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Rack mounting tube replacement specifications – SWR Sound Professional Bass Preamplifier Marcus Miller User Manual

Page 11

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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