JBL 124A (1960s)
The JBL 124A is a pro-oriented 12-inch woofer from the 1960s. It shows up in monitor and sound reinforcement conversations more than in living rooms. What's documented comes mostly from enthusiast sources and a few spec databases. JBL's own original bulletin for this model hasn't surfaced in this research, so the record is thinner than for some of the company's home-market drivers. Period publications of the era discussed the merits of objective speaker evaluation, a topic relevant to understanding drivers like the 124A Audio (January 1972, p.75).
What the record does show is a driver built for work, not for casual listening. The 124A is a 12-inch woofer rated at 30 watts with a frequency response of 45-8,000 cps and a 16-ohm impedance. It uses a 4-inch edgewound ribbon wire voice coil, an Alnico V-6 magnet structure with 18,000 gauss flux density, and a cone made of "damped, radially oriented fiber" with a rolled surround. All of that fits JBL's professional transducer design of the era. The outer diameter measures 12.25 inches.
Owners on the Lansing Heritage forum describe a notably stiff suspension that isn't ideal for home hi-fi use without equalization. One user noted they're "efficient and clean, but lack deep bass," while another reported good midbass punch with a rolloff below 70 Hz in a ported cabinet. A measured DC resistance of roughly 11.5-12 ohms on a sample pair is consistent with the 16-ohm nominal rating. Forum discussion also places the 124A in C50 Sovereign and other monitor cabinets, and in JBL's Sonic Systems outdoor speakers. These usage claims are user statements, not factory documentation. One moderator note: the 124A is frequently confused with the JBL 123A, a foam-surround home woofer. They are different drivers.
If you're looking at one today, be aware that most surviving examples need reconing. Original surrounds were cloth or paper; many units have been refoamed with aftermarket parts, which can change the compliance and tonal balance. Speaker Exchange offers a cone kit at around $85, and a typical eBay listing for a used pair runs in the $150–$200 range. There's no official sensitivity rating, cabinet recommendation, or production year range documented — the "1960s" attribution comes from forum commentary. For a driver that JBL built for professional duty, the 124A remains a somewhat obscure but respected piece of the company's pro lineage.
Known specs:
- 12" woofer, 30 watts power capacity
- Frequency response: 45–8,000 cps
- Impedance: 16 ohms
- Voice coil: 4" edgewound ribbon wire
- Magnet: Alnico V-6, 18,000 gauss flux density
- Outer diameter: 12.25"
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- JBL 075
- JBL 077
- JBL 120Ti
- JBL 124H
- JBL 130A/130B
- Braun AUDIO-1 (1965)
- Braun AUDIO-250 (1965)
- Magnavox Component Systems (1972)
- Acoustic Research AR (1967-1976)
- Acoustic Research 11