Warwick Thumb BO Four-String Bass review

An unsung bass classic finally gets some acknowledgement

  • £1959
  • $3500
The Thumb BO has endured, while graphite models have waned in popularity.

MusicRadar Verdict

A stunning and unique instrument that really needs to be tried before you can fully appreciate what it can do? A classic bass? We think so.


  • +

    Ergonomic, down-sized body. Throaty, rasping tones. Punchy delivery. Excellent quality build.


  • -

    The price used to be an issue, but thanks to this new construction there is little to fault now.

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Launched at a time when graphite was considered the bass material of choice, Warwick's exotic, all-wood Thumb bass was seen by some to be totally dead in the water from the outset.

Strange then that 25 years later, not only is the Thumb still very much in the running, it has become something of a classic, while those fibrous fancies have waned in popularity.

"In spite of the full scale length and small body, this is a beautifully balanced bass that begs to be played."

A review of the latest Thumb BO (Bolt- On) will show why these basses are still very much appreciated, but when it comes to analysing what happened to the graphite phenomenon, well, that can wait for another day.

The initial neck-through-body construction and hand-finishing processes used on the early Thumb bass made it a prohibitively expensive instrument for many, but with the introduction of the bolt-on alternative, costs have been modified so that more players can enjoy the experience.

But like any Warwick bass this has a very organic and tactile quality that is delightful to the touch. And there is an added ergonomic element here coming from the curved and downsized body that fits so snugly into the player. Being both practical and comfortable, it soon has player and instrument working as one.


Despite its bolt-on nature this is also still a solidly constructed instrument, and where the neck joins the body there is a whole area of the concave back shaved down to make upper fret access even easier than on a regular reduced heel design.

In spite of the full scale length and small body this is a beautifully balanced bass that positively begs to be played.

Along with the natural wood construction comes a set of active electronics to support the trademark sound of the Thumb, which is known for its clear punchy attack and full-blooded mid-range.


All Warwick basses have the ability to excel in both throaty tonal qualities and sound projection but this fully active circuit takes those elements to a higher level.

This tonal slant is usually associated with good use of middle frequencies, yet interestingly this doesn't come from a dedicated onboard middle control, but rather from the blending of the pickups.

This is never an exact science, but the Thumb operates within tight parameters with plenty of options as you alter the blend, so finding the tone you want soon becomes second nature.

Fitted with a brace of active MEC J-style pickups and associated two-way electronics it packs plenty of wallop over that tasty tonal spectrum. It has a distinctive growling character with great low end but remains clear and well defined in action and packs a mighty punch.

The dual stacked bass and treble controls work from centre detents, as does the blend control, so touch reference is easy. Although there is plenty of variation on offer, pull up the volume control and you defeat the active circuit to unleash a second sweep of passive sounds.

This sound is considerably tighter and cleaner and relies totally on the blend control and physical pickup positioning to vary the tone. It allows the natural sound of the bass to emerge and the lower output reveals some lovely funky hollows so is ideal for studio use.

The Thumb bass is something of an unsung classic, and could perhaps be considered the PRS Custom of the bass world. It certainly has that exclusive quality about it, yet in this more cost effective - albeit still pro - bolt-on guise it has become more attainable.

It's one of the most compact full-scale basses ever produced and still feels like a hand-built instrument in every respect.

With an abundance of presence and attack added to that bottom-end growl, it's no wonder that Warwick basses are so loved by metallers and funkists.

Yet a bass as good as this can be whatever you desire it to be - it's all down to your imagination and flair, so make sure you try one. But beware, the more you play it the more you'll want it.