Top Panel (Controls & Features); Input Jack; Thru Output Jack; Deep Switch - Mesa/Boogie SUBWAY BASS DI PREAMP Owner's Manual

TOP PANEL (CONTROLS & FEATURES)

INPUT JACK

This jack (located on the right side of the chassis) is the instrument INPUT that feeds the first stage monolithic
J-FET buffer amp of the SUBWAY BASS DI-PREAMP. The input sensitivity of this input buffer amp is adjustable with the ACTIVE/
PASSIVE switch, the active position being about 10dB less sensitive (lower gain) than the passive position. When a ¼" (6.3mm) plug
is inserted into the jack, the power is automatically turned on, but please note that it is important for the ¼" (6.3mm) plug to be of the
TIP-SLEEVE type as TIP-RING-SLEEVE types may not engage the turn-on circuit properly. It is always good practice (and customary)
to inform the FOH/monitor engineer that you will be turning your PRE-DI on or off so as to prevent any pops or unexpected signal
into their system(s).

THRU OUTPUT JACK

the input jack. This signal is identical to (and not isolated from) the signal from the bass itself. It is not a buffered output, and would
typically be used to feed the instrument input of a stage amp.

DEEP SWITCH

This switch engages the DEEP filter, our take on classic low frequency response enhancement and extension.
Engaged, there is a mild boost in the very low frequency response while also lowering the effective high pass filter frequency. This
combination brings a more round, thicker, fatter response to the bottom end. When using this preamp with small (compact style) cabinets,
and especially with large amounts of bass eq boost, be aware of the possibility of damage due to overpowering at higher volumes.

ACTIVE/PASSIVE SWITCH

may have a signal level up to 10dB greater than a typical passive bass. If you find that you are operating the gain control near the
low end of the control's rotation in order to prevent the O/L LED from flashing, switching this switch up (into the ACTIVE position) will
reduce the input sensitivity (gain) by ~10dB, allowing greater control range and freedom from overload with high output active basses.

HIGH PASS FILTER

treme low end, especially under high drive conditions. This precision 4 pole filter has a turnover frequency that is set at approximately
30Hz with minimal ripple response. While HPF's have been standard fare within the pro audio industry for decades, this feature has
only appeared in bass guitar amplifiers within the past few years (with a few notable exceptions). This filter also provides additional
mechanical protection to the speakers by limiting the power to the speaker below the frequency range that the speaker cabinet cannot
provide adequate acoustic loading to the drivers. This is one of the primary (and preventable) causes of premature speaker failure,
especially with compact speaker cabinet products.
INPUT
THRU
OUTPUT
ACTIVE ON
VOICING
PASSIVE DEEP
SUBWAY
BASS DI-PREAMP
This jack (located on the left side of the chassis) is the instrument THRU OUTPUT that is parallel to
This switch sets the sensitivity of the J-FET input buffer. Often (though not always), an active bass
While not a visible switch or control, it is an important internal feature in maintaining control over the ex-
BASS TREBLE
HIGH MID
LOW MID
®
PAGE 2
MASTER
INSTRUMENT
INPUT
POWER