S600 BMR Torque Settings

I know it has already been discussed to death.
Yesterday i had a BMR replaced at home by our Naim service manager. He advised me to check them again today when the sealing glue was fully dressed. i know that the BMR hex screws are 3,6 nm and today were still fine.
However i inadvertently turned the one on the outside leaf spring which is the same size.
Is there someone of you who knows if the leaf spring screws (outside ring) have the same torque setting of 3,6 nm ?

Regards
Roberto

Sorry, i meant 2,0 nm, 3,6 was for SL2

R

I would also like to know the torque setting for all the screws,
Drivers and sub frame ect

I have a pdf file with 600’s drawing, parts and spec, i can’t upload here. You can eventually pm
me.
Regards
Roberto

1 Like

The Ovator S800 are 2, and I found 1.97 sounded best on mine. Given tolerances on torque driver it was really to make it a bit under 2. Yes - I tried several minor changes lower than the recommended setting and listened and tuned mine to give the best result. Too tight and you lose low-level background info and too loose and it goes dull and transients and timing suffers - there is a ‘just right’ spot near or at Naim’s recommended setting.

S600 uses very similar housing so I’d think it is also 2

DB.

Yes,
Factory specs for 600 are 2nm for BMR and 3nm for the bass unit.

Regards
Roberto

I can confirm that the BMRs are 2Nm, the leaf springs are 2Nm & the bass drivers are tightened to 4Nm then backed off & set to 3Nm.

Regards
Neil.

It should be noted that this is only for fitting a new Bass unit to bed-in the gasket seal - for an existing set of drive units you do not need to re-do it to 4 and then back-off back to 3 as it was already done and you have had the speaker running that way for a long while. Re-tightening it to 4 on an older gasket may not be a good idea - unless you have a new drive unit to fit.

The way that worked well with my Bass units on both S600 and now S800 was to slightly loosen all the bolts but not too much, then re-tighten them in a circular sequence around the drive unit until returning to the first bolt and re-checking it.

This worked better than the ‘cross-tension’ approach (opposite sides) which I think is meant to be used when first assembling a new unit to makes sure it is linearly-seated from new. I tried that approach and it was inferior to what I suggested above - but try it and see as it does not break anything.

I found slightly less than 3 for the bass worked better than 3 and above 3 gave a blunter sound with less background musical information.

This is just what I found and I’m not saying it is the best way to do things, just what I experimented with and found works.

…also you don’t need to re-do all this very often. After the first 6 months from new was the worse, then I re-checked a year later and it was very minor and I’ve not felt it needed several years since then - but will probably check mine sometime ahead and certainly if I feel the system has crept ‘off’ over a long time, which fortunately mine does not seem to have at present since last tightening some 4 years ago.

DB.

Cheers everyone, just need to check mine, plus get a torque wrench that goes down to 2 as the small one i have doesn’t and only just noticed that it didnt

Indeed I suspect you are correct - I pulled that info from the process instructions for a new build S600.

Thanks for pointing that out.

Regards
Neil.

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