What improvements can I expect to see with improved bearings?

[Wakefield Turntables]

I'm thinking about getting my technoarm upgraded by J7. I notice has does an upgrade for £100 for Rega 250's to upgrade the bearings. Any ideas what improvements I'd expect to see sonically??

A

[YNWaN]

It depends; in what way are they 'improved'?

If they are of a higher ABEC rating, it is worth looking up what this specification refers to.

http://en.wikipedia.org/wiki/ABEC_scale

Ball-race bearings are designed for constant rotation, relatively high rotation speed and good load bearing ability - non of these aspects are particularly pertinent to the requirements of a tonearm. Indeed, the speed of movement is so low that many bearings will be operating at the edge of overcoming static friction and the specific viscosity of the oil used in the bearings is likely to have greater impact than the absolute roundness of the individual ball used. In addition, bearings are usually pre-loaded in an arm. This is where pressure is applied to the inner hub relative to the outer cage so that slack in the bearing is reduced; too much tension and friction soars, too little and the bearing is loose.

What is likely to make more difference that the ABEC rating is the specific materials and construction of the bearings used, their pre-load adjustment and the lubrication quantity and viscosity. Another significant issue is how true the bearing surfaces are relative to each other, but this is largely an issue of arm machining accuracy.

No doubt the bearings used do impact on the sound, but specifically predicting what this impact will do is difficult as it depends on a number of different parameters and how they interact. There is no guarantee that you necessarily like the change and it is likely that some aspects will be improved for the better, but at the expense of others.

Arm design is toward the forefront of my mind at present.

[Wakefield Turntables]

Thanks mate! I wish I could supply you a little more information, J7 simply states that the bearings he supplies are Rega's top specification, whatever that is??

[YNWaN]

Oh, that does refer to the ABEC rating then

[YNWaN]

I feel I should add that I am not criticising the ABEC specification (or anything, in particular, in fact). What I am pointing out is that the ABEC rating refers to a group of specification requirements aimed at giving a guide to quality with a view to implementation of the bearing in a completely different manner than that found in a tonearm.

What Rega apparently do, and this is easy to do if you have a lot of bearings, is match bearings. All components are built to a tolerance. By matching components to those with a similar absolute measurement one can significantly decrease the effective tolerance level.

[DSJR]

Just get a bloody RB301 and have done with it. All the housings are stainless steel and not brass, the bearing races and shafts are hand matched to each other, not in the 250 the Techno Arm is based on and you get a proper tracking force gauge too. According to Noel Keyward, the RB301 removes the two small resonances that the 300 exhibited and is, to all intents and purposes, completely inert now.

I know the Techno Arm is modified by Michell and I'm informed the bits are then sent to Rega for final assembly. It's still based on the humble RB250 as all these third party bodge-ups are, although to be fair, it's one of the most elegant of them all and probably one of the best out there. The 301 has leapfrogged most of them and the reason why the RB300 series haven't been used as bodge-up donors is because of the way they're made - too difficult to disassemble without the proper jigs I was firmly told by both rega and Mike from Moth Marketing, who used to be one of the few with these service jigs and special torque wrenches for the bearings. The torque setting Rega uses beat my weak wrists when trying to tighten up a freshly made arm. The young chap making it torqued it up in seconds.........

[YNWaN]

To be frank, "just get a 301" largely parallels my own thoughts on your dilemma.

[Mr Kipling]

Who's frank? Is that Earnest's brother?

[YNWaN]

:)

[synsei]

Frank made me do it... :eyebrows:;)

[Wakefield Turntables]

Just get a bloody RB301 and have done with it. All the housings are stainless steel and not brass, the bearing races and shafts are hand matched to each other, not in the 250 the Techno Arm is based on and you get a proper tracking force gauge too. According to Noel Keyward, the RB301 removes the two small resonances that the 300 exhibited and is, to all intents and purposes, completely inert now.

I know the Techno Arm is modified by Michell and I'm informed the bits are then sent to Rega for final assembly. It's still based on the humble RB250 as all these third party bodge-ups are, although to be fair, it's one of the most elegant of them all and probably one of the best out there. The 301 has leapfrogged most of them and the reason why the RB300 series haven't been used as bodge-up donors is because of the way they're made - too difficult to disassemble without the proper jigs I was firmly told by both rega and Mike from Moth Marketing, who used to be one of the few with these service jigs and special torque wrenches for the bearings. The torque setting Rega uses beat my weak wrists when trying to tighten up a freshly made arm. The young chap making it torqued it up in seconds.........

I don't want a 301 :ner: I want to keep the techno arm. I asked my original question partly out of ignorance and partly because I like the idea of improving what I already have:) the techno arm sits in my second system and only gets occasionally, if I wanted an inert tone arm I'd simply switch to my SME V.

[Beobloke]

My own experience of sending an arm to Audio Origami for a bearing service (Alphason HR-100S) suggests that not only does it come back feeling a lot less wobbly than before, but bass tautness imporves and the increase in soundstage width and stability was nothing short of astonishing. Well worth doing if you have any doubts over the health of your bearings, but less worthwhile if they're in good fettle. Johnnie will advise you though - he's most definitely not the sort of chap who will take your money just for the hell of it.

Incidentally, if you have a standard RB250, then this...


Just get a bloody RB301 and have done with it.

...is spot on! However, as you have a Tecnoarm, I'd stick with it. As Dave says, it's one of the best modded variants out there.

[sq225917]

-insert tedious note to the fact that ABEC rating/measurement has not a single parameter that in anyway could help to ascertain if one is better than another for a tonearm-

I'd float the idea that the most important thing about a tonearm bearing is how it is seated and adjusted.

[Wakefield Turntables]

My own experience of sending an arm to Audio Origami for a bearing service (Alphason HR-100S) suggests that not only does it come back feeling a lot less wobbly than before, but bass tautness imporves and the increase in soundstage width and stability was nothing short of astonishing. Well worth doing if you have any doubts over the health of your bearings, but less worthwhile if they're in good fettle. Johnnie will advise you though - he's most definitely not the sort of chap who will take your money just for the hell of it.

Incidentally, if you have a standard RB250, then this...



...is spot on! However, as you have a Tecnoarm, I'd stick with it. As Dave says, it's one of the best modded variants out there.


Adam, thanks very much, I'm going to speak to jonnie today.


-insert tedious note to the fact that ABEC rating/measurement has not a single parameter that in anyway could help to ascertain if one is better than another for a tonearm-

I'd float the idea that the most important thing about a tonearm bearing is how it is seated and adjusted.

Simon, point taken mate, and that's one of the things I hate about hifi, how uncertain things can be :( considering what you and Adam have said I think the best course of action is to counsel j7.

Thanks again guys.

[YNWaN]

I'd float the idea that the most important thing about a tonearm bearing is how it is seated and adjusted.

Yes, in my own rambling way, that's what I was trying to say :).

[sq225917]

Yeh, johnnie won't take em out if he doesn't think he can fit another set in better.

[Wakefield Turntables]

Just spoken to j7 and the idea behind the improved bearing spec to help tracking which can only be a good thing! So the techno arm is going tomorrow for new bearings, updated cart tags, and possibly some Teflon coated silver. :eyebrows: should take a week and then this will sit on my second system.

:cool:

[YNWaN]

By what mechanism do they improve tracking?

[Wakefield Turntables]

Supposedly the tone arm experiences less drag as its tracking through the transverse plane I would expect this is due to the tone arm experiencing less drag and resistance from the bearings:scratch: but you could be onto something with your point you made earlier about how the bearings are housed?? I'm not an expert but it sounds plausible

[YNWaN]

Hmm.....if there is a resistance this is, essentially, a static load and I wouldn't expect tracking to be improved.

One of the advantages (there are also disadvantages) of a unipivot is that the bearings are inherently aligned and, if done properly, have extremely low static friction.

[Mr Kipling]

Last year ferreting about for diy arm ideas found a posting from one individual who had made a simple unipivot, and was more than happy with it. So much so that he felt it made his Ekos somewhat redundant.

[Wakefield Turntables]

Hmm.....if there is a resistance this is, essentially, a static load and I wouldn't expect tracking to be improved.

One of the advantages (there are also disadvantages) of a unipivot is that the bearings are inherently aligned and, if done properly, have extremely low static friction.

Perhaps this is the phenomenon that he was describing??

[sq225917]

Yeh, a good unipivot should have less stiction in the lateral plane. 'Should' however isn't always achieved. There's plenty of bloaty, overweight unipivots out there.

[YNWaN]

Well, it should have less stiction in both planes; but as you say, the arms bearing(s) is only one aspect