ASTOR AST-EQ50GZMg Vacuum Tube Phono Equalizer Amplifier
Product code: EQ50GZMgASTOR AST-EQ50GZMg Vacuum Tube Phono Equalizer Amplifier
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Choose vacuum tubes for the core of record playback.
Equipped with two PHONO inputs, this vacuum tube phono equalizer carefully renders everything from the outlines of the sound to delicate reverberations.
High-Quality Phono Equalizer Using Vacuum Tubes
The AST-EQ50GZMg is a vacuum tube phono equalizer amplifier developed byASTORIt is designed with a circuit configuration using two 12AX7 tubes and one 12AU7 tube, carefully preserving the richness, texture, and delicate musical expression of analog records.
The amplification circuit uses the company's new typeHigh-Fidelity· Adopts a high-efficiency circuit. By configuring the third stage as a cathode follower, consideration is given to both signal extraction and transmission to subsequent devices. This is a full-fledged phono equalizer that carefully examines the configuration of the amplification stage and output stage using vacuum tubes.
Three-stage configuration using 12AX7 and 12AU7
Combines the 12AX7, which has a high amplification factor, with the 12AU7, which has electrical characteristics suitable for the output stage. This configuration is designed to amplify with the 12AX7 and reduce output impedance through the third-stage cathode follower.
The cathode follower is a circuit method that does not aim for voltage amplification but considers the connection conditions with subsequent devices. This design concept demonstrates a balance between the amplification performance required for a phono equalizer and the stability of signal transmission.
Equipped with two PHONO inputs
The rear panel is equipped with two input terminals, PHONO 1 and PHONO 2. The input selector switch is also located on the rear, allowing connection of two analog players or tonearms and the selection of the input to use.
There is one output, OUTPUT 1. Without adding complex functions, it integrates the functions necessary for analog playback. It also accommodates systems that use multiple analog sources.
Adopts AST-55PK transformer
The AST-55PK transformer is used. A dedicated transformer is also placed in the power supply section that supports the vacuum tube circuit, emphasizing stable operation.
In a vacuum tube phono equalizer, it is important not only to handle amplification circuits for tiny signals but also to ensure the stability of the power supply and measures against unwanted noise. This unit, including the circuit configuration and the power supply,ASTORIt is designed with a seemingly solid and reliable construction.
52S aluminum alloy chassis and 5mm thick front panel
The chassis uses 52S aluminum alloy with a thickness of 1.2 mm, and the front panel is made of 5 mm thick aluminum material. Additionally, by using 52S aluminum alloy with a thickness of 1.2 mm for the mid-plate for mounting components, the structure is designed to hold internal components securely.
The thick front panel and the simple aluminum chassis also give it a calm appearance. Only the power switch is placed on the front, with input switching consolidated on the back. While equipped with the necessary functions, the design is finished in a neat manner with unnecessary decorations minimized.
The external dimensions are W220 × D350 × H140mm, and the weight is approximately 3.4kg. It is designed in a size that is easy to handle as a standalone phono equalizer, housing three vacuum tubes and a dedicated transformer.
Wideband design from 10Hz to 50kHz
The manufacturer’s published frequency response is 10Hz to 50kHz. It is designed with ample range from low to high frequencies, aiming to naturally reproduce the musical information engraved on analog records.
This phono equalizer pursues playback that utilizes the rich musical expression of vacuum tubes while preserving the clarity of sound contours and spatial perspective.
| Product Model Number | AST-EQ50GZMg |
|---|---|
| Type | Vacuum Tube Phono Equalizer Amplifier |
| Vacuum Tubes Used | 12AX7 ×2, 12AU7 ×1 |
| Transformers Used | AST-55PK |
| Preamplifier Circuit | New TypeHigh-Fidelity・High-Efficiency Circuit / 3-Stage Cathode Follower Type |
| Frequency Response | 10Hz–50kHz (Manufacturer Published Value) |
| Input Terminals | PHONO1, PHONO2 (RCA / 2 Systems) |
| Input Selector | Rear Switch |
| Output Terminals | OUTPUT1 (RCA / 1 System) |
| Front Panel | Aluminum Alloy, 5mm Thick |
| Chassis Material | 52S Aluminum Alloy, 1.2mm Thick |
| Component Mounting Plate | 52S Aluminum Alloy, 1.2mm Thick |
| External Dimensions | W220 × D350 × H140mm |
| Weight | Approx. 3.4kg |
| Power Supply | AC100V |
| Warranty | No manufacturer warranty |
Sound quality tendencies from the design perspective
The AST-EQ50GZMg is a tube phono equalizer featuring an amplification circuit using 12AX7 and a cathode follower configuration using 12AU7. While you can expect the thick and smooth sound characteristic of tubes, the third-stage cathode follower makes it a configuration that also considers the load conditions on the output side.
The 12AX7 has a high amplification factor and is a vacuum tube suitable for amplifying the small signals required in a phono equalizer. When combined with the 12AU7, it can be expected to deliver playback that emphasizes midrange density, the realism of the sound image, and natural reverberation.
In addition, the front panel uses 5mm-thick aluminum alloy, and the interior is equipped with an independent component mounting mid-plate, showing attention to the structure of the chassis. Despite its simple appearance, the layout carefully organizes the amplifier circuit, power supply, and chassis elements.
Equipped with two PHONO inputs, it is also suitable for analog systems that switch between multiple players and tonearms. This is aimed at those who prioritize the combination of circuit design and vacuum tubes.ASTORThis is a phono equalizer.
