Double Four bass combo

Setting a new mark in the ‘more decibels per kilogram’ arms race, this tiny 70W combo packs some staggeringly grown-up tone. Review by Gareth Morgan

The modern trend for downsizing and weight reduction in bass amps is something that should be applauded by bass players of all generations and all stylistic leanings – and Phil Jones Bass, alongside the likes of markbass, Genz Benz and euphonic audio, has been at the forefront of such developments with its Briefcase and Bass Cub models. PJB’s Double Four combo is the latest addition to this excellent line.

Built at PJB’s own factory in China, the Double Four is, in combo terms, tiny, standing 170mm high, 281mm wide and 204mm deep – or, in other words, about half the size of a compact microwave oven. Cushioned by a choice of two sets of rubber feet (you can stand it up like a computer tower), the cabinet is constructed from MDF, used for its extra density and reduced resonance compared to plywood. It’s coated in a hard epoxy coating (red, white or, for Ј20 less, black) and this, together with two PJB Neo Power type C 4” neodymium speakers, is the key to a paltry payload of 4.02kg (8.86lbs). Each speaker is powered by its own highly efficient Pulse Width Modulation (PWM) amplifier, a low-operating-temperature system that helps maintain a tight, punchy sound without muddiness or boom. Behind them PJB has fitted a Rectangular Auxiliary Low Frequency Radiator (RALFR) which only deals in the lowest frequencies and cuts the load on the 4” units, therefore improving efficiency and power handling. It also all amounts to a cone area greater than that of an 8” driver.

As well as a three-band EQ offering up to 18dB cut/boost, the control panel features a chrome selector switch for active/passive and global mute and an aux section with mini-jack in and level control for all your play-a-long needs. You also get a headphone mini-jack socket and a Line Out jack socket.


If you’re harbouring any preconceptions about the quality or size of tone you’ll get from this little belter, cast them adrift right now. And if you’re expecting ear-splitting volume and earth-shaking bass response, forget that too. But do expect a fully realised reproduction of your bass’s sound with the same qualities you’d expect from a bigger amp. Active bass players may not need recourse to the EQ so the key is a little care in setting the input level: flick it to High and start somewhere near 9 o’clock and, verily, your tone will be clean and natural-sounding, right down to the B string if fitted. The quality of sound is quite simply amazing.

If you do involve the EQ you’ll be staggered at how much low end that RALFR facility will reproduce – it’s like having a concealed extension cab. Boosting mid makes things punchy and refreshingly un-nasal, and pushing treble gets you cut and bite without increases in fret or finger noise.

Elsewhere, the Aux section with its level control works really well, giving a clean reproduction of backing tracks in whatever form you choose.


The fact that a combo as small as this can give you a clean, fully realised sound with real depth is brilliant; but the output level and quality of tone make it a quite simply amazing little unit. The RRP looks high but actually, when you compare it to similarly spec’d competition, it’s very reasonable – and while it doesn’t come loaded with effects, the Double Four’s combination of tonal quality and portability is unbeatable. Buy one now!

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