SBL owners, help needed please

Hi all,

Naim newbie here but hopefully not for long. I’m looking at some S/H SBL’s and after lengthy discussion, it sounds as if the coupling spikes between lower and mid unit may have been tampered with. So I can confirm, can anyone tell me how long they should be or alternatively what the gap is between mid and lower? Obviously I need to factor in the thickness of the Ali pad but that will be pretty insignificant.
Thanks in advance.

The gap when assembled should be around 6mm, maybe 5mm or 7mm. Do you have a picture of what is causing concern? You mention the aluminium pad, which attaches to the middle box, but not the gaskets - presumably you know exactly how to put them together using the spikes, pads, gasket and silicone.

I’d suggest you request that information from the support team at HQ. If you were to adjust them, I’d do it using a piece of glass to ensure I’d got them all level and set at the right length.

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I don’t believe they are adjustable, I’ve certainly never heard of it. If they were adjusted to be longer they would then be wobbly in their threads.

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Thank you, yes I do and that’s the reason both I and the seller think something is amiss - when sat on the spikes, the underside of the mid unit touches the gasket. He estimates the gap at 3 -4 mm. As we both understand it, there should be a gap which would be filled by the sealant. Never seen the spikes but I imagine they are fixed length with a flange so that they are all the same height when installed.

Thanks Clive, I did wonder but wasn’t sure I would get an answer, are they contactable through here?

Have a look at this thread…there are some decent pointers in there and not a bad revision if you are attempting to re-do the seals…

I don’t like the look of nails holding the aluminium pads in place.

Thinking about this just now, the reason you have a narrow gap is probably because the pads have been pierced through. The spikes should just make a slight impression in the pads. When you’ve taken them apart it will be quite clear if this is the case. If so, I’d remove the old pads as described and fill using Ronseal High Performance wood filler, which is a two part filler, but dries hard. I’d use the staples, which I seem to recall were provided in the gasket kit, to secure the new pads in place.

Apply a thin smear of Fairy liquid to the top of the new gasket and the underside of the mid box before applying a uniform bead of silicone to the top of the gasket.

That’s all from (>20 years ago) memory, so if I’ve got it wrong, I do apologise.


Its quite easy with a kit to do it yourself.

in 5mm.

You also need to change the pad with new one.

Personnally i have bought neoprene (20x20x5), loctite 595, and some aluminium pad, and i have done it myself on my 2 pairs of SBL.
There is no one here who can do it, and the cost to send it for reparation is so expensive that there is no way to get it done by an official dealer.

No I didn’t like the naily bit either…

The staples look perfectly fine to me. As has been said it’s a case of removing the pads, filling the holes with the Ronseal mentioned, and attaching new pads. Everything should then be fine.

Thanks all, I think I will go for them, always up for a bit of a project!

Tip #3765278: Don’t overtighten the tweeter housing.

However the user manual states that the “spikes should pierce the aluminium pads and just make contact with the wood beneath”…

There are 2 versions of the manual it transpires, you are both right…I suspect that the indentation only instruction didn’t guarantee contact on all 4 spikes. The last update was the pierced version.

Why would the nails be any worse than staples? Just the larger holes…?

I’m not alone in disliking the nails as I see @c2photo felt the same. Although I’ve not watched the video again (has it been deleted?), I think it’s just that when I do any type of restoration, I like to get back to the original spec or better - that’s just me. Besides, the tacks do look a bit tacky (pun intended).

That’s fair enough, but given that the nails would be hidden anyway, I’m not sure how much difference it would make.

For me, the woofer box support and the gasket sealing is one of the weakest parts of the SBL design - it’s mechanically vulnerable and has low consistency / repeatability. I’m working on possible solutions which might deal with these weaknesses.