Sound Supports (tonearm plates and boards)

[YNWaN]

Dave, if you tried to have small batches of such an item precision machined and finished, you would soon know where the money went.

However, I agree that the bearing construction of the Aro is interesting. As you say, a shaft running inside a sleeve, free to rotate and filled with silicone oil. The inner shaft rests on a small ball-bearing. The arm pillar is constructed not unlike the main bearing of many turntables.

[Marco]

Hi Dave,

I wonder about all this rigidity thing, as one is in danger of moving the resonances somewhere else?????

Hardwood seems a good place to go...

I know what you mean and suspect that there could be something in what you say.

At the moment I've reversed the armboard, so that the inner ring is sitting on top of the outer one, which although this means that VTA is slightly compromised (although not by much with the SPU, as it's a tall-bodied cart), it allows the tonearm to be supported upon the whole solid structure of the T/T, rather than merely fixed onto a plate 'floating' inside a big hole, see what I mean here:





In that configuaration, sound quality was phenomenal, however I had no way of knowing whether that was due to the new armboard arrangement, or simply because I'd just upgraded to a whole new tonearm - or a combination of both!

However, when I get my Ortofon tonearm back, I intend to test the theory in isolation by comparing one configuration against the other, in order to ascertain the best compromise: 'stepped-down' armboard, 'floating' inside a big hole, with VTA spot-on, versus a 'flat' armboard, rigidly coupled to the T/Ts main structure, but with VTA slightly out.

Anyone fancy taking bets on what will sound best?

I know that Martin T has already done this comparison, and reported excellent results, although in his set-up the reversed armboard merely allowed him the extra height to get VTA spot-on with his Dynavector arm, so I suspect that he was in a win-win situation with that one!

On another note, I'm also hopeful that a material as rigid and inert as solid ebony, made as an armboard, will act as an effective foundation for the tonearm - we shall see!

Marco.

[Marco]

Over the last few years I've done a lot of work with armboards, arm termination and the method by which arms and armboards are mounted. I've made a lot of prototypes, done a lot of modelling and done a lot of listening. What I would say is that my findings suggest that absolute stiffness and rigidity are not necessarily the optimum solution.

I bet that your ex-wife had a somewhat different view!



More seriously, I agree. There are simply too many variables (a significant one being the construction of the T/T in question and the tonearm used) in order for there to exist one universally 'best' armboard solution - and that applies to everything else in audio.

However, the more I think about it, the more I'm confident that, on the Techy, a rigidly fixed flat armboard, made of *whatever*, will sound better than a 'stepped-down' armboard, made of *whatever*, 'floating' inside a big hole...

Therefore, I think that's what I'll ask Steve to make for me, and then find out if Arthur could produce a bespoke, slightly thicker, Achromat for me, say 6 or perhaps 7mm, instead of the normal 5mm, so that VTA is spot-on with the rigidly fixed armboard, and then (hopefully) get the best of both worlds!

Marco.

[Stratmangler]

Therefore, I think that's what I'll ask Steve to make for me, and then find out if Arthur could produce a bespoke, slightly thicker, Achromat for me, say 6 or 7mm, instead of the normal 5mm, so that VTA is spot-on with the rigidly fixed armboard, and then (hopefully) get the best of both worlds!

Marco.

You'd be better off fitting the bearing support plate first

[YNWaN]

However, the more I think about it, the more I'm confident that, on the Techy, a rigidly fixed flat armboard, made of *whatever*, will sound better than a 'stepped-down' armboard, made of *whatever*, 'floating' inside a big hole...

Are you; I'm not.

At the moment I've reversed the armboard, so that the inner ring is sitting on top of the outer one, which although this means that VTA is slightly compromised (although not by much with the SPU, as it's a tall-bodied cart), it allows the tonearm to be supported upon the whole solid structure of the T/T, rather than merely fixed onto a plate 'floating' inside a big hole..

Having the inner section of your two piece armboard above the outer ring doesn't make it any more (or less) rigid than when it is mounted below below the outer ring - in terms of how rigid the structure is, it doesn't make any difference whether the inner section is above or below the outer section, they make the same contact with each other and are attached in the same way.

If you have another armboard made out of a different material it will sound different - but that will be at least as much to do with the different material it is made from as it is to do with the fact that it may be a one piece construction as opposed to a two piece.

[Marco]

Are you; I'm not.

Well, it worked well for Martin!

Having the inner section of your two piece armboard above the outer ring doesn't make it any more (or less) rigid than when it is mounted below below the outer ring - in terms of how rigid the structure is, it doesn't make any difference whether the inner section is above or below the outer section, they make the same contact with each other and are attached in the same way.

No, Mark, there is a difference... If you look again at the above pic, you'll see that the inner ring now makes much more contact than before with the outer ring, and the whole armboard structure is more rigid, as a result.

Whereas before, the inner ring was simply 'floating' inside a big hole, mainly being supported by just the edge of the outer ring, which meant that the arm collar, supporting the tonearm, didn't have a rigid surface underneath it, rather just a big hole. It does have a rigid surface underneath it, the way I have it now

Do you get what I mean? If not, Martin's post (#6) explains it a bit better, here: http://theartofsound.net/forum/showthread.php?t=13537

The bottom line is that reversing the armboard in this way appears to have a postive sonic effect on the Techy!

If you have another armboard made out of a different material it will sound different - but that will be at least as much to do with the different material it is made from as it is to do with the fact that it may be a one piece construction as opposed to a two piece.

Yup, I get that.

Marco.

[Marco]

Hi Chris,

You'd be better off fitting the bearing support plate first

Neither Martin or I could detect much difference, sonically, when did the comparison at his place last year. It's also an utter ball-ache to fit, so I'm passing on that one

Marco.

[Stratmangler]

Hi Chris,



Neither Martin or I could detect much difference, sonically, when did the comparison at his place last year. It's also an utter ball-ache to fit, so I'm passing on that one

Marco.

I'm thinking of the VTA issue

[Marco]

Ah, I see... Only problem then is that it may expose the electronics underneath the platter, and look unsightly.

It would depend on whether the 'skirt' of the Funk platter was deep enough to hide the 'innards' of the T/T, once it was raised by the bearing base plate... It's one to ponder!

Marco.

[Stratmangler]

It would depend on whether the 'skirt' of the Funk platter was deep enough to hide the 'innards' of the T/T, once it was raised by the bearing base plate... It's one to ponder!

Marco.

Is this a roundabout way of saying that you're not refitting the Mike New Platter?