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testing a crossover

hi guys and girls i have a
problem with my 3 way  wilmslow-audio mirrage speakers , I am hoping you can help me with the problem,.
Lately my power amp went pop and i sent it away for repair,when i
received it back {repaired} it went pop again,on sending it back to
the repair technician ,he has come back to me ,and asked me to take
some ohms readings on the speakers, on testing the speakers , i run
these speakers using 2 power amps{Arcam Alpha 10s,using one for low
pass{bass} and the other for MID/HIGH,this is the amp which keeps
blowing,on the high /mid,on testing the terminal the bass{low pass}
read {left speaker]7.9 ohms ,right speaker bass 6.8ohms, But on the
left and right speakers hi/mid ,both read 0.0 ohms,{which we all know
is wrong}
BUT the strange thing is,when the blown amp was away,i only used one
power amp to run both speakers in bi wire config,and they worked
ok,all being a bit lack of bass and tightness,but still sound great.
So i stripped both speakers and checked the drivers,all 6 drivers
where good no shorts reading approx correct ohms for age,{Speakers
disconnected from x over}.can any one help with this,i would be so much in debt.
kind regards Mark
likklegerry

Showing 7 responses by rodman99999

rodman99999
6,206 posts
 
@likkelgerry-

       "30 years of Hifi, i dont think one meal will cover that....you know how we get!!"

        Exactly why I'm single, again (well: one of a FEW reasons, anyway)!
rodman99999
6,206 posts
 
@likkelgerry-    I do not envy you being so far from someone versed in electronic repair.

       Here's hoping you are able to locate the issue and get it resolved, without having anything further go awry with your amp.

        Unless the bi-amp configuration made a MAJOR leap upward, regarding sound quality, to your ears; I'd button things back up and run with one!

         Meanwhile: take the Wife OUT for some Meshana Skara or Mousaka and help her relax!     Top it off with some Marudnik (are wild berries in season over there?) and make her love you, again!

                                


       
rodman99999
6,206 posts
 
@fiesta75-     " I just don't want the OP to do anymore work on the boards before doing tests. It seems like he is doing rework in the middle of the tests and that could make some tests invalid. This could create more problems as I'm sure you know."

                              I get that and agree, fully!

       Still believing the problem to exist outside of the crossover components themselves: I'll stop flapping my fingertips!

     
rodman99999
6,206 posts
 
@fiesta75-   I don't see a post, from you, dated 6-16 @ 7:06pm, at all.

     Nor anything vaguely explaining why nonpolarized caps behave like they do and are supposed to, when presented with DC, which was my ONLY intent and, as I've mentioned twice now, "just FYI/fun facts"..

      I did see something about connecting DC, and what readings may occur, at the terminals, from you.

      Given his question, regarding his DMM readings, when changing the polarity:   "Diode test on mid/high -OL
when reversed is flashes 2.2xx,then goes to OL
every time i reverse leads it flashes something {2.2xx}not sure its voltage,it doesnt tell me that"      to which I replied,  wasn't even posted until 6-22 @5:10am, I have to ask:

                                                     Are you a prophet?
rodman99999
6,206 posts
 
@likkelgerry-  Apparently: I wasn’t clear enough, when answering the question you posted (on 6/22).

     NOTHING in my answer has ANYTHING TO DO, with the problem you’ve experienced. (specifically why I stated, "just FYI/fun facts")

     Any PROPERLY FUNCTIONING nonpolar/bipolar capacitor, will act the same way, when presented with DC.

     Once they charge in the direction of the DC current’s flow, they BLOCK any further DC, which (when used as coupling caps) is their intended purpose.

     What I suggested would not damage ANYTHING bigger than the typical tweeter, OR: I wouldn’t have suggested such.

                          Obviously: my use of the word, "POP" triggered something.

                             btw: I still stand by my first post to this thread (on 6/10).

     IF your crossovers were truly functioning properly (everything sounded as it should), when correctly connected to ONE amp, all of those crossovers’ internal components were fine, to start with.

                                              "...my wife is going crazy."

                                                             I’ll bet!
rodman99999
6,206 posts
 
@likklegerry-    re: Your first post on this page:

 "Diode test on mid/high -OL
when reversed is flashes 2.2xx,then goes to OL
every time i reverse leads it flashes something {2.2xx}not sure its voltage,it doesnt tell me that"

      Only here to address that question, as I didn't notice any other answer (just FYI/fun facts).

       A non/bipolar cap, when presented with DC, will charge in one direction.  Reverse the polarity and it will discharge and charge in the opposite direction.

            That's what your DMM is reading, for that brief instant.

       As an experiment: Connect a non/bipolar cap in series with a speaker.    Don't use a tweeter, unless it's expendable.

        Touch a 9V battery's + post to the open lead of the cap and -, to the open speaker terminal.    Hold it there, for a few seconds.     Longer: the greater the cap's values

         Reverse those connections and you'll hear a *POP, every time.

                                        *The cap, discharging
rodman99999
6,206 posts
 
    Wilmslow Audio built some fairly complex crossovers, for some of their systems, though I’m not familiar with the Mirage’s.                                                                                   A DMM can easily read impedances, through the inductors in a woofer’s series circuitry.     The capacitors in mid/tweet series circuits are another story.                              I could (easily) be wrong, but: I’d put my money on the speakers/crossovers being OK and something in the amp, or cables/connections: the culprit.
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