SFB-500.4v2

The SFB-500.4 V2 is a four-channel full-range amplifier with 500W x 4 at 1 ohm, 300W x 4 at 2 ohms, and 200W x 4 at 4 ohms, for 2000W total. It stays stable down to 1 ohm on every channel, which is unusual for a four-channel and the reason people choose it.

That stability changes what you can wire. Instead of one pair of speakers per channel, you can parallel several, which is exactly how P.A. mid and high arrays, large marine systems with multiple zones, and multi-pair car builds get powered from a single chassis. With 500W available per channel, each of those speakers gets real power rather than a share of leftovers.

SFB stands for Sundown Full Bridge, the Brazilian-style platform built around output per cubic inch. Filtering includes a variable 12dB low pass from 50 Hz to 6 kHz and a variable 12dB high pass from 15 Hz to 6 kHz, plus variable 12dB bass boost at 50 Hz, so the amp handles component sets, midbass drivers, or bridged bass duty.

Frequency response is 10 Hz to 20 kHz at -3 dB, input impedance is 56k ohms, input sensitivity is 5V max, and signal to noise ratio is 100 dB. Protection circuitry covers thermal, voltage, speaker short, and DC-offset faults, with power, protection, and clipping indicators. An optional wired remote with clipping indicator is available.

A 180A fuse is recommended. Dimensions are 9.75 by 8.28 by 2.75 inches.