Mesa/Boogie M6 Carbine Combo bass amp review

The 600W M6 Carbine combo is hand-built in Petaluma, California from marine-grade birch plywood. It’s bulky – 761mm high, 546mm wide and 454mm deep – and hellish heavy at 43.6kg/96lbs, but it has two castors at the rear for tilt-and-roll operation. Phew.
The M6 has not one but two 300W neodymium-magnet 12″ speakers and an HF driver with a level attenuator. The control panel is simple and businesslike with Gain, which induces warm 12AX7 valve distortion furthest clockwise; Bass, shelved at 55Hz with a +/-20db pull feature; Mid (boost only); and Treble (+/- 20db from 723Hz upwards).

Mesa/Boogie M6 Carbine Combo bass

The Voice dial has five clickable midrange settings – extreme cut, gently scooped mids, two boosts, and a bypass. There’s a DI Level control (pull to bypass the preamp), an Active/Passive switch and, on the back panel, two speaker outs, an XLR DI Out, FX loop and Tuner Out jacks and sockets for the footswitch, which controls the Voice knob and muting, but costs extra.


There’s massive power waiting under the Carbines bonnet – and it’s not just volume. The bass response is frightening, especially in Deep mode, but with a natural warmth courtesy of the 12AX7. For most gigs you’ll never need to boost Bass unless you’re feeling sadistic towards the audience, but the M6 doesn’t sound woolly; there’s plenty of definition, and the Mid control can remove any slack in focus. Even though it’s boost-only, 12 o’clock on the Mid knob feels natural; add more and the M6 goes from classy punch to full-on aggression. Boosting Treble increases the bright harmonic content; adding the horn creates a thinner, more hi-fi top-end, but fret-noise is an issue.
The Voice dial’s settings 1 and 2 offer smoother, slightly less-defined starting points while 3 and 4 are all about attack and impact. Either might be useful as a quick tonal fix relating to the type of room you’re in or the stage you’re on.

Mesa/Boogie M6 Carbine Combo bass

M6 Carbine Combo

Description: Single channel 600W 2×12″ transistor/valve combo. PH Neo 300 12″ speakers and HF driver in a 22mm marine-grade birch cabinet with front porting. Made in USA
Price: £1599.99
Controls: Gain, Bass, Mid, Voice, Treble, DI Level and Master volume (pull for Mute) controls, Active/Passive switch. Two Speakon/jack speaker outs with Impedance switch, Input, Tuner Out, FX loop (with Effects Bypass switch) jack sockets, Mute and four Voice Function footswitch sockets, XLR DI Out with Ground Lift
Range Options: M6 Carbine head and rackmount head


There’s a feeling of solidity and dependability about the M6, from the build quality to the variety of sounds on offer. Admittedly it’s heavy and not inexpensive, but if you must have some form of quality valve element in your sound, these two elements are par for the course. It’s well worth a look.

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