Alternative platters ?

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Originally Posted by REXTON

I dont think I will be upgrading thats just the point. For the time being I'm happy.

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It's not worth it if you don't use the 45rpm facility and are happy with your T/T.

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I'm glad Simon liked my deck and TBH there wasn't really a bake off. Simon fetched me a very impressive piece of kit over for a listen.

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Cool... Which was?

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I think people should listen a little more closely to what Simon and Mark have to say they have some great ideas.

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I totally agree. I've always rated (and largely agreed with) what they both have to say about hi-fi, as long as Simon doesn't wear his belligerent 'objectivist's hat' too often (as evidenced on pfm and elsewhere)!! ;)

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My own personal theory with regards the 1210's evolution is simplification of the PCB and removal of all the excessive crap that's on the PCB. If I had the knowledge I'd mod the PCB even further and remove the ability to spin at 45 rpm, a simple dedicated circuit which was specifically designed to spin as accurately as possible at 33rpm which could take into consideration increased platter mass (i.e. Mark's idea) via fuzzy logic. What I need is a simple PCB with these features which can be soldered directly to my PCB under my MN platter.

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Sounds like an interesting plan. I hope you can achieve it! :cool:

Marco.

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Originally Posted by Marco

Sure, but all of the above assumes the use of a high-mass platter, not entirely compatible with the T/T's control circuitry.

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That is specifically what I was referring to - I did make it clear, I thought.

In theory, at least with respect to the compensation circuit, the lower the platter mass and the lower the rotational inertia, the better. The fly-wheel effect, as seen in many other turntables, specifically does not apply in this instance because the platter speed is actively monitored and compensated for - adding inertia simply makes this more difficult.

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Originally Posted by YNWaN

When it applies correction it assumes that this is made instantly, if it is not it continues to act against that and continues to do so even it is unable to.

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Thus the 'warble' at 45rpm with a heavy platter as it continually tries to compensate, the momentum of the platter takes longer to respond than it expects, and it compensates again ad infinitum.

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Originally Posted by REXTON

What I need is a simple PCB with these features which can be soldered directly to my PCB under my MN platter.

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Such a thing does not exist I'm afraid. You would need a custom programmed chip and custom control board (from scratch).

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Originally Posted by YNWaN

That is specifically what I was referring to - I did make it clear, I thought.

In theory, at least with respect to the compensation circuit, the lower the platter mass and the lower the rotational inertia, the better. The fly-wheel effect, as seen in many other turntables, specifically does not apply in this instance because the platter speed is actively monitored and compensated for - adding inertia simply makes this more difficult.

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Yup, spot on. Your position on the matter was clear to me, Mark. However, I simply wanted to make it equally clear (beyond question), for all those reading, that the problem you describe is not inherent in the stock Technics T/T, nor with the lower-mass aftermarket platter designs from Funk (and probably also Mike's ETP platter).

What's rather satisfying in all of this, from a personal point of view, is that my decision to move from using a high-mass platter, to a lower-mass one, has been technically vindicated (as well as sonically, some time ago, using my own judgement criteria). Martin also occupies the same happy position :)

Marco.

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Originally Posted by MartinT

Thus the 'warble' at 45rpm with a heavy platter as it continually tries to compensate, the momentum of the platter takes longer to respond than it expects, and it compensates again ad infinitum.

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Yes, precisely. However, an aspect of this, though at a lower level, is likely to still exist at 33.3 rpm.

Rexton's deck just couldn't reach 45, not even close. I imagine there's a voltage limit in the circuit some where that can be overidden to fix this, though the compensation loop speed will still be an issue. Heavy platters are probably not the 'ideal' for these decks as Marco has already noted. Which probably explains why even the Sp10 MK3 came with a light platter despite its monster motor.

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Originally Posted by MartinT

I now have the Funk Mk. II hub and platter and will be setting it up for listening tonight when I get home. When I relate my findings, everything I say will be 'IMO' ;)

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Don't take it so hard, old man. :) I did state that my comments were meant for those who tend to read things quickly and are given to follow another person's preferences blindly; not a personal slight on you. The only time they should blindly follow someone is when *** I *** say something is awesome. Then, it's just cold hard fact. :D ;)

Yeah, the monster motor, is there to better achieve the theoretical instant variation in speed, to better overcome inertia of the platter, not to overcome extra stresses placed on the system.

No offence was taken, Biff. Just gently yanking (!) your chain :)