JBL 2108H (1980)
The JBL 2108H is a 20 cm cone mid-woofer released in 1980. JBL developed it specifically for the 4315B studio monitor system. It sold in Japan for around ¥40,000 per unit in 1981. The driver was meant to be mounted in a small sealed enclosure and to run in a four-way system between 250 and 2000 Hz.
It's an 8-ohm driver with a sound pressure level of 93 dB/W/m (new JIS), an fo of 40 Hz, and a rated frequency band of 400 Hz to 5 kHz. Continuous program input is rated at 75W, measured by sweeping 100 to 500 Hz. Magnetic flux density is 10,500 Gauss. The driver weighs 5.5 kg and is 9.2 cm deep. The recommended minimum enclosure volume is 11.3 liters.
Not much information survives on this model beyond its link to the 4315B. A forum discussion comparing it to the JBL 112A says the two drivers are essentially the same except for the magnet - alnico in the 112A, ferrite in the 2108H. The same compatibility question (“JBL 2108H 112A compatibility 4315B?”) shows up in more than one place, which suggests the 2108H may have served as a replacement or alternative to the 112A in the 4315B. Parts suppliers sell replacement foam surrounds, which implies foam rot is a known service item.
No production end date, overall dimensions, or official JBL datasheet have surfaced. The driver turns up now and then on the used market. One Craigslist listing asked $125, and it also appears in Russian and Japanese listings, often in parts/reconing contexts.
- Type: 20 cm cone mid-woofer
- Impedance: 8 Ω
- SPL: 93 dB/W/m (new JIS)
- Frequency band: 400 Hz – 5 kHz
- fo: 40 Hz
- Continuous program input: 75W
- Magnetic flux density: 10,500 Gauss
- Depth: 9.2 cm | Weight: 5.5 kg
- Enclosure volume: 11.3L or more
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 124A
- JBL 124H
- Braun AUDIO-1 (1965)
- Braun AUDIO-250 (1965)
- Magnavox Component Systems (1972)
- Acoustic Research AR (1967-1976)
- Acoustic Research 11