Revox Plenum B MKII
The bass driver is 10 inches. The studio pedigree and the fragile foam are what define this rare Swiss speaker.
Overview
The Revox Plenum B MKII is a 3-way speaker system, likely built for professional monitoring. The exact years of production are undocumented. European market listings and repair suppliers consistently call it "Revox Plenum B MKII." Variants like "MkII" or "B-MkII" are just typographical drift, not model differences. One known pair traces back to Deschamps Recording, which lends some credence to professional use, though no official documentation confirms widespread studio adoption.
No specs have been published: no frequency response, sensitivity, impedance, or cabinet dimensions. Collectors note a 10-inch (25cm) bass driver, but that comes from replacement parts listings, not original manufacturer data. Being a 3-way design suggests a dedicated midrange and tweeter alongside the large woofer, a configuration aimed at accurate spectral balance. Available sources say nothing about crossover topology, driver materials, or cabinet construction.
What is known is that the foam surrounds on the bass drivers degrade, a common fate for speakers of this era. It has become the central fact of the Plenum B MKII's afterlife. Replacement kits are available, using polyether-based surrounds with micro bubbles for flexibility and lightness, a modern material meant to outlast the original formulation. One owner, after replacing the bass drivers, posted simply: “I’m very happy with them.”
Specifications
| Manufacturer | Revox |
| Product type | Speaker |
| Driver configuration | 3 way |
| Bass driver size | 10" 25cm |
Historical Context
Listings describe the Revox Plenum B MKII as "studio monitors/audiophile speakers," which points toward professional studio use. Its association with Deschamps Recording is anecdotal, from a single owner, but it supports the idea that the speaker saw service in a working studio. A 1983 price list names it alongside other Revox models like the Forum B and Piccollo, suggesting a broader product family. The exact relationship between these models remains unexplained. No documentation outlines its design philosophy, target market, or technological lineage.
Collectibility & Value
Listed as "RARE," the Revox Plenum B MKII occasionally surfaces on the secondhand market. One pair was offered at 129.00 € (including VAT) in "good condition," with noted cosmetic flaws like severe paint damage on the top panel. The original price was 179.00 €. The most consistent maintenance issue is foam surround degradation, and dedicated re-foam kits are available. One kit, priced at approximately £55.92, includes polyether foam materials designed to improve longevity. Collectibility appears niche, driven by Revox's reputation and the speaker's studio-adjacent provenance rather than documented performance metrics.
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