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Roksan Aretmiz counter weight

Pete MB&D

Pete Maddex, the one and only!
Hi Chaps

Been messing with the lathe made a replacement counterweight from nylon and brass.

Its got a 19mm hole through it done by holding it sideways in a 4 jaw chuck and ending up using a 19mm router bit to open it up to size once I had gone up through the drill sizes.
A m8 stud on formed on the bottom to screw the brass weight and a couple of groves where cut for the O ring dampers.
I might try a copper one if I can find some bar large enough.

Roksan Aretmiz counterweight by Pete Maddex, on Flickr

I made it the same weight as the existing one so I can swap and see if it made any difference, I had a quick blast once I had tightened up the arm, the MDF shrinks in winter loosening up the 32mm nut on the Aretimz, it sounded very nice on Just what I needed by the Cars.

Pete
 
Very pretty, looks like a large aesthetic improvement on the stock Roksan one.
Maybe a nice bit of black Delrin instead of the nylon just to match the tonearm black?
 
Thanks, it’s modelled on the later counterweight and I have some black nylon on it’s way to me for that very reason.

pete
 
Is nylon heavy enough? The later (replacement) weight, which as you point out is of similar design as yours, is made of metal and even has an option to allow more weight to be added at the bottom; useful for getting the whole thing close to the arm pivot
 
The later (replacement) weight, which as you point out is of similar design as yours, is made of metal and even has an option to allow more weight to be added at the bottom; useful for getting the whole thing close to the arm pivot

Using a heavier weight is not useful for getting the CBW nearer the pivot. Getting it nearer the pivot is entirely inescapable.

Getting the CBW nearer the pivot reduces the arms effective mass (counter-intuitively given that the mass of the CBW is increased), and seems to be a recent fetish. I haven't searched at length but it strikes me very odd indeed that it appears that all tonearms with all cart's sound better with a lower effective mass, as I can't find anything that says otherwise. Strange indeed that all tonearm manufacturers have always been wrong.
 
You could sell that you know. I can see the HiFi Plus write up as I type....

'The use of nylon effectively decouples and dampens any resonances and the brass reduces the ringing of the standard steel, itself damped further by the o-rings placed at the optimal positions for standing waves within the structure. With our reference AT95 super cartridge, this advanced weight made backgrounds darker and the horn section on several tracks were definitely more 'horny'.

Sorry
 
I have been looking for an Arti counterweight to upgrade my Tabriz, to zi spec. Could I commission you to make me one?
 
Hi Gareth

Looks like the counterweight stub is different, does yours have a grove in the stub?
It needs a grove to stop the collar that the counetrweight rotating.

Pete
 
Hi Gareth

Looks like the counterweight stub is different, does yours have a grove in the stub?
It needs a grove to stop the collar that the counetrweight rotating.

Pete

No, it is smooth as the regular counterweight is only held in place by the internal rubber o ring
 
OK, I thought all it needed was a collar, obviously more complex, ah well.

This was the original zi upgrade kit

roksan_tabriz_zi_2.jpg
 
So they just added a smaller version of the original counterweight with a locating point for the new suspended counterweight. Is that foam on the internal edge of the suspension frame for the new counterweight?
 
OK, I thought all it needed was a collar, obviously more complex, ah well.

This was the original zi upgrade kit

roksan_tabriz_zi_2.jpg
The pictures on line show a groove in the top of the stub to stop the collar rotating, that upgrade kit looks like they are just relying on the o rings to stop it rotating.

Pete

Just had another look on line and it looks like it hasn't got a grove, just a reflection on the light, I think i would struggle to machine the internal groves for the o rings I dont have tool to cut them.
 
So they just added a smaller version of the original counterweight with a locating point for the new suspended counterweight. Is that foam on the internal edge of the suspension frame for the new counterweight?

Looks like it doesn't it. Pete's original has the same as well.
 
The pictures on line show a groove in the top of the stub to stop the collar rotating, that upgrade kit looks like they are just relying on the o rings to stop it rotating.

Pete

Just had another look on line and it looks like it hasn't got a grove, just a reflection on the light, I think i would struggle to machine the internal groves for the o rings I dont have tool to cut them.

No problem, it is just one of those things. I have been casually looking for the zi upgrade kit for a couple of years and apart from some expensive whole arms, not been able to find one so got excited seeing your version
 
Gareth

Measure the diameter of your shaft, just thinking if its possible to grind a tool that would fit inside the bore of the collar.

Pete
 


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