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LP-12 Naim Aro Owners Please Read

For something like an Aro/Keel, there is no play for cartridge adjustment.

Smart people buy an Ekos - which I understand has headshell slots - and don't have this problem. :p Or even a non-Linn arm.

Regards,

Andy
 
Distance from pivot centre to centre of the offside cartridge bolt hole is 224.5mm. It's the same on all issues of the drawings I have so probably safe to assume this has not changed.

Any other dimensions you care to share?
 
Smart people buy an Ekos - which I understand has headshell slots - and don't have this problem. :p Or even a non-Linn arm.

Regards,

Andy
Linn did something that seems blindingly obvious: provide a third hole for the Troika, Arkiv, or Akiva but also provide slots so that any cartridge within reason can be used.

What about SMEs? They don't have slots do they? You are stuck with a fixed offset angle and can only adjust the spindle-to-pivot distance to match the effective length any given cartridge gives you. Not ideal, but OK in practice?
 
Mark,

You seem to be confusing the issue. The Linn/Naim spec is 211mm making it ideal for a Linn MC cartridge with 7mm bolt to stylus distance. The Naim spec of 212.5 makes it ideal for a cartridge with a bolt to stylus distance of 8.5mm and makes it closer for a majority of other cartridges. Simple as that. I have no commercial interest but I am trying to clarify what others have failed to do.

And the above continues to be the elephant in the room with regard to a fixed sub-chassis with no play.
 
And the above continues to be the elephant in the room with regard to a fixed sub-chassis with no play.

Que? :) Shirley the "elephant in the room" is an arm which doesn't have headshell slots (as all of this argument would go away if it did). :p

Regards,

Andy
 
Distance from pivot centre to centre of the offside cartridge bolt hole is 224.5mm. It's the same on all issues of the drawings I have so probably safe to assume this has not changed.

Now I find that to be an interesting specification because Naim states the effective length of the Aro to be 229, 230 or 230.5 depending on what spec you believe to be true.

This statement was put out by the person on The Vinyl Engine who put together the tonearm database:

You can calculate the approximate effective length by measuring the distance between the horizontal pivot centre and the centre of the headshell slots and adding 9.5mm - this will give you the location of the stylus tip with an average cartridge. You could then either use the mounting distance of the arm which is closest in effective length, or optimise your mounting distance for Baerwald/Loefgren/Stevenson alignment using the alignment calculator.

If that 224.5 number is correct then I don't see any cartridge giving you any of the effective length numbers that Naim states unless someone knows of a cartridge with 6mm bolt to stylus, that would match with an effective length of 230.5mm.
 
There is no such thing in phono cartridges as a 'standard' distance between mounting points and stylus tip. It is for this reason that headshells are furnished with slots so go out a buy a proper tonearm instead of complaining about being locked into some manufacturers mindset.
 
It doesn't have to be a Troika though - other Linn cartridges (including the Akiva) have the same geometry.
 
Hence 'Troika sized'...

Presumably the best solution for other cartridges is to enlarge the holes on the ARO headshell into slots.

Paul
 
There is no such thing in phono cartridges as a 'standard' distance between mounting points and stylus tip. It is for this reason that headshells are furnished with slots so go out a buy a proper tonearm instead of complaining about being locked into some manufacturers mindset.

Absolutely! :) Although the problem is not with the mfr, I suggest, but with the buyer. Naim made some deliberate design choices when they created the Aro and it was designed for use with Linn cartridges. As long as the buyer realises this and therefore uses only Linn-spec cartridges ... all will be well.

Although I wonder how much effort would be involved in extending the bolt holes into slots? :confused:

Regards,

Andy
 
Goto http://www.vinylengine.com/overhang_shift_calculator.php put the numbers in and look at the distortion plots. All three values, spindle-pivot, offset and overhang have to be right to achieve a given alignment. So if your cart isn't Troika sized then the alignment will be sub-optimal wherever you put the arm base.

Paul

Except that when you move the arm base mount position you also potentially change the spindle-to-pivot value. Different cartridges can be accomodated but it means changing the spindle-pivot distance to minimise tracing errors.

The best solution is to have this hole fixed - i.e. drilled at the exact distance required. Failing that, the ability to adjust the armboard is the next best solution. As mentioned earlier, Loricraft take this approach and it's a really good solution. The earlier Linn subchassis/armboard also allowed a degree of adjustability here. There has been at least one other solution available to adjust the Aro, with fine engineering and convenience but one that compromised certain aspects of the Aro's performance, in my view.

Unfortunately, convenience aside, slotted headshells are not such a good idea from a sound quality point of view (one of the deliberate design choices Naim made that Andy mentions above). I don't think Naim are alone here. SME don't use a slotted headshell, instead allowing you to adjust the position of the base/pivot to accomodate different cartridges. This way you have the benefits of a more rigid headshell but you do lose out at the base.
 
Now I find that to be an interesting specification because Naim states the effective length of the Aro to be 229, 230 or 230.5 depending on what spec you believe to be true.

This statement was put out by the person on The Vinyl Engine who put together the tonearm database:

You can calculate the approximate effective length by measuring the distance between the horizontal pivot centre and the centre of the headshell slots and adding 9.5mm - this will give you the location of the stylus tip with an average cartridge. You could then either use the mounting distance of the arm which is closest in effective length, or optimise your mounting distance for Baerwald/Loefgren/Stevenson alignment using the alignment calculator.

If that 224.5 number is correct then I don't see any cartridge giving you any of the effective length numbers that Naim states unless someone knows of a cartridge with 6mm bolt to stylus, that would match with an effective length of 230.5mm.
2 points: the 224.5 mm dimension is for pivot to outer cartridge mounting hole, not for pivot to the midpoint between the 2 holes; and you can't simply add the numbers to get effective length because of the offset angle.

I assume the 9.5 is a rough approximation to allow for both cartridge variation and the offset angle.
 


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