[Vangelis]

My question is about the 3.7i xover design and specifically the signal to path the fuse holder, that's all, nothing else. Respectfully, I ask folks to stay on topic and please not turn my question to debate about the usual, that can't make a sonic difference. Really please, I just want my question answered.
Thanks

[Davey]

I answered your question.  It won't make any sonic difference which way the fuse is installed.

If you try installing the fuse both ways and you hear a difference........then you're hearing things. 

I don't care what the manufacturer says.  If they claim these fuses are directional in an AC circuit, then they're full of it. 

Some things are true whether we believe them or not. 

Dave.

[kevin360]

It has been addressed.  It's just that some folks refuse to believe the conclusion. 

Fuses are not directional......and even if they were it wouldn't make any difference in this case since it's an AC circuit.

Any other conclusion (or claim) is a non-sequitur.

Dave.

I disagree with the second half of the middle line.

I think the better way to state your point (and it's better because it turns the tables on the erroneous concept) is that if the fuses are directional, then they aren't appropriate for this application.

[Davey]

There's always a critic. 

I'm getting really good at sensing when people are not getting the answer they want to hear.  And I think we have a case here.

I can tell Vangelis that there is no signal entry or exit on the fuse holders....and that the fuses are not directional....and that there is no signal direction for anything.....but I just don't think it's the answer he wants to hear.

Dave.

[Rclark]

I have a question for the Magnepan factory. How does it feel to make such incredible speakers?  I fired mine up last night after many, many months of running something else, and if you have the space for their displacement, there is no replacement.  Or something like that 

[SteveFord]

Here is the official answer to the great fuse controversy:

An audio signal is alternating current (AC). Current goes both directions. We have never heard a satisfactory explanation why these devices are directional. A diode is directional, but you would not want that in the signal path.

[Davey]

There's no "great fuse controversy."    But, it's a good answer from Magnepan and completely correct.

There is no direction of signal flow for tweeter and midrange fuse holders.  There is no entry or exit......whether it's a 3.7i design (or any other.)

The directional installation requirement for these "directional" fuses is complete nonsense.

Dave.

[bdp24]

There are a couple of great threads concerning the issue of fuses on the Music Reference AudioCircle forum. Before you put a Hi-Fi Tuning Fuse in your tube power amp, you will want to read what Roger Modjeski has to say about them. Hopefully BEFORE your amp is damaged by one!

[jarcher]

Yeah - lets please not migrate the fuse debate over to the planar circle.  Think that one's 

[Davey]

I don't really think there's a debate or controversy on the HiFi tuning fuses.  They're a total snake oil product, plain and simple.

Regarding regular fuses......I think Magnepan should get rid of fuses and fuseholders entirely on their speakers.  They serve no useful purpose at all, but provide multiple possible connection failure points and also possibilities for distortions even when the fuses are intact.  If some sort of protection for the ribbon tweeter is deemed necessary, there are way better safety options than fuses.

Dave.

[jarcher]

It would seem that the fuse thing is perhaps a legacy remnant for Magnepan design and unnecessary and detrimental.  But perhaps those guys have some reason I as a non engineer am missing.

So that would be a good Magnepan question : why the fuse / fuse holder?  Is it REALLY necessary, or just something they think they need from a product reliability / liability stand point?

[Davey]

Yeah, I think that's probably correct.

However, I'm not convinced there's a reliability (or even liability) concern here, any longer.  Power amplifiers are much better designed nowadays with respect to protection of both themselves and the speaker load.

If a liability concern, Magnepan should simply state they are not responsible for damage to drivers from poor/marginally protected amplifiers.

Any potentially damaging transients that might make it to a speaker load are most likely externally created and would not be prevented by a fusing scheme anyways.

For the life of me, I can't figure out why somebody would want to insert HiFi Tuning fuses in their signal path.  But, the mind of an audiophile works in mysterious ways I guess. 
If there's a concern for the ribbon tweeter, I would use a resetable polyswitch.

Dave.

[SteveFord]

You ask, you get:

The fuses are needed to protect the drivers. That is what fuses do.

---------------------
They have protected my speakers over the years when upstream components (amps, preamps) decided to blow themselves up.

[Davey]

Yeah, I guess that's what I'd expect them to say. 

However, the query here is less about the "protection" aspect of the fuses but more about the non-linearities of the fuse under normal operation.  It seems like that aspect of the fuse operation might not be understood by them. 
Replace the existing fuses temporarily with a 30 amp glass fuse and see if you can't hear the difference immediately.

Anyways, depending upon the failure, it's speculative to assume the drivers wouldn't have survived if the fuses weren't there.

Oh well.

Dave.

[Vangelis]

Steve, There are threads even with in the Planner circle to debate issues and make make blanket statements regarding how a listener can't possibly be correct in their interpretation. My assumption here is that this / your  thread titled "Do you have a question for the Magnepan factory" was to be conduit to consolidate questions that Magnepan owners can ask questions to the factrory. I was in error. Perhaps my mistake was to frame the reason for my question. it's  clearly apparently that you feel my question is without merit. Perhaps you might make a disclaimer that only questions you consider valid will be passed on to Magnepan. Thank you for your consideration.

[kevin360]

This is not about contradicting anyone's personal interpretation. Your initial assumption is simply erroneous – there is no signal flow direction. Steve posted Magnepan's official response (Magnepan is the 'We' at the start of the third sentence - the fourth sentence echos my previous comment). Ergo, your latest assumption is also wrong – you were not snubbed. I'm sorry that you find the answer unsatisfactory, but that is the only answer that could have been given. Steve does not need to add the disclaimer you suggest, nor does the reason for your question have anything to do with the meaning of the word 'alternating' (alternating current).

As a matter of fact, Dave's initial reply was restricted to your question. His reply presaged Magnepan's. It was a simple statement of fact, completely devoid of value judgment. In an AC circuit, the signal flow is bidirectional.

The correct answer to your question is the best answer you can be given, even if it's not the answer you want to receive. Would you rather someone lie to you?

I don't know about you, but I continue to learn (about as much as I can). Often, learning forces me to change the way I think about things. Embrace these chances for adjusting your paradigms – they represent the power of culture at its best. 

[jarcher]

I think he's received a reasonable and reasoned response to his question.  He is also welcome to ask Magnepan directly if he wants the same answer repeated directly from them, or contact the fuse manufacturer to see if they have anything else to say.  I don't detect any bias or refusal to recognize merit in Steve's response to his question. 

[SteveFord]

Those are the answers from Magnepan.

An audio signal is alternating current (AC). Current goes both directions. We have never heard a satisfactory explanation why these devices are directional. A diode is directional, but you would not want that in the signal path.

The fuses are needed to protect the drivers. That is what fuses do.

[Davey]

Gents,

This one's a no-win situation.  Ahem.

It's irritating...to me at least...that these kind of snake-oil products foster this kind of misunderstanding in the audiophile community.  I wish I knew the solution. 

Oh well.

Dave.

[SteveFord]

Don't buy their stuff, I guess.

Okay, back to Questions Only, please.