Soulnote P-3 Preamplifier

GND switching input selector

One major factor affecting sound quality deterioration in preamplifiers is GND loops and noise intrusion when connecting multiple sound sources. One way to eliminate this problem is to adopt a switching method on the GND and signal end so that unselected devices are held in a state where their connectors are unplugged. And to avoid any interference from the relay connection, the selectors in this unit all use the RSR-2-12D.

Complete dual monaural construction

This unit utilizes a dual monaural construction that employs two identical and dedicated sets of I/O terminals, circuit boards, power supply circuits, power transformers, relay drive circuitry, and relay power supplies for the left and right channels. The microcomputer power supply, including the transformer, is also completely separate. A photocoupler keeps control signals completely separate from the relay, the only point of contact with the signal system.

Completely separate GND

The left channel, right channel, and control systems each have a ceramic-insulated chassis to achieve complete separation of the left, right and control GND. Each GND can be connected through the rear switch settings, but because each GND is completely separate, the listening experience offers an incredible expansive three-dimensional sound field with expressive, natural sound.

Vertical transformer mounting

The transformer is mounted vertically on the circuit board, so any harmful leakage flux is oriented parallel to the circuit board, to prevent possible circuit ingress.

Optical rotary encoder with double bearings and flywheel

The flywheel effect from the large, solid aluminum volume knob and the two large-scale bearings used to eliminate mechanical backlash combine to create a solid and extremely precise volume control.

Unfixed AC inlet base

The AC inlet uses the Jodelica ETP-600CU. By not mechanically fixing the aluminium AC inlet base, rear panel dumping is prevented, resulting in more expansive sound quality.

Audiovisual source bypass function

Each XLR and RCA circuit has an audiovisual source bypass setting that can fix volume and output with zero gain.

Floating construction

The Type-R circuit board and top cover are mounted in a floating construction without mechanical fixing. Freeing the P-3 from mechanical stress and the harmful effects of air dumps creates a natural sound quality and soundscape similar to removing the top cover.

GND anchor

The left and right side metals are isolated from the main chassis by ceramic washers and are directly connected to separate left and right GND. This amplifies the benefits (more expansive soundscape and clearer feeling) of the left and right GND floating construction.

Multiple device connection system

Multiple devices can be connected using UART signals. Master and slave settings allow all slave settings to follow those of the master. This allows duplicating differences in the master volume to the slaves. This feature enables, for example, multi-amplifier volume control via a digital channel divider following DA conversion. And, of course, these connections completely avoid GND loops or other issues thanks to the floating GND control system.