Nordost QBASE QB6 Mark III mains distribution block

REVIEW
Steve Dickinson
Apr 16, 2025

Whether you view the mains block as a functional accessory or a fundamental cornerstone of a system determines your approach to its price. I’m firmly in Camp Cornerstone, but with a clear caveat – price doesn’t always reflect performance. I’ve been using the Mark II version of Nordost’s QBASE QB6 mains block, which back in the day cost around £1,600, for several years now. It’s the version with six UK-spec mains sockets instead of the eight Schuko fittings on the European-spec QB8. It’s been a stable and stabilising part of my system since it arrived because very few main blocks have come my way which get close to its performance, and fewer still challenge it, regardless of price.

Now, Nordost has released the Mark III version of the QBASE QB6 (and the QB4 and QB8 versions for the markets which use US, EU or Australian-type mains connectors). The main visual difference is that the Mark III’s aluminium end caps are now anodised black rather than the plain silver finish of the Mark II. It’s just a stylistic change rather than a functional one, but it does help to distinguish a Mark III from a Mark II visually. The configuration and shape of the QBASE QB6 is essentially unchanged (but watch out if you are swapping these out because the position of the ‘Primary Earth’ socket, whose earth connection is configured to a lower impedance than all the other sockets, has moved). The slim, rectangular shape, as well as being practical and easy to site, continues to reflect Nordost’s thinking on the mechanical tuning of the casework partly by the proportions of the case itself, the better to manage vibrational effects.

However, there are functional changes under the skin and one other external change, which I’ll get to shortly. The ‘Primary Earth’ socket remains with its lower impedance earth connection, but Nordost has also paid some attention to the earth paths within the unit. It’s still a star earth topology, but the internal traces for positive and negative are now physically separated from the earth, which now runs along the opposite side of the internal board (whereas in Mark II, they all ran alongside each other), to minimise noise from the live side being picked up on the earth. This, together with changes to the impedance of the lifted earths on all but the Primary Earth socket, is said to improve separation between all sockets and deter crosstalk between sockets via the earth paths. The PCB traces have also been beefed up to reduce impedance and improve current handling capability. The external earth socket, which is used for easy connection to Nordost’s QKORE grounding units, remains.

A base for your QBASE

The other external change is that Nordost now provides a pair of neat aluminium brackets, which can be bolted onto the underside of the unit via the fixings used for the rubber feet. Unscrew each pair of feet, offer up the bracket and attach using the machine screws that held the feet in place. The brackets then cradle the QBASE unit and permit it to be seated securely on a quartet of Nordost’s own Sort Kones (or, for that matter, any number of aftermarket cone-type equipment supports) rather than sitting directly on the floor. This isn’t just an opportunity to flog more Sort Kones, either; I’d go so far as to say that you’re unlikely to realise the full potential of Mark III’s performance unless you address how it is supported.

You don’t know what you’ve got till it’s gone

I wasn’t unhappy with the performance of my old Mark II unit until approximately 30 seconds after I’d installed the Mark III. It turns out that everything was subtly averaged out via the Mark II, an effect not unlike the music being gently compressed. To be clear, most mains blocks I have heard do this to an extent, and the QBASE Mark II does it somewhat less than most. Until the Mark III came along, the effect did not draw attention to itself, and I would have described the noise performance as one of the strengths of the old Nordost block, which has always seemed to draw out more vibrancy and energy than most rival units.

Take ‘Lisboa’ from The Absence by Melody Gardot (Decca). By comparison, the Mark II version sounds slightly airbrushed; via the Mark III textures gain definition and focus, the clock bells that open the piece are more clearly defined, and their pitch is better expressed – more obviously a melodic peal – this is not mere background colour, it’s contributing to the mood. A slight, and previously unremarked bloom in the bass has been addressed by better separation of all the individual musical elements, the bass doesn’t bleed into the overall presentation to anything like the same extent.

‘Amalia’, from the same album, now there’s more texture and body to Ms Gardot’s voice, the better to appreciate the intimacy in the music; the band has a pleasing jauntiness, the guitar accompaniment in particular, assumes a more important role in proceedings. It seems the attention given to the earth paths has been highly effective in reducing the parasitic effects of earth-borne noise, letting all the separate elements in the music occupy their own space, and time. The old Mark II already outperforms most mains blocks I’ve encountered, so it’s been illuminating to discover how much more performance there is for the asking.

And that’s with the Mark III resting on the floor, as my old block had done. Time for some Sort Kones. Covered amply in these pages before so that I won’t dwell on the construction, but these come in various flavours; I already had a set of the entry-level AC Kones (aluminium post and base, ceramic ball), and Nordost kindly sent me a set of the intermediate BC (bronze post and base) Kones to try with the Mark III. The AC Kones undoubtedly moved things further in the right direction, improving timing and revealing more textures in the notes.

Still, it wasn’t until I fitted the BC Kones that it was clear just how good the QBASE QB6 Mark III enabled the system to resolve and separate the individual parts and threads to the music. Take Stanley Clarke, and an old favourite like ‘Bass Folk Song No 10’ from The Stanley Clarke Band (Heads Up). With the QBASE QB6 Mark III on the BC Kones, the piece is an end-to-end funkfest; the inner harmonies have more colour, and the leading edges of notes are faster, cleaner and more tightly focussed. It’s easier to appreciate how he bends notes and plays with the timing, working with the percussion to create the funkiness. More information about his use of ornaments, string harmonics, and the textures and harmonies he creates. You can, of course, enjoy the music without all this extra information (as I have done with the QBASE QB6 Mark II), but even so, the additional performance available with the Mark III is somewhat more than just ‘nice to have’ and elevates familiar recordings to the level of ‘newly-discovered’ all over again.

You don’t need the Sort Kones to appreciate the benefits of the QBASE QB6 Mark III. The changes to the internal wiring arrangements bring their suite of improvements to the party, but the Sort Kones do help to wring out musically significant improvements that build on those new strengths and virtues. Given the ease of using the new brackets, it is worthwhile to think about the QBASE + Sort Kones as a system. In those terms, the additional cost of the BC Sort Kones adds about 30% to the price of the QBASE QB6 Mark III, but if what the Mark III brings to proceedings matters to you, it makes a lot of sense.

In recent years it has become increasingly obvious to many that proper attention to mains power distribution is fundamental to getting the best out of your hi-fi system. More recently, the harmful effects of earth-bound noise have become apparent as techniques for dealing with it have improved. The Nordost QBASE QB6 Mark III builds on the considerable strengths of the units that went before it, bringing significant benefits to timing and the resolution of fine but musically important detail. Used by itself, it offers a fundamentally secure basis for a high-performing setup. Still, in making it easy to use with adequate support and isolation products, Nordost has firmly put the performance of the Mark III in the top tier. It’s not an inexpensive solution, but if you consider it an upgrade to your sources and amplification, it’d be hard to get this much improvement for a similar outlay anywhere else.

Technical Specifications

Type: 6 outlet, unfiltered UK mains distribution block with earthing connector. Choice of 13-amp or 16 Amp IEC input.
Price: 13 Amp £2,300, 16 Amp £2,600
Eight socket QBASE QB8 Mark III available for US, EU, or AUS power sockets