Most of the 5000s which are extant are the RX-5000. The "RX-" designation is a solid bearing. There exist some SX-5000s as well. The "SX-" prefix denotes an air bearing turntable. The SX-8000 and the SX-8000 II are roughly similar, but the SX-8000 II is physically more 'integrated', and it usually comes with a vacuum hold-down platter. The SX-8000 tends to go for less than the SX-8000 II but I have not seen an SX-8000 II for sale for many moons (last one I saw went for something like $15-16k if I remember correctly). The SX-8000s I have seen recently (last 18mos or so) have gone for $9-15k on Japanese internet auctions, in varying condition. There seem to be a fair number more of them out. I have never seen an SZ-1 for sale, though I imagine if it came out, it would be more than the SX-8000 II.
I have an SX-8000. I have compared it to the best Japanese DDs of the era but not to rim drive tables. I have not heard a table before or since which digs as much info out of the groove as the SX-8000 with a MAX-237 arm (don't have a 282) and a ZYX UNIverse. When perfectly dialed in, it is a very smoooooooth sound. The large DDs (Exclusive P3, Technics SP-10Mk2 & Mk3, and Sony PS-X9) are also quite good, and you 'feel' the drive which you don't get with the Micro, but the Micro is soooo quiet. |
T-bone or others, what do these 2 tables sell for? I would imagine that they must be quite pricey. A friend of mine bought the 5000 recently and is telling me (he lives far away) that he has not heard anything better. Has anyone compared them to the rim drive tables like the garrard 301 or the Lenco? Bob |
price is ok. will keep my eyes open. |
The last few I have seen go through the internet auctions in Japan have been in the area of JPY 150-175,000 (call it US$1500-1750). I would say they come up about 3-6 times a year. |
t bone,thanks a lot for your good advise. I put all my Katagana and Hirgana together (the Kanjis are all gone...), very interesting and I will definitely go for it.
thanks a lot |
Thuchan, there is a standalone Micro Seiki product called the HS-80, which was a high-speed inertia unit (made to be added to the 1500/5000/8000 series models). It would probably give much the same effect to the SX-8000 as the motor on the SZ-1 accomplishes. When they come up in the market, they are seriously expensive, but they are probably easier to find than an SZ-1. You can see a picture here (about halfway down the page). |
Let's not turn this into a discussion of Saskia, it's meant to be about the Micro Seikis. I used it as an example only. |
Mark, I understand the calculation but do not understand (from reading the webpage) where the 'gearing coefficient' comes from - higher speed flywheel providing gearing vs 33.3? rim-weighted platter increasing effective rotational inertia when compared to solid mass? |
T Bone
The equivalent mass given by OMA is calculated according to the method I used.
It's not the mass of a platter equivalent to the total inertia of the system, this would be even higher (around 400 lbs). IIRC Win decided to use the more conservative figure - he's a big believer in understating and over-achieving.
Mark Kelly
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Mark, Thanks for posting. I had not seen your first post when I wrote and i had not looked at the VK page linked. I was noting the mass moment of inertia of a solid with zero angular velocity (which is the way all Japanese TT specs historically have shown their mass moment of inertia spec - which if I'm reading your idea correctly, reconciles with your recalc above because the coefficient of the square of the gearing is... 1. When I think about it, when my Exclusive P3's capacitors went, it was probably going something like 750rpm too (until I shut it down). If I could harness that and use the spindle, I could have gotten something like 1000 tons/cm^2 (a lot more weight and much bigger r^2). I will go away and digest some of this. As to the Saskia, I had previously read the 'effective mass of 200lbs' bit on the OMA homepage, but as there is no other information, and I have not seen any other info on the table elsewhere, it is difficult for those of us less in the know to understand how that comes about. I will assume (and we all know what people say about that), that the tightly controlled external rotor motor when combined with the turntable's heavy platter results in an effective mass of well over two hundred pounds means that "because it is rim drive not belt drive, when combined with a platter of X mass, we get effective mass of X+Y mass." There is so little information on the OMA page that anyone with a modicum of info could probably see where I am wrong on this too, but I couldn't quickly find any info months ago when I first looked. |
Lewm, of course you need to see both units in person to have a better decision-bases. Nevertheless the solid buttons of the RY-5500 II and their haptics are a statement of High-Quality engineering and machine building I do not see at the SZ-1m so far.
The link Pcosta provided gives a very good picture of the unit and of the buttons. What matters more than taste of design is the in-built fly-wheel concept and the air bearing of the SZ-1m which T-Bone has described. Maybe I should look for an extra fly-wheel unit for the 8000. |
The system seems to have eaten the post on equivalent mass, so I'll do another.
The idea is analogous to the method of calculating equivalent mass for tonearms and the calculation is the same: divide the moment of inertia by the square of the radius of action, the result being an equivalent mass.
Using a standard radius of action of 150mm, the equivalent mass of the flywheel arrangement for the Micro Seiki is 2.58 kg.m^2 / (0.15m)^2 giving 115 kg.
Note that due to distribution of mass, a TT platter would have to be about 200 kg to achieve this equivalent mass.
Mark Kelly
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T-bone
The problem with that idea (besides complexity) is that you lose most of the advantage of running an external flywheel because your gearing ratio is much reduced. Using the effective mass analogy as given above, a 5 kg flywheel of 150mm diameter coupled "outside to outside" would add about 3 kg of effective mass to the platter.
As a contrast, the motor arrangement in the "Saskia" table adds an effective mass of about 85 kg.
In any case there are other ways of addressing the limitations of belt drives regarding creep (which is what I assume you mean by "the belt tension issue". There will be a completely new take on the issue exhibited at RMAF come October if everything goes to plan.
Mark Kelly
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Thanks Raul. I remember that number now (which I bet is for platter only; the motor flywheel would add another 8-10% to that number for the SZ-1). I think the Verdier and the highest-end Final Audio tables may have a higher moment of inertia (as would the table that Dertonarm put together a while ago) because of slightly massier platters, but it wouldn't be too much bigger (in the case of the Verdier at least) and I could probably suffer through ownership of the SZ-1...
Wonder why more people don't build dual-voltage motors (one high-voltage motor rim drive motor for start-up and another for maintaining speed on a belt drive). If you did that, you could run a VERY big flywheel and use the outside of your flywheel as your belt pulley, which would mean that you'd largely eliminate the belt tension issue (which Mark Kelly has written about). And this, in turn, makes me think back to the big thread about massy platters, belt drive vs DD, and alternate drive mechanisms that got reasonably technical. |
The required figures are in the link provided above.
The motor / flywheel has an inertia of 5.1 x 10^-3 kg.m^2.
It turns at 750 rpm, so the inertia referred to the platter is multiplied by the square of the gearing ratio.
22.5^2 = 506.25 so the total moment of inertia = 506.25 x 5.1 x 10^-3 kg.m^2 which is 2.58 kg.m^2.
In the perfectly ridiculous unit of tonnes.cm^2 this is indeed nearly 26. |
Dear T bone: You are right, the number is 3.5 tons/cm2 for both: the 8000 and the SZ-1.
regards and enjoy the music.
Raul. |
The SZ-1 motor has a built-in flywheel (which helps to make the motor box 6kg heavier than the SX8k2 motor unit) which also has an air bearing, and the floating flywheel is supposed to make the drive even smoother. The flywheel, will of course, raise the overall moment of inertia a bit as well (though not by a lot).
note: I am not sure where the VK gets their moment of inertia number. 26 tons/cm2 is way too high. Given the size/weight of the platter, you'd be physically limited to about 4t/cm2 - which is still pretty good (the biggest direct drive tables were less than half that, but they had torque going for them too). |
If you've never seen an SZ-1 in person, or since you have probably never taken either motor apart, how can you tell? The motors may be identical, but the SZ1 motor may come in a fancier chassis to match the rest of the turntable. If you can find an SZ-1 go ahead and buy it. It will probably make you feel better. When you do, I would like a chance to buy the 8000. |
Thanks for your answers and the link. Looks like the suction section is part of the motor unit in both machines, but it looks to me that the 8000 motor unit is of better built quality and the design is nicer (at least in my eyes) |
I have no personal experience with any of the Micro, but they look like an engeenering feat. Especially the SZ-1
Here is a link for some more info on the Micro's.
http://www.thevintageknob.org/THEVAULT1/SZ1/SZ1.html
Not much info on the SZ-1 and almost impossible to find outside of Japan. |
I can't imagine the SZ-1 having a better motor that the RY5500 motor on the 8000-2, but then again, I have never heard or seen a SZ-1 in person. The 8000 is my all-time favorite MS table. I think that your friend is just playing with an audiophile's insecurity. Awesome table! |
