⌈ ACCUPHASE unveiled its first stereo amplifier half a century ago, in 1973. Since then, this Japanese brand has become one of the most recognized and respected ones around the world. The company has earned its reputation by offering primarily high-end amplifiers (including those working in Class A), preamplifiers and CD and SACD players. We are testing the E-700 integrated amplifier, which operates in class A. ⌋

TESTING ACCUPHASE PRODUCTS in my case reminds me, and has for a long time, of dancing. And it's the dance of a close-knit couple who know each other inside out, have seen a lot, and experienced many things together as well. And they still love what they do. They know each other's moves, figures and arrangements, and yet each performance is different, each time the temperature of the performance is different from the previous one. All the more so because this dance is closer to spontaneous activity than to a calculated and meticulously planned “reenactment.”

The thought occurred to me as soon as I saw the E-700 amplifier. After all, it has a form factor I've known for many years, its basic physical characteristics are well known to me, as are the technical solutions used in it. It differs a bit, that's also one of the “constants” in Accuphase products, but as far as the design is concerned, these differences are rather cosmetic, gently improving functionality and ergonomics. More of a change of emphasis than a remodeling of the design.

And this is something that makes this company the envy of many other manufacturers, and something that some, including other well-known Japanese brands, seek to emulate. Consistency, because that's what it's all about, results in small changes that nevertheless accumulate, after a few generations reaching a critical mass that changes the paradigm. This was also the case with this company's products, which a few years ago leapfrogged the sound to a much more mature, saturated and resolved one. And all this was done primarily by slowly improving technical parameters. It’s just that they improved the ones that really matter.

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⸜ A few simple words…

鈴木雅臣 MARK MASAOMI SUZUKI
General Manager

⸜ Team of engineers who developed E-700, (from the left) Miyajima-san, Nakamura-san and Itoh-san • photo Accuphase

» KENICHI ITOH: » MECHANICAL DESIGN • Mr. Itoh has worked at Accuphase for 19 years. He previously designed the C-3900 and C-2900 preamplifiers, as well as the PS-1250 and PS-550 AC power conditioners and other products from our brand. He enjoys traveling in his standard Toyota Hiace camper. This summer he traveled with his family to the Hokuriku region with his adorable beagle dog, Nana.

⸜ Mechanism coupled to the volume knob • photo Accuphase

» TAKAYUKI MIYAJIMA: » ELECTRONICS– preamplifier, output stage, and sound quality assessment • Mr. Miyajima has worked at Accuphase for 9 years. Accuphase's original technology, ANCC (Accuphase Noise & Distortion Cancelling Circuit), is his invention, also applied to the E-700. He recently bought a small DSP-based guitar amplifier that inspired him to play the bass guitar, a skill he hasn't used in a long time. He now aspires to be the Jaco Pastorius of his dreams :)

⸜ E-700’s output stage • photo Accuphase

» TAKEHIKO NAKAMURA: » ELECTRONICS – microprocessor assembly, programming and more • Mr. Nakamura invented our original AAVA (Accuphase Analog Vari-gain Amplifier) volume control technology and designed the E-5000, E-4000, C-2900, P-4600 and other amplifiers. He recently replaced his 4-cylinder Toyota Allex with an 1800㏄ engine with a 3-cylinder Toyota Yaris with a 1500㏄ engine. The Yaris offers better fuel economy than the Allex, but has less acceleration. He is fully aware of these trade-offs.... MS

⸜ Inside of the E-700 • photo Accuphase

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▌ E-700

ACCUPHASE's E-700 is an integrated amplifier. It replaces the E-650 in the range, only after seven years (!); test → HERE ˻PL˺. It features no file player module, nor Bluetooth connectivity. And yet it is one of the most functionally versatile amplifiers on the market, competing with the top products of its type from the 1970s.

It operates in Class A in push-pull mode, delivering 35 W / 8 ohm, 70 W / 4 ohm, 140 W / 2 ohm and as much as 160 W / 1 ohm (with music signal). We know that after exceeding it, the amplifier switches to Class AB and offers even higher power. The company's website reads:

The E-700 Class-A integrated stereo amplifier offers excellent sound quality thanks to advanced design technology developed over 50 years. Using the latest circuitry and high-quality materials, this amplifier guarantees high-purity signal transmission from the input to the output.

The preamplifier section features AAVA's innovative balanced volume control, providing even higher sonic precision. Thanks to optimized component placement, PCB topology and grounding circuitry, as well as a unique ANCC solution in the current-to-voltage conversion circuit after volume control, the amplifier achieves low distortion and minimal noise level.

⸜ accessed: 9.20.2024.

FRONT • A distinctive feature of the company's products are the thick aluminum front panels in a color said to be “champagne.” It's a shade of gold that Accuphase chose many years ago and that you'll find in all its products.

The layout of the components on it is also repetitive, although there are minor differences between successive models. In the middle there is a thick plate of tempered glass, with the VU-meters placed behind it, which act also as output power indicators. They are implemented on LED rulers, just as in the E-650. Between them there is a green illuminated logo, and under it a red LED module. On it we can read the volume, the sampling frequency of the digital signal or the selected load of the phono cartridge. This is because the device can be equipped with a D/A converter module called DAC-60, as well as a phono preamplifier, AD-60.

Below there are small red LEDs, indicating selected digital input, filter, tone, mono, etc. The associated keys are placed under a tilting plate, when opened moving stately and silently - a minor example of this company's advanced engineering. Under the flap there are knobs that allows us to change the tone, balance between channels, as well as activate the input to the power amplifier. There is also a delightfully archaic solution here, namely an output switch for recording. There are many more functions and buttons - for a list of them let me refer you to the manufacturer's website.

The two most important knobs, input selector and volume control, are located on both sides of the glass plate. Next to the former are additional, also red, LEDs. Let's add that the volume encoder has been housed in a fantastic-looking element made of aluminum blocks and is coupled by a gear transmission. As a result, one operates this amplifier as if it were part of a space rocket, that is, with confidence and slight resistance. At the bottom edge one finds a mechanical AC power switch, a button that mutes the sound by 20 dB in increments, and a headphone output, connected to a dedicated headphone amplifier. It looks great.

REAR • An indication of how functionally advanced the tested amplifier is the number of connectors on the rear panel, populated with inputs and outputs. Since the previous generation, all the company's top units are a fully balanced designs, from input to output. Hence the presence of such, symmetrical jacks, but only two pairs of them. In the same form we get the input to the power amplifier and the output from the preamplifier.

The vast majority of jacks are RCA inputs and outputs. The manufacturer apparently assumes that, except for a CD player (SACD) and one other product of this type, the rest of the equipment in audio systems is of unbalanced design. And they are not wrong about it. That's why we get as many as five RCA line inputs, plus a tape loop, another input of this type, and a pre/amp input and output. At the XLR inputs to the power amplifier there are switches that allow user to change the absolute phase, and for the rest there is a switch on the front panel. Next to it there are slots ready for DAC-60 and AD-60 modules.

The speaker terminals are solid, gold-plated and produced specifically for this company. We can use banana plugs, spades or “bare” cables in them (yuck !). There are eight terminals, meaning each channel is duplicated. Historically, companies have offered dual outputs - A and B - to “sound an extra room,” is a quote from one of the old catalogs. Today they come in handy for a bi-wire connection, in which separate cables run the signal to the midrange section and separate ones to the woofer section. And then there's the classic IEC-type AC power inlet.

TECHNOLOGY • Accuphase describes the design of their amplifier as follows:

The output stage uses the latest instrumentation amplifier method, which, combined with the advanced MCS+ circuit and current feedback gain circuit, helps improve a variety of sound characteristics. Making full use of the highest quality materials and pattern technology, this amplifier provides low impedance, a guaranteed damping factor of 1000, and ideal drive for various types of speakers.

⸜ Ibidem.

The most important information is that the device is a balanced design throughout the entire circuit, from the XLR input jacks to the speaker outputs; the signal behind the RCA jacks is symmetrized. The preamplifier is a special design, a solution called Instrumentation Amplifier. On the Texas Instruments website we find the following description:

An instrumentation amplifier (INA) is a very special type of differential input amplifier; its primary focus is to provide differential gain and high common-mode rejection. INAs offer high input impedance and low output impedance; newer devices will also offer low offset and low noise.

The unique combination of a high common-mode rejection ratio (CMRR) and high accuracy make INAs especially attractive for applications with small error budgets such as motor controllers, battery test equipment, analog input modules, LCD test equipment and patient monitoring systems.

⸜ BRENDAN HESS, What Is an Instrumentation Amplifier?, →www.TI.com, accessed: 10.10.2024.

Accuphase has been using these types of amplifiers for some time. They are an extension of technologies that this manufacturer developed long ago, particularly the: MCS+ and Balanced AAVA. MCS+ (Multiple Circuit Summing-up) is, as the manufacturer says, a technology for improving the performance of analog amplifier circuits. The principle is similar to the company's MMB and MDS systems. Instead of simply connecting multiple circuits in parallel to form a single gain path (circuit), in MCS+ there are parallel circuits, but separately powered. This solution was first found in the CX-260 preamplifier from 2001.

AAVA (Accuphase Analog Vari-gain Amplifier) is a signal level control circuit, replacing the classic potentiometer. Since the music signal does not have to pass through a resistance in it, impedance changes at its output are eliminated, regardless of the position of the volume knob. This results in a high signal-to-noise ratio and low THD. In this circuit, the voltage signal is converted into a current signal, regulated as in professional mixers, and then converted back into a voltage signal. The E-700 uses a balanced version of it.

And finally, there's the power amplifier, which is built using with four pairs of MOSFET transistors, operating in a push-pull arrangement, yielding up to 35 watts in class A at 8 ohms, but as much as 140 watts at 2 ohms (!). The manufacturer has been striving for years to keep the output impedance of this circuit as low as possible. With this in mind, he redesigned the circuits at the output a few years ago, replacing the Zener coils with ones with a square cross-section and replacing the protection relays with MOSFET transistors. Also the connections are to be shortened to a minimum. As you can see, this is having an effect, because, Accuphase's claimed damping factor is as high as 1000, which is a very high value.

And then there's the power supply, with a large toroidal transformer and two, also large, filter capacitors. Separate power supply runs serve the preamplifier, power amplifier and logic circuits. The transformer has been flooded with vibration-damping material and shielded.

The remote control is a classic unit for this manufacturer, that is, reminiscent of the 1970s. The housing is cut from an aluminum profile and is, of course, champagne-colored. The buttons are stiff and have a clear point of operation, which is refreshing after the trashiness that many, often expensive, devices come with.

▌ SOUND

HOW WE LISTENED • The Accuphase E-700 integrated amplifier was tested in the “High Fidelity” reference system. It was compared to a split reference amplifier, combining the Ayon Audio Spheris III preamplifier and Soulution 710 solid-state power amplifier. During the test, the unit stood on its feet on the top carbon shelf of a Finite Elemente Pagode Edition Mk II rack.

During the test, I used the Ayon Audio CD-35 HF EditionSACD player and a Lumin T3 file player as sources. The signal between the player and amplifier was sent via Crystal Cable Absolute Dream RCA interconnects. The amplifier was powered using Harmonix X-DC350M2R Improved-Version cable, and the signal to the speakers was supplied by Crystal Cable Da Vinci speaker cable. The Accuphase was driving Harbeth M40.1 speakers, and I should add that I connected a Nordost QKore artificial ground to the ground terminal.

» RECORDINGS USED FOR THE TEST ⸜a selection

⸜ AVISHAY COHEN, Summertime, SP (2024).
⸜ MATT DUSK, I Wanna Be Arround, SP (2024).
⸜ SHEMEIA COPELAND, Blame It On Eve, Aligator Records/Tidal, FLAC 24/44,1 (2024).
⸜ ZBIGNIEW PREISNER, Effroyables Jardins, A Colorful Storm/Tidal, FLAC 16/44,1 (2024).
⸜ ASHNIKKO, ARCANE i LEGAUE OF LEGENDS, Paint The Town Blue (from the series Arcane League of Legends), Riot Games/Tidal, FLAC 16/44,1 (2024).
⸜ NILÜFER YANYA, My Method Actor, Ninja Tune/Tidal, FLAC 16/44,1 (2024).
⸜ ALISON MOYET, Key, Cooking Vinyl COOKCD921AM, CD (2024).

» HIGH FIDELITY Playlist: Accuphase E-700 is available at TIDAL → HERE

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STEREOTYPES ARE GOOD. They are helpful. Although we grumble at them, or at least we play off that grumbling in public, privately seeing nothing wrong with it, without stereotypes we would have died out long ago. They facilitate a quick assessment of reality and take off most of the thought processes that our brains would have to perform to come to, usually, similar conclusions.

But it is also true that the reference point of stereotypes, that is, the set of data on which our minds base them, changes over time. This was also the case with amplifiers operating in Class A, and one of the leaders of this change was Accuphase. This is because we stereotypically associate this class of operation with warmth, silkiness, saturation of the midrange, with omission or marked limitation of band’s extremes.

This perception of them was established in the 1980s, when - mainly - British companies like Musical Fidelity and Sugden, and in the 1990s, in the US, Pass, offered devices intended to be a counterbalance to the light and low-saturated, often jazzy, devices from Japan, made by the companies we today often refer to as “corporations.” And while you can still find these types of products, their sound is nevertheless specifically “tuned” in that direction, and it doesn't come from the fact that they work in Class A.

I’ve mentioned Accuphase - for many years, amplifiers from its range, working in class A, have sounded completely different from this stereotype. And the E-700 seems, in some sense, a point of arrival, a clarification of the assumptions that were made at the time. And that was: transparency, and speed, and harmonic saturation, and - finally - energy flow.

Because it's playing extremely energetic. ˻ 10 ˺ Summertime, a track taken from AVISHAY COHEN's new album of the same title, almost “jumped” out of my speakers. And that's not easy, because the Harbeths in general, and the M40.1 in particular, require high currents, mostly impulse, to do such a thing. This is exactly how the class, so to speak, of Class A is manifested by this manufacturer. The sound was remarkably vivid, almost “live.”

And at the same time, the band’s extremes were superbly controlled. There was a combination of deep textures of timbre and impact, speed in the bass, or double bass and kick drum. In contrast, the cymbals had a “golden” aftertaste, but their weight, sonority and selectivity were above average. I remember well the excitement of listening to the E-650, and I can say that this time it was similar excitement, but with even better sound.

For the new amplifier from this manufacturer is uncommonly resolving. The purrs of the double bass player, the small “extra-musical” events, but also the way of playing, phrasing, delicate changes in vocals, all this was shown by the amplifier with panache and class. Because class is precisely something that shines through from underneath it all. MATT DUSK from the single I Wanna Be Around, where there is a big band orchestra, but also a calm, swinging rhythm, thus sounded not only clear, accurate, but also sweet and with control. My wife and I are already looking forward to his concert in Krakow next year!

This control I am talking about is not an “iron grip,” if I may say so. Rather, it's something like an inner certainty coming from experience, but not that of an elderly person, but of a person at full strength, content with his life, who doesn't have to prove anything to anyone or “carry out” anything. That's why the song Blame It On Eve from the SHEMEIA COPELAND album sounded great, well, just great. It's classic blues, but with a spark, an energy that this music often lacks in modern times.

I got a wide panorama with it, but with Copeland's vocals clearly located in front of me. The solo electric guitar interjections in the second stanza, in the right channel, the baritone sax playing “underneath,” on axis, and the vocals in front of it - all this was not only that extremely clear, because it was, but it was also plastic and eminently selective. In the sense that I could hear all these elements, but also that they played together - this is a very good production.

The bass guitar extended very low in this recording and had an extremely well-controlled attack. And it was strongly saturated at the same time - and this is the “new class A”. Not - long, pleasant, but ultimately “too slow” decay, but - attack, power, fire. And this is what the E-700 gives. But not only that. This is multidimensional playing with excellent differentiation. So not everything will be “forward”, because not all music requires it.

THANKS TO THE ABILITY TO DIFFERENTIATE, and I mean better than most amplifiers, the magnificent, wonderful Effroyables Jardins (Générique 2ème Variation) from ZBIGNIEW PREISNER's new album, the soundtrack to the film of the same title, played only on piano, supported by percussion instruments, on a long reverb, sounded from the E-700 delicately, incredibly spacious, but also with undercurrents of emotion. And these are transmitted by the energy, not only in the form of “slam”, but also spread out over time, but spread out in the right way.

And when we play recordings that are supposed to be a “wall of sound,” like ASHNIKKO's Paint The Town Blue, ARCANE and LEGAUE OF LEGENDS from the Arcane League of Legends series, we get that wall. But not uniform, but malleable - yes, even in such an energetic, rapped track, we get exceptional selectivity and differentiation of sound sources, both timbral and spatial. Therefore, the E-700 appears like a kind of power plant connected to a control panel controlling it in a perfectly clear way.

Because also, listened to immediately afterwards, My Method Actor, a track from English singer NILÜFER YANYA's excellent new album of the same title, the piece sounded dynamically wide - in bandwidth and space - but also deep, primarily in timbre, but also - once again - in space. Because this is an amplifier that on the one hand is not indifferent to music, but on the other hand is such a good differentiator that any kind of music is celebrated by it, details are brought out, and the whole is saturated.

That's why it was such a pleasure, an absolute chill, to listen to CAL TJADER and STAN GETZ's album entitled Sextet in the PureFlection version from First Impression Music. The delicate sounds of Tjader's vibraphone, Getz's saxophone that floats a bit, a bit like that of a “bar” saxophone, were all shown by the tested device in a relaxed, unforced manner.

Because THAT is what true Class A is. Energy, speed, harmonics, depth, but also selectivity. You see, I'm probably familiar with all Accuphase amplifiers from the last, let's say, fifteen years, including the latest, top-of-the-line ones. And along with the E-5000, the representative of its offerings from the AB-class world, the E-700 is for me the “golden mean of Accuphase’s lineup.

HEADPHONES • The headphone amplifiers in Accuphase devices, whether preamplifiers or integrated amplifiers, are refined circuits. Not just add-ons, but part of the whole. The one in the E-700 perfectly controlled the HiFiMAN 1000 v2 planar headphones, offering a dense low sound. I didn't even have to reach for the tone controls to get dense, saturated vocals in the foreground and low bass underneath with the Moyet’s album.

The latter somehow does not go exceptionally deep, and the upper treble is slightly withdrawn, making the midrange the most important element of the presentation. But the midrange is filled and dense with a strong midrange and bass breakthrough. Even if, as with the Copeland album, the sound was lighter and the whole focused on the midrange, but without the same strong saturation as before, it was not slimmed down. On the contrary, the saxophone had a dark tone and was massive. The delicate sounds from Preisner's album, on the other hand, gained spaciousness, as this is another advantage of this amplifier. It was wide and deep, but also airy.

It's a very well-differentiating headphone amplifier with a dense low-end and high dynamic range.

▌ Summary

YOU SEE, Accuphase is a remarkably consistent company. It has built up its lineup over many years, and has done so in such a way that each higher model really is better, in one respect or another. But it's also the case that in these two amplifiers, the E-5000 and the E-700, it has managed to bring together everything it has learned so far, with the latest technology, and serve it up in a way that doesn't force us to change, to “move up” to a higher model.

Also, we have a choice between the meatier, warmer playing of the E-5000 and the even more energetic, even more resolving sound of the E-700. Both are an excellent way to spend time with music. The sound of the tested device does not bring fatigue, does not put listener to sleep either. It is perfectly balanced, in every respect. This is how only high-end tube amplifiers used to play. Today - also the transistor E-700. bravo, bravo!

▌ DESIGN

The E-700 IS A BIG and HEAVY integrated amplifier. It operates in Class A in push-pull mode.

ON THE OUTSIDE • When it comes to mechanical construction and planning, Accuphase's devices are benchmarks in the audio industry. Structurally, they are extremely solid, thanks to thick aluminum front panels and rigid sheet metal forming the other walls. The side panels are double-layered, with aluminum parts bolted to the main body. Accuphase has for years placed its equipment on the feet it manufactures. They are made of high-carbon steel, which is supposed to offer better damping.

All the manipulators are made of aluminum, and the transparent panel is not acrylic, but glass - it's tempered glass. The moving parts are made in such a way as to give solid support and to give the user the impression of dealing with an expensive product, which, after all, the E-700 is. Added to this are the colors - orange of the display and VU-meter indicators, red of the LEDs and green of the logo. This is put together in such a way that it looks both discreet and functional.

INSIDE • The interior of the unit is divided by screens into three sections: input, power amplifier with power supply, and AAVA and logic circuits. There are also separate boards for XLR and RCA inputs, and that's because right behind the latter are the signal balancing ICs. This one is switched in hermetic Omron relays. The XLR sockets are gold-plated, but the RCAs have gold-plated ground only and are soldered, not screwed in. This is an element that I think could be improved in the future.

When the input is selected, the signal runs to the front panel, to the signal level control circuit. As we said, it's an Accuphase Analog Vari-gain Amplifier (AAVA) circuit in balanced form, this manufacturer's own development. It is built with integrated circuits and uses a separate power supply.

And finally we get to the power amplifier boards. They are screwed directly to large heat sinks, which heat up a lot. So a lot of free space should be left around the E-700. The circuit is entirely discrete, that is, it was made of transistors. Some of the components are surface-mounted, but a large part are classic, through-hole resistors and capacitors. The latter look very good and come from Rubycon and Elna, among other companies. Since they have an increased thermal load capacity, they are supposed to work for a long time without drying out (this is the most common reason for the deterioration of the sound of old equipment).

The current section uses four pairs of MOSFET transistors: IRFP9140 and IRFP240. Their manufacturer is the renowned Vishay company. Behind the transistors there is an output circuit, with a Zener circuit and large coils to stabilize the operation of this section. They have a square cross-section and are made of high-purity copper. Protection circuit features MOSFET transistors rather than relays, which made it possible to reduce the output impedance. This section has a separate board, into which speaker terminals are screwed - gold-plated, solid, comfortable to operate.

The transformer is shielded and screwed to an additional plate rather than directly to the bottom of the chassis. The screen is extruded, and this is the element that differentiates the E-700 from the most expensive amplifiers from this manufacturer, featuring screens cast in aluminum. It is accompanied by two Accuphase logo capacitors of 56,000 μF each, manufactured for the company by Nichicon.

As usual - perfectly clean design, well thought-out topology, and the system uses good components, although within the “industrial” norm. ●

▌ Technical specifications (according to the manufacturer)

• Max output (RMS): 35 W / 8 Ω, 70 W / 4 Ω, 140 W / 2 Ω, 160 W / 1 Ω (with music signal).
• Frequency range:
Line input: 20-20 000 Hz (+0 / –0.5 dB),
Power IN: 20-20 000 Hz (+0 / –0.2 dB) @ full power,
Power IN: 3-150 000 Hz (+0 / –3 dB) @ 1 W
• S/N (A-weighted):
line inputs RCA/XLR: 103 dB, main in: 117 dB
• THD: 0.05%
• Intermodulation distortion: 0.01%
• Damping factor: 1000 (8 Ω / 50 Hz)
• Damping: -20 dB
• Tone control:
BASS: 300 Hz/± 10 dB (50 Hz),
TREBLE: 3 kHz/± 10 dB (20 kHz)
• Loudness: +6 dB (100 Hz)
• Headphone output: > 8 Ω
• Power consumption: 0.3 W (standby), 220 W (IEC 60065)
• Dimensions (W x H x D): 465 × 191 × 428 mm
• Weight: 24.9 kg

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THIS TEST HAS BEEN DESIGNED ACCORDING TO THE GUIDELINES adopted by the Association of International Audiophile Publications, an international audio press association concerned with ethical and professional standards in our industry, of which HIGH FIDELITY is a founding member. More about the association and its constituent titles → HERE.

→ www.AIAP-online.org