EPSA Super-Compressor

From Chronopedia

EPSA Super-Compressor

What is a “Super-Compressor” dive watch?

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“Super-Compressor” refers to a patented case sealing method developed by watch case manufacturer Ervin Piquerez S.A. (EPSA). The design takes advantage of the water pressure the case is exposed to at depth to press the case back against the o-ring seal . More depth equals more water pressure equals greater seal. Dual crown Super-Compressor watches typically have a depth rating of 600 ft. This same concept was employed by Omega in the Naiad crowns used on Seamaster 300 watches in the ‘60s. Well regarded as being very high quality and watertight, EPSA manufactured the S-C cases in a variety of styles from the late '50s until bankruptcy closed the business in the mid-'70s. The fact that so many survive today is a testament to their quality.

Are all Super-Compressors dual-crown, internal bezel watches?

No. Super–Compressor refers to the method of case sealing and nothing else. Dual crown styles are the most commonly seen, but there are single crown cases that have the Super-Compressor designation. ===Are the large case dual-crown models called “Super-Compressor” and the small case models simply called “Compressor”?=== No. As stated above the term “Super-Compressor” refers only to the case sealing method. Both the small cased models (36mm) and large cased models (42mm) of the dual crown style are Super-Compressors.

What are Compressor and Compressor 2 types, and how are they different from the Super-Compressor?

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Both the Compressor and Compressor 2 types have snap on case backs. Compressor 2 types use a shaped case (i.e. square, cushion or tonneau), not round. Compressor and Compressor 2 watches while water resistant, are commonly seen in "fashion" watch styles, and while designed to be water resistant are not dive watches. The exception to this is the triple-crown Compressor cased JLC Polaris. The Super-Compressors use a screw-on case back, excepting the Enicar models which use a bayonet mount caseback. The Super-Compressor designation is used on both single and dual-crown types.

Do all Super-Compressors have a screw-on case back?

Many of them do, but not all. The Super-Compressor cases manufactured for the Enicar Watch Co. are the exception. They use a bayonet mount for the case back, similar to the way a camera lens mounts.

Are all dual-crown, internal bezel watches EPSA Super-Compressors?

No, similar styles were produced by a number of other manufacturers. Dual-crown internal bezel watches that are very likely EPSA manufactured cases have been seen, but do not employ the S-C technology for the case back. Dual-crown replica watches have recently begun to appear on ebay. These watches have a number of Super-Compressor design details like cross-hatched dual-crowns and an internal bezel, but are modern/new manufacturer replicas, not authentic Super-Compressors.

How do I identify an EPSA dual-crown Super-Compressor?

EPSA S-C watches can usually be identified by the trademark dive helmet inside the case back, sometimes on the outside of the caseback. Dual-crown S-C watches typically (but not always)have cross-hatched crowns, sometimes you’ll see the manufacturers signature with the cross-hatching behind. With few exceptions, the crowns are characteristically fat and chunky. If it's a screw on case back there should be a spring assembly inside the caseback rim. The upper crown located is at 11 minutes and the lower crown at 19 minutes on the case, regardless of the case size or style. EPSA Super-Compressor Brevet (patent) numbers may also be present: Screw-on case backs carry the numbers 317537 and 337462. Bayonet mount (Enicar cases) case backs have the number 314962.

How many different manufacturers used dual-crown Super-Compressor cases?

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Dual-crown Super-Compressor cases were very popular and used by many watch manufacturers, from the very best like JLC, Zenith and Longines to relative unknowns. Here's a list of companies known to have used the dual-crown Super-Compressor case, compiled by Dave at the MWR Forum.


How may different sizes of dual-crown cases were offered?

Commonly seen are the large case dual-crown which is 42mm and has 22mm lugs, and the small case dual-crown which is 36-37mm and has 18-19.5mm lugs. There are a small number of ladies sized dual-crown S-Cs which are 26mm.

Where can I get case parts for a dual-crown Super-Compressor?

A number of critical parts which are specific to the dual-crown S-Cs are nearly impossible to find. Crystals are specific to each case design, and there were many different styles. The internal bezel is held in place by the crystal and tension ring, and these were manufactured specifically for these watches. I have heard of instances where generic crystals were fitted, but with less than satisfactory results.

The star gear which turns the bezel is not available. Cross-hatched crowns are not available. Generic crowns can be substituted, but value points will be deducted from any watch not having correct crowns.

When considering any dual crown S-C for purchase, make sure it's complete and operating correctly. If you've got one that needs parts, you may have to find a parts-grade watch (maybe more than one) to get what you need.


Super-Compressor , screw-on case back, both dual-crown and single-crown, all sizes

  • BREVET 317537
  • BREVET 337462

Super-Compressor, bayonet mount case back, dual-crown, all sizes

  • BREVET 314962

Compressor, snap-on case back

  • BREVET 313813


Credits http://scubawatch.org/EPSA_SC_FAQ.html