East U-RETRO 4 KNOB DELUXE Manual

The U-RETRO 01 4 KNOB DELUXE, based on the J-RETRO 01, is a universal highly flexible
on-board preamp and EQ system. The standard pots have 10.0mm threaded bushes to allow
rear mounting in the wood of a bass body. Flat wire connections to the pots allow for flexible
layout.
Its high quality circuit uses one single knob and three dual concentric knob stacks. It includes
a passive blend plus a 3 band equaliser with bass, variable frequency mid, treble and bright
function. A passive tone circuit is also included which operates in both active and passive
modes.
The passive tone pot has a push/pull function which switches between active and passive
paths:
ACTIVE Signals from the pickups pass through the passive blend, passive tone, into the preamp input
stage. Then through the equaliser and volume section within the active circuitry, and on through a low
impedance output stage to the jack.
PASSIVE Signals from the pickups pass through the passive blend, passive tone and then on through the
passive volume control section which feeds the jack.
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VOLUME & BLEND
!
VOLUME
The upper knob is the Volume.
When used active, this knob has active circuitry after it so that the feed to your amplifier is a low
impedance drive. A 0-12dB preset allows gain adjustment for the input stage of the preamp.
!
BLEND
The lower outer knob is the Blend, fully operational in both active and passive modes, sets the
balance between the pickups. This is a very conventional control type, used in many different types of
basses. Turn it fully clockwise for the neck pickup alone, and fully anti-clockwise for the bridge
pickup. The midway position, which has an indent, gives an equal mix of both pickups.
!
BASS & TREBLE
!
TREBLE (+12dB @ 3 kHz, -12dB @ 1kHz)
The upper knob is the Treble control with boost and cut. The central 'flat' position is indented. The cut
settings work on lower frequencies compared to boost to give a deeper sound when the top is rolled off.
!
BRIGHT (+8dB @ 7kHz)
Pull the Treble knob for the Bright setting.
!
BASS (+15dB @ 50Hz)
The lower outer knob is the boost only Bass control. The frequency band of boost gets progressively
lower as the boost is increased. An indent midway is included to aid the setting of this control.
Continued over:
U-RETRO 4 KNOB DELUXE
Active/Passive Preamp for Bass Guitars
(Stack Knob)
(Stack Knob)