidal transformers are massive (16,000µF of supply filtering per channel), and the circuit board layout is neat and clean. Component quality appeared to be first-rate as well. A lot of thought went into the internals of the HK 990 including dual-path technology for allowing pure analog and pure digital audio processing within the same chassis, dual differential input stages with their own high-voltage supply, a cascaded pre-driver stage to reduce high-frequency distortion, thermal tracking to bias the current of the output stage in real time, and a DC servo to ensure that the DC level of the amplifier output remains within a set limit. It has been a long time since I have seen this level of quality construction from a "mainstream" manufacturer.

The HD 990, while not having the mass of the HK 990, is also nicely built. The chassis is solid, and the CD drawer is quiet and smooth without displaying the "chintzy" feel that so many plastic drawer trays have today. My only quibble revolves around the HK 990's volume control knob. While I loved the white backlighting, the plastic knob itself has a fair amount of play and wiggle to it that just doesn't match up with the overall quality of the rest of the unit. I'd like to see something a bit sturdier in the future.


Setup

After appreciating the build quality and overall design of the HK 990 and HD 990, I have to admit that my expectations had been raised significantly and I could not wait to get both components set up and running. As this would be a strictly 2-channel review, I slid the HK 990/HD 990 into the rack in my den listening room and connected my Paradigm Reference Studio 20 V3 speakers mounted on Dynaudio Stand 4 speaker stands via Tributaries 12 gauge speaker cable. Source components were my faithful Yamaha DVC-750 5 –disc SACD/DVD-A/CD player and of course, the HD 990. I hooked the Yamaha up via analog RCA so that I could enjoy 2-channel SACD and DVD-Audio discs and connected the HD 990 via analog RCA, digital coaxial, and HRS-Link so that I could compare the differences between the three connection types. With all of the connections made, I went through the easy to use setup menu to associate the named inputs with their requisite analog or digital source. The front panel of the HK 990 shows all of this information clearly, so if you've been spoiled by the on-screen GUIs of recent home theater-geared equipment, don't worry. I also appreciated the HK 990's ability to set a level for each input. This allows you to adjust the "gain" for each source input to ensure that you get the same overall volume level when switching between sources. Every receiver/pre-amp/integrated should have this extremely useful feature.

With all of my sources configured, I moved on to the EZSet/EQ feature. Similar to other automated room EQ systems like Audyssey, the EZSet/EQ attempts to correct the sound at your listening position for any anomalies caused by your listening environment. After connecting the included microphone to the front panel jack, the process is simple. Press the "Speaker Setup" button on the front panel of the HK 990 or the remote and the calibration process beings with the choice of a manual or automated setup. Manual is good if you only want to set the crossover point for your subwoofers (if you have any). If you select the automated routine, tell the system if you have one or two (or zero in my case) subwoofers connected. If you do have a sub, you have the option of configuring a crossover point manually or letting EZSet/EQ decide for you. If you chose the manual option, you'd set the crossover point now. Choices range from 40Hz to 200Hz at 10Hz intervals. With the crossover set, the system asks you to place the included microphone at the listening position. Be sure to set it at ear-level for best results. After two frequency sweeps, you will be asked to place the mic two feet in front of the left speaker for additional measurements. You finish up by placing the mic two feet in front of the right speaker and letting the frequency sweeps run again. Don't forget to hit the "enter" button on the remote to save the configuration once complete.

Once you've completed the EQ setup, you gain access to four sound modes for digital sources. The first is "DSP," which runs the signal through the A/D converter, DSP chip, and D/A converter prior to volume adjustment. DSP mode allows access to the tone control circuitry if you wish to adjust bass or treble response. Next is "EQ1," which only applies room equalization to the subwoofer (if connected) frequencies. Then there is "EQ2" where subwoofer and midrange frequencies up to 1kHz are corrected, leaving the treble response unaltered. Finally there is EQ3, which applies compensation over the entire frequency spectrum. You can also go back into the "input setup" menus to apply DSP to analog sources, which then allows you to adjust gain, bass, and treble or apply any of the three EQ settings.


In Use

HK 990 Integrated Amplifier

My first listening experience with the HK 990/HD 990 duo was a bit of a revelation for me. Typically, an old Denon 3802 A/V receiver powers the Paradigm Reference Studio 20s that sit in my den listening room. While I've heard enough high-quality gear to realize my Denon is by no means state-of-the-art, I was completely unprepared for how much better the HK 990 made things sound. I typically run through a set of demo tracks when I first fire up a component to get an overall feel for how a new piece of gear sounds and to get a "pre-break-in" benchmark. As soon as I started playing my first track my wife came downstairs, walked into the den and said, "Wow, it sounds so much clearer." She stood and listened for about a minute, saw the evil glint in my eye and then asked, "What are these going to cost me?" She knows me far too well. What really shocked me was that I had just fired the HK 990 up, so there had been absolutely no warm up or break-in time yet. Things could only get better from here and I rubbed my little paws together with glee.

Harman Kardon 990 Integrated Amplifier and HD 990 CD player for the Audiophile

I used the HK 990/HD 990 for about four weeks (about 100 hours) of casual music listening before settling down for any critical sessions. To be honest, I did not notice any appreciable difference in sound quality versus the out-of-the-box state, so break-in is probably not necessary with the HK 990. I did feel that the amp needed about 15-20 minutes of playback before sounding its best though, so keep that in mind when you demo the product. I did my first listening session with my Yamaha changer as the source, so I could get a feel for the sound of just the HK 990. I kept all DSP/EQ modes off, keeping things in the most pure "Direct" mode. I started with my long-running favorite demo, Reference Recording's "Symphonic Dances" by Rachmaninoff (RR-96CD). In a word, the sound was stunning.

The first thing I noticed was the absolute clarity of the signal. The noise floor was so much lower than I was used to. There was no hash or grain to the sound, which just made musical details stand from the background. This led to a vast improvement in apparent detail, without any extra brightness or glare. Even detail in the bass was improved, making things like tympani hits easier to distinguish from one another. Treble detail also improved remarkably, without any extra bite or brittleness to the sound. Mid-range tones were clear and beautiful. I also found that the soundstage width and depth had increased noticeably. Imaging was improved as well; it was now easier than ever to pick out where certain instruments were arranged in the mix. The most noticeable improvement had to be in the bass though. The HK 990 took firm control over the 7" midrange/woofer in my Studio 20s, resulting in much tighter, punchier bass attack. Bass definition, pitch, and rhythm were also noticeably improved. Even more surprising to me was that it sounded like I was getting slightly deeper bass as well. Perhaps it was the increased power of the HK 990, but all of these attributes helped give the music a large increase in dynamic punch, which suited this type of large scale symphonic track very well.

Harman Kardon 990 Integrated Amplifier and HD 990 CD player for the Audiophile

Next I queued up "Mediterranean Nights" (Avalon B0001LJCZW) and put on track 13, "Hasta Pronto." This track has a quick moving natural bass line that can get a bit muddy on a less revealing system. It was remarkably clear and easy to follow with HK 990 in my system and also seemed to reach a bit deeper as well. Besides the bass, the Spanish guitar sounded just right and the hand claps that run throughout the song were completely natural sounding. I also played track 9 from this disc, "Con Ternura," as it is one of the most beautiful, yet haunting guitar melodies I've ever heard. The tone was perfect, with natural decay to the individual notes and a great sense of reverberation (probably studio enhanced just a bit) from the body of the guitar.

Harman Kardon 990 Integrated Amplifier and HD 990 CD player for the Audiophile

Harman Kardon 990 Integrated Amplifier and HD 990 CD player for the Audiophile

Vocals tracks shined just as much as instrumentals through the HK990. I put on the 2-channel SACD track from Diana Krall's "Love Scenes"(Verve B0002DSUEI) and skipped right to track 11, "My Love Is." While this disc sounds great on just about any system, I was particularly impressed with it through the HK 990. The natural bass intro was awesome, and Krall's voice sounded even smoother and sultrier (is that even possible?). After listening to a few other tracks off the disc, I moved over to Melody Jardot's "My One and Only Thrill" (Verve B002RD4UZ4). "Who Will Comfort Me" and "Your Heart Is As Black As Ice" both sounded wonderful, with Ms. Jardot's beautiful tone ringing through clearly. This CD is not as slickly produced as the Diana Krall SACDs, but it still sounded great.

After playing some additional rock and electronic tracks, I realized that I had never heard my Paradigm speakers sound so good. Maybe it was just equipment synergy, but the HK 990 and Studio 20 V3s made for a marvelous pairing. The HK 990 made my Paradigm's sound like a far better speaker, and they aren't too shabby to begin with. Even so, I found myself wishing that I still had the excellent Dynaudio X16s (see my review here) around. The tonal qualities and increased resolution of the Dynaudios plus the beautiful tone, clarity, and punch of the HK 990 would most likely be a match made in heaven. Bottom-line, the HK 990 is certainly up to the task of driving any high quality "audiophile" speaker.

HD 990 CD Player

As it was obvious that the HK 990 had some incredible sonic chops, I now focused my attention on the HD 990 CD player. The first thing I did was compare the different outputs of the HD 990 using the same demo tracks I played on my Yamaha changer. The analog outputs were smooth and refined, and presented a bit more musical detail than my less expensive Yamaha changer. Given that the HD 990 uses a single Analog Devices AD1955 DAC per channel combined with a 24-bit/384kHz asynchronous sample rate converter, I was not too surprised at the quality of the output. Due to the lack of any extra balanced XLR cables I was unable to test out the true balanced outputs of the HD 990, but if I were going to run analog I'd definitely use the balanced connection. From my experience a true balanced connection sounds a bit better, plus it outputs a higher level signal.

Harman Kardon 990 Integrated Amplifier and HD 990 CD player for the Audiophile

Next, I tried the digital outputs. The coaxial digital output sounded slightly less rich than the analog outputs and seemed to have a slight edge to it as digital often does. I reconfigured the CD input on the HK 990 to accept a digital signal via HRS-Link and ran through my test tracks again. It took me about 30 seconds of "Mediterranean Nights" to realize just how much better digital sources sound when you can remove most of the jitter from the signal. The sound was more smooth and natural, without that slightly harsh glare inherent to most digital music. Things simply sounded more "analog" to me. While these differences are subtle, the longer you listen the more you can spot them. While listening to Charles Brown's "Alone at the Piano" (Savoy Jazz B00015HVHO), I started to notice how individual piano notes seemed to ring truer. Each note would decay more slowly into the background. As I grew up in house with two piano players, this increased sustain stuck me as completely natural and much more correct than the clipped notes I typically associate with digitally-reproduced piano. Switching back to "Mediterranean Nights" I noticed a similar effect on guitar notes. Individual notes just seemed to hang in space a bit longer, which gave the music an increased sense of body and impact. The music just seemed closer to what you hear during a live performance. As much as I enjoyed the HD 990 via its analog outputs, I used the HRS-Link connection for the rest of the review period. Via HRS-Link, the HD 990 produced the best Redbook digital sound I have ever heard in either of my systems.

Since I was so impressed with the sound of the HK 990/HD 990 pairing, I asked Harman Kardon to explain exactly how HRS-Link worked. Per Harman Kardon's engineering department "In order to avoid too much A/D and D/A conversion along the signal chain, it is preferable to keep the signal in the digital domain from the source to the processing point. While using a CD player, you can use the SPDIF connection thus you keep the signal in the digital domain. But in doing so, you rely on the SPDIF receiver PLL to extract the clock signal, so quality may vary a lot depending on the signal integrity. In order to avoid the possible increase of jitter related to this stream reconstruction inside the receiver we include the Ultra-Low Jitter Digital Connection (HRS-Link) between the source unit (HD 990) and the HK 990. The HRS-Link uses a RJ45 connector and some LVDS drivers/receivers (Low Voltage Differential Signaling) working at high frequency and carrying the following signals:

  • System and data clocks of the amplifier
  • Data stream from the CD player

When the HRS-link is established the CD player doesn't use its internal clocks but locks itself to the external clocks delivered by the amplifier. The data extracted from the disc is then stored into buffers asynchronously and formatted synchronously to the amplifier clocks into 24 bits and up sampled to a 96 kHz stream. The result is a jitter free connection between two units, similar to having the CD player inside the amplifier. Jitter is less than 1ps RMS." While I lack the test gear to verify the amount of jitter, my ears tell me this spec is spot on.

I also spent some time feeding MP3s (128kbps - 320kbps) through the HD 990 and was impressed by how the up-sampling of the HD 990 managed to remove some of the brittleness and lack of musical body that I often attribute to highly compressed sources. While I could still tell how inferior MP3 is to even CD, the tracks were at least listenable now.

With the HD 990 feeding Redbook CD to the HK 990, it was time to see how effective the EZSet/EQ was at correcting a digital signal. With the dedicated button on the HK 990's remote it was incredibly easy to cycle through EQ settings rapidly. EQ1 only engages room correction for the frequencies covered by your subwoofer(s), but as I didn't have any connected there was no real change to the sound. EQ2 adds midrange correction to the signal and did appear to smooth out the frequencies up to 1KHz. While the midrange did sound a bit smoother overall, the lack of correction in the treble now made the sound a bit unbalanced, as the treble now sounded a bit over-emphasized. Hitting the EQ remote button once more moved the HK 990 into EQ3, which applies full-spectrum room correction. The extra treble emphasis was now gone and the sound at my listening position was very nicely balanced. However, as I typically find with room correction systems the EQ seemed to take a bit of the life away from the music. There was a subtle loss of dynamics and clarity, though it was less through the Harman Kardon pair than through other correction systems I've heard. To my ears (and in my room), the EZSet/EQ system works best in an "all or none" mode. Hitting the EQ button again brings you back to an uncorrected state and lets you hear the difference for yourself. If I had a room with larger peaks and suck-outs I would probably leave EQ3 on all of the time, but as my room is pretty well balanced I spent the remainder of my time with the EQ off.


Conclusion

The HK 990 integrated amplifier and HD 990 CD player are stunning achievements for Harman Kardon. They are beautifully crafted and artfully designed components that will blend well into almost any décor. More importantly, they offer a level of performance that is simply fantastic, regardless of price. The HRS-Link between the HK 990 and HD 990 offered some of the best digital sound I have ever heard and the analog inputs of the HK 990 will do justice to just about any high-quality source component. If you appreciate the pure musical joy that quality 2-channel audio can deliver I highly, highly recommend that you give the HK 990/HD 990 combo a serious audition. If it weren't for the fact that I have more pressing A/V needs right now, the HK 990 and HD 990 would be staying in my home indefinitely.

*Note: As I was finishing this review, I received news that Harman Kardon founder Dr. Sidney Harman (1918 – 2011) passed away from a sudden illness. Dr. Harman's contributions to the world of high-end audio were numerous, and his influence will be sorely missed. The incredible capabilities of the HK 990 and HD 990 are prime examples of the impact he has had on this industry and the company that bears his name.