John East J Retro- Chrome Preamp for Jazz Bass®

3 Band -- 3 Knob, 2 Switch:

Volume/Blend Stack -- Treble/Bass Stack -- Mid/Frequency Stack -- Active-Passive Switch -- Pickup Switch

The J-RETRO 01 is designed to fit directly into standard "Jazz" style basses without modification, including a PP3 (9V) battery, in most cases. 

Its high quality circuit uses three stacked knobs and includes an active blend circuit plus a 3 band equaliser with bass, variable frequency mid, treble and bright function. 

A very gentle built in contour gives immediate colour without detracting from the basic sound of any bass. The active blend circuit prevents the loss associated with many passive basses where, when both pickups are up full, the signal from one pickup feeds into the other and vice versa.

However, a switch is included to allow a passive equal mix of both pickups. A second switch - basic "get-you-out-of-trouble" passive mode is included in case the battery dies in crucial circumstances, and this mode allows some useful settings too.

Includes all knobs.

Easy to fit, no routing or mods to most J style basses.

A standard PP3 (9V) battery fits under the plate in the standard cavity in most cases.

***NOTE : John East preamps use an active blend.  In passive mode, the blend pot does not function. Therefore, a player can use the pickup switch to alternate between both pickups on or the bridge pickup on only. For most players, the passive mode is a ‘get out of trouble’ mode for situations such as live gigging where a battery failure occurs. *** 

VOLUME & BLEND  (Knob stack nearest the neck pickup)

VOLUME

The upper knob is the Volume.

This knob has active circuitry after it so that the feed to your amplifier is a low impedance drive.

BLEND & PICKUPS SWITCH

The lower outer knob is the Blend balance for the pickups.

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.

The balance between the pickups is continuously variable with progressive level compensation towards the single pickup settings.

BASS & TREBLE  (The middle knob stack)

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.

MID LEVEL & FREQUENCY  (The knob stack nearest the jack)

BOOST/CUT (+/- 12dB)

The upper knob controls the amount of Midboost or cut at frequencies according to the setting of the Frequency knob. The midway indent is the 'flat' position.

FREQUENCY (150Hz - 3kHz)

The lower outer knob is continuously variable and sets the Mid frequencies for boost or cut.

ACTIVE PASSIVE SWITCH  

(By the jack) Towards the jack for active, the opposite for passive.

POWER

The power is switched on automatically when a mono jack is plugged into the socket.

Below are impressions and anecdotal thoughts gathered over the years. Some are our own and some are from customers.

• One of the most profound upgrades to my Jazz Bass®!
• Rich deep tone in a small tweak
• Tonally, this preamp is extremely versatile
• Easy Install
• Has turned my cheapo MIM J Bass® into a killer!