cable burning

After you've stopped laughing, maybe somebody has an answer for this. I have Transparent speaker cables. At the amp end of this cable there is a black plastic cover. This is where the cable is seperated into two connecting ends....about 5" or so. I recently bought new amps and the posts are at each end of the amp. The cables didn't have enuff spread to reach. My local audio dealer said he could have the cables sent to Transparent and for a cost they would extend the ends to what ever I needed. Where I work, we make some cables for barcode reading guns. Thinking I could save a few $ I brought mine in thinking we could take those plastic boxes off and recover the cables with some sheathing and it would give me the extra length I need to reach the posts. We had a little trouble with a resister that was glued into that plastic box but we were able to make it work. I had just barely enuff length to make the connection. I have Mag 3.7 speakers and they are fairly new....about 120 hours on them now. So, I havn't been playing anything to loudly, till the other night. I decided to crank it up some. All was well until, here it comes....I see smoke comming up from behind one of the amps. A thin line like from a cigarette left burning in an ashtray. At the same time I smelled it. I hit the off button on the CD and dived to the off buttons on the amps. Upon further review I could see that the speaker cable right where we had covered that resister was melting. After waiting for it to cool off, I covered it with some electrical tape and turned it back on just to see if it would still play. No problems Sounds fine. My intention now is to do what I should've done and send them in to be fixed professionally. Seeing as how I have very little knowledge of all things electrical, anybody want to try and explain what happened?
Thats why you should never buy cables first. As for explaining what happened, that's easy; something is not working properly and caused a failure.
Ok, now how 'bout somebody with a brain wanna try?
Maybe the resistor wasn't properly reattached? Something missed in addition to the resistor? Hard to say as this is way over my pay grade.
One possibility is that the new covering that was applied doesn't allow heat to be conducted away from the resistor as efficiently as the original enclosure, and the heat is essentially trapped. Another possibility is that the new covering isn't able to withstand the temperatures that the resistor normally reaches under high volume conditions. A third possibility is that if the resistor was resoldered when the work was done, it was damaged internally by the heat from the soldering iron or gun.

-- Al

Heat = power.....
Wonder how much amp output power the thing consumes?
Good question, Jim. MrSchret, were there any markings on the resistor, from which it might be possible to determine its value? Also, what was its approximate physical size (length and diameter, if it is cylindrical)?

-- Al
does beg the question of what that resistor is doing for you in the first place if you can smoke it and things sound fine.
I was going to ask the same question?
A resistor in a speaker cable? WHERE?
Count me in with Paulsax and Magfan. WHY?
Here is the manufacturer's description of the rationale for the passive components in their cables.

From a qualitative (non-quantitative) standpoint pretty much everything in their statement strikes me as making sense. The quantitative significance of the issues their networks are intended to address, on the other hand, is IMO perhaps best characterized as speculative.

-- Al
Thanks for all the suggestions. I'm sorry but I can't be any help as far as the resistor value. Just from a common sense approach I think Almarg may have hit it with the idea that it was covered so tightly may have trapped the heat in. I never imagined that that much heat could be sent thru a speaker cable. In the original form that resistor is located inside that plastic junction box cover where the cables spread apart. I may have just suffocated it. Since this happened I've got about 12 more hours played and everything sounds fine. I will be taking them to be repaired properly very soon and I will ask them why this happened and pass it on then.
Al, Thanks for the link. I wonder why "Noise interferes with a cable's ability to transfer an audio signal with the richness, smoothness, and naturalness of music". Transparent cables filter frequencies over 1MHz that are not audible but could possibly modulate audio signal, but there is no non-linear element. Tweeter's membrane might be non-linear at higher frequencies but it won't move at 1MHz. I would suspect more interference with amplifier by injecting noise into it since output is also an input (for the feedback) and is low impedance only for low frequencies. If that's true then shouldn't filtering network be located on the amp and not the speaker side? Does it have boxes on both sides?
Hi Kijanki,

Your comments are well founded, IMO, and I completely agree with them. I have no particular knowledge of the specific 1 MHz corner frequency, but I assume your information about that is good.

There is a "network" near both ends of the cable, as well as a physically larger one that is not located near an end. See these pictures for example. I suppose it can be presumed that the network at both ends is just a resistor, as MrSchret found to be the case at the one end.

Will any of that result in an audibly significant benefit in any given system? IMO it's speculative at best, as I had said. Even if the cable is determined to sound better in a given system than other cables that it may be compared to, that doesn't necessarily mean that the "networks" are the reason.

Best regards,
-- Al
Thanks Al. I found 1.3MHz frequency on the second page of the article but forgot to look at the picture. I wonder what is inside of this big box in the center.
Well, I've already made a mistake by mess'n with the little plastic cover. I have no intention of doing the same with the big box in the middle. Again, when these go in to be repaired properly I'll question what goes on in those enclosures. Something tells me you won't need an answer cause you'll have it figured out before then.
no, I really think we won't Mrschret! Personally I think the 1.3Mhz stuff is hooey but the stated "reason" whey some products work often has nothing to do with if they actually work or not. My favorite is the speaker cable conditioned with many gillions of volts in a carefully controlled process that looks like a static discharge device. May sound devine but nothin about that is controlled and the work carefully is not even in the same area code. Luck with your cables.