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Magnepan Full-range ribbon and planar speakers |
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#1
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Fuses and Ribbons in the 20.7
If I understand it correctly, fuses are supposed to protect the ribbon by breaking/burning before the ribbon does. That has NOT been my experience with the 20.7s.
In my case, more often than not, the ribbons break and the fuses remain intact. In about two years of ownership, I have broken more ribbons in the 20.7 than I did in over a decade of ownership with 20.1 and 3.6 prior to that. Is anybody else experiencing something similar with ribbons breaking before the fuses? |
#2
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Only had that happen once in my modified MGIIIa's, blew the fuse twice though. That time was my stupidity, The ribbon let go during an audio get together at my house only to notice the next day. :^(
Regards, Jim
__________________
It's all about the Music, but I sure like the way my gear makes it come alive! |
#3
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I don't own the 20.7, but I run the 3.7i speakers and haven't had any trouble with blown fuses or ribbons. I play them reasonably loud at times, but never push them too hard. Typically fuses can only protect drivers by limiting the current flow and resultant power delivery, whereas if you push your amp too hard distortion can cause the driver to blow without blowing the fuse. When you have blown the ribbons are you playing them very loudly and possibly pushing your amp into clipping distortion? The amp driving Magnepans needs to have sufficient current capability into their four ohm impedance, and higher power amps tend to be best suited to driving them effortlessly in my experience without damage.
Last edited by audio bill; 06-15-2016 at 06:44 PM. |
#4
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Quote:
I just had two blown tweeters and the filament in the fuses did not even curl. In the past, if I was playing the 3.6s very loud, I would check the fuses afterwards and if the filaments looked a little bit 'crooked' I would replace them. This time, with two ribbons gone, the fuses look like nothing happened. It is very odd. |
#5
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Sorry to hear about your ribbons failing. Frustrating.
I've had my 20.7s for over three years and they are working flawlessly. I even changed the tweeter fuse for one with a slight higher current rating than the original(3.0 amps instead of 2.5 amps) and I have not had any failures yet. You might have a flawed crossover that sends too much current to the ribbons. |
#6
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#7
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I have had no trouble with my 20.1's, but I had a ribbon just die in my old 3.6R's. It was never explained.
__________________
Poland: Silenzio, Simaudio, Luxman, Bricasti, Bryston, Shunyata, Stax, Meze, Linn, Audeze, and Dan Clark Headphones, Stax, Wireworld, Crystal, Nordost, Siltech. Home Main System: Magnepan 20.7, Pass Labs XA 100.5, Audio Research Reference 6, Esoteric P-03, D-03, G0-Rb, DV-60, Clearaudio Innovation & Tangent arm, VPI HW19 MK4 & ET 2.5 arm, Mark Levinson 37, Aesthetix Rhea Signature, Magnum Dynalab Etude, Kiseki PHS, Sumiko Palos Santos Presentation,Wireworld, Crystal Absolute Dream, Shunyata, Acoustic Zen, and Stealth cables Other Avalon Arcus, Snell Type AIII, Tympani IV, Green Mountain Europa, Martin Logan CLS, Tympani 1D, Counterpoint, GAS, Yamaha, Levinson, Perreaux, Proceed, Theta, Linn, and other collectibles, including 60 different headphones and 30+ headphone amps, over 60 cartridges, and too many cables, stands, and tweaks to list. |
#8
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Seems odd that the fuse doesn't protect. Sorry if its an obvious question but is the fuse the correct rating and type i.e.delay or instantaneous. You could try a slightly lesser value of fuse if you still get a persistent problem. I also wouldn't think the Classe is to blame.
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#9
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In my case as well as the other few users, the fuses are stock standard fuses and have never been swapped out.
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#10
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blown ribbons
I too have had multiple ribbons go..in both channels, not due to amps..bryston 28sst2's..spoke with bryston and magnepan ..wendell informed me to make sure to notify him directly of blown ribbons in 20.7's.
Hope it was just a bad batch of ribbons..so far so good..6+months with no problems...in the first 2 years I think i went thru about 4 tweeters....lol |
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