Altec Lansing 420A (1968)
A 38 cm full-range speaker unit with a bi-flex cone design, released in 1968.
Overview
The Altec Lansing 420A is a 38 cm special cone type full-range speaker unit introduced in 1968. Designed for high-fidelity audio applications, it features a unique bi-flex construction that integrates multiple cone elements to extend frequency response and improve dispersion. This speaker was used in the Altec 879A Santa Ana system, indicating its role in professional and high-end audio setups of the era.
Specifications
| Type | 38 cm special cone type full-range speaker |
| Frequency characteristic | 25 Hz to 14 kHz |
| Lowest resonance frequency | 27Hz |
| Impedance | 8 Ω |
| Rated input | 25W |
| Allowable input | 50W |
| Magnet used | 4.9 kg Alnico V |
| Magnetic flux density | 11,400 gauss |
| Crossover frequency | 1 kHz (Mechanical) |
| External dimensions | Diameter 386x Depth 178 mm |
| Weight | 7.9kg |
| Voice coil | 75 mm diameter voice coil with aluminum ribbon wire edgewise winding |
| Magnetic circuit type | 11,400 gauss, 4.9 kg internal magnetic type Alnico V |
| Frame | Strong aluminum die-cast frame |
Design
The 420A is known as a bi-flex speaker, featuring a large cone with a 16 cm diameter inner cone of differing stiffness, integrated into a multi-damped corrugation. At the center, a light alloy dome radiator handles high-frequency output up to 14 kHz. The magnetic circuit uses Alnico V magnetization controlled to avoid over-excitation, preventing uneven quality and loss of holding force. This design supports wide-band performance without a separate tweeter.
Product Family
The 420A was incorporated into the Altec Lansing 879A Santa Ana speaker system, suggesting it was intended for use in high-performance installations where full-range clarity and durability were critical.
Market
Original pricing for the 420A was ¥54,300 per unit around 1970, rising to ¥57,800 after a price revision, then settling at ¥54,700 by 1976.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.