From the original Ampeg owner’s manual — this effect has been discontinued and perhaps not that many were manufactured:
“Basic
understanding of the SUB-BLASTER and its operation will result in the
ability to use each of the sounds that the unit can produce. Don’t be
afraid to experiment with all of the controls — a little time spent
with the SUBBLASTER will enable you to use the unit to its fullest
capacity.”
“The “Direct” control adjusts the amount of unaffected
signal added to the output. The gain structure of the SUBBLASTER is
designed so that maximum headroom is preserved throughout the direct
signal path.”
“The “Octave” control adjusts the amount of
“octave” effect added to the output. Tracking accuracy has been greatly
improved over other octave pedal designs. On a five string bass, better
results will be obtained by fretting the note on the B (fifth) string,
fifth fret, rather than playing it as an open E on the fourth string.”
“The
tracking will be maximized in the middle of the neck by using the neck
or rhythm pickup. Tracking will still function well in all ranges with
the bridge pickup, but for optimum results the neck pickup is
recommended.”
“The foot switch permits a return to straight sound
without clicks or pops at a level equal to the SUB-BLASTER output
level. Thus, you do not have to reset your volume control on the
amplifier each time you switch the effect on and off.”
“The
SUB-BLASTER uses a “true bypass” switching system so that when the
effect is turned off, the signal is literally connected by wires from
input to output. The input and output jacks (marked “guitar” and
“amplifier”) also provide battery on-off switching. When not in use —
unplug the input (“guitar”) jack to conserve battery power.”
“When
using multiple effects, place the SUB-BLASTER early in the signal chain
— before distortion, envelope, chorus effects. This is because the
SUB-BLASTER likes to see a pure sine wave signal — the waveform
modifications produced by the aforementioned effects may have a
disruptive effect on the operation of the SUB-BLASTER. Always place the
SUB-BLASTER as close to the signal source as possible.”
