The impression of Japan’s top Hi-End audio brand Accuphase has always been mature, sophisticated, and upright. The brand name of Accuphase is composed of “Accu,” the prefix of “Accurate,” and “phase.” As the name implies, “Accuphase” means pursuing precision and perfection to achieve the most ideal music reproduction and playback effect. The purpose of Accuphase is to produce audiophiles that are astonishing and close to perfect audio products. Accuphase E-470 integrated amplifier, this is a new model of Accuphase’s comprehensive expansion second only to E-600.
The Accuphase E-600 integrated amplifier is a pure class A amplifier, and the E-470 amplifier is a class AB architecture. What is the difference between the two? The performance of the two is very similar. The difference is only in the sound characteristics. Some audiophiles prefer pure Class A amplifiers. The E-600 can satisfy their preferences, while the E-470 is a better choice with more substantial thrust and better compatibility.
Compared with the predecessor E-460, the E-470 wins in lower noise and higher damping coefficient, which means it has a stronger driving force. The key to such an improvement is that many technologies from the flagship C-3800 pre-amp and A-200 have been transplanted. How low is the noise of E-470? The speaker’s noise transmitted by the E-470 is only 34μV, 63% lower than the previous generation E-460, which is fantastic!
The noise of the E-470 can be reduced to such a low level. How did Accuphase do it? One of the keys is using a new generation of exclusive AAVA volume control technology (Accuphase Analog Vari-gain Amplifier) from the C-3800 flagship pre-amp.
The computer central processing unit is used to control the current value of the sixteen current valves according to the angle of the volume knob, resulting in tens of thousands of different combinations and bringing up to 65,536 levels of sound control accuracy.
Run in full analog stateThe Accuphase E470 amplifier’s advantages are high accuracy, and the whole process is carried out in a pure simulation state. Therefore, those compression, distortion, and errors that may occur between A/D and D/A are eliminated. Even the volume balance control between the left and right channels is achieved through the same mode.
More importantly, it is not an attenuated sound control but a gain-type sound control. The impedance value, frequency response, and sound quality are constant under any volume, ensuring a high signal-to-noise ratio, low distortion, and no crosstalk. The distortion and noise caused by the contact loss of the varistor are all eliminated.
The input signal selection setting is also the same as the flagship E-600. The logic circuit controls the relay to switch on the input/output, achieving a shorter and more direct signal channel, significantly reducing signal loss and distortion, and the probability of interference by noise intrusion.
The E-470 power amplifier part adopts the most proud circuit architecture of Accuphase, MCS (Multiple Circuit Summing), the latest and improved version of MCS+. A current/voltage converter is formed by connecting multiple groups of the same circuit in parallel, combined with current feedback correction technology. That is, at the signal output end, the current is returned instead of voltage. Therefore, the impedance of the return point is extremely low. The phase drift and time difference are almost non-existent. The distortion parameters can be significantly improved in exchange for an excellent signal-to-noise ratio, which is extremely quiet and clean.
Powerful Driving Ability
The damping coefficient of E-470 is as high as 500, which significantly exceeds the 200 of the previous generation E-460, which means that it has a better ability to drive speakers. E-470 outputs 180 watts at 8-ohm load and 260 watts at 4-ohm load in terms of output power. It is a standard high-power design.
The key to the significant increase in the damping coefficient of E-470 lies in Balanced Remote-sensing technology, which is a negative feedback circuit. The unique feature is that the signal detection point is set closest to the speaker output. And the negative feedback of the connection ground is also handled. In this way, the output impedance is significantly reduced, but total harmonic distortion and common mode distortion are improved.
Please note that the speaker output uses a unique low-impedance inductor, and the relay of the protection circuit is changed to a more durable and lower impedance MOS-FET switch. These designs are also helpful for improving the damping coefficient.
Triple Parallel Push-Pull Structure
Each channel output stage adopts a triple parallel push-pull structure and uses three pairs of MOS-FET silicon field-effect transistors (Toshiba K3497 / J618) the same as E-600 or even flagship A-200, bringing (260 watts 4Ω, 180 Watt 8Ω) full output power.
The power supply of Accuphase E470 uses an extensive and high-efficiency toroidal transformer, which is highly shielded and shockproof. Coupled with two Nichicon tailor-made 40,000μF / 80V aluminum electrolyte filter capacitors (E-600 capacitor specifications are two 47,000μF / 71V), forming a considerable lineup of power supply systems.
Besides, it is very common to use relays for the protection circuit switches of the output terminals. However, the new generation of Accuphase uses more feverish methods to replace it with MOS-FET semiconductor switches to eliminate the effects of unstable factors, loss, and aging of the relay’s mechanical contact, to obtain higher reliability and durability. The most important thing is to ensure that the signal flowing through will not be degraded by mechanical contact.
Independent Pre-amp and Power amp
E-470 integrated amplifier can be regarded as a combination of independent pre-amp and power-amp. It has a pre-amp output and power-amp input. Even if it is upgraded in the future, E-470 can be used as an independent pre-amp or power amp that continues to operate. Besides, E-470 can purchase phono amplifier and DAC modules. The latter also has a USB interface. If you don’t have a lot of space to accommodate a complicated system, E-470 is a high-quality choice for an integrated amplifier.
Each input of Accuphase E470 can be preset for forwarding/reverse (0 or 180 degrees) independently. The timbre circuit can independently adjust the treble (3kHz) or bass (300Hz) for +/-10dB step-less adjustment. When it is not needed, the timbre circuit can also be bypassed to reduce sound quality least.
Loudness compensation ([email protected]), headphone output, mono switching, and two sets of heavy-duty speaker wire binding posts A or B can be switched independently. It is also equipped with XLR pre-stage output and post-stage input that E-460 does not have. The XLR post-stage input is more intimately equipped with a phase switching function corresponding to the pre-stage with different output phase specifications.
In addition, two card slots are reserved on the left side of the back of the case. Several modular circuit cards can be purchased when necessary, including decoding circuit cards and phono circuit cards. The DAC-40 decoding circuit card is based on the MDS++/24bit/192kHz decoding circuit with high sound quality and high specifications and is equipped with coaxial, optical, and USB (HD) inputs. AD-30 phono amplifier circuit card (MC‧66dB gain, 30/100/300Ω input impedance/MM‧40dB gain, 47kΩ input impedance). There is also a LINE-10m line-level input circuit card.
Accurate Image and A Wide Sound Field
The first test is the Mahler Fifth Symphony performed by the San Francisco Symphony Orchestra conducted by Michael Tilson Thomas. When the trumpet sounded, it looked impressive, with brightness and lines. As soon as the bass drum is played, the dynamic impulse and intense sound burst feel quite solid.
There is still no tension or splitting under strong sound pressure output, and it shows the low noise side of E-470. The sound field background is almost dark, making the foreground more vivid and three-dimensional. The different lines of the copper tube, E-470, are all clear, three-dimensional and vivid. The tone still has a little Accuphase warm tone, but it is just like the warm tone of the lights in the concert hall and does not affect the overall expressive feeling.
The strong ensemble strongly reflects the high power of E-470, coupled with the driving force and control force under the 500 damping coefficient, it is indeed clear and eye-catching, and it spreads the entire orchestra openly. There is no loose, messy or entangled interconnection in the sound field. There is no excessive sound weight reduction, but a comfortable feeling that makes people feel the image, positioning, and hierarchy, without pressure or jam.
Piano Playing is Smooth, Clear, and Neutral
“Beethoven” is played live by Russian pianist Evgeny Kissin. It contains live recordings of Beethoven performances from 2006 to 2012 in various places. The sound effects of the whole album are very natural, clear, and vivid. Accuphase E470 is a perfect interpretation. The sound quality is neutral and full with density and weight, and the touch of the piano strings is clear and natural, and relatively neutral.
It reproduces the smooth rhythm and speed of the performance. The high-pitched keys have a brilliant and powerful sound, and the low-pitched keys have a majestic majesty. The bass’s rate and cleaning are quite clear, and the weight and rhythm of the playing are visible. What I hear through the E-470 is a perfect piano and an outstanding performer. The listening distance is appropriate and comfortable. The piano The contrast between the intensity and the sound’s speed is very clear and very satisfying.
Listen to “Come Away With Me” by Norah Jones to show the sound texture and beauty of the E470 integrated amplifier. The tone is very neutral, pure, and detailed, with subtle dynamic fluctuations with softness and layering. The human voice is dense, the image is clear, and it sounds full of energy.
I have also listened to a lot of popular music that I thought was a little inadequate in the past. Some of them sounded inadequate in bandwidth and a little compressed, some were not good enough in sound quality, or the three-band equalization was not good, but I heard them on this system. All have improved a lot. Perhaps the sound of this system is neutral enough and pure enough energy, or it may show the music bandwidth that it should have. The past noisy feeling has disappeared, the high frequency is more pleasing, the low frequency is more controlled, the overall extension is better, and the sound is cleaner.
Inheriting superior technology from Accuphase’s 40th-anniversary model, Accuphase E470 integrated class A amplifier is a perfect upgraded version of E460. The core of the preamplifier part is a further evolution of the AAVA type volume control. The power amplifier block is equipped with the latest measurement amplifier topology to enable fully balanced signal transmission.
The MCS+ method improves key performance parameters by using multiple identical circuits in parallel, and current feedback provides the best stability. Therefore, the low impedance output stage reaches a damping factor of 500. MOS-FET switches replace relays for speaker protection, helping to ensure first-class electrical characteristics and improve long-term reliability. MOS-FET devices’ power arranged in three parallel push-pull pairs for each channel greatly enhances the amplifier’s ability to drive low impedance loads.
If the room area is not large and you are looking for a one-step integrated amplifier, Accuphase E470 is the right choice.