Versions:
A: Unit with Shuguang 5Z4P + USA 5687
B: Unit with Linlai 5U4G + USA 5687
C: Unit only, without tubes
Reference circuit diagram provided; actual component parameters may vary from the diagram and are subject to the components installed inside the unit.
Unit Components Overview
- Standard configuration includes one Shuguang 5Z4P rectifier tube and one USA-made 5687 amplifier tube (random selection from Sylvania, RCA, GE, or Raytheon).
- 70W pure copper wire power transformer (model 764010) and 10H 80mA high-inductance choke (EI48X30) are built with high-quality, high magnetic flux iron cores. Both choke and power transformer feature fully shielded casings to minimize magnetic leakage, finished with anti-rust paint for an elegant appearance.
- 5Z4P tube rectification (compatible with various 5V imported rectifier tubes such as 5U4G, 5AR4, 5Z3P, 274B, etc.; transformer filament current designed for 3A). Utilizes two 33UF Japanese Rubycon capacitors, one 180UF Japanese Rubycon low-impedance capacitor, and one 0.1UF film safety capacitor, together with a 10H choke forming a CLRC filter circuit for low ripple and a quiet background. Tube rectification offers finer high frequencies and a smoother, more rounded sound compared to solid-state rectification.
- Dual 200V 80mA high-voltage power supply. 5687 tube uses 3.15V-0-3.15V 1A AC power supply with center tap grounded, effectively reducing noise. This filament connection preserves the musical richness of AC filaments while eliminating hum, resulting in a lively and dynamic sound quality.
- No input coupling capacitor. Output coupling employs Japanese Tokyo Electronics TE 0.22UF MKP premium film capacitors in parallel with 0.1UF USA Sprague capacitors, delivering excellent high and low frequency performance.
- Key circuits use well-known brand carbon film precision resistors with copper leads, providing a rich, premium tube sound.
- Japanese ALPS 16-type potentiometer.
- Ceramic tube sockets with gold-plated copper leads.
- Gold-plated pure copper RCA jacks, durable and secure.
- Sound Quality: This unit produces a rich, full-bodied sound with an extremely quiet background, high dynamic range, and high amplification factor.
- Weight: 3.5kg
- Chassis designed in vintage Western Electric style, made from 1.2mm thick steel with spray coating. Dimensions: 220mm depth (including knob and RCA jacks), 180mm height (from chassis feet to top of 5Z4P tube), 160mm width.
Technical Specifications
1. Input Sensitivity: 300mV
2. Voltage Output: Approximately 10x voltage gain.
3. Signal-to-Noise Ratio: 96dB
4. Frequency Response: 20Hz - 38kHz (-2dB)
5. Input Impedance: 100kohm
6. Output Impedance: 2kohm
7. Channel Separation: 65dB
