RDL ST-PH1 Stereo RIAA Phono Preamplifier / Adjustable Gain 40-60 dB / Balanced Outputs

Description

The ST-PH1 is a compact stereo phono preamplifier designed to convert low-level phono cartridge signals to professional line level. It provides accurate RIAA equalization and low-noise amplification for moving-magnet cartridges. The unit maintains signal integrity near the turntable to minimize noise and interference in downstream equipment.

Each channel features a standard 47 kOhm unbalanced phono input and an adjustable gain range of 40 to 60 dB at 1 kHz. Outputs are capable of driving balanced or unbalanced lines and can feed high or low impedance loads. The design includes adjustable left and right output level controls to match downstream equipment.

Technical performance includes THD of less than 0.03 percent into high impedance and less than 0.015 percent into a 600 Ohm load across 10 Hz to 30 kHz. Noise is specified at below -75 dB relative to +4 dBu and the unit offers 18 dB of headroom above +4 dBu. Frequency response follows the RIAA equalization curve for accurate vinyl reproduction.

The ST-PH1 incorporates RDL SupplyFlex power input configuration – allowing connection to floating 24 Vdc sources, bipolar supplies of +/-12 Vdc or +/-15 Vdc, or ground-referenced 24 Vdc supplies at 60 mA. Outputs are nominally +4 dBu and the unbalanced output is 6 dB below the balanced line level. The outputs are rated to drive 300 Ohm lines for robust connectivity.

Typical applications include professional audio systems, broadcast studios, DJ rigs, and AV installations where turntable signals must be converted to line level close to the source. The unit is suited for both stereo and mono configurations and integrates easily into racks or tabletop setups. Installing the ST-PH1 preserves signal quality for mixing, recording, or distribution systems.

Installation is straightforward and the compact form factor simplifies placement near turntables. The front panel provides level adjustment while the power input supports multiple power wiring topologies for flexible system integration. Built to professional standards, the ST-PH1 delivers reliable low-noise preamplification for analog vinyl sources.