A couple of years back, at the annual wet Welsh weekend that is the Green Man festival, I stumbled drunkenly into a half-empty marquee just as San Francisco psych-rockers Wooden Shjips were taking to the stage. I had come looking forward to Animal Collective, Grizzly Bear, Wilco and Four Tet and to be honest although I had heard of Wooden Shjips, for some reason I had them down as yet another uninspired garage band and had never really given them any attention. How wrong I was. Their forty-minute set was one of the best shows I have ever witnessed, leaving the weekend's big name headliners trailing in their dust.

On the Sunday night, having decided against spending another freezing night in a leaking tent, we set off home after the last band; my exhausted companions soon fell asleep while I, sober as a judge and dosed to the eyeballs on caffeine pills, tried not to fall asleep at the wheel. I had bought a copy of the latest Shjips CD, Dos, from the on-site Rough Trade shop and – figuring it to be good driving music – put it on and promptly zoned out. I don't recall anything else about that journey, but when I pulled up outside my house five hours later, the album was still playing.

Wooden Shjips guitarist Erik "Ripley" Johnson accounts for half of Moon Duo - the other half being his other half, Sanae Yamada - and despite the obvious difference in group dynamic (the Shjips are a quartet) the two bands sound very similar. On Mazes, their debut album proper (following a string of singles and an album-length EP, Escape, on the Woodsist label), Moon Duo replace live bass and drums with keyboards and primitive sampled beats, but have no problem weaving the same kind of hypnotic trance spell as their beefier big brother. Heavily indebted to the likes of original Krautrockers Neu! and pioneering electronic minimalists like Silver Apples and Suicide, both groups subscribe wholly to the theory that less is more; droning, repetitive two-chord riffs and sparse, propulsive drums, fleshed out with blistering electric guitar solos. Not a particularly original idea, admittedly, but one that has proven effective time and again, and while this kind of soaring psychedelia could have been made anytime over the last forty years, Ripley and Yamada attack it with enough passion to make it one of the year's most thrilling records so far.

In less capable hands, such a stripped-back approach could get old very quickly, but Moon Duo make a little go an awfully long way. Whilst earlier releases rarely deviated from the Wooden Shjips' formula of motorik rhythms and wind-tunnel guitars, Mazes offers a considerably wider stylistic range, from the Stooges stomp of opener 'Seer' to the title track's modish Booker T-isms and 'Run Around''s amphetamine-fuelled skiffle. The songs are cleaner, too, and more concise; no longer buried deep in the mix under layers of reverb and noise, you can actually make out Ripley's lyrics, and with most tracks clocking in at around the five minute mark, these jams never outstay their welcome.

It's Yamada, however, who proves to be Moon Duo's secret weapon, her bank of keyboard sounds and knack for an earworm riff providing the focal point for – amongst others - the album's strongest track, the haunted, droning dub skank of 'Scars'. Ultimately, while Mazes sees the pair rising above mere side-project status, they are clearly still the flip-side of the Wooden Shjips coin, but that is no bad thing. Yamada and Johnson's Bermuda Triangle trip might not be as direct or intense, but it's nevertheless one you'll want to take again and again.