ESS Eclipse Model 2240 (c. 1976)

Little is documented about the ESS 2240 outside a single period review. It was an electronic crossover, sold by ESS under the "Eclipse" name, for use in multi-amplified speaker systems. Audio (July 1976, p.56) gave it a full Equipment Profile and measured the crossover frequencies as exceptionally accurate - within 0.5 dB of the marked -3 dB points in the worst case.

The 2240 had seven crossover frequencies per channel: 100, 150, 200, 250, 500, 800, and 1250 Hz. A multiplier button shifted the whole set to 1.0, 1.5, 2.0, 2.5, 8.0, and 12.5 kHz. Slopes were 12 dB per octave. Frequency response in the pass bands was within 0.25 dB from 20 Hz up to the crossover point on the low-pass side, and from the crossover point to 20 kHz on the high-pass side. Gain was 0 dB in each pass band. The unit was a standard 19-inch rack-mount profile, 1¾ inches tall and 9 inches deep, and it weighed 5 lbs. Price in 1976 was $300.

The review verified the crossover frequencies by sweeping the outputs and found them very precise, generally much closer than the ±0.5 dB worst-case figure. Beyond that review, information on the 2240 is thin. No service manual, production totals, or later commentary has surfaced in the usual collector channels.

Type: Electronic crossover, 2-way stereo
Available crossover frequencies: 100, 150, 200, 250, 500, 800, 1250 Hz (multiplier ×10 for 1.0–12.5 kHz)
Slope: 12 dB/octave
Dimensions: 19 × 1¾ × 9 in (48.3 × 4.4 × 23 cm)
Weight: 5 lb (2.3 kg)
Price (1976): $300