Welcome! Need support, you got it. Or share your ideas and experiences.
Return to Planar Speaker Asylum
71.239.112.200
I was enjoying my 20.1's and noticed my rt speaker tweeter was out, replaced the fuse but the new one just fried right up, visually the ribbon looks fine I checked the connections and they are fine. Whats causing the fuse to burn right up?
Follow Ups:
Apparently there is a short somewhere on the way to the tweeter - like stray strands from the wire. You can take out the tweeter and measure it's resistance to see that it is ok, and if so you will probably need to open the speaker and check the tweeter crossover to make sure nothing is shorting there and the capacitor is working properly. You can use the opportunity to install a higher grade capacitor and better fuse and fuse holder.
To be sure, the tweeter cap should be disconnected and measured with an LC meter (you can use a PC with REW software instead of an LC meter.
You can also check if the problem has something to do with your amp by swapping amp channels to the other speaker.
Another possibility is that the high pass cap in the external box is not working properly and letting in signals at too low a frequency so that might burn your fuses. I don't expect that is an issue.
I remember doing a 'kick test' for capacitors.
Hook the leads from a DVM up and the resistance will go VERY low and immediately begin RISING as the cap charges. When the cap is fully charged, resistance SHOULD be in the meg range or greater.
That is a 'fast and dirty' way to see if it is still ACTING like a cap or is shorted / open internally.
The meter? In those days *(pre DVM) I had a Simpson VoltOhmist. (260) They apparently made a bunch of different versions of this meter. The company supplied unit had a mirrored meter and enough current to check SCRs and such.
Too much is never enough
I found it! when I tilted the speaker for further checking I saw that the ribbon had failed and broke,so looks like a call to magnepan will be in order.
Thanks to all for your help.............
Another example of a fuse not protecting the ribbon tweeter.
In any case, you need to find the cause of the failure before blowing another $100 on a tweeter replacement. Consider the cap in the HP filter - if it is shorting then the impedance of the HP filter would be about the same as the shunt coil ( < 0.5 ohm) and this would blow the fuse and apparently the ribbon as well. Just put an ohmmeter across the leads of the cap -- if you get a low reading (should be infinity), the cap is bad.
Edits: 08/09/15
So do you think I have more of a problem than just the ribbon?
I was wondering why I would still blow a fuse if the ribbon was broken. I would hate to replace the ribbon if there were another problem causing it.
Neo is correct. It's certainly worth checking other components in the crossover network and/or wiring to verify everything is good. Otherwise you might install a new ribbon and have it fail as well.
The fact that you blew another fuse with the ribbon already bad points to this possibility.Dave.
Edits: 08/09/15
The ribbon and the fuse are very similar - basically a thin strip of metal. Which one blows first is a horse race -- they both heat up to the melting point -- and there is no reason that it can't be a dead heat. In any case, these things don't go pfft without a reason.
A little troubleshooting is required. An easy first test would be to disconnect the external box, remove the midrange fuse and probe the input terminals with an ohmmeter. You should see infinite resistance after the first few seconds. If you see anything other than that it's an indication of a short circuit....or internal connections touching when they shouldn't....or bad 10uF capacitor....or something similar. If that's the case you'll have to break into the speaker and investigate further.
Dave.
No, everything is the same.
About two years ago the mid range failed the plastic that mounted the inductor was melted it turned out that the panel failed and I sent it back to Magnepan for repair, at that time I replaced the inductor and the caps for the mid range but left the tweeter stuff alone.
When I put a new fuse in the tweeter never comes on and the fuse just does a slow burn.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: