Post power cut treble fault

Posted by: Bosh on 25 April 2018

Unfortunately I didnt get thhe the system quickly enough after a 10 second(ish) power out and the re-connection which was accompanied by a high pitch screech has resulted in very much attennuated treble - I'd guess at 20% of previous output

Its an active SL2 system so anyone any idea which box has taken a hit? Is it likely to be the treble power amp, the SNAXO crossover (or its PS) or the tweeters themselves although I'd have thought they'd just blow completely?

Posted on: 25 April 2018 by Richard Dane

It may well be the tweeters. You could put back the PAXOs and try running passively. That should quickly isolate where the fault lies. If all fine, then suspect treble amp.

Posted on: 26 April 2018 by douglas

In an earlier time I ran a pair of Naim 135's and KEF 107's. I heard a tiny whistle and found the LH tweeter was wrecked.

All this a week before Christmas! The crossover in the speaker had failed and also taken out one of the 135's. KEF no longer had spare tweeters so I managed to get a pretty good match from Wilmslow Audio. KEF did have a pair of crossover units so the head units went to Maidstone for fitting. Both 135's went to Salisbury for servicing.

It took till late January before all was back to normal.

Douglas.

Posted on: 26 April 2018 by Innocent Bystander

Listen closely beside the tweeters - are they both subdued or just one? If one then swap over the cables between the two tweeter power amps to see if the priblem swaps sides - that would tell you if it is the tweeter itself or so ething before it in the system.

If both channels similar, is there distortion, especially if you turn up the volume? Purely reduced output duplicated between tweeters doesn’t immediately strike me as a fault with the tweeters themselves.

Posted on: 26 April 2018 by Bosh

Thanks for all the input.Just got a chance to look at it again and after 24 hours with the treble amp off it seems the right treble has kicked back to normal

So, to save a trip into the filthy depths of the loft to get the paxos I swapped the tweeter leads over and its now definitely the treble on the left speaker that is subdued (and also distorted?!)

Therefore the finger does seem to point to tweeter damage, although why has the right one now recovered? Do I get a replacement tweeter to drop in (I only replaced them a couple of months ago after a system re-connection accident) or is it prudent ot get another pair?

Posted on: 26 April 2018 by Japtimscarlet

Get a pair

Put them both in

Keep the working one as a spare

Simples!!