Phasemation CM-1500 Hybrid Passive Preamplifier

Hybrid passive transformer attenuator preamplifier with -10 dB / 0 dB / +6 dB gain switch and balanced / unbalanced I/O

The Phasemation CM-1500 is a hybrid passive preamplifier built around a transformer-based attenuator designed to preserve signal purity while offering flexible gain structure. It combines the high input impedance of a passive control center with the low output impedance needed to drive a wide range of power amplifiers. A 23-step attenuator provides precise volume resolution, while a three-position gain switch allows the CM-1500 to integrate seamlessly with everything from high-efficiency speakers to low-gain amplifiers.

The attenuator transformer uses an ultra-thin Super Malloy core and PC-Triple C wire to deliver a wide frequency response with low distortion. Gold-plated rotary switches, high-quality RCA terminals, Neutrik XLR connectors, and a rigid copper-plated steel chassis with a 10 mm aluminum front panel all work together to minimize noise, vibration, and mechanical resonance. With both balanced and unbalanced inputs and outputs, the CM-1500 offers versatile system configuration while maintaining a clean, natural signal path.

Specifications

Form: Hybrid passive preamplifier

Input Impedance: 47 kΩ or more

Output Impedance: 250 Ω or less

Channel Separation: 100 dB or more (20 Hz–20 kHz)

Frequency Response: 10 Hz–100 kHz (+0, -3 dB)

Gain: -10 dB / 0 dB / +6 dB

Input Terminals: RCA × 3, XLR × 2

Output Terminals: RCA × 2, XLR × 2

Dimensions (WHD): 16.93″” x 3.66″” x 14.25″” (430 x 93 x 362 mm)

Weight: 14.33 lb. (6.5 kg)