INTRODUCTION
This 2A3 SE valve amplifier is a class A power amplifier which has high linearity and low distortion, are capable to delivery 5W to 8Ω speaker for each channel. The first stage is SRPP constructed by 6SN7 twin-triode tubes and the final stage is a common-cathode 2A3 tube. The high voltage is supplied by a RT400 tube rectifier. The tube filament voltages can be supplied either by AC or DC voltages. For tube filament with DC voltages, one LV30B-5A and LV30 low voltage regulator are required.
SPECIFICATION
● Vacuum tubes: two 2A3 and two 6SN7 vacuum tubes.
● Voltage gain: 1.7dB
● Gain flatness: <0.9dB for 20-20kHz
● 3-dB Bandwidth: 31.2kHz
● Frequency range: 20-20kHz
● Input Impedance: 87k Ohms
● Input sensitivity: 3.5V RMS
● S/N Ratio:
> 98dB (5W, 8 ohms, 1kHz)
>110dB (5W, 8 ohms, 1kHz, a-weighted)
● THD+N < 4% @1kHz
● Maximum Output Power: 5W at 8 Ohms
● Output transformer 10-15W:
Primary impedance: 2.5k/3.5k Ohms 120mA
Secondary impedance: 4, 8 and 16 Ohms
● Stereo single-end input and output
● Power requirements: one or two 260-290V DC (total 300mA), 6.3V AC/DC (1.5A), and two 2.5V AC/DC (2.5A).
● PCB dimension: 196mm (W) x 175mm (L)
● PCB thickness: 2.4mm, double layer, 2oz copper.