 You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Ok, so I have some Ruark CL30 3 way speakers. I recently got a new (used) amp. When trying the new amp I thought something sounded a bit odd, and found that one of the mid drivers was not making any noise. After a few hours of trying to dismantle them, I have got the problem driver out and it is reading open circuit, so I am guessing that is bricked. I wasn't playing them particularly loud so I can't see why, noting visible on the outside of the driver to suggest a problem.
Anyway I tested the DC resistance across the binding posts which read open circuit, for the mid range on both the speaker without the driver and the healthy speaker. Same for the tweeter, and the bass woofer read about 5ohms. Reading across the broken woofer connections I get around 1.5ohms. This doesn't seem right to me, or is it?
Not sure if the amp can be blamed for the problem or whether this is an unhappy coincidence.
Anyone?
Could be right - the tweeter and mid almost certainly have series caps which block DC and the woofer probably has a big series inductor with high resistance and some impedance correction RLC bits which might pass DC with the resistance showing.
It sounds reasonable: if the drivers are still wired to the crossover when you're measuring them then you wont get the readings you expect. Also - is the amp connected when you're measuring?
#Edit: I'm just checking some old working ruarks here and the impedance at the binding posts show open.
Thanks, though it might be due to caps but couldn't remember enough of school. Surprisingly little I can find on the net considering the geekyness of the subject
Amp not connected
Oops I missed your last post there before my edit above.
Thanks, which do you have?
Any idea what the chances are that a faulty amp would have done it? It's a bel cano pre3 and s300 power if that helps!
I've a few different sets of Ruarks: the ones I checked are Talisman II's.
I guess an amp could do it - but I'd guess you'd hear something going wrong. Assuming you've not being using it at vol 11.
Are you able to disconnect and compare the 2 crossover's components? That;s where I'd start : capacitors etc.
Also do you know what driver make / model the midrange is? They tended to use the same makes across models (eg VIFA / Scanspeak / SEAC etc).
#Edit - What I'm getting at is that the midrange is probably knackered. You have a fair chance of picking up a used driver on ebay - possibly from a differently model ruark or even a different brand of speaker. What caused the problem: I'm not sure but I'd eliminate as many variables as possible.
Thanks, very useful. Yeah it is a scan-speak, I have found a replacement though at the moment it seems he will only sell a pair which is prohibitively expensive. It is a bit painful getting to the crossover but I have looked at the one with the faulty driver, there is nothing visibly bad, caps all look ok from the outside (they appear to be Ruark branded) and the resistors also fine. No blown caps or burn marks.
And nope, sadly wasn't going up to 11!
Could just be a dodgy driver, little you can do (sometimes you can fix wiring on woofers)
I used to do Ruark's warranty, and design, 20 years ago!
Yeah I remember that from a previous thread! Can't see any problems with the wiring on the woofer, but then I haven't taken it apart (have not taken the magnet off or anything, is it possible to do that?
Looks like I'll be shelling out for a new driver anyway
Have you spoke to Ruark? They were able to supply me with a new tweeter for my Sabre2's a few years ago.
Wilsmlow have been really helpful in the past too
http://www.wilmslow-audio.co.uk/
I haven't, but I will try, when I previously spoke to them they weren't very helpful as they had stopped doing the big speakers