Package include
1. M7C SRPP Preamplifier Kit (Stereo) No Tubes
2. Assembly Manual

 

Introduction

The circuit design is referenced to the Marantz and the output stage is modified to 12AU7 SRPP to provide width bandwidth and low distortion. The design values are adjusted and optimized. The input stage uses 12AX7 in common cathode, whereas the output stage uses 12AU7.  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 12AX7 and two 12AU7 vacuum tubes.

·        Voltage gain: 20dB

·        Bandwidth: 500KHz

·        Frequency Flatness: 20-20KHz (+/-0.1dB)

·        S/N Ratio: >91dB

·        THD: 0.02% @Vin = -1dBm and 1KHz

            0.05% @Vin= -10dBm and 1KHz

·        Input impedance 470KΩ

·        Output impedance 3KΩ

·        Two single-ended and two single-ended 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 (50mA) DC, and one 12.6V (1A) DC.

·        PCB dimension: 19.3mm (W) x 15.6mm (L)

·        PCB thickness: 2.4mm, double layer, 2oz copper.

Optional
1. Toroidal Power Transformer T30L
2. HV400 Voltage Regulator Kit