JBL 3110
The JBL 3110 is an active electronic crossover network in a rack-mountable 19-inch chassis, built for professional or serious home use. Documentation is thin. No production years, original pricing or period reviews have surfaced, but the surviving specs show a flexible, utilitarian unit.
The front panel has a crossover frequency selector knob with four positions - 200, 500, 1200 or 5000 Hz. It also has gain controls (0 dB to -40 dB) for both the high and low frequency outputs, and a power on/off switch. The rear panel carries one pair of input terminals and two pairs of output terminals, one for high-pass and one for low-pass. The filters are 12 dB/octave Butterworth. Input sensitivity is rated at 0.5 V, input impedance at 50 kΩ, and output impedance at 200 Ω, with a maximum output level of 10 Vrms. Frequency response is specified at 20 Hz-20 kHz (±3 dB) with THD of 0.1% and a signal-to-noise ratio of 100 dB. It runs on 100-120 VAC or 220-240 VAC, 50/60 Hz, and weighs 9.2 kg. Dimensions are 19″ × 5.25″ × 7.5″.
Known specs:
- Crossover frequencies: 200 / 500 / 1200 / 5000 Hz (selector knob)
- Filters: 12 dB/octave Butterworth
- Gain controls: 0 dB to -40 dB (high and low outputs)
- Input: 0.5 V sensitivity, 50 kΩ impedance
- Outputs: high-pass and low-pass, 200 Ω impedance, 10 Vrms max
- Frequency response: 20 Hz-20 kHz (±3 dB)
- THD: 0.1%
- S/N: 100 dB
- Power: 100-120 VAC or 220-240 VAC, 50/60 Hz
- Dimensions: 19″ × 5.25″ × 7.5″; weight: 9.2 kg
Outside equipment directories and auction catalogs, almost nothing is recorded about the 3110. No service information, production quantities or model variants (e.g., 3110A or 3110B) have been confirmed. It appears to have been a straightforward, functional piece of JBL's professional lineup. Period publications from the late 1980s list the 3110 in professional audio equipment directories alongside other loudspeaker accessories, which suggests it was marketed as a standard component for installation use Sound and Communication (August 1989, p.84).
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