ESS PS-4750

The ESS PS-4750 is a large, floor-standing 3-way loudspeaker from ESS, the company best known for the Heil AMT tweeter. Documentation on this model is thin — no production years or original price are recorded — but the specs that survive paint a picture of a serious, high-output speaker. A period advertisement in HiFI-Stereo (December 1975, p.17) referenced the PS-4750 as a turntable model, a naming coincidence that adds to the confusion. It was a vented (bass reflex) design with four large side-firing ports, a 12" poly woofer (two per cabinet), a 4½" poly midrange, and a 1" soft-dome tweeter. Crossover points were set at 350 Hz and 4 kHz. Rated sensitivity was a very high 100 dB, with a frequency response of 22 Hz to 30 kHz and an 8-ohm impedance. The binding posts were 5-way gold-plated and bi-wireable. Each cabinet weighed 95 lbs and measured 39" x 18" x 15" (H×W×D).

On the ESS side, the record is mostly user testimony. One owner on an audio review site reported owning a pair for 30 years and still finding them excellent. Another bought a pair in 1981 and found them "very harsh" and "really bright" no matter what he did — though he described his pair as a 4-way tower with a horn tweeter, which conflicts with the 3-way, soft-dome spec sheet. That discrepancy is unresolved; the official spec listing says 3-way with a dome tweeter, and that's the version recorded here. There is no information on current market prices, common failure points, or recommended amplifier pairing.

Known specs, as documented:

- 3-way, floor-standing, bass reflex (four side-firing ports)

- Drivers: 2 × 12" poly woofer, 1 × 4½" poly midrange, 1 × 1" soft-dome tweeter

- Crossover: 350 Hz / 4 kHz

- Frequency response: 22 Hz – 30 kHz

- Sensitivity: 100 dB

- Impedance: 8 ohms

- Power handling: 250 W RMS / 1000 W peak

- Bi-wireable, 5-way gold-plated binding posts

- 39" × 18" × 15" (H×W×D), 95 lbs