The reason why the speakers work with a single amp and not when bi-amped is because the crossover is using different sets of inductors and capacitors. When the speakers are bi-amped you are using one set of inductors and capacitors, those are the caps or wiring that has the problem. The inductors are not the issue in my opinion. The wiring is suspect, if the caps test good. Think about what I've said thus far and tomorrow we'll get into the testing if you insist on repairing these crossovers. At this point, I don't think it's necessary for you to measure the DC at the amplifier outputs although that is always good info.
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
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
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- 119 posts total
ill try draw a schem.but its difficult, but ill do my best@ likklegerry, If you can print-out the crossover pcb photo and add all the component position on it with wiring and post the picture, maybe we can figure out the schematic and go from there. https://www.wilmslowaudio.co.uk/ekmps/shops/wilmslow/images/crossover-pcb-452-p.jpg an example: https://ibb.co/3zyQRyG |
OK,lets have a go with this,i have asked wilmlow for adivice ,schems and any help they can give me,but they just say send it in to us,and are not coming foreward with any other help,which is a shame,as these speakers were not cheap,for me anyway.. ive checked the AC voltage on both amps amp driving mid/high which has popped twice, now repaired but running in another system {all good} readings left channel -0.001v {AC] right channel -0.001v {AC] good amp[never popped} runs bass, left channel 0.002v [AC] right chan. 0.002v AC all other components turned off, except amps At this point i should add a little more history,after i got the amp repaired and plugged it back into the system,after about 3 hours it went pop again,so i sent it back to the technican,after ttwo days of him looking at it,he sent me an email asking me to checked my speakers,which is when i realised that was where the problem was,so i dont think it is either amps,i now run the repaired amp in another system which seems to be good,so i think the problem is in the crossovers,as all driver read the correct-ish ohms,but what i find very strange,is that both xo s have gone us,this is a puzzle to me. I am totaly open to any options,but as a retired guy,money is a factor,but would love to find out the fault,but if its easier,i have another two power amps in boxes,but there are lower in power {Arcam Alpha 9p s}. Another question ,is it not AC at the speaker terminals ?,im not sure!! I have removed the caps from one crossover{or one lead} and they check out to be ok on all caps, What do you think maybe suspect on the wiring,or is it just my soldering ?. ANYWAY I THANK YOU SO MUCH FOR ANY HELP regards Mark PS if you can give me a day to work out a schem.that would be great. Mk |
Are you measuring the resistance across IP- and IP+ on the PCB? It looks to me like IP+ routes to two resistors (2.2Ω and 3.3Ω), there's lots of clearance between the tracks and no obvious short. So even if there were a problem further down the line you'd expect to see at least 1.3Ω across the inputs. It's rare for resistors to fail closed circuit so I wouldn't go looking there just yet. The 2.2Ω is in series with the 12µ cap which will block DC, I can't work out what the 3.3Ω connects to under that big cap, but I still can't see how there'd be 0Ω across IP- & IP+. I'm sure I'm missing something. I can see fibres on the PCB conductors but assume they're hot glue or stuffing material. Even so I'd start by cleaning up the copper connected to IP- & IP+ and measuring the resistance across those if you haven't done so already. I'd also check the multimeter by measuring a known value e.g. a resistor that's out of circuit. You wouldn't believe the number hours I've wasted going down a rabbit hole only to find I've measured something wrong or missed something obvious. I'm sure you'll get there in the end with the help of some others here... good luck. |
- 119 posts total