Direct Drive for Dummies - the Langer No.7 Turntable Drive Kit

Or – How to turn a plank into a High-End turntable...

Langer No7 set
[Italian version here]

Product: Langer No.7 Direct Drive turntable DIY-Set “Premium IV”
Manufacturer: Langer Audio See also Germany
Cost, approx: 3500 Euro (inc German taxes) (YMMV)
Reviewer: Geoff Husband - TNT France
Reviewed: September, 2015


The phrase There are more ways than one to skin a cat could have been invented to describe the art of getting music from the tiny grooves of an LP record. You don't need me to list the huge variation in plinths, suspensions and of course philosophy courses that come with each one. But nothing so splits the turntable community as the choice of mechanism to actually spin the disc at 33.33 rpm.

So forgive me a diversion from what should be a review – to a brief summary as to why manufacturers persist in the direct-drive concept.

A given is that accuracy of speed is essential. The pitch of music demands that the platter spins at 33 1/3 rpm – something that is not as easy as it sounds;-) Lets say you have a classic belt driven platter powered by a mains-referenced AC motor (50 or 60 Hz) – this being the most common solution. Where are the potential errors and problems.

1 – the mains frequency of 50 Hz. This dictates the speed that a motor spins – and typically this frequency varies by around +/- 1% (see - something of no significance to your washing machine but noticeable in a turntable. The solution is to provide a synthesised 50 Hz (essentially an amplifier producing a 50 Hz tone from a quartz clock regulator) – attractive but rarely with the 'heft' of direct mains to offer massive torque.

2 – belt slip and bounce. There are many different belt materials out there - rubber, kevlar, fishing-line, silicone etc. The elastic belts offer better isolation from the motor and often good grip on the pulley at the cost of 'bouncing' i.e. stretching and contracting to cause medium term speed variations – especially after start-up or transient-induced drag. Very stiff belts still bounce (at a higher frequency) are more stable but are more likely to slip under load. There is no perfect solution.

3 – The belt inevitably pulls the platter to one side – thus loading the bearing unevenly and meaning the bearing has to be bigger/draggier and potentially noisier than otherwise. Opposing pulleys or multiple motors can obviate this but at the cost of another set of spinning bearings and rotors and the potential noise they inevitably bring. On a solid turntable this is a problem, but on a suspended turntable with the motor off the chassis (e.g. Linn LP12) the effects of the belt on symmetrical and consistent suspension movement is massive and very difficult to resolve – solve this by moving the motor onto the chassis and you are no longer insulating the platter from the motor...

4 – machining variations in the diameter of the motor and platter pulleys, and belt diameter (where the belt runs in a groove), inevitably mean that getting a platter to run at exactly 33 1/3 is almost impossible unless you use a synthesised power supply which can be varied to allow fine speed adjustment. And of course things like temperature may mean this needs regular tweaking... More to the point any slight eccentricity in any rotating part will cause flutter or wow and I've had some very well reviewed turntables here that I've considered deeply flawed because of this.

And so the attraction of a direct-drive is obvious. By making – in effect – the platter and motor as one concentric unit you only have one bearing instead of two (one for the platter, one for the motor), that bearing is perfectly balanced and always evenly loaded, no spring or slip in the drive-belt, a chassis and suspension free of torque reaction and because of the lack of slip and parasitic effects a powerful motor can be used giving very quick start-up and big torque reserves. Lastly the slow turning of the motor won't develop resonance and vibration well into the audio-band as does a fast spinning motor.

Game-set-and-match to the direct-drive, and why in the 70's the big Japanese companies invested millions in producing high-end direct-drive turntables. Most small European/US specialists didn't have the resources to compete head-to-head in such development and so almost all stuck with belt-drive and widely available AC (and later DC) motors.

But it didn't quite work out as you'd expect. Over the following years the consensus opinion was that direct-drives were fundamentally flawed – to the point where the Japanese competition were looked down on as being technology for technology's sake.

So why not? Well take an AC motor – just a small one – and run it in your hands and you'll feel the vibration – caused by the motor 'cogging' or accelerating and decelerating as the coils move over the magnets. More coils, better power supplies, changes like 'Hall-Effect' motors and the like reduce this but the feeling was that the 'flutter' (relatively high frequency speed variations) and the fact that the motor noise was right 'there' directly driving the platter heavily compromised the performance and made many consider it a flawed concept. And then there was speed stability. Proponents of belt-drive pointed out that many direct-drive units (and many were cheap) would 'hunt' as their speed regulation would allow speed to go above 33 1/3, then overcorrect to below that speed, then correct again – much better to have a big heavy platter driven by a rapidly spinning motor via a belt – QED.

Looking back was some of this down to prejudice? The cheap versions of the technology inadvertently damning the hi-end implementation? The domination of the Hi-Fi press by very vocal Western hi-fi specialists? Or perhaps the fact that many of these Japanese decks were equipped (burdened?) with equally highly complex and often automatic arms?

Some evidence is to be seen in the second-hand market, where many of these Japanese 'dinosaurs' are starting to fetch serious money, often to be partnered with modern arms, with different plinths and with far more sophisticated power supplies. A quick look on Ebay shows mint Direct Drive turntables like the Technics SP10 fetching over 3000 Euro and modified units even more. A direct parallel can be drawn with the much derided, and now sought after idler-drive turntables...

So with 20+ year-old direct-drive turntables fetching serious money there comes a point where there has to be interest in producing a new direct-drive turntable – and personally I was both pleased and excited to try one of this rare breed – the Langer Direct Drive unit.

Langer have produced a nice looking turntable which I have no doubt is very well engineered (at around 6000 Euro). But I wanted to do something a little different because Langer also offer a complete motor/control unit kit and at 3500 Euro (inc VAT) is priced pretty near some 20+ year-old 'classic' direct-drives on the market. For those looking for less 'drop-in' solutions there are various cheaper combinations of motor, platter electronics etc.

The kit comes in essentially 3 parts. The motor/bearing/subplatter all assembled and ready to go complete with wiring, the anodised 3 kg aluminium platter and the off-board power supply in it's neat alloy box. Drop the motor into a plinth, plug in the wires, drop the platter on-top and go – I'm sure in a competition it would be possible to build a working turntable in under an hour. The motor unit is very compact and neat and just drops into a hole you cut in the plinth. It consists of a brushless Hall-effect motor with opto-electric feedback designed to provide healthy torque at start-up and then just a gentle top-up as needed. The power supply has buttons for on/off, 33 1/3 and 45 rpm and a couple of screw type speed adjusters on top – these were not needed. To quote from the Langer website

“As the motor bearing is also the platter bearing, we spent special attention on its design. The radial force is carried by a precision sinter metal bearing. For the axial forces, we spent the motor a bearing bottom out of polyamide (sic). This design guarantees very low noise movement and high precision bearing gap, combined with long life”

As the bearing - unlike most designs - doesn't have to deal with significant lateral forces, it's very short length compared to conventional turntables is acceptable and helps the compact nature of the unit.

Doing it on the cheap :-)

Although the choice of building a DIY turntable from the kit is very interesting for the reader, it inevitably compromises the review as far as sound-quality is concerned and for that I apologise to Langer at the outset. My aim was to build up a working turntable but the kit had to be returned, and the resultant turntable effectively scrapped at the end. Was I going to spend a few hundred hours and several hundred Euro on something that was going to be useless to me? No. If there's a rich millionaire out there happy to bankroll me playing with sophisticated plinths for the readership of TNT then I'd like to hear from him, but Lucio isn't that person;-)

So the design brief was to make something cheap and dirty – cosmetics were a zero priority, but that didn't mean that I would ignore certain principles, and simple is often better so let's give it a go ;-)

Building the plinth

With a tight budget and limited time the obvious route to take was a solid plinth. As with many manufacturers, the ease of working and consistency made some form of wood the natural choice. Of course the go-to option would be to use MDF – a plinth made of say 3x18mm slabs of same - glued, or screwed, or bolted together (each different sonically) perhaps layered with some damping material would be a great option but in my workshop there just happened to be a slab of hardwood left over from a worktop project. Weighing over 10 kgs the thought that it might actually look good too made it my choice. I gave it a few taps and it seemed pretty 'dead' – certainly better than many MDF plinths I've had here and so why not;-)

First job was simply to mark out the position of the motor unit and arm – a 5 minute job – then just route out the two holes with a hole drilled for the take-out wires. Total time 1 hour. The Langer unit helps by being incredibly compact and neat, and the off-board power supply meant no need for holes for switches etc.

Langer No7 bare board

Now to what I think is one of the most neglected parts of turntable design – balance. I guess 90% of commercial turntables have four feet. Why? If you have four feet, especially if they are adjustable, you inevitably have each foot carrying a different weight – frequently one of the four will carry virtually nothing. If you are using compliant/sprung feet then the bounce frequency of the four will be utterly different – it's madness. With three feet the load is spread, each foot will carry a substantial amount, but with 10 minutes work you can make sure that each foot carries EXACTLY the same amount – it doesn't need some magic formula or complex measuring devices – just a ruler, a pencil, a protractor and a bit of wood with a nail in it:-)

[Find Centre of Gravity]

Look at the picture below. What I've done is placed the motor unit into its position on the plinth. I've then taken the weight of the chosen arm and filled a glass with water to exactly that weight (much easier than faffing about taking arms on and off). Now take your piece of wood with the spike on it and try to find the point where the turntable balances on that point - it's quite easy.

Finding the balance

When you've found that point just press down hard and the point will make a deep mark in the base – this is exactly the Centre of Gravity (C of G). Remove the motor and glass and turn the plinth over now draw 3 straight lines from the centre each 120 degrees apart. Your feet will now go on those lines, each the same distance from the C of G and will inevitably carry exactly the same weight.

finding foot position

You can have them as close to, or as far from the centre point but as long as they are equidistant they will always carry the same weight. In my case I used foam blocks as feet, but spikes or domes would be worth trying and of course you can position them to match your turntable support – the wider apart the more stable but any reasonable distance will do.


All that then remained was to screw the motor unit it and fit the arm. I used an RB300 and also a new arm from Sibatech just to give some variety. The included one-piece platter is beautifully machined from a single aluminium casting then anodised and topped with a thick rubber mat – something it needs as the platter rings like a Tibetan singing bowl (quite beautiful but I'm not sure it's ideal!).

Motor fitted

Is this a high-end plinth? No. But it is simple, avoids some basic errors of more complex plinths and much to my surprise it looked really good in the flesh – the contrast between the raw wood and the high-tech arm/platter working far better than I had any reason to expect;-)

In operation

The motor unit comes complete with an off-board power unit and as well as offering both 33 1/3 and 45 rpm this also allows for fine speed adjustment. This was pre-set at the factory and tested with both a strobe and the Feickhert adjust+ showed perfect 33 1/3 and 45 rpm with an excellent wow-and-flutter figure of 0.03%. Very unscientifically I placed my ear hard against the plinth and listened while the motor turned and heard absolute silence. Very, very few turntables pass this test and listening to a disc with unmodulated groove confirmed this. This is a major victory for the Langer - dismissing a couple of the 'problems' associated with direct-drives. Start-up was very fast and operationally the unit was faultless for the 6 week review period.

Sound quality

And now the caveats – not of the motor performance, but the limitations of this review. What I have reviewed is unique – you can't buy one and even if you copied my design you'd inevitably have major differences. The plinth is the simplest possible and though it might turn out to be the best possible it's far more likely to be the base standard of a very wide range of abilities with ever more sophisticated plinth designs. Therefore for me to say 'it doesn't soundstage as well as the Blackbird' is just stupid and misleading – with the right plinth it might be the best turntable in the world – I have no way of knowing. Want I can do is to try and identify what the turntable is getting right, and some limited discussion on how it reacts to different arms – any more would be worthless speculation on my part.

So – the fact that it is an extremely pitch-stable and quiet drive-unit is a given – it's world class. The platter showed no visible run-out, the engineering is superb.

For the review I used two very different arms - the Rega RB 300 and the Sibatech Abis SA 1.2 which were both fitted with the excellent Dynavector 20x2 – which seemed to match each admirably - but the reason for using two such different arms was to see if the turntable (and remember the Langer part will only provide some of the signature) was capable of distinguishing between the arms, or whether it's own character dominated proceedings to the point where you were listening to a turntable rather than a combination of turntable, arm and cartridge. It was the only way to have some guide as the the performance of the unit in isolation. In this respect the experiment was wholly successful.

Firstly I was pleased to note that my 'breadboard' plinth resisted feedback rather well and helped both arms produce a relatively uncoloured view of events. I found no evidence of motor breakthrough (very few even high-end turntables are totally silent) and playing a bit of Thelonius Monk's piano proved good pitch stability far better than any meansurement.


I have a full review of the Sibatech to come, but the difference between the arms was clear. 'My' turntable clearly showed the strengths and weaknesses of both. Firstly the Sibatech is an arm that uses the now obsolescent SME headshell mount, and as in common with most of the breed I found the arm a little bandwidth limited. Yes the bass was deep and reasonably tuneful, but there was a woolliness to it that if the RB 300 hadn't proved so good in this respect I could have blamed on the turntable. The RB 300 is of course an excellent budget arm and something with a reputation as a giant-killer, and here the clean, fast bass worked well and this solid foundation to music is most generally an attribute of a good turntable – so what I can say was that the Langer wasn't screwing up;-) At the top end again the RB 300 showed it's class with fine attack and decay of things like crash cymbals, the retrieval of leading edges in electric guitar etc. Again the Sibatech trailed noticeably sounding a little soft and rounded, lacking some of the ambiance of discs that that pull this off. Where the Sibatech scored was in a mellifluous midband and smooth, controlled reproduction of where most of the music resides – somewhere between 200 and 3000 Hz. Here the RB 300 ended up sounding just a bit grey and mechanical next to the more organic and powerful Sibatech.


These differences were all plain to hear (often from the next room) showing a pretty transparent turntable, and all the while the combinations – both of them – avoided the dreaded bloom or overhang that lesser turntables can exhibit – in particular with female vocal like Nina Simone or Mary-Chapin Carpenter which can wind-up many systems. I did try replacing the rubber with an acrylic mat topped with leather but the differences were marginal.

The bottom line here is that the overall performance of my 'bread-board' turntable was perfectly competitive against other turntables of a similar cost. What it doesn't show is the possible heights that could be scaled by a more sophisticated plinth or better/different arm combination – however I'd be very surprised if there was not a lot more to come from the Langer with a bit more time and effort expended...

But why is this such an exciting product? Because it brings so many possibilities to the DIY builder. The unit is so compact that it can be fitted into all sorts of places – a beautiful old radiogram, hidden behind a painting, built into a windowsill etc. It also allows any designer great freedom to produce plinths without having to consider the parasitic effects produced by an elastic-band tugging at the platter and taking up loads of space – or the problems of isolating such a motor – with the Langer the motor is just 'there' – you can't do anything about it so can concentrate on other things. With a conventional design every change you make will have knock-on effects to the drive system and so added variables make the whole design process more complex. I had visions of using car brake disks and drums, old tree stumps, exotic tripod-mounted and spring carbon-fibre creations, sitting on the top of a V8 engine, in the centre of an antique mill-stone, raiding a graveyard for a tombstone... Perhaps I had a lucky escape...

The limitations are few and primarily concern the choice of platter. The supplied metal platter is a very nicely built piece of kit and matches well, but because of the very short bearing I'd be loath to balance a large heavy platter on top of it – even though the motor plainly has the torque to deal with it. If you do want a more substantial platter then my advice would be that it would have to be underslung with the C of G somewhere co-incident, or maybe below the bearing – in fact I have visions of doing a rather sexy design using an old Gyro platter;-)

The one snag is the price – 3500 Euro is a lot of money - but a complete turntable can be built (as I've shown) in an afternoon for 3510 Euro;-) I felt immense frustration in not being able to spend time and money on producing something really special using the motor but hey-ho – that's just how it had to be. But there is a postscript. Alfred Langer started on this quest for the perfect direct-drive when he bought up the remaining stocks of the Dual direct-drive motor and offered them to DIY builders*. Whilst the Langer Drive has taken much of his time he still offers these kits including power supplies and mounting plates and so you can start your Odyssey for considerably less – and I just happen to have one of these kits here – watch this space;-)

*Alfred Langer's Dual site is a place of wonder -

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