Thanks for all the comments/suggestions.
Some thought provoking stuff that I’ll consider.
As I said originally the system sound is not a problem and I’m happy with that. It is more how it looks.
I may open a dedicated thread as suggested, but for now, thanks again for the suggestions.
I’m trying to find out a little more about my father’s ATC’s before deciding what to do with them.
TomTom James kindly contacted ATC to help identify them, apparently they’re S70’s from 1979, their second speaker after their first launch, the 50. Beyond this, I know very little about ATC generally
Anyone know any more about these?
Could do with some TLC - which I’m sure ATC would be happy to do (at a price). I can imagine once done they would sound pretty good though?
Send them to ATC for service, and keep them forever. Nothing compares to them
they may be difficult to service as there is cut off date later than 1979 where they can do anything to the midrange dome but deffo worth an ask.
I once asked Alan Sircom if a Supernait 3 with added power supply would drive well a 40. He said that ideally I should get a more powerful amp.
I’d agree. When I auditioned SCM40s driven by 250DR against actives I felt it lacked some tightness and drive that the active version had in spades. I’m aware others happily use a 250DR and even a SuperNait with them, but I wouldn’t myself.
Roger
Same situation here! I had Bowers and Wilkins DM6 from 1979…they were restored and then unfortunately I had to sell them, so to keep these it would be a good decision. They are jewels.
If I could turn back time, I would never sell mine Bowers Wilkins.
Exactly the same experience in my room/system
I’m sure, however too big for me!
Thanks for the comment. I should remember that lesson from my NAIT 3 - paired with some wonderful B&W P5s, it never did have enough drive for those speakers. Replacing it with a Supernait 3 was the best thing I ever did (and replacing the tweeters). 26 yrs on and those speakers still sound incredible, so bearing in mind comments from @xfproductions and others, any auditioning will be done with extreme care.
So the circle closes… those who may have had a passing interest in my speaker swapping may know that after 2yrs with Atc scm11 I fancied a change…
Tried Pmc 20.21- too thin and bright, Kef ls50, nice but the rear port was annoying, demoed Pmc prodigy1 , very good and nearly bought, prodigy5, too much bass!, Pmc 25.21i, really good and nearly bought. All of those speakers had there strengths and some more flawed than others in my room but I missed the atc bass and midrange and I can’t justify over £2k on 25.21i so Tony @BasicallySound offered me his exdem … ATC scm 11 …in black ash this time
back in the fold!
Welcome back! 
Are you planning to open up the rear to make them single wired?
Is so can you take pictures how you do this, still reluctant myself as mine are under warranty still!
These are under warranty as were my last ones… I may but using jumpers at the moment. But if so then I’ll document.
Me too … it would be good to meet up with other Naimites.
Whose leading on the negotiations?
Just a note here; while Naim are happy for members to discuss other brands here, it’s not really on to use the forum to arrange visits to other manufacturers. This should be done via the manufacturer themselves or through one of their dealers. Thanks.
I can fully understand returning to where you were happiest with the sound.
It’s exactly why my Keilidh’s are back where they belong.
Glad you’ve found your happy place again…
Beautiful speakers very nice 
