Package Include
1. 12AU7 Balance Tube Preamplifier Bare PCB
2. Assembly Manual
INTRODUCTION
The circuit design is modified based on Audio Research preamplifier and the design values are optimized. It supports both single-end and balance input and output (RCA and XLR). Basically, the circuit is differential amplifier with two cascade stages. The input stage uses 12AU7 with moderate voltage gain, whereas the output stage uses 6DJ8 (6N11). The differential amplifier provides high PSRR and capability to noise rejection. The signal paths of this PCB layout are designed in symmetry for both channels. Dedicated power rails, ground, and signal paths, altogether are taken into design considerations so that all are to minimize the parasitic, cross interference, and influence of RFI.
FEATURES
· Two 12AU7 and two 6N11 (6DJ8) vacuum tubes.
· Voltage gain: 16dB (single-ended) and 22dB (balanced)
· Bandwidth: 20-100KHz
· Frequency Flatness: 40-20KHz (+/-0.1dB)
· S/N Ratio: >94dB
· THD: 0.147% @Vin = 0dBV and 1KHz
0.243% @Vin=10dBV and 1KHz
· Input impedance 500K Ω
· Output impedance 400 Ω
· Two single-ended and balanced inputs.
· Two single-ended and balanced outputs.
· Symmetric layout design and signal paths with minimum parasitic.
· Dedicated ground and power rails layout design.
· Two large reservoir decoupling capacitors for power rails.
· Power requirements: one 260V (80mA) DC, one 12.6V (0.5A) DC and one 6.3V (0.8A) DC.
· PCB dimension: 21.8mm (W) x 13.5mm (L)
· PCB thickness: 2.4mm, double layer, 2oz copper.
Options
1. T30 Toroidal Power Transformer
2. HV400Variable HV Regulator Kit
3. LV30 Variable LV Regulator Kit
Pre-Amplifiers
