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LP-12 Naim Aro Owners Please Read

John said:
I wonder who has? I think most must just be going by whatever Naim provides at the time which seems to vary from 209.5 to 213!

Now if we had someone who did all the measurements, perhaps they could tell us the effective length for a given pivot to spindle and cartridge bolt to stylus distance. Still waiting for some genius to come up with that answer.
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Well, I know one person who has more than one Aro to measure, an actual blueprint of the original drawings, and designs his own sub-chassis intended for use with Linn carts. So i know at least one person does it right for the cartridges they intend it to be used with.

You don't need a genius to come up with that answer you just need to be able to use the tools on vinyl engine and know the actual pivot to bolt centres distance. I understand it's easier to copy someone else's work than to do your own and for that reason- I'd not hold your breath...
 
Paul R said:
The pivot-spindle is nothing to do with the effective length. The EL comes from the arm's actual dimensions, the PS comes from where the turntable manufacturer decides to put the arm base. Which in most cases would be implied by the arm dimensions and a decision about alignment policy. The numbers on the Naim website are not consistent and obviously need more investigation.

I posted a table of actual effective lengths and offsets for various cartridge dimensions upthread.

Paul
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I believe you are mistaken, Paul. Leff = P-to-S distance + overhang.

(And overhang is related to cartridge bolt-hole-to-stylus distance.)

Regards,

Andy
 
sq225917 said:
Well, I know one person who has more than one Aro to measure, an actual blueprint of the original drawings, and designs his own sub-chassis intended for use with Linn carts. So i know at least one person does it right for the cartridges they intend it to be used with.
Click to expand...

Well it must be a big secret because there have been queries that have yet to be addressed by anyone in this thread.
 
I believe you are mistaken, Paul. Leff = P-to-S distance + overhang.
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The effective length is the distance from the arm pivot to the stylus. It is a function of the arm and cartridge geometry (for an ARO at least).

So I'm not sure what your point is.

Paul
 
So do I. Anyone wanting the info should measure up and do their own sums and not expect a free ride.
 
John said:
Well I just got a couple emails with information to add to this thread.

1. The bolt to stylus measurement for a Linn Akiva is 7.1mm.

2. Phonosophie uses a pivot to spindle spec of 213mm when mounting a Naim
Aro to their Phonosophie No. 3 turntable.
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Interesting. We must assume that 7.1 applies to the Troika and Arkiv too. The later Ittok with the 3-hole fixing and Ekos must be correct for all, surely?

Something is wrong with the Aro's spec. When used with an Akiva, the effective length cannot be 229, the offset cannot be 24, the pivot-to-outer-front bolt cannot be 224.5, or some combination of those.
 
John said:
From Vinyl Engine:

Effective length : distance from stylus tip to pivot point (mm)
O/H (overhang): distance from stylus tip to spindle centre (mm)
O/S (offset): offset angle (degrees)
Pivot to spindle : distance from pivot point to spindle centre (mm) this is normally the same as mounting distance

Since the stylus tip is a part of two of these measurements, it would be nice to know the "stylus" being used because the bolt to stylus measurement affects that measurement!
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Errr ... what do you imagine that Paul R and I have been doing? The question is: is the information we've been given correct?

Overhang is simply effective length minus pivot-to-spindle. It adds nothing if you've already got those.
 
sq225917 said:
Well, I know one person who has more than one Aro to measure, an actual blueprint of the original drawings, and designs his own sub-chassis intended for use with Linn carts. So i know at least one person does it right for the cartridges they intend it to be used with.

You don't need a genius to come up with that answer you just need to be able to use the tools on vinyl engine and know the actual pivot to bolt centres distance. I understand it's easier to copy someone else's work than to do your own and for that reason- I'd not hold your breath...
Click to expand...
We've been given that (or something just as good). If we also had the angle between the bolt holes and the line from those to the pivot, we would have all we need. It wouldn't be possible to measure that with enough accuracy but if it's in the drawings ...
 
andyr said:
I believe you are mistaken, Paul. Leff = P-to-S distance + overhang.

(And overhang is related to cartridge bolt-hole-to-stylus distance.)

Regards,

Andy
Click to expand...
Paul is right. EL is dictated only by the arm's geometry and the bolt-to-stylus distance. It remains the same regardless of which TT it's on, or even if it's not on one at all.
 
Nik said:
Interesting. We must assume that 7.1 applies to the Troika and Arkiv too.
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I recall reading somewhere that the Arkiv (at least Arkiv A) was 7.8mm and that Akiva was indeed shorter. But I cannot recall where that was and I just cannot find that article/reference anywhere, either. I may of course be wrong, but if my recollection just happens to be right and the source was accurate, the Troika could also have been 7.8mm.

Br,
Teme
 
Teme said:
I recall reading somewhere that the Arkiv (at least Arkiv A) was 7.8mm and that Akiva was indeed shorter. But I cannot recall where that was and I just cannot find that article/reference anywhere, either. I may of course be wrong, but if my recollection just happens to be right and the source was accurate, the Troika could also have been 7.8mm.

Br,
Teme
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Then the Ittok/Ekos and Aro cannot be right for all those.
 
John said:
Well it must be a big secret because there have been queries that have yet to be addressed by anyone in this thread.
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John, I have access to two Aro's, I have the original plans for said arm (also for the recommended armboard cut-out), I have produced CAD drawings from the plans, I also own five Linn MC cartridges (which I have also measured) and have access to a number of others.

It's not a big secret as such, but nor am I a free R&D resource for Greenstreet (or anyone else).

In conclusion, I am happy with the geometry decisions I have made.

Paul R said:
I think it is quite clear.

Paul
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Yes, I agree.
 
Nik said:
Then the Ittok/Ekos and Aro cannot be right for all those.
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I know little about the technical side of any of this, but find it extraordinarily hard to believe that the ITTOK, EKOS or ARO aren't suited for Linn cartridges. But, then, this whole thread has turned into an example of needless obfuscation, with too many contributors willfully ignoring the published specs for the ARO.

On a happier note, the Dynavector XX-2 II in my LP12/Keel/ARO sounds superb!
 
graham55 said:
I know little about the technical side of any of this, but find it extraordinarily hard to believe that the ITTOK, EKOS or ARO aren't suited for Linn cartridges. But, then, this whole thread has turned into an example of needless obfuscation, with too many contributors willfully ignoring the published specs for the ARO.

On a happier note, the Dynavector XX-2 II in my LP12/Keel/ARO sounds superb!
Click to expand...
If the Akiva has a different stylus-to-bolt measurement to the Arkiv and Troika, those arms cannot be right for all three as the third bolt allows no adjustment to compensate.

Just what are the published specs? If you mean the ones currently on the Naim site, they differ not only from the drawings others have but also from those for the Ekos, which would be odd if they are both suitable for 3-bolt Linn cartridges.
 
graham55 said:
I know little about the technical side of any of this, but find it extraordinarily hard to believe that the ITTOK, EKOS or ARO aren't suited for Linn cartridges. But, then, this whole thread has turned into an example of needless obfuscation, with too many contributors willfully ignoring the published specs for the ARO.

On a happier note, the Dynavector XX-2 II in my LP12/Keel/ARO sounds superb!
Click to expand...

I know what you mean, but I think it has also been fascinating to get a detailed insight in to some of the finer points of arm/cartridge geometry and also to see the assumptions that have been made.

Yes, there seem to be a number of people trying to justify their own positions here, but in some ways I'm glad this is being explored in depth. It confirms my suspicions that some companies are not as professional as they might lead us to believe and I would not be surprised to discover a few errors.
 
graham55 said:
I
know little about the technical side of any of this, but find it extraordinarily hard to believe that the ITTOK, EKOS or ARO aren't suited for Linn cartridges. But, then, this whole thread has turned into an example of needless obfuscation, with too many contributors willfully ignoring the published specs for the ARO.

On a happier note, the Dynavector XX-2 II in my LP12/Keel/ARO sounds superb!
Click to expand...

However lovely the DVXX-2 sounds, the fact of the matter is that, as the Aro does not have headshell slots, it will only be perfectly asligned with a cartridge which has the bolt-hole-to-stylus distance assumed by the Aro designers. :(

Regards,

Andy
 
Nik said:
If the Akiva has a different stylus-to-bolt measurement to the Arkiv and Troika, those arms cannot be right for all three as the third bolt allows no adjustment to compensate.
Click to expand...

We may never know as Linn is unable to share that information. I have confirmed 7.1mm for the Arkiv and can only assume that the bolt to stylus is 7.1mm for the Troika and other Linn MC's as well. The 7mm is one I've seen bandied about for years. On the Ekos, the Troika is more towards the front of the slotted headshell, I assume that is because 7mm is at the short end of the range for bolt to stylus measurements. The extra slot room at the back of the headshell I assume is to accommodate for longer cartridges. So if the Aro and Ekos have the same geometry as some claim, then 7mm is ideal for an Aro and anything else, given the 211mm pivot to spindle spec, is not.
 
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