[curbfeeler]

I found that the Norse Series Bi-Wire Jumpers from Nordost made a huge difference in tonal purity, intelligibility and coherence compared to the brass nickel-plated jumpers supplied by Magnepan. The length of these is critical, and they are only made in multiples of the length typically supplied. For the 3.7 the Z-plugs are indicated. Not expensive, so worth a try. http://www.nordost.com/74/norse-series-bi-wire-jumpers
I use the least expensive HiFi Tuning fuses on the 3.7. I may try the Supreme fuses at the tweeters after reading the observations made here. I make no claim to know the science behind the effect of custom fuses. I have heard what they do to improve the sound of my system. Even the orientation of a fuse has made a difference in my Bryston DAC, which observation could induce spasms among the logicians here. When I threw the 3.6 over for the 3.7 I blindly oriented the fuses on the 3.7 as I had for the 3.6. Something wasn't right. I reversed the orientation of the fuses and voila!

[SteveFord]

Out of curiosity, has anyone damaged a Maggie by running without a fuse - too much power, tube blows up, done something stupid with the preamp, etc.?
On the flip side of the coin, who here (other than myself) has popped fuses?

[josh358]

Out of curiosity, has anyone damaged a Maggie by running without a fuse - too much power, tube blows up, done something stupid with the preamp, etc.?
On the flip side of the coin, who here (other than myself) has popped fuses?

I used to blow fuses on my 1-D's. And Mark Winey told me that he's blown fuses on his 3.7's. He's also run them without the fuse, and reports a minor increase in clarity. But he gives the same advice we usually do -- you have to know your system first, otherwise, you risk a very expensive mistake! And Wendell hastened to add that they can tell, so if you screw up it isn't going to be a warranty repair.

Someone posted a photo of a rather spectacularly melted diaphragm on the Asylum maybe a year ago. It had wrinkles in it and what looked like a footprint.

[josh358]

Even the orientation of a fuse has made a difference in my Bryston DAC, which observation could induce spasms among the logicians here. When I threw the 3.6 over for the 3.7 I blindly oriented the fuses on the 3.7 as I had for the 3.6. Something wasn't right. I reversed the orientation of the fuses and voila!

One of the possibilities that comes to mind is that the plating on the fuse or holder was dirty or corroded. This will lead to a subtle increase in distortion and then someone will put in a new fuse or even change its orientation and notice a difference, and conclude that it's a consequence of the new or reversed fuse when in fact, it's more like working a scratchy pot or switch back and forth to clean it.

Even if the transfer function of the fuse were asymmetrical with respect to the direction of current flow, e.g., it was acting like a diode, it wouldn't sound different on a reasonably symmetrical AC signal. And if it's acting like a diode, you have contact rectification problems that won't be solved by flipping it.

[Emsquare]

Out of curiosity, has anyone damaged a Maggie by running without a fuse - too much power, tube blows up, done something stupid with the preamp, etc.?
On the flip side of the coin, who here (other than myself) has popped fuses?

I've popped them in SMGa's. And out of curiosity I derated the fuse I was using for the 2.6 ribbon element from 3A to a 1A to see if they would hold at the volume I listened at. It took several days but I eventually got one. I was almoat proud of that but felt that it was all I could do to get one.

I decline to be one to encourage you into taking the gamble because lightening can and does strike and I want nothing to do with it. I assume your Magnepan's are still under warranty? Mine aren't and I'm a part time idiot to begin with. So I went with some push on clips that fit the fuse terminals to see if it did somethiing good. Darned if I could tell a difference so I undid it after a while.

[Emsquare]

One of the possibilities that comes to mind is that the plating on the fuse or holder was dirty or corroded. This will lead to a subtle increase in distortion and then someone will put in a new fuse or even change its orientation and notice a difference, and conclude that it's a consequence of the new or reversed fuse when in fact, it's more like working a scratchy pot or switch back and forth to clean it.

Even if the transfer function of the fuse were asymmetrical with respect to the direction of current flow, e.g., it was acting like a diode, it wouldn't sound different on a reasonably symmetrical AC signal. And if it's acting like a diode, you have contact rectification problems that won't be solved by flipping it.

You mean there is no downstream on an AC signal? Who'da thunkit? To be clear, I'm trying to be funny again. Do I really have to type in the disclaimer that points out the scenarios where you can get it to be somewhat downstream?

[josh358]

You mean there is no downstream on an AC signal? Who'da thunkit? To be clear, I'm trying to be funny again. Do I really have to type in the disclaimer that points out the scenarios where you can get it to be somewhat downstream?

One asymmetrical scenario that comes to mind is source and destination impedance. It doesn't have a practical impact on analog audio in something the length of a fuse, but in video or digital signaling, it certainly could.

[SteveFord]

Emmsquare,
The ones that I popped the fuses on were both long out of warranty.
Operator error with the preamp tape loop buttons - Lynda's kid got the 1As, I got the MMGs.
Lightening - let's not think about that one.

[kevin360]

Mine aren't and I'm a part time idiot to begin with. So I went with some push on clips that fit the fuse terminals to see if it did something good. Darned if I could tell a difference so I undid it after a while.

Well, confirmation bias works in both directions.

On a more serious note (the above wasn't entirely a joke), perhaps you didn't push things. Did you go for your maximum listening volume when probing the sound with bypassed fuses? IMO, that's where the primary benefit is – unless one has a contact issue (then, all bets are off).

As you may be aware, I am more than a part time idiot – I'm on the job full time. When my pico fuses opened for the third time, I threw caution to the wind and went without. Unfortunately, the system is in disarray at the moment – the VAC is awaiting new (3/4s of a century ago, but they're unused except for testing) front end tubes and the Pass has returned to duty for the second time since it was replaced.

I had intended to return to the world of the protected by now – as a means of testing my impression (I have been surprised by going the other direction and perceiving an improvement when I thought the first change was an improvement – can't both be true (ah, the vagaries (and power) of that creative process we call perception)). Obviously, there's no longer a proper framework for a valid comparison to be made – all in good time. In any case, my initial impression accords with Mark Winey's – at my 'full' listening volume.

When I get things back in order and readjust my 'ears', I want to put the stock fuse back in the tweeter circuit. If that verifies my suspicion, then I want to try a pico with a higher rating.

[josh358]

Well, confirmation bias works in both directions.

On a more serious note (the above wasn't entirely a joke), perhaps you didn't push things. Did you go for your maximum listening volume when probing the sound with bypassed fuses? IMO, that's where the primary benefit is – unless one has a contact issue (then, all bets are off).

As you may be aware, I am more than a part time idiot – I'm on the job full time. When my pico fuses opened for the third time, I threw caution to the wind and went without. Unfortunately, the system is in disarray at the moment – the VAC is awaiting new (3/4s of a century ago, but they're unused except for testing) front end tubes and the Pass has returned to duty for the second time since it was replaced.

I had intended to return to the world of the protected by now – as a means of testing my impression (I have been surprised by going the other direction and perceiving an improvement when I thought the first change was an improvement – can't both be true (ah, the vagaries (and power) of that creative process we call perception)). Obviously, there's no longer a proper framework for a valid comparison to be made – all in good time. In any case, my initial impression accords with Mark Winey's – at my 'full' listening volume.

When I get things back in order and readjust my 'ears', I want to put the stock fuse back in the tweeter circuit. If that verifies my suspicion, then I want to try a pico with a higher rating.

It would be great if you could do a blind test and lay this question to rest once and for all. Just a AB test with a switch and someone behind the curtain. I suppose it's too much work . . .

[kevin360]

Actually, Josh, I intend to do something similar. My daughter has very good ears. I want the get her confirmation and I can do so with a test quite like what you suggested. It's impossible to see from the front what is in back, so I can switch between fuses in and fuses out without her knowing which way they are and she can be the test subject.

Hell, I could do that with the Pass amp in place. The only problem is that I pulled the XO out last night and disassembled it for a good cleaning. It'll have to wait a couple of days, but I'll do it.

Of course, I seriously doubt that will put this issue to rest - it might for me, but...

[Emsquare]

Well, confirmation bias works in both directions.

On a more serious note (the above wasn't entirely a joke), perhaps you didn't push things. Did you go for your maximum listening volume when probing the sound with bypassed fuses? IMO, that's where the primary benefit is – unless one has a contact issue (then, all bets are off).

As you may be aware, I am more than a part time idiot – I'm on the job full time. When my pico fuses opened for the third time, I threw caution to the wind and went without. Unfortunately, the system is in disarray at the moment – the VAC is awaiting new (3/4s of a century ago, but they're unused except for testing) front end tubes and the Pass has returned to duty for the second time since it was replaced.

I had intended to return to the world of the protected by now – as a means of testing my impression (I have been surprised by going the other direction and perceiving an improvement when I thought the first change was an improvement – can't both be true (ah, the vagaries (and power) of that creative process we call perception)). Obviously, there's no longer a proper framework for a valid comparison to be made – all in good time. In any case, my initial impression accords with Mark Winey's – at my 'full' listening volume.

When I get things back in order and readjust my 'ears', I want to put the stock fuse back in the tweeter circuit. If that verifies my suspicion, then I want to try a pico with a higher rating.

I am going to answer yes on full volume testing. As to why I didn't reap the benefit of the mod I cannot be sure. This is on the ribbon tweeter only with an electronic crossover in play. Perhaps it is because of tinnitus    Perhaps it is more easily discernible on something like a 1.6 tweeter as it uses quite a bit more energy. The fuses I have measured are less than 1/10th of an Ohm and barely register on the meter that I have.

I've read your response to Josh and am interested if you can use a switch to determine if your pico's yield something worthwhile.

PS. This is something I have missed from the Planar Asylum. The sense of humor has declined greatly as of late. And if we can't laugh at ourselves... well, you know. One of my favorite proverbs has to do with not underestimating the ingenuity of a fool.

[Davey]

I think a viable testing method for various fuses would be to take a differential measurement across the fuse while in operation.  Some of the computer testing suites (in two-channel mode) could perform this without too much trouble.  Looking for a difference between two inputs is a powerful testing scheme that allows viewing of very small differences.

Obviously, if significant measuring differences are noted then the fuse is affecting the signal passing through it.  All fuses will exhibit some type of measurable difference, so it would be preferable to have a variety of fuses (or protection devices) to test so relative differences could be seen.

Cheers,

Dave.

[kevin360]

Wow Dave! I had the same thought while in the shower this morning. 

I agree Em - this is supposed to be fun.

[josh358]

I think a viable testing method for various fuses would be to take a differential measurement across the fuse while in operation.  Some of the computer testing suites (in two-channel mode) could perform this without too much trouble.  Looking for a difference between two inputs is a powerful testing scheme that allows viewing of very small differences.

Obviously, if significant measuring differences are noted then the fuse is affecting the signal passing through it.  All fuses will exhibit some type of measurable difference, so it would be preferable to have a variety of fuses (or protection devices) to test so relative differences could be seen.

Cheers,

Dave.

I gather that the high current harmonic distortion is real and easily measurable -- well, if you can avoid blowing the fuse, that is. The question I have is -- is it audible in practical use?

That's assuming of course that high-level harmonic distortion is the problem here.

[josh358]

Actually, Josh, I intend to do something similar. My daughter has very good ears. I want the get her confirmation and I can do so with a test quite like what you suggested. It's impossible to see from the front what is in back, so I can switch between fuses in and fuses out without her knowing which way they are and she can be the test subject.

Hell, I could do that with the Pass amp in place. The only problem is that I pulled the XO out last night and disassembled it for a good cleaning. It'll have to wait a couple of days, but I'll do it.

Of course, I seriously doubt that will put this issue to rest - it might for me, but...

These issues never get put to rest.

I just read a powerpoint of a presentation by Leo Beranek in which he says, "The work of Dr. Barbara Shin-Cunninham at Boston University has shown that human listeners sub-consciously adapt to an acoustic environment over a period of 10-20 minutes." Interesting, no? And kind of makes me wonder whether half of what we do by way of testing, either ABX or long-term -- or even short term -- is valid.

That being said, I'm a big fan of practical single blind experiments. I think they're a happy medium between complete subjectivity and the confusing and insensitive ABX test -- though a positive result in an ABX test can be useful indeed. The result may not make it into JAES, but at least it gives us some idea of whether it's worth spending time on this. I often use a similar technique -- someone with good ears who doesn't know what she's listening for -- and nine times out of ten, it confirms what I thought, but there's that tenth time when I realize I've been fooling myself, like when I thought I'd conquered the imaging problem caused by the mantle in my listening room and hadn't.

[Davey]

I don't know how "audible" fuse-induced distortion would be, but whatever its characteristics are, it should be measurable with a scheme as I described.  Obviously we wouldn't see harmonic distortion levels anywhere near the levels the transducers themselves generate, but it still might be an interesting experiment.

If anyone would like to send me a set of hifi-"tuning" fuses, I'd be happy to evaluate them in this way.

Kevin,  I don't know what to say about your shower comment. 

Cheers,

Dave.

[josh358]

I don't know how "audible" fuse-induced distortion would be, but whatever its characteristics are, it should be measurable with a scheme as I described.  Obviously we wouldn't see harmonic distortion levels anywhere near the levels the transducers themselves generate, but it still might be an interesting experiment.

If anyone would like to send me a set of hifi-"tuning" fuses, I'd be happy to evaluate them in this way.

Kevin,  I don't know what to say about your shower comment. 

Cheers,

Dave.

Apparently, the distortion is caused by thermal cycling and can be significant near the point at which they blow. I wasn't able to find the reference I was looking for -- as I recall, it has a table of harmonic distortion as a function of current -- but I found this measurement and discussion:

http://books.google.com/books?id=Qpmi4ia2nhcC&pg=PA457&lpg=PA457&dq=loudspeaker+fuses+distortion&source=bl&ots=hBz7h3HGYg&sig=qChSrBBQq6EJ9k7weQU9G3Ae_Hk&hl=en&sa=X&ei=sonGT7OJDvTH6AHl8tWjBg&ved=0CFYQ6AEwAg#v=onepage&q=loudspeaker%20fuses%20distortion&f=false

I read somewhere that the problem with the Hi Fi Tuning fuses is that they don't blow when they're supposed to! Well, at that price, they'd better not. I don't know if this is accurate, or just another Internet rumor.

[Emsquare]

Wow Dave! I had the same thought while in the shower this morning. 

I agree Em - this is supposed to be fun.

This is what you think of in the shower? Huh ... And I thought it was just me. I salute you sir.

[Emsquare]

I just read a powerpoint of a presentation by Leo Beranek in which he says, "The work of Dr. Barbara Shin-Cunninham at Boston University has shown that human listeners sub-consciously adapt to an acoustic environment over a period of 10-20 minutes." Interesting, no? And kind of makes me wonder whether half of what we do by way of testing, either ABX or long-term -- or even short term -- is valid.

I tend to believe it. How many times have we had a tweeker in the group that can't help but muck with the equalizer, the loudness countour, the filters, the this, the that and the other to get the sound to be better? With a properly lubricated group of people, who are getting into the music later in the evening, it probably won't sound like anything is amiss. Yet when the sleep overs get up the next day or come back after the days activities and go to turn the music on ... holy crud. You know darned well that's the state it was in when it was turned off last night and it didn't sound like the mess you are hearing now.

This is why I place emphasis on initial impressions after making a change to the rig. Make the change, turn it on and leave the room and close the door. Let it warm up to operating temperature and then see what there is to hear. I tend to think that the stated 10 -20 minutes is the most useful before the auditory system starts to make sense of the new balance of what one may be hearing. And it's not uncommon to know in the first minute.