Fine instruments though the Pro Series Wals were Ian and Pete were not content to rest on their laurels – still eager to fulfill their vision of the perfect bass guitar.  This took a step forward in 1981 as the Pro series basses were phased out and replaced by the “Custom Series” – the staple Wal range (with some tweaks and additions along the way) to this day.  In this transition phase a number of basses were built with "Pro bass" serial numbers (starting with PB) which were to all intents and purposes Wal "Custom Series" basses.  These Wal equivalents of the Fender "Nocaster" still cause confusion over the nature of the Pro series to this day!  The "last ever Pro" bass (PB1859), completed on March 28th 1981 was just such a transitional bass!  Subsequent basses started with a W serial number - presumably W1860.

The "Custom Series" dispensed with the Pro series' scratchplate - surface mounting the pickups and controls - and replaced a solid ash body with a mahogany body core faced with a selection of exotic woods.  As much as you can ever have a "standard" range with a builder which takes such a custom building approach as Wal, the standard woods used for the facings are paduak, wenge, American walnut or hydua/schedua.  Pete always reckons that for fretless basses walnut is the premium wood to use. 

The new neck were similar to the Pro series - 34"/864mm scale length and 21 frets but with a slimmer headstock allowing straight string bull over the nut.  Biggest change, however, was probably to the electronics.  The standard package was now twin pickups with a powerful active circuit offering volume, pickup pan and separate tone controls for each pickup.  The volume included a push/pull knob which also activates the "pick-attack" feature.  This adds a narrow band of high frequencies to the overall tone setting to provide a more dynamic. percussive attack - ideal for helping the bass cut through a muddy live mix.  The tones are low-pass shelving controls governing each pickup.  They also each have a push/pull switch which engages an active boost (quasi-parametric) giving a more distinctively "active" tone.  A balanced XLR output comes as standard on all "Custom series" basses.  A choice between chrome and gold hardware was now also available.

In March 1986 Wal introduced a 5-string bass with a 24 fret neck and a revised body shape (Mark II) which was also applied as an option to the 4-string basses. This Mark II body shape included  more asymmetric body horns with an extended upper horn.  This significantly increased the mass of the body.  In addition the included 24 frets and a revised headstock shape).

Tragically, Ian Waller died suddenly of a heart attack in 1988 and his passing was marked across the music industry.  Despite this irreplaceable loss, Pete Stevens was determined to carry on Ian's legacy and continue building world beating basses. 

Through the course of the 1980s, the Wal Custom became a staple of studios and stages throughout finding favour with artists as diverse as Paul McCartney, Dire Straits, Spandau Ballet, Mick Karn of Japan and Geddy Lee of Rush (at least two Wals even appeared on stage at "Live Aid" in Wembley Stadium in the hands of Martin Kemp of Spandau Ballet and John Illsley of Dire Straits).  The bass line on the original "Band Aid" single, "Do they know it's Christmas" (one of the biggest and most influential singles of all time) was powered by Wal.  By the end of that decade it was being considered by many as the "industry standard" for studio basses.

The original "Custom Series" design (Mark I) of four control electronics and a mahogany/exotic wood laminate body has since formed the template for all further developments and versions of the Wal Bass.

The Wal MIDI Bass.

An interesting aside in the history of the Wal bass it the MB4 midi-bass. In the mid 1980’s an Australian bass player called Steve Chick, frustrated with what was already on the market, decided to develop a working bass synth system which combined accurate note tracking with immediate sounding notes.  He hit on the perfect solution to solve the “midi delay” dilemma – the almost imperceptible (but still noticeable and distracting) delay caused by the time taken for the midi hex pick-up to sense the note being played.  His system did not rely fully on the hex pick-up for pitch information.  Instead, sensors were built into the frets (each of which was split into four separate pieces) to determine the basic pitch of the note.

Around 1990 the Wal MB4 Midi bass was launched to much acclaim - mostly because it actually worked without the delay which had plagued other midi-bass systems.  Unfortunately, after only a few years, the rights to Chick's midi-bass was bought up by US guitar giant Peavey for the development of their Midibase and then Cyber-bass.  This brought an end to the production of the Wal MB4 midi-bass. These remain sought after items on the second hand market.