John East J Retro Preamps

Control Configuration

1. Volume/Blend Stack
2. Treble/Bass Stack
3. Mid/Mid Stack
4. Blend & Pickups Switch
5. Active/Passive Switch
6. Available in Chrome Finish

Description

The J Retro 01 Bass Preamp is designed to fit directly into standard "Jazz" style basses without modification, including a 9v battery. Its high quality circuit uses three stacked knobs and includes an active blend circuit plus a 3 band equalizer 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, but this mode allows lots of useful settings too.

Easy to fit, no routing or modification on most basses.

A standard PP3 battery fits under the plate in the standard cavity in most J-style basses.

Technical Specifications

Volume/Blend Stack

The upper knob is the Volume which has two sections under the same knob. A high impedance for the passive path and a low impedance section is used for the active circuitry. When used active, this knob has active circuitry after it'so that the feed to your amplifier is a low impedance drive.

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. Important:- The Pickups switch (by the blend) must be set pointing towards the jack for the Blend to function.

Treble/Bass Stack

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.

Pull the Treble knob for the Bright setting.

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/Mid Stack

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

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

Towards the jack for active, the opposite for passive.