Wal Basses
Electronics Features
4 string Mk1 American Walnut facingsWal flat response, humbucking pick-ups; moulded in black A.B.S. with three point spring mounted height adjustment for four string basses and epoxy potted four point spring mount height adjustment for five and six string models.

These pick-ups contain individual matched pick-ups for each string, thus eliminating imbalances, crosstalk and intermodulation. Plated pole-pieces are adjustable with a 1/16th” socket hex driver provided.

Wal printed circuit electronic modules use high stability, closest tolerance components and graphite wiper pots, with push/pull gold contact switches. All controls are designed for ultra low noise, interference and distortion-free performance. Powered by a single 9-volt battery.

Balanced DI and transformer isolation provides clean, reliable and safe studio or stage or stage mixer feed without the need for an external DI box.

Standard ¼ “jack output for amplifier feed. Insertion into this socket switches on electronics. A dummy or unconnected jack plug MUST be inserted when using DI output alone.

Pick-ups, P.C. Modules and output sockets are all interconnected via shake proof, polarized connectors for easy removal and replacement. All cavities are screened against external electrical interference.

Control Functions
Volume Knob: rotary adjustment of output volume, pull to actuate pick-attack. A narrow band of high frequencies is added to the overall tone-setting to provide dynamic, percussive attack.

Both overall output level and pick-attack level are trimmable from inside the bass.

Pick-up Mixing Knob:- This silently mixes the levels of the pre-EQ’d pick-ups to any desire ratio whilst keeping the combined output level constant.

Tone-Knobs:- These operate electronic, low pass filters whose roll-off frequencies vary with the position of the control. Fully clockwise at 10, the spectrum is full and flat. As the controls are backed off, the spectrums of the appropriate pick-ups are foreshortened. (Roll-off 12dB/Octave).

The dominant tone character varies, therefore, throughout the entire range of control. Pulling-up the knob produces a quasi-parametric boost of about 10dB to the harmonics which lie at or near the roll-off frequency set by the rotary position.

This provides the characteristic ‘active’ sounds so popular today, without the clinical quality common to many circuits. By using the pan mixer like a master tone control, in conjunction with the pick-up controls, an endless range of subtle tones and dynamic effects can be created, with or without the pick attack. On left-hand models all rotary functions are reversed to right-hand.
4 string Maple electronics cavity1) Jack output: switches battery on as jack is inserted.

2) 600 ohms balanced line output.

3) Trim pot: adjustment for cutting low bass frequencies for each pickup. Mainly relevant to 5-string basses with low ‘B’ strings.

4) Trim pot: level adjustment for pick attack, set halfway for normal level.

5) Master volume control: normally set a maximum. Should less output be required reduce as appropriate, e.g. when using some makes of radio transmitter or when encountering amplifier overload problems.

Note: trim pot function direction changed in the late 80’s from fully clockwise adjustment being maximum to fully anticlockwise for maximum (late 80’s to current day). To double check, adjust master volume trim pot fully to determine direction of all trim pots.