by John Gatski
The technology also is used in Lexicon’s sister professional audio company Crown’s series of sound-reinforcement amps. Harman originally developed the amp technology for Lexus’ $375,000 high-end mid-engine LFA sport car so the car could have plenty of power without a space-hogging amplifier. The DD-8 puts all these watts into a 120V AC-supplied amp that is only one-rack space tall and weighs just over 9 pounds.
The DD-8’s core feature is the Drive-Core technology, which places all the components on silicon chips. Drive-Core, co-developed with Texas Instruments, incorporates an unprecedented level of component integration into an IC that is smaller than a postage stamp. Each channel is spec’d at 125 watts at .05 percent distortion with all channels driven. The unit is said to be 90 percent efficient and standby current is only one-half watt. The amp’s signal-to-noise ratio is impressive (-105 dB A-weighted) versus analog amps, which are generally not this quiet. Gain is listed at 29 dB.
Traditional analog amplifier technology, typically Class A/B, uses a lot of AC power to enable their high-power outputs, and they generate heat, requiring a large amount of space, heatsinks and sometimes fans for cooling. Not so the DD-8. It is positively tiny next to my cadre of amplifiers and receivers; it contains no fan, but with small heatsinks that fit into the confines of the small chassis.
Since the DD-8 is an installation amp, most controls and connections are located on the rear panel. The front contains a power switch and eight channel-status indicators — blue for normal or flashing blue for a shorted channel.
The rear panel tightly accommodates all the connections, which include four pairs of fixed, installer-type Phoenix speaker output connectors. These connectors require attaching stripped bare-wire cable ends via set screws and plugging them into the amp. The connectors are standard for installer setups and make it convenient for non-critical listening tasks (background listening via ceiling speakers, for instance), but limit the size of the cable you can use. I created home-brew banana plug adapters that attached to the Phoenix connectors so I could use my large MIT speaker cables during the review.
Other amp connections include RCA channel inputs, bus inputs/outputs for operating multiple DD-8s as a series of stereo zone amps, and 12V trigger jacks. Eight small plastic output potentiometers allow speaker attenuation from +13 dB to -76 dB. Rear-panel controls also include stereo/mono switches and the local/bus enable switch. You can operate the amp with single mono channels or stereo pairs or any stereo/mono combination. Since each amp chip operates independently, you cannot bridge the channels to achieve more power.
The first thing I noticed was that the DD-8 does not have that “fizzy” hardness of previous generations of digital amplifiers. It is really smooth — almost Class A/B MOSFET-like. This characteristic goes a long way in allowing you to listen to aggressive soundtracks with plenty of treble and not get that gritty feeling in your ear.
The power-save switch and auto-sense activation switch round out the rear panel. Internal relays protect the amp from excessive heat (not likely) or shorted channels. The amplifier can be rack-mounted using the included rack ears, or mounted on a rack shelf with the supplied feet. The front panel is attractive with its silver finish and array of blue LEDs. Best of all, it took up very little space in my rack.
The DD-8 was easy to install and setup in my equipment rack; the most time-consuming task was to strip five pairs of speaker cables to place in the Phoenix connectors, a task installers are used to. I initially used straight 16-gauge zip cord for the review, but I found that such basic cables limited the amp’s sound versus my reference MIT audiophile cables. The amp sounded a bit rolled-off and narrow when using the standard cable versus the MIT’s.
So I soldered on banana plug female jacks to short lengths of 16 gauge wires, screwed in the small sections of stripped wire into the Phoenix connector and plugged the connectors into the amp. Thus, I was able to use my good speaker cables and allow the DD-8 to flex its sonic muscle. If DD-8 customers wants to use better cables than the common-variety 16-gauge zip cord, he will have to create adapters as well, since I found no pre-assembled adapter for this task.
Associated equipment for the test included a pair of USA-made Carver amplifiers (a three-channel and a two-channel amp), recent Onkyo and Sony receivers, Sony XBR-4 52-inch LCD, Oppo BDP-95 universal player/Blu-ray player, and AudioControl Maestro M3 preamp/processor. All line connections were made using Alpha-Core solid-silver RCA cables. Component AC cables and power strip were courtesy of Essential Sound Products, a USA-made line of AC products that are perfect for installers and do-it-yourselfers.
With 125 watts on tap in my moderately-sized room, the DD-8 had no problem delivering 95 dB+ peaks. Yet it was not a fatiguing amp at all.
As is normal in my home cinema reviews, I listened through my Westlake LC8.1s (L-R), Westlake LC2.645 (center) and NHT Ones for the rear channels. A Paradigm Pro-15 powered subwoofer handled the low-bass duties.
After a couple of days of break-in, (letting the amp run with low-level music), I was ready to listen. I popped in the animated Blu-ray Bolt and proceeded to listen to the opening ten-minute action sequence that contains abundant surround cues, aggressive music soundtracks and terrific low bass. Through the Maestro3 preamp, the BD lossless soundtrack is very dynamic with good transient response, The steering of surround effects really comes through as well. With good amps, the impression is all encompassing in the front-to-back and left-to-right separation.
First thing I noticed was that the DD-8 does not have that “fizzy” hardness of previous generations of digital amplifiers. It is really smooth — almost Class A/B MOSFET-like. This characteristic goes a long way in allowing you to listen to aggressive soundtracks with plenty of treble and not get that gritty feeling in your ear. Smooth as it is, the imaging among the multichannels has good width and depth. The bass impact was tight and fast. With 125 watts on tap in my moderately-sized room, the DD-8 had no problem delivering 95 dB+ peaks. Yet it was not a fatiguing amp at all.
The DD-8 relayed good transient detail; it’s not quite as detailed as my high-end Class-A or AB amps, such as my Pass Labs X-350.5 stereo amp, but it is a cut above many high-power receivers and multichannel amps I have auditioned. BTW, the amp is really quiet; I could not hear any low-level noise through the speaker with the preamp volume down, and no added noise with increased gain.
The DD-8 acquitted itself quite well with cinema music soundtracks as well. I listened to The Who - Live at the Isle of Wight BD with its lossless surround and linear-PCM stereo soundtrack. The sound relayed the early 1970s rock flavor, as well as delivering Pete Townsend’s overdriven Gibson SG tone through the classic Hi-Watt tube guitar amp. Keith Moon’s drum cymbals sounded aces, too — that metal cymbal shimmer that you hear through better amps emerged clearly.
Along with numerous Blu-ray movies, I also listened to numerous stereo/multichannel DVD-As and SACDs through the Oppo player to get a handle on the DD-8’s overall music capability. Again, I noted smooth, yet dynamic finesse with big band and orchestral music. Yet, the rock and blues organic tones of the Allman Brothers — Live at Filmore East SACD came through the amp as well. So yes, if you have this amp in your system it can do double duty as a home cinema and as a music component.
My only nitpick regarding the DD-8 is that an amp this good needs good cables to let all the sound out. As mentioned, the standard Phoenix connectors do not allow larger cables to be used. You can get 16-gauge zip cord into the screw terminals, and that is it. It would be nice if a company made an accessory Phoenix connector adapter that could accommodate larger gauge wire ends or even banana plugs. I made my own.
All in all, the Lexicon DD-8 is the result of new technology that allows amplification to be done via digital chipsets. It has taken a while, but the newer generations of digital amps deliver more transparent, smooth, traditional analog-amp-like sound much better than the early ones. Combine the sound quality with the small footprint and low-power consumption, and you have a first rate amp for any installed multichannel sound application, or simply rack-mounting it on its supplied feet as an in-room system. It is not a high-end amp per se, but its sound will impress. The size, power, subjective audio quality and price net the Lexicon DD-8 multichannel amplifier an Everything Audio Network Stellar Sound Award.