Luxury Precision EA4 Flagship Portable High-Power Tube Amp

Maximizing Tube Sound - Part 1

Optimized Tube Preamplifier Circuit: Voltage amplification is handled exclusively by the tube preamplifier, feeding high voltage to the anode.

Unleashed Richness and Tone: This design fully unleashes the unique tone of vacuum tubes, delivering warm, rich, and detailed sound.

Discrete Power Stage: The fully discrete power amplifier is designed purely for power output, focusing on current amplification.

Maximizing Tube Sound - Part 2

ILA Mode and High Gain: The combination of ILA mode with high gain allows for additional tube amplification gain, further enhancing the richness of the timbre.

Active Input Attenuation: Instead of simple resistance voltage division, it actively attenuates the gain of the input stage to preserve every musical detail.

Panasonic Capacitors: Utilizes 12 Panasonic capacitors for coupling in the tube preamplifier stage.

Combination of Multiple Tube Tones

Sound Style Adjustment: ILA and ILH modes, combined with high and low gain settings for the tube, offer 4 rich and smooth sound styles.

Listening Versatility: Allows for adapting the sound signature to unlock diverse auditory experiences depending on the headphones used.

Comprehensive Microphonic Effect Reduction I

CNC Metal Shielding: Features a high-precision CNC machined metal shield to protect the two vacuum tubes.

Vibration Isolation: Incorporates 8 high-damping silicone pads on both sides to absorb mechanical shocks and external vibrations.

Comprehensive Microphonic Effect Reduction II

Designed for the specific resonance frequency of the KORG Nutube 6P1 filament.

Specially selected ultra-high power supply rejection ratio (PSRR) linear voltage regulators, with a resonance frequency of 5.8kHz to reduce valve noise.

Comprehensive Microphonic Effect Reduction III

Filament Constant Voltage Mode: Applies a fixed voltage, using current-limiting resistors and the filament's internal resistance to stabilize the filament current.

Filament Constant Current Mode: Uses a constant current source circuit with discrete components to supply a constant current to the filament.

High Reliability and Low Resistance Batteries

Original Panasonic Cells: Equipped with 6 highly reliable and very low internal resistance 18650 battery cells.

Precision Matching: Each cell in the battery pack is carefully selected with an internal resistance difference of less than 0.5 milliohms to maximize lifespan and performance.

High-Capacity Power Supply Ensures Exceptional Stability.

Battery with 6 x 18650 cells, total capacity of almost 20,000mAh. Two independent high-power, positive and negative power supplies. 16 Nichicon 10 x 12.5mm audiophile-grade aluminum electrolytic capacitors for discrete amplifier power filtering.

The Secret Behind Its High Output Power:
Over 6.5W per channel @32 ohm and 1.2W @300 ohm

The discrete headphone amplifier output uses 8 TO252 power transistors. The components are spaced to facilitate heat dissipation and reduce interference. The emitter resistor of each transistor is composed of 3 resistors in parallel, with a total of 24 precision alloy resistors of 250mW and 0.5% low thermal drift throughout the system. These features ensure that the sound remains stable even during continuous high-power output.



Two Analog Power Settings.

The headphone amplifier can be powered with ±13V or ±15V. The different voltage settings offer distinct sound characteristics, allowing the power to be adapted to a wide variety of in-ear and over-ear headphones.

11-Level Static Current Adjustment (Class AB and Class A)

Class AB Operation: Minimum static current setting of approximately 10mA for lower consumption and fast response.

Class A Operation: Maximum static current setting of up to 50mA for maximum fluidity, warmth, and tonal texture.

Custom Control: Dedicated knob with smooth tactile clicks for easy switching and fine-tuning performance according to the headphones.

Preamplifier / Amplifier Switching Function

Easy Mode Switching: Double-click the power button to switch between Pure Tube Preamplifier Mode and Tube Preamplifier + Discrete Headphone Amplifier Mode.

Prevents Accidental Touches: Avoids abrupt volume changes or unintentional power-ons that often occur with traditional toggle switches.

Volume Control: Art and Technology

Flagship Grade Potentiometer: Same potentiometer used in the LP6 7th Anniversary special edition.

Visible Scale Markings: Design with graduated volume markings to see the exact level at a glance, ensuring fine, precise, and smooth adjustment without sudden volume jumps.