Slovak record label since 1971.

Submitters, please note: Feel free to ask questions regarding Opus here: http://www.discogs.com/group/1754 —> click “more” for additional details:

History
Established in 1971 as the successor to the Supraphon Slovakia branch office, releasing mainly recordings by Slovak artists or with Slovak participation in all genres, as well as licensed releases from major international record companies. Privatized in 1990, owned by Forza Music s.r.o. since 2005.

Catalog# schemes ca. 1971–1990
90## #### = mono
91## #### = stereo
93## #### = digital recording (?)
Catalog# schemes ca. 1990–1998
91 ####-# ### —> the last three digits are possibly “boxed” on the cover: [#|#|#]
—> How to: For mono releases, please always add “Mono” to the format. For stereo releases, always add “Stereo” if a mono version obviously exists. But since stereo 7" records were not a Czechoslovak standard until ca. 1974, you may want to include the “Stereo” tag anyway in such cases.

Retail price code suffix
The catalog number on the cover may have a retail price code suffix attached to it, for example “9113 1234 H”. However, the suffix has been used very inconsequently and is not a part of the actual catalog number. Often the actual retail price was instead printed on the cover or on the center labels.
—> How to: Please do not include the price code suffix or the retail price with the actual catalog number. If present, you should add it to the release notes though.
Partial retail price code list:
e = Kčs 8,– (?, format?)
f = Kčs ?.– (7" Single)
g = Kčs 10,– (7" Single)
h = Kčs 12,– (7" Single)
ee = Kčs 16,– (7" EP)
ff = Kčs ??– (7" EP)
gg = Kčs 20,– (7" EP)
hh = Kčs 24.– (7" EP)
E = Kčs ??,– (10" LP)
F = Kčs ??,– (10" LP)
G = Kčs 36,– (10"/12" LP)
H = Kčs 44,– (12" LP)
ZA = Kčs 50.– (12" LP)
ZB = Kčs 60,– (12" LP)
ZD = Kčs 80,– (12" LP)
ZN = Kčs 120,– (12" LP)

Manufacturing date code
Most Czechoslovak vinyl records pressed between ca. 1967 and 1992 include a three-digit code on the side A center label: ## # The first two digits represent the year, the third digit the half-year of the pressing. For example, a record with code “75 2” on the label has been manufactured in the 2nd half of 1975.
Even if the manufacturing date differs from the sound recording copyright (℗ year), it doesn’t necessarily mean that a record is a re-press. Some releases might have been held back for up to a few years for bureaucratic or political reasons, and the code simply denotes the time window when a vinyl left the manufacturing plant.
First pressings manufactured ca. 1969–1974 sometimes didn’t contain the manufacturing date code at all, in favor of the total duration time for each vinyl side.
Represses are usually identical to the original releases, apart from this code on the label as well as different stamper codes. (Some later represses may have an updated catalog# scheme on the cover though, see above.)
—> How to: Before you submit a record as a unique release based on the manufacturing date code, please first check all previously submitted versions of the same release. Many submitters don’t include the manufacturing date code at all. In case of doubt please contact them in order to avoid duplicates. Note that in most cases, represses are not “reissues”. Only add the “Repress” format tag if you are sure that you own one, and include the original sound recording copyright ℗ year in the release notes.