Building high-end 'tables cheap at Home Despot II

Dopogue, thanks for heads up on the vertical extrusions. Back to the drawing board...

Jlln, I do not expect that flat spotting will be an issue. The o-rings we use are fairly hard and also very durable. Much more durable than materials that were available in the 60's. Also the pressure is quite small. If I am wrong replacement o-rings are about $0.50 and are readily available.

Lewm, I have no idea if there would be an advantage to driving the underside of the plater rather than the rim. From a theoretical perspective there would be slightly more "scrubbing" with the Lenco approach since the driven surface is not moving in a straight line. At first blush this would seem less effective, but who knows. I do like the elegance of the approach.

We may be able to come up with a way to use a Verus motor to drive the underside of the platter. Constant pressure would not be a problem but it may require too large of a drive wheel. I need to think about this.

Mario_b, good questions, thanks for asking. You are correct, as the o-ring wears the speed will change. However, as I noted before the o-ring material is quite durable so it is unlikely that after even years of play that the overall diameter of the drive wheel will change more than a few thousandths. So the speed change will be very small. The controller has switches that provide precise 0.16% speed adjustment steps. So maybe it will advisable to check and possibly re-adjust the speed every year or two.

The Verus controller has a torque adjustment. First of all using the term torque is not strictly correct. This adjustment controls the voltage to the motor which in turn affects the maximum torque that can be delivered. However, the actual torque delivered is a function of load. The load is always much less than the maximum torque so the extra energy is just converted to heat. My point is that the adjustment never actually changes the torque. What the adjustment does change is how rigidly movement of the rotor is controlled by the magnetic field in the stator. The effect is very similar to adding compliance between the motor and platter, but on a much, much smaller scale. Higher voltages are analogous to more rigid coupling. A higher torque setting results in tighter more precise sound. But you can go too far with the sound becoming analytical and dry. I am sure that it is all about precision of speed but I do not think that the lower torque settings are necessarily less precise.

Chris

Johnnantais,

A few corrections. While we no longer produce belt drive motors I do still think that they have a place in the industry. But that place is not at the top.

Induction motors are indeed brushless but they are not coggless. Any single phase AC motor by definition will exhibit nearly 100% torque ripple (or 100% cogging). The incoming power is essentially cycling on and off at either 50 or 60 time per second. When the AC voltage crosses zero then the torque produced by the motor also must be zero. When the AC voltage peaks the torque also peaks.

The RPM of an induction motor is determined by the AC frequency and the number of motor poles. More poles increases the frequency of cogging but in no way diminishes it.

While flywheeling from the platter and/or motor does aid in speed stability it is not a cure. Otherwise the heavy belt drive platters would womp on idlers with relatively light weight platters. Experimenting with a 70 pound platter we still found that subtle changes affecting cogging were clearly audible.

Cogging is always detrimental to good sound. What can be debated is if cogging is better or worse than common fixes. A rubber belt is very effective at reducing the effects of cogging. But it introduces it's own problems that many, but not all, find worse than the cure. An idler wheel is far less effective at reducing cogging effects and also introduces a lot less negative effects. It's all about compromises. But if you start with a motor that does not cog then everything is a lot easier, and better.

I am total agreement about the detrimental effects of "quartz-locking". Thats why we don't use any sort of servo circuit in either the Verus or Certus motors.

Johnnantais,

Is there a link where you explain this mod, so I don't have to read 500 posts?

Also, is lenco 85 a good model for this?

Thanks a lot in advance...

I am looking forward to this.

Hello all. Just to back up jean's claims re old sony stuff. My TA-3200F amp outgunned my Leak tl12+ monoblocks and homemade triode monos in every area mentioned by jean above, to my utter astonishment. As a result i sold the Leaks for $1,200 and kept my $200 sony. the Sony TA-4650 that i have has a dead power stage, but the pre stage has a lovely phono section and partners my 3200 beautifully, driven of course by my red Lenco. Bought a Marantz PM4 (a ken kessler personal recommendation, despite his rather obscure taste in ancient brass bands, sorry ken) a few weeks ago, and its phono stage doesnt match the sony combo, but its line stage may be just ahead. 15 watts per channel into pure class A, some say even better than the Sugden A21 variants.

Hello from the country after a long absence all, I've been very busy with both audio and non-audio related stuff the past couple of weeks. Sorry for the delay Gonglee: no, the L85 is a belt-drive and therefore persona non-grata, go for either an L75 or L78, which both show up quite often on eBay. Anyway you look at it there's a lot of reading to do, so focus those eyes and brain, and good luck and have fun!!

Thanks for the support Gilbodavid, as always. I do have a few Sony stories to relate which address various issues. Over the last two weeks I had to occasionally go to the nearest large town, and waiting for a friend to emerge from work I decided to kill some time in a high-end shop. A fellow is standing there and we get talking. He asks me what source I use and of course I launch into my usual explanation of idler-wheel drives. It turns out he is fresh from the latest high-end audio show where he had spoken with Chris and heard his Verus demonstration, and so was very open to my claims for the idler and the role of torque and weaknesses of belts. It turns out as well that he had a Garrard 401 sitting in a closet and asked if I could fix it up for him. Of course, I said yes, and invited him to come out to the country to enjoy the scenery and hear the Glories of the Idler for himself. So up he shows, and within twenty minutes of listening commissioned me for both the Garrard rebuild AND a Giant Direct Coupled Glass-Reinforced Lenco, which shows just how audible this theoretical cogging is (theoretical in the sense of inaudible). The system?: of course the Lenco/RS-A1/Denon DL-103E combo, going through my Sony TAE-5450 pre; and out to my ESS AMT4s via the Sony TA-3140F amp (in stock form). As always when high-end audiophiles (and this guy is involved in both manufacturing and distribution of high-end components, and was a vice-president of Nortel) hear my system, he gets up and looks behind my components to try and find the explanation for the stunning sound quality (these vintage components truly are stunning, the Heil Air-Motion Transformers still amongst the best drivers ever designed, and the AMT4s perhaps the best matching of woofer to AMTs ever managed), and seeing my 24-ga. solid core and Petras said "Incredible, even your cables are crap!!" I was being disingenuous when I replied "Yep, nothing to point to but the Lenco!" as of course, I know that the AMT4s ARE incredible, as are the vintage Sony components. But asking an audiophile to accept both the Mighty Lenco AND various "crap" vintage compnents is to ask too much, best let it all sink in slowly ;-).

Getting back to the issue of truth and advertising I raised before, I point once again to the foundation which Teres'/Chris's advertising and posts asks us to implicitly accept as fact: "An idler wheel is far less effective at reducing cogging effects and also introduces a lot less negative effects. It's all about compromises." The spoken fundamental assumption is that idler-wheel drives have seriously audible cogging effects AND serious compromises. As I wrote, which was NOT that there was no cogging, these motors are "essentially cogless, once one gets rid of the suspension which amplifies various motor energies, as they spin at an average 1500-1800 RPM, eliminating/smoothing out their own speed imperfections." Anyone who has held a Garrard motor in their hands while it is running has to have been astonished by how little vibration emenates from this massive motor, I know I have. Once one further eliminates any form of suspension for the 'table itself (either springs or the misguided use of rubber in whatever shape), which emphasizes the motor vibration rather than eliminating it (the classic idler set-up mistake), one hears, when the platter is acting furthermore as a flywheel to the motor via the very secure coupling of motor to platter via the idler, smmmoooothnesss and no cogging or smearing, which however is heard VERY& audibly in any belt-drive, massive platter or not. Those who speak of slipping here should try the following simple test: simply press a record brush against a record on a revolving idler and see how much push/torque there truly is. In fact so much that neither DD not belt even approaches the power, which of course speaks for the effectiveness of the idler-wheel approach, which allows for these enormously powerful motors without slipping. The fellow who commissioned two idlers after hearing the Verus is testimony to just how audible this effectively theoretical cogging is. Result trumps theory, not the reverse, something which scientists and engineers would do well to remember. Once again these briliant words spring to mind, the immortal words of Daniel R. von Recklinghausen, former Chief Research Engineer, H.H. Scott: "If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing." I.E., experience trumps theory.

This is not to say that the Verus is not a TREMENDOUS boon to belt-drivers and the world in general, both because it provides an ingenious way to improve belt-drives and save them from a fundamental design flaw, but also provides an ingenious test/experiment/demonstration to underline the weaknesses of the belt-drive I have been going on about lo these many years. BUT, it does not, I believe, improve on a properly set-up idler-wheel drive, though perhaps some day I will get the chance to do the experiment myself on a Giant Direct Coupled and properly restored Garrard.

The trumpeting of the flaws/compromises of the idler-wheel approach is advertising also in another sense: it asks us to accept as fact that the Verus approach is the current top of the potential of the wheel (very debatable), and that Teres' own very expensive DD is therefore inherently superior to the best idler-wheel drives. BUT, if the Verus is NOT superior to a properly set-up idler, then this claim is also debatable. Time and experience will tell, of course I believe a properly set-up idler is currently at the top of the food chain.

So, getting back to DDs, yet another EMT DD owner has gone to the Dark Side, and so sent me an e-mail with the title "Giant Lenco is Sounding EXTRAORDINARY!!!" Furthermore, I have now rebuilt my Sony 2250 into a Giant Plinth, and Direct Coupled it to boot, and it sounded extraordinary as well. As previously written, this 'table is a detail meister, and with the Direct Coupling and Giant Plinth it also took on many of the characteristics of the idler-wheel drive: tremendous PRaT, great flow and musicality, and excellent transient speed. I wondered, "Do we finally have a match for the Mighty Lenco?!?" I sat entranced and amazed, and switched back and forth for a while. I also plugged the Sony into a power conditioner (a Monster) and thought I heard further refinement in the upper frequencies. But, as time went on, it became clear that from the middle range down to the lowest bass the Sony was simply - like a belt-drive - missing all sorts of information. For instance, while the Sony captured the pluck and transient edge of strings, along with the high frenquencies, it lost out on the body of the instrument, the decay and the wood and lacquer, clearly heard on the Lenco. Voices had mouth but no chest, relatively-speaking (against a belt-drive I believe the Sony extracts more low-frequency information). Everything sounded more natural, with more body on the Lenco. And once THIS became audible (it took a while to sink in the Sony was so good), THEN it became clear that the Lenco's high frequencies were also more extended, natural and even more detailed. Nevertheless, the Sony IS an amazing 'table and should be recognized along with the Thorens TD-124s of this world as a classic well worth rebuilding. Just how serious a 'table is the Sony?

Being a Canadian and long in search of a lovely Oracle turntable for my collection, I accepted one Oracle Delphi MKIV, Anniversary Edition, in black and gold, as a trade against the Garrard 401 rebuild/plinth. It predictably suffered badly against the Mighty Lenco/RS-A1/Denon DL-103 combo, and this with SME IV tonearm allied to a Dynavector XX-1. BUT, how will it fare against the Sony/RS-A1/DL-103 combo? THIS I will do over the coming weekend and report on further. In the meantime, the Sony is a true Mighty Classic, and deserves replinthing and a serious tonearm. For those who don't like the dry and dynamically-constricted sound of quartz-locking, but LOVE those soft-touch controls (and boy do I like those piano-key controls!!).

Anyway, that's enough for now I think (breathe a sigh of relief ;-)), the Battle of the Idler is FAR from over, have fun with your discoveries and experiments all!!! Now, back to this country scenery.