Martin's Little Martin, its smallest-bodied guitar, comes in a variety of models, with either HPL or solid Sitka spruce tops, Stratabond laminate necks and Richlite fingerboards and bridges.

"The 'student' or 'travel' guitar has entered the spotlight in the past couple of years thanks to Ed Sheeran"

This 'student' or 'travel' guitar has entered the spotlight in the past couple of years thanks to Ed Sheeran - and, as a consequence, Martin has struggled to keep up with demand. But where Martin goes, Sigma will surely follow.

Once a Martin sub-brand, Sigma, while recently re-enlivened, is no longer affiliated with Martin. The company has nonetheless got in on the act with its TM-12 (solid spruce-topped) model. Cheaper, and made in China, it has an X-braced solid tops, dove-tailed mahogany neck, rosewood fingerboard and bridge, and laminated mahogany back and sides.

Dimensionally, the TM is a very close cousin to the Little Martins, with the same 584mm (23-inch) scale, 14 frets to the body, and a modified 0-14 shape. At this lowly price, the TM-12E is very nicely made, although the spruce top isn't the cleanest we've seen, and it's unbound - the edge appears to be stained like the laminate mahogany back and sides.

The neck, however, is solid wood with an additional heel block and head splice, and there's a very thin rosewood-like head facing. The 'board is a mid- brown rosewood, with nicely rounded edges and cleanly installed frets.

Obviously, in the hand, the neck feels small, but there's plenty of depth, so it doesn't feel ultra-skinny. It really isn't that narrow at the nut, with a 37mm (1.46-inch) string spacing, nor at the bridge, where the 54mm (2.13-inch) string spread is quite spacious.

Sounds

Compared to a full-size dreadnought, the TM-12E sounds pretty small. Ours also suffered from some setup buzzing. We also sampled the mahogany-topped option, the TM-15E, which plays more cleanly (although its frets lacked the mirror sheen of the spruce-topped guitar), and, to our ears, had a more credible voice: it brought a little strength to the unamp'd tonality, compared to the more open sound of the spruce guitar, with its slightly more crystalline highs.

"Played solo, you'll have your work cut out to create a big, rich sound"

Amp'd, the two options move further apart. The Isys T is a neat preamp with volume, an easy-to-read output-muting tuner, contour (a mid scoop with slight treble and bass enhancement) and phase, primarily for feedback rejection but also a subtle tone control when it comes to low-end. And low-end is all-important here, because the guitars themselves aren't giving us much.

That said, again, the mahogany TM-15E option certainly sounds bigger, with a stronger bass. Played solo, you'll have your work cut out to create a big, rich sound: with another guitarist, or tracking parts while recording, both work well.

For the money, this is a very tidily built electro-acoustic. Our advice would be to try a few before you buy, because our spruce and mahogany- topped samples sound and play quite differently.

The mahogany-topped option would be the one we'd pick, albeit with a quick fret polish: to our ears, it sounded more satisfying, both acoustically and amp'd. Of course, you might hear things differently.

But do you need a smaller- scaled 'travel' guitar? Hats off to Ed Sheeran, because, if we had a choice, we'd use a full-size instrument for solo performance or recording. For ensemble playing, however, there's validity to these mini guitars - a bright, bass-light voice that certainly cuts through, and even if you're not travelling, they are fun songwriting guitars.

Plus, if you have children, they're a good way to start them off. This TM is a solid, well-priced example of the mini genre, with classic Martin looks that actually make the Little Martins - or, indeed, the Taylor Babys - of this world look a little rudimentary.