3.7´s, which fuses?....and jumpers?

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kevin360

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Re: 3.7´s, which fuses?....and jumpers?
« Reply #80 on: 4 Jun 2012, 03:58 pm »
That "World's Largest Fuse Measurements Report" is pretty interesting.  :)

Much data on resistance and voltage drop, but not a single piece of data on the MOST important aspect of any fuse.....the blowing (opening) characteristics.  :)

Beware.

Cheers,

Dave.

Well, no - they never say anything about how their products perform the task of a fuse. It's all about what a fantastic piece of wire it is, but we already knew the nominal cold resistance of our stock 2.5A tweeter fuses: it's 0.0513 ohms. In other words, the fuse contributes approximately 1.2% of the total impedance of its circuit - until it heats. It's apparent that the Tuning fuses are (meaningfully?) better wires, but how do they perform as fuses? What are their characteristics? I'm awaiting an answer to an email inquiry, but I'm not holding my breath.

As far as my personal opinion concerning the sonic impact of the fuse (for what it's worth), the best I can say is that the jury is still out. I have an untested opinion that could stand to be improved. This is something that lends itself to a blind test and my daughter has good ears - and she's brutally honest. We're going to give the question of whether no fuse sounds better than the stock fuse a test. I know the result will have limited utility, but it will be an unbiased result - she won't know how it is for each listen and I intend to fake changing things twice. Even though I'll know each time, I'll still sit down and listen for differences as well. If nothing else, it will be a fun experiment.

Emsquare

Re: 3.7´s, which fuses?....and jumpers?
« Reply #81 on: 4 Jun 2012, 11:24 pm »
Well, no - they never say anything about how their products perform the task of a fuse. It's all about what a fantastic piece of wire it is, but we already knew the nominal cold resistance of our stock 2.5A tweeter fuses: it's 0.0513 ohms. In other words, the fuse contributes approximately 1.2% of the total impedance of its circuit - until it heats. It's apparent that the Tuning fuses are (meaningfully?) better wires, but how do they perform as fuses? What are their characteristics? I'm awaiting an answer to an email inquiry, but I'm not holding my breath.

As far as my personal opinion concerning the sonic impact of the fuse (for what it's worth), the best I can say is that the jury is still out. I have an untested opinion that could stand to be improved. This is something that lends itself to a blind test and my daughter has good ears - and she's brutally honest. We're going to give the question of whether no fuse sounds better than the stock fuse a test. I know the result will have limited utility, but it will be an unbiased result - she won't know how it is for each listen and I intend to fake changing things twice. Even though I'll know each time, I'll still sit down and listen for differences as well. If nothing else, it will be a fun experiment.

0.0513 Ω? 51.3 mΩ? Well I didn't know that. Again... part time idiot. Tolerence is ± what exactly?  :D Sorry. I'm being bad again.

And I am looking forward to the father & daughter fuse shoot out. Seriously. I'll take that for a reasonable blind study. I jsut don't think there is a way to improve over a fuseless circuit. And no one will be able to say that it wasn't seriously looked at by some users who shared a curiosity about the question. I might be more reassured by the professional review had I not read some other reviews of some really odd accessories. But then we are getting into the subjective vs objective belief systems and we know where that's going to go. Just pretend I never wrote that.

MaggiesAndCats

Re: 3.7´s, which fuses?....and jumpers?
« Reply #82 on: 5 Jun 2012, 02:43 am »
Ahhh, do tell. Pray thee, what is thine intent? (Can you give us a rough idea?)

Back from a gig, eh? It's been a long, long time since I could say that. It's something of a regret. What do you play (I'm sure I've read it before but I don't remember)? Do you ever have a laugh at the comment some make regarding musicians and sound quality (musicians don't care and apparently can't hear very well, etc.)?

I'm not sure what comprises your modest system...

I have a pair of MGIII's that need rework.  My original plan was to rewire the bass section of the bass/mid panels and mount them in wood frames to augment the bass of my other MGIII's.  It's evolved to still doing the bass section part, but taking the ribbons and mounting them in a separate wood frame with a B-G Neo8 array.   I've recevied some excellent guidance from Josh, Satie, and Andy.  I missed out on purchasing a couple of pair of Tympani T-IVa's a while back that would have been the building blocks for something similar.  With my multi panel idea I could always add Tympani bass panels someday.  Or a pair of DWM's.  Or...

I play bass in a band that plays original and cover acoustic rock along with the usual classic rock depending on the venue.  I find that there are more audiophiles who are musicians than musicians who are audiophiles, if that makes any sense.  Most of the musicians I know who have the funds for a nicer audio system opt to spend them on better instruments and gear.  Same Kool-aid, different flavor...

I added my system to my profile, but basically it's a Jolida JD100a CDP with a Level 1 mod from Parts Connexion into an Audio Research LS-12 linestage into a Behringer DCX2496 modded by Scott Endler into a pair of Audio Research D200 amps into a pair of factory refurbed MGIII's on Mye stands.  My ears and my bank account are both pleased!  Unfortunately it's dissambled right now while I prepare a smaller room as a dedicated listening room.

Regards,

Steve

josh358

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Re: 3.7´s, which fuses?....and jumpers?
« Reply #83 on: 5 Jun 2012, 03:31 am »
I have a pair of MGIII's that need rework.  My original plan was to rewire the bass section of the bass/mid panels and mount them in wood frames to augment the bass of my other MGIII's.  It's evolved to still doing the bass section part, but taking the ribbons and mounting them in a separate wood frame with a B-G Neo8 array.   I've recevied some excellent guidance from Josh, Satie, and Andy.  I missed out on purchasing a couple of pair of Tympani T-IVa's a while back that would have been the building blocks for something similar.  With my multi panel idea I could always add Tympani bass panels someday.  Or a pair of DWM's.  Or...

I play bass in a band that plays original and cover acoustic rock along with the usual classic rock depending on the venue.  I find that there are more audiophiles who are musicians than musicians who are audiophiles, if that makes any sense.  Most of the musicians I know who have the funds for a nicer audio system opt to spend them on better instruments and gear.  Same Kool-aid, different flavor...

I added my system to my profile, but basically it's a Jolida JD100a CDP with a Level 1 mod from Parts Connexion into an Audio Research LS-12 linestage into a Behringer DCX2496 modded by Scott Endler into a pair of Audio Research D200 amps into a pair of factory refurbed MGIII's on Mye stands.  My ears and my bank account are both pleased!  Unfortunately it's dissambled right now while I prepare a smaller room as a dedicated listening room.

Regards,

Steve

There's a pair of IVa's up on Ebay now. Apparently, it's been through a factory rebuild although they don't give a date. It certainly looks nice in the photo. But I think the double III's will have formidable bass.

MaggiesAndCats

Re: 3.7´s, which fuses?....and jumpers?
« Reply #84 on: 5 Jun 2012, 07:02 pm »
There's a pair of IVa's up on Ebay now. Apparently, it's been through a factory rebuild although they don't give a date. It certainly looks nice in the photo. But I think the double III's will have formidable bass.

Thanks Josh.  I only check sites like eBay, Audiogon, AA, AC, Craigslist, etc. once a week or so.  They look to be in pretty good shape, with a few stains on the fabric on the one side that is shown in the pics  The XO's are in fair shape at best externally, but I would be biamping anyway.  Seven hour drive for Maggies that have been in a near-coastal location (MD).   Hmmm...  I suppose I could offer to have Magnepan send them shipping boxes and pay for the shipping.

Double III's would be the least expensive way to go and the separate bass panel would be the first step in a setup with the Neo8's anyway.  They would give about the same square inches as a T-IVa for bass.

josh358

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Re: 3.7´s, which fuses?....and jumpers?
« Reply #85 on: 5 Jun 2012, 11:10 pm »
Thanks Josh.  I only check sites like eBay, Audiogon, AA, AC, Craigslist, etc. once a week or so.  They look to be in pretty good shape, with a few stains on the fabric on the one side that is shown in the pics  The XO's are in fair shape at best externally, but I would be biamping anyway.  Seven hour drive for Maggies that have been in a near-coastal location (MD).   Hmmm...  I suppose I could offer to have Magnepan send them shipping boxes and pay for the shipping.

Double III's would be the least expensive way to go and the separate bass panel would be the first step in a setup with the Neo8's anyway.  They would give about the same square inches as a T-IVa for bass.
I can think of a few arguments for the IVa's -- convenient form factor, bass tuned for large panels, less work overall (the Neo's should fit right in the midrange slots). Also, I think a somewhat later version of the ribbon tweeter, and the recommended fold in the panels improves power response. But, of course, whatever works best. The main question for me would be when these were refurbished. That has a big effect on their value. If they were done in recent years, they should have the new adhesive and should never delaminate. Also, if you have to buy new boxes for them, that should effect their value as well.

One thing,


MaggiesAndCats

Re: 3.7´s, which fuses?....and jumpers?
« Reply #86 on: 6 Jun 2012, 05:53 pm »
I can think of a few arguments for the IVa's -- convenient form factor, bass tuned for large panels, less work overall (the Neo's should fit right in the midrange slots). Also, I think a somewhat later version of the ribbon tweeter, and the recommended fold in the panels improves power response. But, of course, whatever works best. The main question for me would be when these were refurbished. That has a big effect on their value. If they were done in recent years, they should have the new adhesive and should never delaminate. Also, if you have to buy new boxes for them, that should effect their value as well.

One thing,


I checked with the seller, or rather the owners selling agent, and they were refurbished 12 years ago.  This more or less coincides with the release of the 3.6's so I gather the glue could be iffy?

josh358

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Re: 3.7´s, which fuses?....and jumpers?
« Reply #87 on: 6 Jun 2012, 08:41 pm »
Yes, I think the improved glue was introduced in 2005 or so. The glue from the decade before it was moisture-sensitive, and from the era in which the IVa's were made, sensitive to ultraviolet.

So -- they might be in fine condition, no way to know, since it depends on local conditions. But in terms of what I'd be willing to pay I'd assume that they need a rebuild or will need a rebuild in the future.

tberd

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Re: 3.7´s, which fuses?....and jumpers?
« Reply #88 on: 26 Aug 2012, 02:47 pm »
 The best fuses are none at all. I wired around mine in my 20.1R's. No issues for several years now. Don't see any on the way either. Also wired around the tweeter attenuator. No need for anything in the signal path.

 Reason was I saw blue arcing at the fuse holders when the speakers were new. Obviously a poor connection there. Magnepan sent me more of the same garbage fuse holders. They're still in the bag unused. Those fuses got very hot while they were throwing off sparks. Hot enough to burn your fingers. We might guess the resistance was probably through the roof.

tberd