A light and airy sound
There is a notable difference in sound between the AP-701 and AP-507 revealed in the increased resolution and detail retrieval of the new NCOREx module. Another difference is what I would describe as higher illumination. You may ask what “illumination” is supposed to mean, how does that describe sound? The terms dark, recessed, warm, or thick are often used to denote a heavier, less see-through presentation. For instance, an amp that has a darker, less illumined character will present the notes of an instrument or a singer’s voice as opaque, solid, perhaps flat in character. Conversely, a more illuminated amplifier lets the listener hear more into the note itself, and more into the soundstage, as though a light has been directed toward the back of the soundstage, allowing more to be seen.
The effect livens up older recordings to give them a more contemporary feel. Four-decade old CDs of artists like the Alan Parsons Project benefitted from the new module’s teasing out minutia in the recording. The experience of listening to the recordings seemed more like I was entering the studio rather than listening to a product the studio made decades ago.
The AP-507 seemed as a series of spotlights highlighting members of a band such that they stood out against a black background as they played. It seemed easier to pick out the individual contributions of players and singers when in the past they tended to blend into the mix such that it was more difficult to hear them individually.
I tried some challenging music with the amplifier such as ZEDD’s “Automatic Yes” and “Tangerine Rays” from the album Telos. There is a heavy synth presence and massive LF, which the AP-507 and the rest of the TEAC stack rendered cleanly. Another delight was a remake of the Bee Gee’s hit “Staying Alive” by Electro Deluxe. Quickly paced music does not get bogged down with the AP-507, as happens with some class A/B amplifiers. The extra resolution capability of the NCOREx module renders split second dead air space between super-fast bass notes. I typically do not listen to EDM (Electronic Dance Music) with its overwrought LF foundation, but with a capable system, it is quite interesting. If you asked me ten years ago whether I would spend even one minute listening to highly manipulated and punctuated massive bass, I would have laughed at the idea. Yet, here I am considering the quality of music which melodically jagged and plumbs below 20Hz often. Even amid the forest of LF tree trunk-sized notes the lyrics were clean.
Turning to acoustic music, Molly Tuttle’s speedy guitar fingering on “Everything Burns” was captured without running together, which gave it a sense of immediacy. The AP-507 did strike me as a quicker sounding amp than the AP-701. I suspect that is due to the extra resolution I sensed, as notes seemed more complete, with leading and tailing edges easily discernible. Tonally, with the Legacy Wisper the AP-507 was spot on, frankly, one of the most gorgeous pairings of amplifier and these speakers I have experienced. That is quite a compliment to TEAC’s Class D design with the NCOREx, because I have used a fair number of amps that cost five times the pair of AP-507. If a shell of one of those big buck amps was placed over the top of the TEAC amp, I suspect the performance would be adjudged premium due to supposed pedigree of the amplifier.
Compared to the Legacy i.V4 Ultra
I heard wonderful bass elucidation and a surprising degree of macrodynamics from the AP-507. The Legacy i.V4 Ultra is a bit more shaded, less illuminated, and compared to the AP-507 seemed to have a bit more grunt, more heft. I was surprised when I replayed the same tracks with four channels of the i.V4 Ultra in passive bi-amp mode, the closest equivalent to the AP-507 in BTL mode, to hear less output at the same volume setting on the VRDS-701. The output of the AP-507 must be set high, because I had to nearly double the volume on the VRDS-701 to achieve similar listening levels with the Legacy amplifier!
The different gain structure of the two amps might also explain why the electronic noise emitted by the AP-507 is louder than the Legacy amp. Listening closely, the i.V4 Ultra also had the same electronic noise as the TEAC amplifier, but it was about half as loud, much less noticeable. It stands to reason that the higher output of the AP-507 would cause it to emit more noise, but also play the signal with more authority at a given listening level.
That the AP-507 was more impactful in BTL mode bi-wired to the PureAudioProject Trio15 10” Coaxial Speakers was surprising. Looking at specifications, one would be led to conclude that since the i.V4 Ultra offers 600wpc into 8 Ohms and the AP-507 offers 350wpc in BTL mode, the TEAC would be the “weaker” amp. But that was not so. The TEAC had a more intense, perhaps contemporary sound with its unvarnished openness and cleanness.
I was able to achieve a Goldilocks result with the PS Audio AirLens streamer and the TEAC components, along with the PureAudioProject Trio15 10” Coaxial Speakers. Upright bass, piano, and voices are superb with the AP-507. Tonally, the AP-507’s illumination properties make it susceptible to sounding emphasized in the treble, but working with cables moderated it. I use both models of Iconoclast Speaker Cables, the TPC (copper) and SPTPC (silver plated copper). Their tonal properties are slightly different, so that switching them on the bass and mid/treble posts can shift a system’s tonal balance. Initially, I tried the Iconoclast SPTPC on the mid/treble posts because I thought that it would prevent too much treble information. I had put the Iconoclast TPC on the bass because the Perlisten D212s Subwoofers could fill in what was missing. As I listened to Christopher Cross on his Café Carlysle Sessions album, a primary test track to judge the tonality of a system, I heard too much nasal qualities and a bit of strain in his voice when he reached for higher notes. Having built many systems which do not exhibit those characteristics, I knew immediately that there was too much high-end energy. The solution was to swap the speaker cables, putting the copper TPC Speaker Cables on the mid/treble and the SPTPC (silver over copper) on the bass. The tonal balance shifted in a most pleasing way, warming Cross’s voice and still pulling an uncanny amount of detail from the recording.
Two flavors of power
The AP-507 presents itself through two sonic palates, associated with the ability to switch it between Bi-Amp and BTL modes. The Bi-amp mode does not take full advantage of the maximum power offered, but it does utilize both channels at 95 watts into 8 Ohms. Why would a person wish to operate the amplifier in a less powerful mode? All things equal, I usually recommend operating an amplifier at a higher output. On certain occasions, the nuances, the perceptually important characteristics of the sound quality are different enough that one might opt for slightly lower power and an alternative tonal character. Audiophiles who seek lower powered tube amplifiers most often do so because they feel the beauty of the music is better served than with higher-powered solid-state amplifiers.
In this instance, though the macrodynamics and sound stage depth potentially offered by the AP-507 are reduced somewhat by operation in the Bi-Amp mode, the amplifier seems more balanced overall. The illumination characteristic which can seem to emphasize the higher frequencies is lowered, yielding a more mature, mellow nature. In that respect, the AP-507 is more like the Legacy i.V4 Ultra. The i.V4 Ultra is unfailingly inoffensive and can be mated with any speaker without undue emphasis on the top or bottom of the frequency range. The AP-507 is similar when used in Bi-Amp mode, and it does so with about the same macrodynamic impact as the Legacy amplifier. The bonus is that the electronic noise is muted better and may be a nonissue to most users.
The other sonic palate of the AP-507 falls into the category of expected class D amplifier sound, highly detailed and with less coloration or warmth. The output of the amplifier in this mode is truly surprising, and those seeking to drive their speakers with authority should try the BTL mode. The power gained in use of BTL mode would serve well to bring forth more liveliness from speakers having 4 Ohm nominal impedance. However, all speakers benefit from higher, clean power. Do not presume that an 8 Ohm speaker would not be enhanced by the BTL mode. As with other features of fine components which offer alternative modes, the hobbyist must try all arrangements, all settings, to find those which are preferable.
Pay attention to cabling
Those who have been in the game long enough and have handled their share of sets of cables know how critical they are to enhancing the performance of a system. Every cable in every position of a system is critical to optimizing performance.
When I put the PureAudioProject 10” Coaxial Speakers into the system, I wanted to increase the warmth in the midrange. Using the amplifier in Bi-Amp mode, I relied upon a Y Cable at the RCA Analogue output of the VRDS-701 to split the signal so that the pair of AP-507 amps could receive a line level signal, but also that the Perlisten D212s Subwoofers could receive the same signal. For that purpose I used an Audio Sensibility silver OFC cable, but I suspected I could further improve the warmth of the system by replacing it with an Audioquest Y Cable. I needed no exorbitantly priced cable but was able to obtain the desired tonal balance with a set of Audioquest FLX-X F22M Splitters (male to 2 female). The sonic change was akin to if a person had inserted a tube buffer stage!
If upon trying the AP-507 you think that it is too bright, take a close look at your cabling. Interconnects have pervasive influence upon an amp’s sound, and the AP-507 is no exception.
TEAC and NCOREx a solid choice
Class D amplifier modules are so exacting, with so much resolving power that swaths of music that were obscured become noticeable. I have been using some of my reference music for decades, and one would think that every nuance of the recording would be exposed by now. Not so. The NCOREx seems to subtly shuffle recordings much the way an engineer in a studio might tune performances through slight adjustments of small parts of the frequency spectrum, causing the recording to reveal previously unnoticed elements. Listeners who wish to hear everything going on in a piece of music will enjoy the performance of the AP-507.
I wish to steer readers seeking a warm and syrupy sound and who complain that some systems have too much detail or definition away from this amplifier. Such enthusiasts prefer a more convoluted and tonally darker sound, even if it is significantly less revealing of the recording. I wish to promote this amplifier to listeners who cannot get enough of the minutia of a recording. If a tubey, warm sound seems convoluted to you, and a solid state, highly precise sound seems lifelike to you, then likely you would appreciate the AP-507.
If you are flummoxed by the myriad of choices for sources, preamplification, and amplification and wish to simply the process of selecting equipment, The TEAC 700 Series products I have reviewed have been pleasantly surprising in that they perform at a very high level. This is a brand that I can recommend excellent results without spending inordinately on components. As I have used a variety of speaker genres, dynamic, omnidirectional, hybrid line source, dipole, and hybrid horn, with the TEAC separates, I believe that the budget audiophile who adopts TEAC as their system brand will be well rewarded.
Associated Components:
Digital Sources: Bricasti M5 Network Player, PS Audio AirLens, TEAC VRDS-701 Dual Monaural USB/DAC CD Player/Pre-Amp/Headphone Amplifier and TEAC CG-10M-X Master Clock Generator
Streaming Music Service: Tidal premium; Qobuz
Interface: ROON; Audrivana
DAC: (Placeholder) Eastern Electric Minimax with discrete opamps rolled in
Preamp: (Placeholder) Cambrige Audio Azur 840E
Amps: Legacy Audio i.V4 Ultra
Integrated: Heaven 11 Billie Amp Mk2 (two units used in horizontal bi-amp configuration); PS Audio Stellar Strata Mk2 (two units used in horizontal bi-amp configuration)
Speakers: Legacy Audio DSW Clarity Edition; Kings Audio King III electrostatic speakers; Pure Audio Project Trio15 10” Coaxial version; Kings Audio King Tower omnidirectional; Aspen Acoustics Grand Aspen; Wharfedale Opus 2-M2 Monitors
Subwoofers: Perlisten D212s Subwoofers
IC’s: Iconoclast RCA and XLR Generation 2 with Ultra-Pure Ohno Continuous Cast Copper conductors
Speaker Cables: Iconoclast Series 2 TPC Speaker Cable; Iconoclast Series 2 SPTPC Speaker Cable
Digital Cables: AudioQuest Digital Coaxial Carbon 1.5m; AudioQuest Digital Coaxial Coffee 1.5m; Iconoclast RCA or XLR 2m Interconnect used as digital link; Audioquest
USB: AudioQuest Cinnamon USB 1.5m; Audioquest Coffee USB 1.5m; Clarity Cable Supernatural 1m
Power Cables: Iconoclast BAV Power Cord; Clarity Cable Vortex; Snake River Audio Signature Series
Power Conditioning: Wireworld Matrix Power Cord Extender; Tice Audio Solo
- ← Previous page
- (Page 2 of 2)
