Gibson instruments in the 1970s often did not have the most intuitive of controls, especially when compared to their competitors; but this was integral to the broader tonal palettes for which they strived. Varitone equipped guitars had been part of the Gibson line since the 1950s, and the newer Norlin period guitars and basses were less intuitive still; many late seventies musicians were simply not getting the most out of their instruments! So it is no surprise that Gibson attempted to educate owners with printed material and even vinyl records.
Summary of EB3 varitone controls
The following sheet (produced by Norlin in 1978) shows Gibson's description of series 2 EB3 controls. Older series 1 controls are similar, though not identical.
See also the equivalent sheets for the Gibson Ripper, Gibson G3, Gibson RD Artist and Gibson Les Paul Signature basses.

At this point the EB3 bass was right at the end of it's production - just 184 guitars shipped in 1978, compared to a peak of 2421 in 1973 (see the EB3 shipping statistics); the guitar pictured is in the rarer white opaque finish, only available between 1976 and 79.
Gibson EB3 bass for sale
1961 Gibson EB-3 the cleanest original extent w / hang tags 1 of a kind & Minty !
Fort Lauderdale, Florida, 333**, UNITED STATES OF AMERICA
$11495
1969 Gibson EB3 Bass Guitar- 100% Original with Original Case
Glastonbury, Connecticut, 060**, UNITED STATES OF AMERICA
$3700
Gibson EB-3 Cherry Mod 1969 Electric Bass Guitar Original Case Slotted Head Art
El Segundo, California, 902**, UNITED STATES OF AMERICA
$3500
... more
"1973" Vintage Cherry "GIBSON EB-3" with OHSC Serial #056076 in Great Condition
Riverside, California, 925**, UNITED STATES OF AMERICA
$3295
1972 Gibson EB-3 Slotted Headstock Vintage Short Scale SG Bass Walnut w / Case
Seattle, Washington, 981**, UNITED STATES OF AMERICA
$2900
Surprisingly versatile, the EB-3 delivers warm, midrange rich snarl from the mini humbucker in the bridge position, and powerful low end thump from the neck position "Mudbucker " The rotary pickup selector offers a bevy of tones at the flick of a ... more
1972 Gibson EB-3 Short Scale Electric Bass Walnut Finish SG Vintage Gig Bag
Astoria, Oregon, 971**, UNITED STATES OF AMERICA
$1995
Gibson EB-3 Bass Guitar
Santa Barbara, California, 931**, UNITED STATES OF AMERICA
$1800
Gibson EB-3 FRETLESS Bass Guitar Electric Vintage Rare 60??s / 70??s SG Fret Less
Brisbane, California, 940**, UNITED STATES OF AMERICA
$1799
-11 pounder
-nics and dents everywhere, wear here and there. Belt rash
-extra hole from a once moved strap peg
Ive had this for a few years. Im just not a fretless player, but I always dug this thing. Was in this condition when I originally purchased it. Pots look original
Switch #4 and #1 light ... more
Gibson EB-3 Bass Guitar 1967
Horncastle, LN9***, UNITED KINGDOM
£2950
1971 GIBSON EB 3 SLOTTED HEADSTOCK BASS CASE - made in USA
COLOGNE, GERMANY
€444
* CASE ONLY !
* strap that holds case open=GONE
* bottom and top are loose =need reglueing
* tolex has rips
* all latches are working fine
* check all pics
Over 1000 more
GUITARS-BASSES-PARTS in our OTHER
AUCTIONS !!!!
TAKE A LOOK !!!... more
1971 GIBSON EB 3 SLOTTED HEADSTOCK BASS CASE - made in USA
COLOGNE, GERMANY
€439
* CASE ONLY !
* interior has stains
* tolex has rips
* all latches are working fine
* worn but solid
* check all pics
PLENTY of PARTS for SALE
ATTENTION! OVER 1000 more
GUITARS-BASSES-AMPS-PARTS
in our OTHER AUCTIONS !!!
CHECK OUR SHOP OUT -------------->>>>>-------------->>>>>
... more
Gibson EB 3 CASE 1971 - passend für NUR GESCHLITZTE SPINDELSTOCK-Version
COLOGNE, GERMANY
£399
* CASE ONLY !
* strap that holds case open=GONE
* bottom and top are loose =need reglueing
* tolex has rips
* all latches are working fine
* check all pics
* SOLD AS IS - NO RETURNS... more
1971 GIBSON EB 3 SLOTTED HEADSTOCK BASS CASE - Made in USA
COLOGNE, GERMANY
£385
* CASE ONLY !
* interior has stains
* tolex has rips
* all latches are working fine
* worn but solid
* check all pics
... more
1971 GIBSON EB 3 SLOTTED HEADSTOCK BASS CASE - Made in USA
COLOGNE, GERMANY
£385
* CASE ONLY !
* interior has stains
* tolex has rips
* all latches are working fine
* worn but solid
* check all pics
... more
Do you have an equivalent sheet for the Victory Artist bass # what the switches do # thanks how do I get a copy
Hi bassman85 - this series of info sheets was printed in 1978, some three years before the advent of the Victory bass series - the equivalent information appears on page 16 of the 1981 victory bass owners manual, which is reproduced here http://www.vintageguitarandbass.com/gibson/catalogues/1981_Victory_owners_16.php