I don't believe there is a problem that exists on the crossover any longer. Let's just do a few more tests.
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
@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? |
Here are my posts from that day: 06-16-2021 5:40pmOkay, its been a rough couple days. I just got done drawing the schematic and looking at the words and measurements again. Just one note, do all measurement in the resistance mode, not in the diode mode as the diode mode really doesn't tell us anything. You don't need to disconnect one end of the resistors to check each resistor. So with no drivers attached, between the midrange terminals on the crossover board, you get close to 2.2 ohms, but it's not a dead short correct? For the tweeter terminals, you get close to 0 ohms, but not a dead short correct? At the mid/hi amp inputs, you get essentially OL after holding the probes on the terminals for few seconds, correct? What happens when you reverse the leads on the mid/hi amp terminals? Does the meter go to (-) xxx.x ohms then to (+) xxx.x ohms before going to OL? This is a dumb question, but just so I understand everything. When you use only one amplifier to power the speaker in the full range (bi-WIRE) mode, the (+) terminals of the inputs are connected together. And separately, the (-) terminals of the inputs are connected together, correct? The photos are gone, but don't think we need it again. From your DC voltage measurements at the amps, they look healthy. Please answer all of my questions in order, so we don't get confused, thanks.fiesta75404 posts06-16-2021 5:48pmWhich resistor, if it's STILL showing a dead short or 0.00 ohms? This is the one mentioned in post 6-16 @ 12:59amfiesta75404 posts06-16-2021 7:06pmCORRECTION, sorry. The last test on the mid/hi amp terminals on the crossover board; when I asked to to test and then reverse the meter leads and test again. The multimeter should be set on the "diode" test mode, not ohms. The readout should display some voltage then go to OL. When you immediately reverse the leads, the display should read -x.xxx volts, then change to +x.xxx volts before going to OL. Hope your meter has a diode test function, but it's not absolutely necessary. This test just shows that the caps are charging in both directions. I still can't explain why the system worked with one amp when the mid/high amp was in repair... This is troubling. rodman - I appreciate your comments. 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. The only test I want from him before finalizing everything is the dc resistance across the tweeter terminals of the board, because his last info on that makes me think the resistance he measured was below what I expected from a 0.22 mH inductor. All help is welcome. |
- 119 posts total