I thought you were going to relocate that last pair of SBL tweeters that were on the shelf in the store room…….
On the original tweeters the hot glue is applied to rear of the tweeter and covers the soldered end s and terminals. As for why, I think I knew at some point in time but for now cannot recall…
Presumably it was because on some tweeters the terminals were slightly loosely clamped on the tweeter and so could vibrate, or even work loose in use.
And regarding the solder, if they are new build tweeters and the wire is cut so that the old solder is left behind on the old tweeter, then one could safely use modern solder to connect the new tweeters (I still haven’t got round to fitting that new pair I bought a year ago!).
David, you could well be correct.
Personally I would prefer to use the old Crystal 505, as it’s much easier to work with than modern ROHS solders. Only issue would be the socket end, but then you might as well fit new ones at the same time.
If the wires are long enough then I would leave the socket end alone. Anyway thank you for the advice.
Looking at mine just now, I think it’ll be a bit of a stretch, so new wires would probably be advisable if fitting the current revised tweeters. What’s more, I’d rather be dealing with the solder connection and hot glueing with the tweeter out and on the bench - i.e. not through the drilled hole in the arm bracket, so one would need to de-solder at the sockets anyway.
In case it’s of use, Sean Jacobs fitted my SL2 tweeters for me when I replaced them last year.
A syringe of Hylomar blue was included in the Niam spec tweeter box. From what ive read it is used as a gasket (sorry not sealant) between the mounting plate and tweeter, afaik very similar to the SBL tweeters. I actually have dealer instruction for the repair/replacement of sbl tweeters which does include Hylomar Blue application directions. Unsure if this is no longer best practice? or you can just leave what has already been applied at the factory?
Wikipedia on Hylomar Blue makes very interesting reading for those who are interested.
Different types, essentially a gasket that stops horizontal slipping and expansion, used in the aeronautical industry by Rolls-Royce back in the 50s. Im sure many other interesting facts to be had.
You may be right, but I can’t see any signs of hylomar on mine - I guess I’ll know for sure when I remove the tweeters. Certainly it’s required on SBLs etc. as they need to be perfectly sealed, whereas the Sl2s are open.
I can what you mean, just the syringe came with the tweeters from Naim central.
Should be fun to explore at the end of the day.
Yeah, I’ve got an expensive box with spare tweeters “just in case”. Like @Richard.Dane my intention was to only put them in if my tweeters failed, but every so often I do wonder about swapping them out to see if there’s a difference.
I’ve even got replacement adhesive foam that goes onto the front of the tweeter (I assume to help with reducing reflections or helping diffraction or something).
Yes I remember when you brought them the tweeter surrounds were shagged. Did you get the Naim spec tweeters or off the shelf jobs?
Naim spec from the last manufacturing run. They took quite a while to arrive from Falcon - I had almost forgotten about them
It’s like a solder joint stress relief. If you did not hot glue it back. The solder connection will break off
If it’s soldered properly then the wire will break before the solder connection, believe me. Anyway there shouldn’t be any significant stress on it.
When I had to replace the tweeters in my SL2s @Cymbiosis made them up as an assembly of tweeter, new cables and new sockets, all presoldered. The holes for the sockets are keyhole shaped so the sockets can be inserted with the wires already soldered, dropped down into the narrow bit of the keyhole and the retaining nut tightened.
Can’t swear to it but I do think I had to apply a thin film of hylomar blue when installing the tweeters.
Tweeters in my DBLs are only a couple of years old. Two replacement pairs stashed away in the attic.
The sbl tweeters have a small block of brass stick to the back of them, could the hot glue be there for vibration purposes? Or possibly to stop oxidisation? A heat sink? Take you pick .
Many thanks for all the replies
With a lack of response from Scanspeak direct and EU suppliers, I’ve bitten the bullet and gone for the replacement Scanspeak 852100 from Falcon which should be here today with some slightly longer wire just in case the original wont reach
If the tweeter is mounted so the solder lugs are at 12 and 6 o’ clock the mod required should hopefully be only to the mounting ring. I wont know though until I get chance to see it in the flesh whether this re-orientation will cause the side lugs to foul on the upper and lower cabinet. The dilemma will then be whether to attack the cabinet or the tweeter mount arm - I suspect the former to give max integrity to the tweeter mount
Someone suggested using a fabrications company for the mod. rather than doing a DIY job, which I may do being only 8 miles out of Sheffield (although my impetuosity may overrule my common sense!)
Looking at mount ring and the U/S tweeters Ive removed, there is some sticky gunk on them so as mentioned above some has been applied from new, but will take Richards advice and not use Hylomar
I recall there was a specific torque setting for the bass/mid units, is there a specific torque setting for the tweeter?