Bozak B-302 (1957–1971)

At 45.5kg, it arrives like a promise—and a warning.

Overview

The Bozak B-302—more precisely, the B-302A—wasn’t built to blend into the background. It was engineered to dominate a room, both physically and sonically. Though sometimes referred to simply as the B-302 in informal circles, the model as documented across service manuals, collector forums, and vintage listings is consistently the B-302A, a three-way, four-driver floorstanding speaker system introduced in various forms from at least 1957 through the early 1970s. One restored unit dates to 1957; another pair carries a 1971 badge. This span suggests a long, evolving production run, though exact start and end years remain undocumented. Priced around ¥260,000 per unit in the late 1970s, it occupied a high tier among medium-sized systems of its era, according to available documentation.

At its core, the B-302A was an evolution of the B-300, upgraded with the addition of a dedicated midrange driver and a revised crossover network. This wasn’t a minor tweak—it was a recalibration of Bozak’s acoustic philosophy, aiming for greater clarity in the critical vocal and instrumental midband. The result was a speaker that combined the deep, controlled bass of a large sealed cabinet with a newfound precision in the middle frequencies. Owners report a sound that’s both authoritative and articulate, with one noting it delivers “the cleanest bass” they’ve heard from a system of its size. Though small in footprint relative to full-range behemoths, the B-302A carried the sonic weight of Bozak’s reputation for musical sensitivity.

Specifications

Manufacturer	BOZAK
Model	B-302A
Product type	3-way speaker system
Model Rating Method	3-Way, 4-Speaker, Sealed Type, Floor Type
Frequency characteristic	40 Hz to 20 kHz
Impedance	8 Ω
Rated input	50W (MUSIC)
Crossover frequency	800 Hz, 2.5 kHz (6dB/oct.)
External dimensions	Width 600 x Height 765 x Depth 500 mm
Weight	45.5kg
Units Used	For Low Band : 30 cm Cone Type (B-199A); For Middle Range : 16 cm Cone Type (B-209B); For High Range : 5 cm Cone Type x2 (B-200Y); Other : N-10102
Driver configuration	Three-way, four-driver
Cabinet design	Sealed (acoustic suspension)

Key Features

30cm Cone Woofer with Variable Density Paper Diaphragm

The B-199A 30 cm cone woofer forms the bass foundation of the B-302A. Its diaphragm is crafted from a felted paper composite with wool blended into the pulp, engineered using a variable density system. This means the cone is densest at the center and gradually thins toward the outer edge, a design intended to control breakup modes and deliver more linear piston-like motion. In practice, this contributes to the speaker’s reputation for clean, articulate bass—even at higher volumes. The sealed cabinet design further enhances control, trading efficiency for tighter low-end response.

16 cm Mid-Range Driver with Aluminum-Neoprene Sandwich Diaphragm

The addition of the B-209B 16 cm midrange driver is what separates the B-302A from its B-300 predecessor. This driver uses a unique diaphragm construction: a thin sheet of aluminum is sandwiched between two layers of neoprene rubber film, with a stepped profile at the center and periphery. This design aims to combine the lightness and speed of aluminum with the damping properties of rubber, reducing coloration and resonance in the vocal range. Collectors note that this driver was a significant step forward in Bozak’s pursuit of midband transparency.

Dual 5 cm Cone Tweeters with Foam-Damped Metal Diaphragms

High frequencies are handled by two B-200Y 5 cm cone tweeters. These are not conventional dome tweeters; instead, they use a metal diaphragm mounted on a foam rubber platform, which helps dampen spurious vibrations and resonance. For frequencies above 10 kHz, the system relies on a 2 cm aluminum center dome integrated into the tweeter—based on the principle that cone diameter must not exceed the wavelength of the highest reproduced frequency. This dual-element approach allows for extended, detailed highs without harshness, though sensitivity figures are not officially published.

N-10102 Crossover Network with Multi-Amplifier Support

The N-10102 crossover network manages the 800 Hz and 2.5 kHz transition points with a 6 dB/octave slope, a gentle roll-off that preserves phase coherence. What’s notable is the terminal section, which includes a multi-amplifier selector switch and corresponding terminals. This suggests Bozak anticipated bi-amping or even tri-amping configurations, a forward-thinking feature for its time. However, owners report that crossover components—especially capacitors—can degrade over decades, making restoration a common necessity. Upgrades to modern capacitors are frequently mentioned in restoration circles.

Historical Context

The B-302A emerged as a refined iteration of the B-300, designed to fill a niche between compact monitors and full-range floorstanders. Documentation indicates it was positioned as a “high-level medium-sized system,” a label that reflects its balance of size, performance, and price. The model could be assembled from earlier Bozak systems by adding the B-209B midrange driver and the N-10102 crossover, suggesting a modular design philosophy. This adaptability may have extended the life of earlier enclosures, allowing owners to upgrade without replacing the entire system.

Collectibility & Value

Market data is sparse, but one recorded auction lists a winning bid of $292.00 for a pair of B-302A speakers. Given the age and weight, surviving units often show signs of wear or component fatigue. A known issue among owners is driver inhomogeneity—particularly in the woofers—when acquiring mismatched pairs. If both speakers lose bass simultaneously, the fault may lie upstream rather than in the drivers themselves, suggesting a common mode problem in the signal chain. Restoration typically involves crossover work, with many enthusiasts replacing aging capacitors. Tilting the speakers rearward is another common modification, reportedly improving imaging and high-frequency dispersion.