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Conclusion. Listening to music through the Japanese phono stage is like having a bath in essential oils, resting on silk sheets, sipping caffé latte somewhere in sunny Italy, drinking a mug of Paulaner in a small bar in the center of Munich. It's about an excellent balance between individual parts, a conscious choice about sound, clear views on technical matters and last but not least a fantastic man behind it all which makes listening to the REQ-S1 EX like meeting an old friend: a bit of nostalgia mixed with curiosity and a renewed sense of security.

Sounds modeled by this preamplifier are never unpleasant. It’s also an obvious departure from objective neutrality. Nevertheless it doesn't alter the heart of the matter, the value and naturalness of the presentation. Thanks to it all albums recorded and mixed in the analog domain (especially of acoustic instruments) come out great. Others sound a bit worse for this treatment but never bad. Their inferiority is a technical issue of their producer and label, not SPEC's or ours. But perhaps such distinctions are academic. They really only arise from the reviewer's need to talk of differences. While it's possible to get superior resolution, I'm unsure whether anybody really needs it. I tend to think most of us would simply want to hunker down and forget about the world for a while. If that's you, the REQ S1-EX will perfectly suit.

Review methodology. The Japanese phono preamp was compared to the RCM Audio Sensor Prelude IC and fed from three different turntables: the Kuzma Stabi XL2 with Benz Micro Switzerland Ruby Z cartridge; the Dr. Feickert Blackbird equipped with a Reed 3P tonearm and Kansui and Zero cartridges from Miyajima Lab; and the Dr. Feickert Firebird with Dynavector DV509 MkII arm and matching XV-1 cartridge. The preamplifiers were placed directly on the Acoustic Revive RAF-48F isolation platform and the power supply unit on the RST-38. Power cords were Acrolink Mexcel 7N-PC9300. The review compared individual tracks and whole albums. I devoted a separate session to auditioning the preamp with the Phasemation EPA-007 balanced headphone amplifier and HifiMan HE-6 headphones in balanced mode.


Design. The full name of this component is the Designer Real-Sound Audio Phono Equalizer Amplifier REQ S1-EX. The first part refers to the product series, the second to a certain technique and philosophy, the third to the type of equipment and the fourth is the actual name. The unit splits into two enclosures for the amplifying and equalizing circuit (PA-S1) and power supply (PU-S1). Both show meticulous workmanship and are made of steel plates with thick aluminum fronts. Underneath each enclosure is a screwed-on wood plinth forming an anti-vibration platform. This wood was prepared by Oak Village, a Japanese company specializing in wooden products in keeping with the country's 1.300 year-old tradition. The platform consists of a wooden plinth laminated from smaller pieces and three shallow footers. Two screw into the cut-outs, the third in the rear slips into a recess. It looks brilliant.

PA-1S. On the unit’s front are four big toggles with small LEDs embedded in their tips. The first selects MM or MC. The second one activates a subsonic cut-off below 20Hz (7950µs). This is a modification of the 1972 RIAA curve often referred to as EIC RIAA which introduced a fourth correction point. The associated LEDs are green. The third switch activates a cartridge degausser. This sends a small current through the cartridge coil to demagnetize it. It is essential to insure that one's cartridge can undergo this process. Finally there is a mute switch on the far right. These two switches have red LEDs.

All connectors are Swiss Neutrik from Liechtenstein. There are separate inputs for MM and MC cartridges with two gold-plated ground connectors between them. Both have the same potential so we may use either. Apparently the designers’ idea was to enable connecting two cartridges at once or even more likely an MC cartridge and step-up transformer. Next to the MM input we have an input capacity switch with two positions for 100pF and 0pF, next to the MC input an input impedance switch for 20Ω and 200Ω. The output is on RCA and XLR. The output signal runs across quite long leads which suggests a balanced amplifying topology but the circuit is actually unbalanced to add a separate driver IC for the XLR output. Near the rear panel's left edge is the 7-pin XLR connector to connect the unit to its external power supply. All XLR connectors are gold-plated, the RCA connectors get rhodium plating.


The electronic circuit mounts to a large PCB and a smaller auxiliary board hosts the relays and mute circuit. The ultra-simple circuit is based on ICs. The designer believes that only these operational amps are capable of matching the advantages of tubes which is a rather isolated view though Mr. Friedrich Schäfer from ASR champions something similar. The results speak for themselves. The assumption is that the cartridge should see the lowest possible impedance. Hence the MC input stage is based on op-amps using bipolar transistors which excel at working with low-Z low-level signal. The MM input stage features FET input op-amps optimal for high-impedance cartridges. That is why we have separate sections for MM and MC.

The first gain stage is based on Burr Brown OPA627AM for moving magnet and Linear Technology LT1115 for moving coil. According to SPEC the latter is the lowest noise op-amp currently in production. Then beautiful oil-coupled capacitors from Arizona Capacitors get us to the equalizing circuit. Up to this point the signal for MM and MC inputs was handled independently, the active input selected with an Omron relay. Frequency compensation is based on an RC circuit with the most beautiful resistors I've ever seen in audio equipment just like the accompanying capacitors again from Arizona Cap. The latter are manufactured to SPEC specification and bear their logo. These are bypassed with Bennic mica caps. The most important spec seems to be very tight tolerance. The final gain stage is built with two more op-amps, International Semiconductors LME49860 and Burr Brown DRV134. The latter is a balanced line driver for the XLR output. The coupling wires to the output connectors are quite long and like all internal wiring Belden. There are plenty of them run in bundles. Attention to star grounding is evident throughout. Wherever feasible parts are wrapped in vibration-damping materials. The entire inside surface of the top panel is also covered with a kind of vibration-damping mat which doubles as RF shield.


PU-S1. The power supply looks as good as the amplifying unit, features the same casing and a nice front panel with the anti-vibration platform to boot. The front sports just one switch but at that a locking toggle which looks superb. The rear panel features an IEC mains inlet, a fuse and a multi-pin Neutrik XLR power out. As visible from the inside, the IEC socket integrates a simple noise filter. As might have been expected and as I knew it from their integrated power amplifier, the power supply is extremely complex. It mounts on a large circuit board in the form of two separate sections for the left and right channels. These are powered by a large R-core transformer from Kitamura Kaiden. Next to it is a smaller transformer for the relays and LEDs in the main unit. The power supply for the main amplification circuit could easily drive a mid-sized power amplifier.

It features discrete SiC-type Schottky rectifying diodes and two large filter caps per channel. These are followed by Elna Silmic II capacitors and IC-based voltage regulators. There are more Elna caps in the output bypassed by large oil capacitors from Arizona Capacitors and Mallory. The latter brand is currently owned by Cornell Dublier, another American specialist whose capacitors show up with Manley geary. All oil capacitors are high-voltage types (400 and 600 V). What an excellent job!

opinia @ highfidelity.pl








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