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Acoustic Solid Solid Machine turntable

Heavy Metal

Product: 'Solid Machine' Turntable
Manufacturer: Acoustic Solid - Germany
UK Distributor - HiAudio
Price: approx 3000 Euro (YMMV)
Author: Geoff Husband - TNT France
Reviewed: March 2008

[Acoustic Solid machine turntable]
[Italian version]

Introduction

Of all the reviews I've done, this is the one which I've had the most guilt over, simply because this turntable has now been at my home for 12 months without a finger hitting the keyboard! But I do have excuses... How it got here was a little convoluted - I was reviewing the The Cartridge Man's Conductor arm and found it difficult to fit on my Opera turntable. This was down to my ineptitude, but Dr Hugh Unsworth of HiAudio, the UK distributor, said that he'd ask Acoustic Solid send the Solid Machine as it was the turntable they were pushing for sale with the Conductor. I like this because it removes a variable from the review. If the distributor recommends a certain turntable for an arm then if the review goes pear shaped they can hardly complain that there was an incompatibility somewhere. Other manufacturers please note that you'd have a happier reviewer if you supplied interconnects with CD players/amps etc and speaker cables with loudspeakers.

Anyway the turntable was used for the review and very well it did too. So I organised keeping the table for a little longer so that I could do a separate and fuller review of it alone. The turntable then developed a fault and so missed its slot whilst new parts were sent. Then time passed etc, and now I find myself embarrassed at the time it's taken to finally write this review - so apologies all round.

The turntable also arrived just as I'd abandoned my series of back-to-back turntable tests. Though a hugely worthwhile exercise for me I'd had to sell my Orbe/SME to raise cash at a difficult time, and the sheer time taken, and disruption to the system for each review made them impractical. So this review draws on my experience with that series, but inevitably will be more superficial - forgive me.

[Conductor + Solid]

Design and Construction

I've talked about the various advantages and disadvantages of different turntable philosophies in earlier reviews so I won't bore everyone with repeats, but suffice to say that the 'Machine' is very firmly in the solid plinth/high mass family. Its build is beautifully simple - a massive 15 kg platter CNC'd from a lump of proprietary Aluminium/Lead alloy. All the rest of the turntable is made up of the same stuff, all CNC'd and polished to within an inch of is life and then bolted together to produce a 30 kg turntable that still manages to be compact. The only adjustable part being massive Allen bolts inside each foot, that allow for levelling. Also supplied is a 600 grm puck machined from the same alloy and sporting a bubble level at its centre which is as useless for levelling the turntable as every other similar device I've used...

Drive is a simple synchronous motor set in its own polished pod and driving via fishing line. The power supply in my case was a basic wall-wart. And that is it - no philosophy course, no mumbo-jumbo, just a handful of big fat lumps of perfectly finished alloy bolted together and sold as a turntable:-)

Except for one thing -

The one USP (Unique Selling Point) of the Acoustic Solid range is the bearing. This consists of a conventional, and conventionally orientated, tool-steel bearing shaft with a ceramic ball glues to its end to act as the bearing surface itself. The trick bit is that the bearing sleeve is formed from a resin around the bearing shaft. I guess that basically the shaft is dipped into the gloop whilst still liquid and this then solidifies to form a perfect mould around the shaft. The idea being that clearance is vanishingly small assuming the resin doesn't contract, and of course the bearing is a perfect matched pair. The only snag that I could see with this is that the resin part will be a perfect match to the bearing shaft at-one-position-only, and thus its accuracy of fit, once rotated is wholly dependent on the accuracy of the machining of the bearing shaft itself. Obviously this bearing sleeve will have different properties re vibration transfer/noise etc than a conventional bearing.

In use this bearing seemed exceptionally smooth, though with 15 kg of platter it's hard to tell, though once spun up to 33 1/3 by hand, it would stop in 20 seconds. That's a very, very high friction figure. I know many will champion bearing drag/damping as a positive thing in damping short-term speed variation (the logic of the argument still escapes me), but there was no doubt that the motor was working pretty hard, getting hot, and that the string drive had to be bow-taught to drive it. That said the combination with the Conductor worked very well and led to a pretty positive review of that arm.

One thing did bother me though - when we'd been away for the weekend, and the room had got cold, the bearing seemed to tighten so much that the motor simply couldn't get it up to speed and hold it there (even with a helping push) until the room and that hunk of alloy had warmed up.

This bearing drag issue seemed to get worse, stripping cleaning and re-lubing the bearing seemed to help for a few days (the turntable I kept running permanently as with most such designs) then gradually I'd have to move the motor pod to make the string tighter and tighter until the motor was running very hot. Then after a cold snap the situation deteriorated to such an extent that the motor simply could no longer run the turntable. I'd been in contact with the distributor for some while about this and he'd mentioned that he had seen a couple with problems similar to mine but not as extreme, but at this point is was obvious that all was not well with the bearing and that a replacement would be supplied.

Imagine my surprise when the replacement turned out to be not a matched tool-steel/resin pair, but just a replacement sleeve with a more conventional bronze liner. There was no matching bearing shaft and so I just swapped the bearing housing (very easy), added a drop of oil and settled the old shaft into the new bearing.

Now considering that these were not a "matched pair" their fit was exceptional. The bearing took full 24 hours to settle completely even with the motor switched on, and that shows superb quality control at AS's end. Run-down time from 33 1/3 was now 75 seconds which was more typical.

This whole episode was a shame because in every other way the AS proved itself to be utterly simple and fool-proof in operation and though not a complex turntable, the fit and finish was beyond reproach. It always ran spot on 33 1/3 with no adjustment needed (very rare) and I was happy for my kids to use it - no more needs to be said on that! The new bearing has now run for 6 months without a hitch (one other reason for the delay as I wanted to make sure). Nothing is 100% perfect in this life, but its how the company responds to a problem with one of their products that is important - AS seemed to have performed admirably. Dr Unsworth has told me that for rooms that experience big temperature changes, this bronze bearing is probably the better choice (see manufacturers comment). However in the case of the test machine it was rather more than this as the bearing eventually became unusable regardless of temperature so I suspect some damage somewhere along the line. A quick internet search couldn't find any other reference to the problem so I'm happy to conclude that it was a one-off.

In Use

Well I supposed I've covered most of this already - you slot the thing together and go. I think it needs to be on all the time to stabilise bearing temperature but apart from that it's the easiest tt to use I've ever come across. It's possible to fit up to three arms to it by bolting extra armboards on, and it will happily cope with any arm, no matter how big, heavy or long.

Supplied with the turntable were two mats, one a sexy, red leather and the other a 5 mm thick slice of clear acrylic. I fiddled about with these and eventually settled on the leather on top of the plastic. These mats are necessary because despite what you might think, that 60 mm thick platter rings like a bell when struck, so the record needs to be isolated from this. I also tried the Funk-Firm Acromat and as well as being a perfect visual match it also worked at least as well as the supplied mats. However the Acromat does have a label cut-out which means that the puck cannot be used with it, turning the Acromat upside-down didn't help as then with a label the record centre could stand proud. As I preferred the sound with the puck I stuck to the standard issue.

Being a solid plinth design the turntable is especially sensitive to support and I struggled with this for some time. A plain MDF shelf exposed some upper bass bloom and swapping for various mid-mass turntable supports didn't help very much. In the end I regressed to an old favourite of mine, a slab of polished granite (old, reject grave-stone:-) sitting on those big bubble-wrap bubbles. This tightened up the mid bass and really let the whole combination sing, as the support cost a total of 15 Euro it's worth trying...

Sound

As previously mentioned the first arm on the AS was the Conductor, a pairing where the sculptural aspect of the AS made a fine visual match with the mechanical qualities of the Conductor. The result of this pairing can be read here so I won't repeat myself beyond saying that the Conductor, mounted on the AS was a formidable combination but also a characterful one. The phenomenal end-of-side performance, the low surface noise and the mid, and top-end detail you could put down to the arm, but the excellent pitch stability and tight, tuneful bass was down the AS.

To see what a more conventional arm could do I rigged up a Rega RB300, a combination that AS sell as a package, so again something that should work well. In comparison with the Conductor I got a heavier, darker presentation, with greater bass power and slightly better dynamics. Overall it wasn't a match for the Conductor's superb soundstaging and magical midrange detail and fluidity, but at a package price of just over 2000 it was a really impressive performance that would have graced a megabuck system.

Lastly I bolted up another oddball arm in the shape of my Dynavector 507, this time sporting the hugely expensive DRT-1s. This filled in much of the missing bass power and showed better dynamics as well, along with a warmth and flow that makes the 507/DRT an impressive combination.

What playing with these three very different arms showed was that the AS clearly showed up differences, and that in turn indicates a turntable that adds little to whatever is going on in the music. If for example I tried three different arms on an LP12, there would be differences, but at all times the essential, and for some people "charming" character of the LP12 would come through. In fact I recently had the chance to try the latest LP12 in my system and I had to laugh out loud, so instantly recognisable was it. The AS is completely the opposite and in most situations that's how it should be.

But I haven't been concentrating on turntables for the last 3 years to not have some comments to make!

At around 3000 Euro the two turntables I've heard that go hear-to-head with it are the Michell Orbe and the Roksan Roksan Xerxes X. In their own way these two turntables are more distinctive than the AS, but having done arm swaps on both I can hopefully pin down the essential differences so you can at least read this review in the hope of finding which will suit your particular preferences.

First off how does it compare with the Orbe? The one thing the Orbe does brilliantly is the scale and power of music, and the feeling that physically "big" music is happening in front of you in a big acoustic. Here the AS shows its greatest weakness; it can sound small and restrained in comparison, requiring the volume to be turned up a notch to get you pulse racing. The downside of the Orbe is that this scale can rather swamp fine detail and precise imaging and it's here where the AS hits back with a vengeance. Complex midband detail as found on good Jazz records in particular, can get lost on the Orbe wheras the AS separates them out and this in turn helps keep the timing clues, so essential in Jazz, to the fore. On the other hand, put on Holst's 'Planets' - and the power and menace of "Mars" is much more intimidating on the Orbe. And to put things in perspective these are not small differences, you could hear them from the next room. The Orbe also shows some upper bass bloom which is entirely absent from the AS.

The Xerxes couldn't be more different, majoring in an almost frenetic pace, hunting down leading edges, spitting out detail and leaving you breathless. Like the AS it has a tighter and less expansive bass than the Orbe, but here it's even more tuneful. Somehow the AS sounds more even-handed and tends to let the music flow a little more naturally. The Xerxes is closer to the AS but there is still plenty of clear-blue-water between the two.

As for value it's not something I normally concentrate on, but in this case prices are so close and the three turntables are so different that it's hard not to speculate. The AS Machine looks, at first glance, an absolute bargain. It weighs a ton, is beautifully made and that high gloss finish will survive, looking new for a long time. But essentially it's a very simple package made up of just a few machined components. The Orbe and the Xerxes are also beautifully made (the Michell especially so) and more complex, especially the sophisticated power-supplies both use. The truth is that at what by high-end standards is a reasonable price, all three offer something very special that will last for a long, long time... Of course the AS has one undeniable advantage in that it can take multiple arms, something which is increasingly popular, and given its essential lack of character those two or more arms would give very different outputs, so that thus equipped, this turnable is most likely to do all things well.

So time to think hard about pinning down the AS "sound". I think it has a class-leading lack of colouration, a truly transparent midrange and fine treble extension. On the down side this can mean that with some music it can sound a little small and restrained, lacking the fireworks some produce. It times well, though others are better at driving a rhythm along, but is essentially accurate. The bass area is good enough, not as bouncily enthusiastic as some, but as tight as most and totally lacking in resonances. It reminds me of a very good CD player, but better of course:-) This makes matching into a two-source system easier than something like the Orbe which tends to trample CD underfoot so that a system voiced for one doesn't match the other. What music does it prefer? Well none really, and again this is very dependent on arm choice. It wouldn't be my first choice for heavy rock music, or for big orchestral workouts, but it's good enough, and for someone who's tastes in music are eclectic I think you'd be hard pushed to beat it, especially bi-armed. And as for those two arms a Hadcock and a Rega would give a wide choice of tonal palette and not break the bank. For those with deep pockets one of the big SME's and the Conductor would do a similar job.

Conclusion

Well I'm very happy to report yet another top turntable to choose from. That it is unfussy, simple, easy to live with and almost uniquely robust makes it an extremely attractive as a real-world buy. What I'm not happy about is that now having done the test the damn thing will have to go back. I'll miss it not just because it's good (my own, much more expensive, Opera LP 5.0 is excellent), but because it has to be the best reviewers tool I've come across in a very long time. Easy to set up, unfussy, reliable, nothing to break when swapping arms, ability to swap arm cables etc in seconds due to the open design, the chance to directly compare two arms back-to-back and most of all its lack of character, leaving arm differences to show through make it a reviewers dream.

It'll be missed.*

Comment: from Hugh Unsworth owner of HIAudio.

Thanks Geoff for this review, yes its taken longer than we expected but we appreciate your time and effort on this.

Regarding the bearing problem raised we have experienced this phenomenon on one of our demo decks. We know the coefficient of thermal expansion (CTE) of the resin and the stainless steel shaft differs. During show weekends and dealer demonstrations in the winter months, the difference has been found to be problematic to a point.

The effect found by you Geoff in an unheated room left for several days is a situation that can arise. We agree as you found, at very low ambient temperatures, 3C 7C shrinkage of the resin on the bearing shaft with an increase in bearing friction results. One effect has been the extra strain on the motor causing them to run warm. Another can be a slowing in the rotation speed requiring adjustment.

We experienced just this effect at the recent Edinburgh Show in November 2007, where after a cold night in a van, running the turntable on the Saturday we had a slow platter for the morning playing. Once temperatures had stabilised above 11 degrees Celsius the speed settled down. With the turntable being packed away at a temperature of approx 14C on the Sunday after the show.

Acoustic Solid have confirmed they investigated this many years ago at the time they designed the bearing and I can confirm there are many publication regarding CTE and polymer resins with varying amounts of filler to control the absolute CTE.

FYI such large masses of metal take many days to come up to something approaching air temperature, and will never truly reach it.

We have found once the TT has warmed up that all returns to normal again. And yes 70 90s is a typical time for the platter to stop rotating from 33rpm.

I can confirm in this demo deck we know to use a bronze bearing sleeve. This can be an option for anyone buying the deck who intends to use it in a very cold room?!!!?

Dr Hugh Unsworth (PhD in Materials Science) HIAudio

*Note - AS have allowed me to borrow the Solid Machine for use in reviews, which as stated above, it is perfect for - of course this offer was made after the review was written and had no influence on it's conclusions and the turntable remains the property of the manufacturer.

systems used

Copyright 2008 Geoff Husband - www.tnt-audio.com

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