Has anyone ever blown a fuse?

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Emil

Has anyone ever blown a fuse?
« on: 24 Mar 2012, 06:16 pm »
Thinking of bypassing them altogether. Did it with my 1.6s and noticed a very noticeable improvement but have my reservations now with the ribbons on my 3.6s.
So, under what circumstance have you blown one? Improvements worth the risks for those how have done it? Dont be silly and leave the things the way they are?

kevin360

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Re: Has anyone ever blown a fuse?
« Reply #1 on: 24 Mar 2012, 07:13 pm »
Once, under extenuating circumstances, I blew a tweeter fuse on one of my 3.6s. I was working on my tube phono preamp at the time and I erred in my assessment of the completion of the project. All is well now, but I did open a fuse. Knowing full well that the 3.6s were short term speakers, the only thing I ever did to them was mount them on Mye Stands (now supporting the 3.7s). I did dig into the 3.7s a little.

The QR tweeter is fairly robust compared to the true ribbon, but a ribbon replacement is not that expensive (in the grand scheme of things) and I've read reports of ribbons that weren't protected by their fuses. So, you pose an interesting dilemma – to walk the high-wire without a safety net that may not even save you, or to hang on to that security blanket (spawning the next dilemma about which fuse arrangement is best).

My preference for now is to keep the tweeter fuses – primarily because of a fairly recent amp change, but also because that change was from solid state to valves. Still, a voice in the back of my head is telling me to man up and dump the fuse. After all, Magnepan will be happy to help if I kill a tweeter.

Wayner

Re: Has anyone ever blown a fuse?
« Reply #2 on: 24 Mar 2012, 07:32 pm »
Kevin's point is "nail on the head" straight on. Speakers blow because of usually only 2 reasons, amplifier failure, or volume control abuse.

We know that the worst signal a speaker can't deal with is a clipped signal, which in reality is DC voltage. At high current levels, the driver simply can't deal with this, and that energy is turned into heat, which destroys the driver.

Will a fuse stop this? Maybe it will, maybe it won't.

My Martin Logans do not have fuses, and I am the idiot at the controls.

Wayner  :D

SteveFord

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Re: Has anyone ever blown a fuse?
« Reply #3 on: 24 Mar 2012, 08:00 pm »
I've popped the fuses but they've all been due to operator error up at the preamp with the tape in/out buttons on Carver gear.
I don't know what the damage would have been with no fuses in place but fuses are cheap.

Emil

Re: Has anyone ever blown a fuse?
« Reply #4 on: 25 Mar 2012, 04:54 am »
Biggest fear is blowing the tweeter. Not the replacement cost but the installing of a new one. 
How difficult is it? Soldering involved? A big pain the a$$?

medium jim

Re: Has anyone ever blown a fuse?
« Reply #5 on: 25 Mar 2012, 05:16 am »
Kevin:

You have less chances of blowing a fuse with tube amplification as it doesn't clip the same as SS does...you will hear compression of the vocals, especially female vocals with tubes, whereas, SS will just clip and there she blows. 

Most tube amps have a protection fuse in case of a tube failure as well to protect the speakers from spikes. 

Even with all of this, I still prefer to run my maggies with fuses and with vacuum tubes!

Jim

josh358

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Re: Has anyone ever blown a fuse?
« Reply #6 on: 25 Mar 2012, 04:11 pm »
Biggest fear is blowing the tweeter. Not the replacement cost but the installing of a new one. 
How difficult is it? Soldering involved? A big pain the a$$?

The ribbons are designed to be easy to change, you get a new driver from Magnepan, swap it in, and send the broken one back.

If you want, you can save money by just getting the ribbons and replacing them yourself, but that's apparently painstaking work.

rollo

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Re: Has anyone ever blown a fuse?
« Reply #7 on: 25 Mar 2012, 04:56 pm »
Emil, with the volume levels you like now and then, keep the fuses. Too much volume WILL kill the tweeter. I know my buddy Scot Markwell did just that to our Maggies. The tweeter installation was a piece of cake. no worry, just money.
   If you can control your urge and stay away from from the threshold of pain volume  removing the fuse does sound better. Maybe. Leave them in. Blast away. :lol:


charles

Letitroll98

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Re: Has anyone ever blown a fuse?
« Reply #8 on: 25 Mar 2012, 05:54 pm »
Well the OP question is kinda mute for me now because I've removed the fuses in my MMG's.  Obviously these are QRs not TRs like the OP's, but for what it's worth I didn't blow any fuses before I removed them either, using SS amplification.  Sound quality was much improved by removing the fuses from the circuit. 

I would note that none of the other 5 pairs of speakers in the house came with fuses and the one speaker I blew up took out both woofer and tweeter.

josh358

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Re: Has anyone ever blown a fuse?
« Reply #9 on: 25 Mar 2012, 09:24 pm »
Well the OP question is kinda mute for me now because I've removed the fuses in my MMG's.  Obviously these are QRs not TRs like the OP's, but for what it's worth I didn't blow any fuses before I removed them either, using SS amplification.  Sound quality was much improved by removing the fuses from the circuit. 

I would note that none of the other 5 pairs of speakers in the house came with fuses and the one speaker I blew up took out both woofer and tweeter.

Without the fuse, it is possible to damage the quasi-ribbon tweeter if something goes wrong in your system or you play music at insane levels. I saw a photo of a diaphragm that had wrinkled, apparently what happens with planars is that when they heat up, the metal and plastic expand at different rates and eventually they go their merry way and you get delam and wrinkling.

I think the probability of that happening is low if you've had the speakers for a long time and never blew a fuse, but it can happen. Whereas according to Wendell Diller, the fuses are sized to give the tweeters complete protection in torture tests.

Robin Hood

Re: Has anyone ever blown a fuse?
« Reply #10 on: 25 Mar 2012, 11:11 pm »
Whereas according to Wendell Diller, the fuses are sized to give the tweeters complete protection in torture tests.

That's what I want to hear - complete protection in torture tests.

Of course my interest is in seeing just how loud the Mini Maggies can play without distorting or damaging the speakers. Hopefully it is the music distortion that sets the limits and not any permanent damage to the speakers.

goingsolo

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Re: Has anyone ever blown a fuse?
« Reply #11 on: 25 Mar 2012, 11:45 pm »
I saw a photo of a diaphragm that had wrinkled, apparently what happens with planars is that when they heat up, the metal and plastic expand at different rates and eventually they go their merry way and you get delam and wrinkling.

I inherited a pair of MMG with one panel looks exactly like you described - the tweeter strips of one panel were wrinkled looking thru its sock.
I didn't know/think the tweeter was blown because I could still hear the high freq coming out when playing music.  I threw them into storage because the panel with wrinkled tweeter sounded softer than the other side and didn't have time to investigate yet.

Do you think I would still hear music (hi freq) with a blown tweeter?

josh358

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Re: Has anyone ever blown a fuse?
« Reply #12 on: 26 Mar 2012, 12:57 am »
Do you think I would still hear music (hi freq) with a blown tweeter?

Definitely, as long as there's no break in the wire. I've read that even speakers in which the wires have mostly lifted from the diaphragm will still make sound.

You could talk to Magnepan about repairing the MMG, though given that a used pair goes for $400 the repair might turn out to cost more than it's worth. Even if the repair doesn't turn out to be financially practical, you might be able to sell the good MMG on Ebay to someone who's in the same boat.

I.Greyhound Fan

Re: Has anyone ever blown a fuse?
« Reply #13 on: 26 Mar 2012, 01:17 am »
I inherited a pair of MMG with one panel looks exactly like you described - the tweeter strips of one panel were wrinkled looking thru its sock.
I didn't know/think the tweeter was blown because I could still hear the high freq coming out when playing music.  I threw them into storage because the panel with wrinkled tweeter sounded softer than the other side and didn't have time to investigate yet.

Do you think I would still hear music (hi freq) with a blown tweeter?

Wrinkling of the wires is sometimes normal and can come that way from the factory.  When I bought my 1.6's I noticed that the wires had some wrinkling.  I brought them back to the Magnepan factory as I live 20 min away and they said that can be normal and that they try to pair those speakers with white sock coverings so it is not as noticeable.  They gave me a new pair by the way and they sounded no different. Does the speaker buzz at all?  It it does then the wires need to be re-glued and you can buy the glue from Magnepan.

josh358

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Re: Has anyone ever blown a fuse?
« Reply #14 on: 26 Mar 2012, 01:20 am »
Wrinkling of the wires is sometimes normal and can come that way from the factory.  When I bought my 1.6's I noticed that the wires had some wrinkling.  I brought them back to the Magnepan factory as I live 20 min away and they said that can be normal and that they try to pair those speakers with white sock coverings so it is not as noticeable.  They gave me a new pair by the way and they sounded no different. Does the speaker buzz at all?  It it does then the wires need to be re-glued and you can buy the glue from Magnepan.

I've seen that wrinkling. The problem I'm referring to is wrinkling of the Mylar diaphragm due to thermal damage. That's a different story (unless I suppose it's very minor).

goingsolo

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Re: Has anyone ever blown a fuse?
« Reply #15 on: 26 Mar 2012, 01:43 am »
I've seen that wrinkling. The problem I'm referring to is wrinkling of the Mylar diaphragm due to thermal damage. That's a different story (unless I suppose it's very minor).

I am sorry if I am off topic from the OP. 
That was my first planar experience so I am not familiar with terminology (wires vs diaphragm).  What I saw was the 8 shinny strips that on the tweeter side of the panel were wrinkle compared to the other side which has perfectly straight strips.   

josh358

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Re: Has anyone ever blown a fuse?
« Reply #16 on: 26 Mar 2012, 02:28 am »
OK, that's not a problem then, as Greyhound Fan said the foil is sometimes wrinkled out of the factory. Which leaves open the question of why that speaker sounds duller than the other. Did you check the tweeter fuse?

rw@cn

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Re: Has anyone ever blown a fuse?
« Reply #17 on: 26 Mar 2012, 03:42 pm »
How do they sound? Crank 'em up  :lol: