EA-550 Phono Amplifier

EA-550 Phono Amplifier

A separate 2-unit phono amplifier featuring an all-discrete, fully symmetric, non-feedback circuit design—crafted to reveal the true essence of music and the artist’s passion.

Believing that “analogs still have much more to offer,” Phasemation has expanded its lineup of non-feedback phono amplifiers—including the EA-1000, EA-500, EA-350, EA-300, and EA-200—to meet the needs of analog disc enthusiasts. Now, with the new EA-550, small imperfections have been eliminated through a refined semiconductor circuit and a newly developed built-in MC transformer featuring a split winding structure and high-purity PC-TripleC copper in the secondary winding. The EA-550 delivers a new level of sound quality and musical expression.

Adopted a strong chassis structure of a 2 unit box with Lch and Rch being independent and completely monaural.
Following the elegant design of CA-1000 / T-2000, a strong housing structure consisting of a 10mm thick aluminum slant front panel, a 1.6mm thick copper plated steel chassis base and a 1.6mm thick copper plated steel sheet cover was adopted and this ensures rigidity and reduces magnetic deformation.  A heavy weight metal insulator that blocks external vibrations is used for the feet.  In addition, the played sound supported by the left and right divided equalizer part and the powerful power supply part has high S/N and high resolution.  The played sound can be enjoyed with overwhelming realism and with a panoramic stage.

V-I / I-V conversion type all-stage symmetrical non-feedback amplifying circuit due to all discreet parts.
The negative feedback amplifier which is the mainstream of modern amplifiers constantly compares the input and output signals for both the semiconductor and vacuum tube and this difference (amended signals) can be amplified with high precision at low cost because it is amplified as an input signal. However, there is a time delay between the input and output signals which cannot be solved theoretically and this generates a TIM distortion and the like and this is a big reason why sound satisfaction cannot be attained from negative feedback amplifiers.

At Phasemation, amplifiers of semiconductors and vacuum tubes are all composed of non-feedback amplifiers. For non-feedback amplifiers, there are no amending operations like the negative feedback amplifiers and therefore high precision/technology of structured parts and circuits are required.  As a result, it is played with no information remains on the sound source (record) and in terms of sound quality, it can play the music with excellent inspiration, dynamics, and shadowed (or the like) expressions.

Prolific Features

1. Three input terminals are equipped and MM/MC switching is possible for each. In addition, inputs 1 and 2 support balanced inputs due to the XLR connector.
2. A 2nd order CR type low cut filter with non-feedback is equipped.  Plays warped phonograph records without any music deterioration and prevents the speakers (woofers) from shaking.
3. Three types of playing curve changeover switches are equipped.  For the equalizer characteristics, along with the RIAA characteristics for the previous stereo, Mono1 (used on the DECCA label and so forth) and Mono2 (used on the Colombia label and so forth) are equipped as a particular characteristic for a monaural. This will allow higher fidelity playback than the DECCA and Columbia labels.
4. A "degaussed" circuit is equipped.  By choosing “degauss” with the functions and playing the record for about 30 seconds, the MC cartridge with a metal core that was magnetized is degaussed and the sound quality becomes clear.

Adoption of parts having high sound quality

On the signals

1. A 1% grade metal film resistance with marginal rated capacity and reputed high sound quality parts such as a Micar capacitors using silvered Micar plates for dielectrics are used on the RIAA elements which have high influence on the phono amp's sound quality.
2. On the signals, ELNA’s SILMIC audio grade electrolytic capacitors and metal film resistance of a 1% grade are used. 

On the power circuits

1. The switching noises are few and adopts Rohm’s SiC diodes which have a reputation for high sound quality.
2. We adopted a large-volume electrolytic capacitor that is of highest rank in audio grades of metal plated terminals which uses Nichicon’s low resistance electrode foil on the commutating capacitor. In addition, the decoupling capacitor adopts ELNA’s SILMIC II.
3. Low noise zener diodes are used combined with the adoption of shunt regulators that exclude the feedback circuit and this structures a fast and extremely low noise power circuit.
4. The power transformer uses a transformer of low leakage flux using an R-core particularly for each of the positive and negative power supplies, a total of 4. It eliminates negative effects due to the common impedance of the ground (earth) from each bridge rectification.

Form:  V-I/I-V conversion type all-stage symmetric non-feedback equalizing amplifier
Input Type:  MM & MC
Input Sensitivity:

• MM: 2.5mV
• MC: 0.13mV

Suitable Cartridge Output Impedance: 

• MM:  47kΩ or less
• MC:  1.5 - 40Ω

Gain: 

• MM:  38 dB
• MC:  64 dB

Input Conversion S/N Ratio:

• MM:  –120dBV
• MC:  –140dBV

Rated Output Voltage:  200 mV (1kHz)
Rear Curve Tolerance:  ±0.5dB (20 - 20kHz)
Power Consumption:  10W(100VAC 50 - 60Hz) for each ch
Dimensions:  211 (W) × 93 (H) ×360 (D)
Weight:  5.5kg (12.13 lbs) for each Ch