Rack mounting tube replacement specifications – SWR Sound Professional Bass Preamplifier Marcus Miller User Manual
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To preserve the beauty and reliability of your preamp, we
recommend that you install your preamp in a rack case. The
Marcus Miller Preamp is completely ready to be rack mounted
and needs no additional parts or accessories other than the
rack screws and the case itself.
The Marcus Miller Preamp takes up two full rack spaces
(3 1/2"). If the rack in which you mount your preamp requires
that the rubber feet on the bottom of the chassis be removed,
please remember to keep the screws handy in case you wish
to reattach the rubber feet at a later date.
Please routinely check the mounting and chassis screws
which can vibrate loose due to transportation and use. We
recommend that at least once a month that the Marcus Miller
preamp be removed from the rack case and all outside screws
be tightened and all connections in your rack case be checked
to preserve the beauty and reliability of your equipment.
A 12AX7 dual triode vacuum tube (valve) is at
the core of your Marcus Miller pre-amplifier.
Typically a 12AX7 tube will last several
years, but through heavy use and frequent
transportation jarring, it is possible to have a
tube last less than a year.
When to replace the preamp tube: Sometimes, tubes become
noisy or “microphonic” (the amp sounds like a glass chime
tinkling during certain notes) as they wear out. But other times,
tubes will fail without warning. If your amplifier stops working
and other possible causes have been eliminated (breakers,
cords, etc.), have an authorized service center inspect your
amplifier for tube failure.
PART NUMBERS
4405200000 (120V, 60Hz) USA
4405203000 (240V, 50Hz) AUS
4405204000 (230V, 50Hz) UK
4405206000 (230V, 50Hz) EUR
4405207000 (100V, 50/60Hz) JPN
POWER REQUIREMENT
50W
PRE AMP
INPUT IMPEDANCE: >820kΩ (Front panel Inputs);
10kΩ (Rear panel Input)
SENSITIVITY: +4 dBu preamp output with 12mV 1kHz input, Gain and Volume at MAX, all tone controls flat (center detent),
Aural Enhancer at mid position, Effects Blend at DRY, Bass Intensifier, Compression, and Boost OFF
TONE CONTROLS
BASS: ±15dB @ 70Hz
TREBLE: ±15dB @ 3kHz
VARIABLE SEMI-PARAMETRIC EQ: LOW: ±15dB @ 35Hz–180Hz
MID: ±15dB @ 180Hz–1kHz
HIGH: ±15dB @ 1kHz–5kHz
COMPRESSION
GAIN REDUCTION: –22dB maximum, selectable PRE or POST EQ
THRESHOLD: –10dBV to +10dBV
RATIO: 1:1 to 20:1
ATTACK TIME: 10mS to 600mS
RELEASE TIME: 250mS to 2.5S
EFFECTS LOOP
SEND IMPEDANCE: 220Ω
RETURN IMPEDANCE: 10kΩ Balanced
DI OUTPUT
Tube driven transformer coupled output. 600 Ohm output impedance.
FOOTSWITCH
4–button (0075431000)
DIMENSIONS
HEIGHT: 3.5 in (8.9 cm)
WIDTH: 19 in (48.3 cm)
DEPTH: 11 1/8 in (28.3 cm)
WEIGHT
13 lb (5.9 kg)
Product specifications are subject to change without notice.
Rack Mounting
Tube Replacement
Specifications