Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.
This piece could be called A Tale of Two Amplifiers: “It was the best of times, it was the worst of times . . .” Actually, times were pretty good, as this review would be my first chance to directly compare two amplifiers since acquiring a Neohipo ET30 amplifier-speaker switching unit from Amazon ($159.95; all prices in USD). The two units were the Dayton Audio A400 power amplifier ($899), the subject of this review, and my own NAD C 275BEE (discontinued, $1495 when available). I was looking forward to this.
The two amplifiers are similar in many ways, starting with their power ratings: 165Wpc for the Dayton, 150Wpc for the NAD, both into 8 ohms, from 20Hz to 20kHz. Their rated total harmonic distortion levels across the audio spectrum at full power are low, and they both have outputs for only one set of speakers. But they have differences as well. The NAD has a special power supply that can provide instantaneous peak power well above its rated output; its level control is rather small and hidden on the back. The Dayton has a conventional linear power supply, while its level control is large and in the middle of the front panel. The A400 has both balanced and unbalanced inputs, while the C 275BEE has only unbalanced.
Description
The A400 stereo power amplifier is a beast physically; it measures 6″H × 17″W × 17.5″D and weighs 45.2 pounds. Its appearance is even more substantial than these specs indicate, due to its all-black enclosure and large level control on the front. The only light comes from the LED outline around the power button, which can be deactivated if desired. Otherwise, it’s a block of black.
Its back panel is more interesting. On the top left are the right-channel inputs and outputs, both XLR balanced and RCA unbalanced, selected by a switch underneath the connectors. The RCA and XLR outputs can feed another amp, the outputs to which are not affected by the position of the mode switch (balanced or unbalanced) or the level on the volume control. The upper right has a duplicate set of inputs, outputs, and switch for the left channel. In the upper-middle are a switch that chooses between stereo or bridged mono mode and one that determines whether power to the amp is controlled by the front-panel power switch, the presence of an input signal, or a 12V trigger signal. Next come the in and out 3.5mm jacks for the triggers, and finally, a switch to douse the front-panel LED.
Four meaty speaker terminals dominate the lower-center portion of the back. They’re designed to handle either banana plugs or bare wire. Over on the right side are a switch to choose between 115V and 220V mains power and a three-prong IEC power inlet. The supplied power cord looks heavy enough to power much of Manhattan if need be.
The only accessories are two heavy-duty rack mounts and the screws needed to secure them to the amplifier’s chassis. A thorough user’s manual is also included. The amplifier is covered by a fairly generous five-year warranty. It is manufactured in China.
While the A400’s web page and physical packaging describe it as a “2×200 Watt” amplifier, the owner’s manual provides different power ratings. I contacted Dayton Audio for clarification, and their product manager sent me updated measurements, all but the bridged mono rating following FTC regs, 20Hz–20kHz: at 4 ohms, 200Wpc at 0.01% total harmonic distortion (THD); at 8 ohms, 165Wpc at 0.05% THD; and 500W mono at 8 ohms in bridged mode, with 0.01% THD. This thing is a powerhouse, with very low THD.
For bridged operation, the speaker load should have minimum impedance of 8 ohms. There’s a large discrepancy between the 500W spec provided by Phillips and the 700W spec given in the A400 Product Manual. “The bridged output will only bass [sic] audio from the left channel input,” the manual states. “The A400 is not designed to sum the two input channels to mono.”
Setup
Other than dealing with its heft, unpacking and setting up the A400 was easy. The amp is held in place within its box by heavy foam forms, to which the rack mounts are taped. The manual and rack-mount screws come together in a bag, while another bag contains the power cord. Connect the speakers to their terminals, choose which inputs you’ll use and select them on the input switches, and attach the input interconnects. Very simple; very direct.
For this review, sources comprised a Music Hall Stealth turntable equipped with an Ortofon 2M Blue cartridge, a Cambridge Audio Azur 650C CD player, and a Dell Precision 3630 desktop PC feeding an iFi Audio Zen DAC. All sources were connected to my vintage Apt Holman preamplifier. My preamp has two sets of line-level outputs. I connected one set to the Dayton amplifier and the other to the NAD amp, and connected their speaker outputs to my new Neohipo ET30 amplifier-speaker selector. The ET30’s speaker outputs were connected to a pair of Acoustic Energy Radiance 3 floorstanding speakers, which were placed 6.5′ apart and 3′ from the front wall of my listening room.
Listening
My first selection was a performance of Hector Berlioz’s “Le Corsaire Overture” by the Baltimore Symphony Orchestra conducted by David Zinman, from their album La Marseillaise & Other Berlioz Favorites (CD, Telarc CD-80164). The piece starts softly but soon shakes the room. The A400 threw a fine soundstage with significant depth and delivered a broad frequency range with excellent deep bass response. The strings sounded as one, while the brass made quite the sonorous noise; this piece has lots of brass parts. Detail was impressive, with good location of instruments.
No listener would ever mistake John Pizzarelli’s singing voice for Frank Sinatra’s. However, Pizzarelli recorded a fine album of Sinatra favorites called Dear Mr. Sinatra (CD, Telarc CD-83638) with the Clayton-Hamilton Jazz Orchestra. On Sinatra’s hit song “Witchcraft,” the A400 presented Pizzarelli, both singing and on guitar, well out in front of the orchestra and very closely miked. There was convincing depth to the performance, especially with the orchestra, and the sound spread from one edge of the soundstage to the other. I particularly enjoyed the full, rhythmic reproduction of Pizzarelli’s guitar.
Purely by chance, I became a big fan of the British jazz singer Claire Martin back in the 1990s. Her album The Waiting Game (CD, Honest Entertainment CD-5018) contains a lot of great songs, but my favorite is “Better Than Anything,” on which she’s accompanied by semi-acoustic electric guitar, piano, bass, and drums. Imaging and soundstaging were impressive. Through the A400, the bass and drums spread from the center to the left. The piano and guitar spread from the center to the right edge, then moved to the center during their solos. Martin was dead square in the middle and mostly out front. Dynamics were impressive as well. Martin can go from whispery to loud in a heartbeat, as she does on this song, but the A400 handled the changes easily. She sounded extremely natural, with a rich alto that the A400 showed off very, very well.
Probably my favorite smooth-jazz group is Fourplay, led by keyboard wizard Bob James. Their The Best of Fourplay, originally released by Warner Bros. in 1997, was remastered in 2020 and released by Evosound as a hybrid SACD/CD (EVSA765M). The remastering sounds even better than the original, which I thought couldn’t be topped. The keyboards have been brought forward, as has the guitar. The drums have even more slam. I chose “Bali Run” as a demo because of how it showcases the interplay of the instruments. The A400 made it easy to appreciate the improved sound on the remastered version. The bass seemed to dig even deeper with more punch. I was greatly impressed with the delicacy of some of the keyboard notes through the Dayton amp.
Now it was time to swap my classical/jazz cap for my good-time, honky-tonk hat. I dragged out Marshall Chapman’s Me, I’m Feelin’ Free (LP, Epic KE 34422) and dropped the needle on “Rode Hard and Put Up Wet.” This one sounds like the lead-up to a barfight scene from Road House. Chapman is out front and has electric guitar, drums, bass, and horns behind her. I was presented with good extension; good slam on the drums and bass. Her strong voice sounded terrific, very honky-tonkish, as it should on this song. The A400 definitely matched my “let’s-rock-out” mood. It boogied!
To keep the party going, I cued up “Viva Las Vegas,” my favorite track from ZZ Top’s Greatest Hits compilation (CD, Warner Bros. 9 26846-2). I’ve never heard three guys make such loud music. Dusty Hill (RIP) sings lead, right in front, and plays bass; Billy Gibbons’s guitar and Frank Beard’s drums are positioned somewhat back. As with the Marshall Chapman tune, the A400 was eager to rock out. The bass guitar and kick drum were tight, with good slam. Hill’s voice was strong and Gibbons’s guitar punched through effortlessly. This cut gave further proof that the A400 is just as ready to rock as it is to reproduce other genres.
Comparison
There are reasons the NAD C 275BEE cost more in 2015 than the Dayton Audio A400 does today. For one, the A400 is sold direct-to-customer through Dayton’s parent company, Parts Express. Also, the NAD has the advanced circuitry that allows for that instantaneous peak power far above its rated output. The A400 is a more basic unit, but is definitely no slouch. Having both amplifiers connected to the ET30 selector made it easy to compare the two.
Based on listening to multiple musical genres on both, it’s my feeling the NAD C 275BEE is more attuned to reproducing classical and jazz (the genres I listen to most) than rock. It does a great job on the first two and a more-than-adequate job on the last. But for rock, the A400 bests the NAD with a bit more upper-midrange presence. Not a lot more, but enough to hear the difference. Just enough to reject the old saw, “All amplifiers sound the same.”
For instance, on Leonard Bernstein’s West Side Story Symphonic Dances, performed by David Zinman and the Baltimore Symphony Orchestra (CD, London 452 916-2, the A400 delivered slightly more deep bass than my NAD C 275BEE. On “Bali Run” by Fourplay, the A400 bettered the NAD by having a more open-sounding upper midrange. As mentioned, on Marshall Chapman’s “Rode Hard and Put Up Wet,” the A400 really wanted to rock hard. The NAD wasn’t quite so into the music, with less rhythm and slam than the Dayton Audio. Similarly, on ZZ Top’s “Viva Las Vegas,” I favored the A400’s pace, rhythm, and slam over the NAD’s.
Conclusion
At $899, the Dayton Audio A400 is a real deal, especially considering it comes with a five-year warranty and, if you buy it from parent company Parts Express, you have 60 days to decide whether it’s for you. If you’re in the market for an affordable, higher-powered basic amplifier, the A400 should be on your list. The fact that it holds its own with the NAD C 275BEE, and in some cases bests it, makes the Dayton Audio A400 a great choice.
. . . Thom Moon
thom@soundstagenetwork.com
Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.
Associated Equipment
- Speakers: Acoustic Energy Radiance 3
- Power amplifier: NAD C 275BEE
- Preamplifier: Apt Holman
- Analog source: Music Hall Stealth turntable with Ortofon 2M Blue cartridge
- Digital sources: Cambridge Audio Azur 650C CD player; Dell Precision 3630 desktop PC running Windows 10 and JRiver Music Center 30, feeding an iFi Audio Zen DAC
- Interconnects: Manufacturer-supplied for turntable and computer-to-DAC; Linn Silver analog for CD player; Dayton Audio analog from DAC to preamplifier; Morrow Audio MA1 analog from preamp to NAD power amplifier; WireWorld Luna 8 analog from preamp to A400 amplifier
- Speaker cables: Audtek 14-gauge OFC (oxygen-free copper) cable terminated in banana plugs
Dayton Audio A400 stereo/mono amplifier
Price: $899
Warranty: Five years, parts and labor
Dayton Audio
705 Pleasant Valley Drive
Springboro, OH 45066
Phone: (937) 743-8248
Website: www.daytonaudio.com
Email: info@daytonaudio.com
