Phasemation EA-550 dual-chassis MM/MC phono amplifier with fully discrete non-feedback circuitry, balanced inputs, 64dB MC gain and built-in MC transformers.
The Phasemation EA-550 is a high-end two-chassis phono amplifier built around fully discrete, all-stage symmetrical non-feedback circuitry.
Designed for serious analogue playback, the EA-550 combines independent left and right channel construction with newly developed MC transformers, substantial power supplies and carefully selected high-grade components.
Its architecture is intended to preserve the smallest musical details contained in the record groove while delivering high resolution, natural dynamics and a large, stable soundstage.
Completely Monaural Dual-Chassis Architecture
The Phasemation EA-550 uses two completely independent chassis, one for the left channel and one for the right.
This fully monaural arrangement separates the equalizer circuitry and power supplies between channels, helping reduce electrical interaction and improving stereo separation.
Each chassis uses a rigid mechanical structure with a 10mm-thick slanted aluminium front panel, a 1.6mm copper-plated steel chassis base and a 1.6mm copper-plated steel cover.
Heavy metal insulators are used to reduce the influence of external vibration and provide a stable mechanical environment for the sensitive phono circuitry.
Fully Discrete Symmetrical Non-Feedback Circuit
At the heart of the EA-550 is a V-I / I-V conversion type all-stage symmetrical non-feedback amplification circuit constructed entirely from discrete components.
Phasemation avoids global negative feedback throughout its semiconductor and vacuum-tube amplifier designs, choosing instead to develop circuits capable of operating with high precision without corrective feedback loops.
This approach is intended to preserve transient information, dynamic expression and subtle tonal shading without introducing the time-related artifacts associated with conventional feedback architectures.
The result is a direct, highly resolved presentation designed to retain the musical energy and spatial information contained in the original record.
Newly Designed MC Step-Up Transformers
The EA-550 incorporates newly developed MC transformers using Phasemation’s special split-winding structure.
High-purity PC-TripleC copper wire is used for the secondary winding material, reflecting the company’s long experience in MC transformer design.
These internal transformers allow low-output moving-coil cartridges to be handled within the same carefully controlled analogue architecture, eliminating the need for a separate external step-up transformer in many systems.
High-Quality Power Supply and Components
The power supply of the Phasemation EA-550 receives the same level of attention as the signal path.
Rohm SiC diodes are used to minimize switching noise, while high-grade Nichicon and ELNA SILMIC II capacitors are selected for the power circuits.
Low-noise zener diodes are combined with shunt regulators to create fast, low-noise power supply circuits without relying on feedback regulation.
Four R-core transformers are used in total, with separate transformers for the positive and negative supplies of each channel, helping reduce shared impedance effects and unwanted interaction between power stages.
Three Inputs with MM / MC Selection
The EA-550 provides three phono inputs, with MM / MC selection available independently for each.
Inputs 1 and 2 also support balanced XLR connections, allowing compatible cartridges and tonearm systems to be connected using a balanced signal path.
This flexible input architecture makes the EA-550 particularly suitable for analogue systems using multiple turntables, tonearms or cartridges.
Low-Cut Filter for Warped Records
A second-order CR-type low-cut filter is included to reduce subsonic energy caused by warped records.
The filter is implemented without global feedback and is designed to reduce unwanted woofer movement while maintaining musical integrity.
RIAA and Monaural Playback Curves
The EA-550 provides three playback equalization curves.
In addition to standard RIAA equalization for stereo records, dedicated Mono 1 and Mono 2 curves are available for older monaural recordings, including labels such as Decca and Columbia.
This allows collectors of historic pressings to reproduce older records with equalization characteristics more appropriate to their original mastering standards.
MC Cartridge Degauss Function
The EA-550 also incorporates a dedicated degauss circuit.
By selecting the degauss function and playing a record for approximately 30 seconds, the circuit can help demagnetize the metal core of an MC cartridge.
This feature is intended to restore clarity and reduce the influence of residual magnetization within compatible moving-coil cartridges.
The EA-550 accepts moving-coil cartridges with output impedances from 1.5Ω to 40Ω, making it particularly suitable for Phasemation’s low-impedance reference MC cartridges.
Its 64dB MC gain, built-in transformer stage and balanced input capability allow a premium cartridge such as the PP-2200 to be integrated directly into a complete Phasemation analogue front end.
Together, the EA-550 and PP-2200 combine Phasemation’s cartridge, transformer and non-feedback phono-amplifier technologies in one coherent system.
Phasemation EA-550 Awards
The Phasemation EA-550 has received recognition from several leading Japanese audio publications for its analogue engineering and sonic performance.
Audio Excellence Award 2020
Gold Award
Ongen Publishing
Audio Excellence Award 2020
Silver Award
Ongen Publishing
MJ Technology of the Year 2019
Honorable Mention
Seibundo Shinkosha Publishing
Best Buy Components 2020
3rd Place · Phono Equalizer over ¥500,000
Stereo Magazine · Ongaku no Tomo sha
The Phasemation EA-550 is ideally suited to Phasemation’s low-impedance moving-coil cartridges, making it a natural foundation for a complete analogue front end from the same manufacturer.
is the most natural partner for the EA-550, combining Phasemation’s flagship cartridge engineering with the phono amplifier’s dedicated MC transformer stage, 64dB gain and wide cartridge compatibility.
is also an excellent match, bringing flagship-derived magnetic-circuit technology, low 4Ω impedance and a 0.3mV output into a system built around the EA-550.
Both cartridges fall comfortably within the EA-550’s MC compatibility range of 1.5Ω to 40Ω, allowing the phono amplifier to work naturally with either model.
Specifications
Form
V-I/I-V conversion type all-stage symmetric non-feedback equalizing amplifier
Input Type (Cartridge)
MM
MC
Input Sensitivity
2.5 mV
0.13 mV
Suitable Cartridge Output Impedance
47 kΩ or less
1.5 to 40Ω
Gain
38 dB
64 dB
Input Equivalent S/N Ratio
–120dBV
–140dBV
Rated Output Voltage
200 mV (1kHz)
Rear Curve Tolerance
± 0.5 dB (20Hz to 20kHz)
Power Consumption
10W (100VAC 50 – 60Hz) for each Ch
Dimensions
211 (W) × 93 (H) ×360 (D)
Weight
5.5kg for each Ch
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