The wonderful thing about turntables is that they inspire a wide variety of ideas about how best to go about the tricky job of extracting the vibrations from a vinyl groove. On the one hand they are pretty crude, all that’s required is to get the groove to rotate under the stylus at the right speed and allow that stylus to travel across the record unimpeded. This is why there are some very cheap record players available for the fashion conscious that while they are built to the lowest possible standard still manage to extract a signal from ‘vinyls’. But doing this job well is quite a challenge, very few turntables are close to being tonally neutral and there is an intrinsic problem with pick up arms that sweep across the record as the majority do. This is because tangential arms can only get the stylus exactly in line with the groove in two places on the record, in between and either side of those points the angle is slightly wrong and this introduces tracking error.
The parallel or linear tracking arm was created to get around this and has been around for decades in one form or another, usually exotic but occasionally down to earth, Technics made a lot of affordable parallel trackers in the ‘70s and ‘80s for instance. The difficulty with this approach is getting the cartridge to move smoothly across the vinyl, some use motors to achieve this and others such as Clearaudio have used rails but the air bearing approach has long been considered the best solution in high end circles. However, air bearing arms have traditionally been expensive to make and require an air pump to be active and getting one of these to be quiet enough is also an issue.
Holbo from Slovenia have not only put an airbearing arm on their Airbearing Turntable but also use air pressure to support the platter when it’s spinning. This has also been done before but is extremely rare presumably for the same reason as you don’t see airbearing arms; cost and pump noise. The benefit of this approach with the turntable itself is that you can spin a fairly high mass platter without having to support that mass on a spindle bearing, something that requires precision engineering to do without this interface introducing mechanical noise.
Unusually the Holbo turntable is delivered with its platter in place and there are no transit bolts to stop it moving. It relies on mass and the absence of a supporting bearing to keep it in place and this seems to work. It’s not until you connect up the airline and turn on the pump that it will spin. The arm is similarly disinclined to move along its airbearing shaft if there’s no air coming out of the invisible holes on its surface, and even then it needs to be clean. Apparently Holbo are making a cover for their turntable because dust is the enemy and if left for a few days the air shaft needs cleaning with a microfibre cloth to get the arm moving smoothly.
The arm itself is a slimline affair with an effective length of six inches and an effective mass of 7.5g which puts it into the low mass category of arms below 9g, which theoretically means that the arm is best suited to high compliance cartridges. Which excludes most modern moving coils, however Holbo’s Bostjan Holc tells me that it works with low compliance cartridges and that “All Koetsus from Black to Coralstone and also Denon DL103R play like violins”. Apparently SRA (stylus rake angle) and azimuth (the angle of the stylus in the groove when viewed from the front) are critical however.
It’s a fairly simple design with a carbon bonded aluminium tube, minimal headshell and relatively small hanging counterweight, the latter is adjusted by loosening the stainless weight and sliding it along the shaft. This makes setting downforce precisely a little tricky but it’s better than some, however the ease with which the cartridge is set up more than makes up for this. The beauty of a parallel tracker is that you don’t need to precisely align the cartridge in the headshell using a gauge because the stylus just needs to be in line with the arm and there’s no room to twist the cartridge in the headshell. You do however have to ensure that the stylus tracks the record in line with the centre spindle by using a supplied gauge and adjusting the distance to the airbearing.
Next you set VTA/SRA which is very easily done with the silver knob atop the arm base, and finally the angle of the airbearing shaft needs to be adjusted such that the cartridge slides toward the centre of the platter when there is little or no downforce, a hex bolt in the base allows a small amount of tilting adjustment. Azimuth can be adjusted by loosening a small screw in the arm mounting and carefully twisting the arm.
The platter is made of aluminium with a thick engineering plastic (Delrin or similar) top part and weighs five kilos, the motor is a DC type that drives the perimeter of the platter with a round section belt and speed can be changed with a switch on the back of the plinth. The power supply for for the motor and the compressed air pump are built into a single unit that has long (circa 4m) connections, in the case of the air this is a clear plastic tube of around 6mm diameter. The air pump is extremely quiet, so much so that it’s easy to forget to turn it off after you’ve stopped playing records, so when Holbo revised the turntable to MkII status they made the on/off switch for the platter do the same for the pump.
The Holbo has RCA phono sockets for the cartridge’s output which means you can use your preferred cables but does add a connection in the path of a very weak signal. I used Townshend Fractal interconnects and hooked them up to a Tom Evans Groove SRX Anniversary phono stage. I fitted a Transfiguration Proteus MC cartridge to the headshell and was glad to find that the cartridge tags are sprung, which means they aren’t too tight or too loose as can be the case with the standard connectors. The feet on the Holbo are metal and tipped with small spikes and initially I put them on the glass top of a Townshend stand, a few tracks later it became clear that this interface of hard materials was making the sound hard too, so some Blue Horizon spike receptors with cork bases were placed between the two and this smoothed things out nicely.
The music from records played thereafter had plenty of shape, power and strong vocal projection with deep bass revealed on many tracks and plenty of inner detail. John Martyn’s Solid Air was particularly good, with excellent scale and depth of image thanks to the strong reverb around the voice. The burred edge of Danny Thompson’s double bass was particularly well resolved as was the fluid keyboard sound which really shone, this is not just a good album musically but is a great recording and production too.
I got hold of an original pressing of Tom Waits’ fabulous Swordfishtrombones album and contrasted it with the Simply Vinyl re-release I’ve been listening to for some time now. The Holbo revealed the original to be more open with the voice much more in the spotlight, it sounds as if SV went for a thicker, plusher sound with the remaster in an attempt to make it sound sweeter but they smothered some of the magic in the process. The track 16 Shells from a 30.6 proved to be sheer joy, it’s energy was so inspiring that I just had to get up and leap around. The Holbo/Proteus combo is more than adequate to the task of revealing the nature of mastering variations and pointing out which ones are clearly best, and once again you can’t beat an original. Switching to something rather different in Chasing the Dragon’s direct to vinyl cut España with the mezzo soprano of Rosie Middleton it was good to hear it tracking the high energy of voice and the dynamics of the orchestra with ease. The only thing it didn’t like were any problems with the vinyl which were hard to ignore, this album has had a hammering but the Holbo is a bit more fussy about vinyl condition of than some.
When it comes to untangling complex music the Holbo is remarkably adept, even the discordant Tom Waits keyboard piece Dave the Butcher made musical sense, something it never does on digital and rarely achieves with vinyl. It can also do dramatic orchestral works a real favour, the Four Seasons may be overplayed but with this degree of coherence it remains powerful and inspiring. The woody tones of original instruments adding to the realism of the experience. I also started to appreciate Abdullah Ibrahim’s latest release Solotude, this didn’t grab me initially but this combination of turntable and cartridge brought out the melodic lines a treat in what must be his warmest recording in a long time.
The latest incarnation of the Holbo Airbearing Turntable, which added a clamp to the package, is very reasonably priced for what you get, which is a fully air powered design of the sort that very few make now or ever. It’s nicely put together and well built, all it really needs is a dust cover. The fact that it tracks the vinyl in the same way as the cutting head on a mastering lathe gives it a distinct advantage and one that the results live up to, I recommend you have a listen.