Moon Groove Master GM4 review

Vintage styling on a modern build – a winning combination? We investigate one of Japan's finest bass makers

Moon Groove Master GM4
(Image: © Future)

Guitar World Verdict

A solid performer, but you’d expect near-perfection at this price.


  • +

    Pleasing visuals.

  • +

    Standout tones.


  • -

    Headstock bias.

  • -

    Ineffective control pots.

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Known more for their connection with Larry Graham and his white Jazz Bass variant, Moon Guitars has been producing instruments for over 30 years. This example from its Groove Master range combines a package of classic looks and styling at a significant price. 

This model was custom-ordered, so personal modifications are possible should you wish to go down the custom route. Given that it tips a hat to the original ’51 Precision design, do we get more than vintage sounds?

Build Quality

Resplendent in a Magenta Mist gloss finish, the old-school visuals come thick and fast on this bass. The vintage Telecaster headstock design, original '50s body curves, three-ply dark tortoiseshell scratchplate, and chrome two-control plate all contribute to the vintage vibe. With contouring front and back, rolled fingerboard edges and an extensive lower cutaway, player comfort is clearly a priority.

Despite weighing in at 8.6 pounds, there is a slight balance issue, even on a strap – this headstock really wants to head south! However, a little player intervention keeps the neck, and the bass generally, at a comfortable angle. Thankfully, the neck is a joy to play, with a profile that sits somewhere between a shallow C-shaped profile and a slightly fatter than normal D-shape: either way, it works.

At 1.65”, the nut width suggests a broad fingerboard, yet the neck is unsurprisingly comfortable, due in no small part to the low-tension strings, the excellent setup and a high level of overall finishing, with no sharp fret ends either side of the fingerboard. Black dot markers appear on the front and side facings, Oxalis pickups have been used in a P/J configuration, and black hardware has been incorporated, including reverse open-gear machine-heads.

Moon Groove Master GM4

(Image credit: Future)

Sounds and Playability

Acoustically, the bass exhibits a very noticeable sustain and a strong resonance, suggesting a bright tonal response may be the order of the day. Plugging in confirms this: fans of Graham will be pleased to hear that the slap tone is punchy, with every nuance standing out. Panning between each pickup highlights the tones you would expect from a split-coil and a single-coil unit in their respective positions.

Whether you seek clarity and honk from the bridge pickup, or a solid low-mid thump from the neck unit, you’ll easily find those tones. The bass is set up with two stacked volume controls and a separate tone control – sadly, these are very much of the on/off variety, with little steady change between the two extremes of each control.

Moon Groove Master GM4

(Image credit: Future)

This is a shame: you would expect this sort of thing to have been addressed on a bass at this price. However, the available tones are impressive enough, and the Groove Master will happily accommodate any playing style you wish to employ. 

The slap tones have character and clarity, while the fingerstyle tone is full and slippery, and the pick tone has an impressive, grinding quality. Open up the tone control fully and a throaty, raucous sound is all yours.

Despite the headstock bias, playability and comfort have been addressed to the player’s benefit. The body sits perfectly, offering assurance that this is a bass to be played, as well as offering a fine vintage visual. The neck is a player’s dream, and in a world where sub-19mm string spacing is all the rage, this is one occasion where 19mm feels just right.

Moon Groove Master GM4

(Image credit: Future)


This is a fine bass with a lot going for it, but it could be better with a few tweaks. Maybe this bass was specced with this control set – it was a custom order, after all – but at this point in bass history, the volume and tone controls really should work across the whole turn. Still, the tones on offer are very impressive, and overall, this is a very playable instrument. 


  • PRICE: $2,800
  • MADE IN: Japan
  • COLOR: Magenta mist, gloss fi nish
  • BODY: Alder
  • NECK: Maple, 34” scale, gloss fi nish
  • NECK JOINT: Bolt-on, four bolts
  • NUT WIDTH: 42mm
  • FRETS: 22
  • PICKUPS: Oxalis split-coil and single coil pickups (P/J setup)
  • ELECTRONICS: Passive
  • CONTROLS: Volume/volume (stacked), tone
  • HARDWARE: Black hardware, standard bridge, open-gear machine heads
  • WEIGHT: 8.6 lbs
  • CASE/GIG-BAG INCLUDED: Moon gigbag
  • LEFT-HANDED OPTION: Yes, as a custom order
  • CONTACT: Moon

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