marems Posted March 24, 2015 Share Posted March 24, 2015 Well I decided I would try out a high end power cable in my system since the local dealer gave me on to try out. Installed it on my amp and watched a movie with my son. Listened to some music the following day with no problems. When to turn it on last night and nothing, I had some spare slow blo fuses so I put a new one in and popped that one, and then another after that.... I was pretty worried and wondered what happened, my power conditioner didn't show a fault so it was not a power input issue. I ohmed out the power cable and found the ground leads on it were open with no resistance. So much for the upgrade Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted March 24, 2015 Share Posted March 24, 2015 LOL sorry but that is ironic! high end power cables actually hurt you performance, in fact they kill it but on a serious note that is a bummer. i bet the company that sold it to you will be pissed when they have to fork over money for new mcintosh gear 1 Quote Link to comment Share on other sites More sharing options...
marems Posted March 24, 2015 Author Share Posted March 24, 2015 Yeah it sucks, gota pack it up 150 lbs boxed! Ugg it came on a semi trailer when I ordered it from audio classics lol. I got to bring it there, cause luckily they are a Mac dealer. They said they will pay for repairs if they can prove the power cable did my amp in, they also said they will give me a loaner amp to get me by till mine is fixed, I personally think it fried something with that ground wite being open in the cable. Hell I didn't notice a diffence with it at all just a bunch of snake oil! Quote Link to comment Share on other sites More sharing options...
babadono Posted March 24, 2015 Share Posted March 24, 2015 Huh? How can an open ground blow up an amplifier? I assume you're talking about the "green" wire. Back in the day(before it got stolen) my Mac 2105 did not even have a ground connection, just a 2 wire prong. I'll be interested to hear what they find. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted March 24, 2015 Share Posted March 24, 2015 I am also confused. Is this a 3 prong cable (hot, neutral and ground). With the cord disconnected from the amp and the outlet, is the voltmeter reading a small number (or 0) or "open" (a very, very large number) when you measure between the hot (narrow blade) and the neutral (wide blade) or between the ground (round pin)? If there was a short (reading 0 or a very small number), then the fuse may have saved the day. My guess is that the amp may be fine in spite of your tinkering. Good luck with it, -Tom Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 I am also confused. Is this a 3 prong cable (hot, neutral and ground). With the cord disconnected from the amp and the outlet, is the voltmeter reading a small number (or 0) or "open" (a very, very large number) when you measure between the hot (narrow blade) and the neutral (wide blade) or between the ground (round pin)? If there was a short (reading 0 or a very small number), then the fuse may have saved the day. My guess is that the amp may be fine in spite of your tinkering. Good luck with it, -Tom Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 (edited) My friend who is a electrician measured both hot and neutral leads on the power wire and was ok, tested the ground leads and no reading at all (no resistance) possibly broken ground wire in the power wire. I spoke with a couple of Mac techs today and they said that if there is no ground at all when a short or a power surge came thru it would hurt the amp, which is why they tell u not to use a cheater plug on 3 prong power cables, the amp is designed and engineerd to have a 3 prong power cable at all times. I just happen to have that kinda luck yesterday and something fried. I replaced the fuses on the amp 3x and popped them each time. The Mac tech said "Do not try and energize the amp anymore because there is something seriously wrong with the amp for it to be blowing the fuses like that ". I can tell you its so frustrating Edited March 25, 2015 by marems Quote Link to comment Share on other sites More sharing options...
Bubo Posted March 25, 2015 Share Posted March 25, 2015 If it ain't broke............ Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 I heard that! Ugg Quote Link to comment Share on other sites More sharing options...
Bubo Posted March 25, 2015 Share Posted March 25, 2015 Huh? How can an open ground blow up an amplifier? I assume you're talking about the "green" wire. Back in the day(before it got stolen) my Mac 2105 did not even have a ground connection, just a 2 wire prong. I'll be interested to hear what they find. All of the old stuff floats, my impression is that the new stuff does not. Quote Link to comment Share on other sites More sharing options...
Bubo Posted March 25, 2015 Share Posted March 25, 2015 On the subject of expensive cables power or speaker. It would be interesting to do a blind test between platinum speaker cables and 12 GA power extension cord with the ends cut off. Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 Huh? How can an open ground blow up an amplifier? I assume you're talking about the "green" wire. Back in the day(before it got stolen) my Mac 2105 did not even have a ground connection, just a 2 wire prong. I'll be interested to hear what they find. All of the old stuff floats, my impression is that the new stuff does not. Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 I agree with u bubo about the ground not floating on the newer 3 prong amps or anything 3 prong. And as far as the expensive power cable for better dynamics etc. ha! snake oil! I learned the hard way I guess :-/ ..... Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 The blind test would be interesting. Quote Link to comment Share on other sites More sharing options...
Karsoncookie Posted March 25, 2015 Share Posted March 25, 2015 Ok, I'm an electrician. NOT an electronics guy. But circuits is circuits. Your electrician should have not necessarily, but ideally disconnected the cord at the amp end before readings. And after initial checks, plugged into wall to confirm volt readings. If he is astute, in that process, probably found your problem You said ground not reading no resistance - You mean to say, I believe, HIGH or open resistance. The opposite. Ohmmeter connected to ground prong, other lead to other end of cable.ground wire (or chassis) if still connected HIGH resistance (open, infinite ohms in practicality) If that's true, in and by itself, that would not lead to any fuse blowing or damage to amp. If amp is fine otherwise. There is never any normal current flow in a grounding conductor unless a "short to ground" scenario. The fuse protects two things - the above, in a catastrophic situation, or a just plain overcurrent from a variety of other reasons. Anyway, the possibility of any manufactured cable midspan open (sans physical damage) is extremely rare. I would have to assume, based on the given info, there was some fault due to improper installation of the cable. Hanging strands or something. Again, not an electronics guy, but if you did have a poor faulting install, the amp is probably not damaged. Bust the fuse certainly may blow, doing its job. And further, depending on the fault location, the fuse could blow whether or not the ground is continuous. My bet is your macheen iz fine. Of course, it is also possible your macheen was called home during this short period of time. But the mathematical possibility chance is pretty small. Interested in what you find out. Lars Quote Link to comment Share on other sites More sharing options...
Karsoncookie Posted March 25, 2015 Share Posted March 25, 2015 Marems also you sed -- The Mac tech said "Do not try and energize the amp anymore because there is something seriously wrong with the amp for it to be blowing the fuses like that ". I can tell you its so frustrating That very well may be, but also just the faulty install of the cord on it's own could easily be blowing fuses. But wise prudent general advice nonetheless. Lars Quote Link to comment Share on other sites More sharing options...
Karsoncookie Posted March 25, 2015 Share Posted March 25, 2015 Please do post in this thread when you get the diagnosis. Very interested in hearing. Lars Quote Link to comment Share on other sites More sharing options...
marems Posted March 25, 2015 Author Share Posted March 25, 2015 Lars, thank you for your input, he did ohm just the cable alone and not while connected to the amp, it looked like it had some heavy bending wear on the cable jacket close to both ends, I'll post a pics of it soon, the cable had no wire strands exposed,( I never would have installed it) and the cable was installed correctly as I have done this type many times before. I just think that there was some kind of voltage issues and the ground was not present to help due to the faulty cable. I swaped out the power cable and tried the original cable that came with the amp and it still blew fuses. Inspected the power cable connection point on the amp as well and it looked normal, (nothing that could cause an arc.) Quote Link to comment Share on other sites More sharing options...
A1UC Posted March 25, 2015 Share Posted March 25, 2015 I find it hard to believe it was the power cable . Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted March 25, 2015 Share Posted March 25, 2015 (edited) Ok, I'm an electrician. NOT an electronics guy. But circuits is circuits. Your electrician should have not necessarily, but ideally disconnected the cord at the amp end before readings. And after initial checks, plugged into wall to confirm volt readings. If he is astute, in that process, probably found your problem You said ground not reading no resistance - You mean to say, I believe, HIGH or open resistance. The opposite. Ohmmeter connected to ground prong, other lead to other end of cable.ground wire (or chassis) if still connected HIGH resistance (open, infinite ohms in practicality) If that's true, in and by itself, that would not lead to any fuse blowing or damage to amp. If amp is fine otherwise. There is never any normal current flow in a grounding conductor unless a "short to ground" scenario. The fuse protects two things - the above, in a catastrophic situation, or a just plain overcurrent from a variety of other reasons. Anyway, the possibility of any manufactured cable midspan open (sans physical damage) is extremely rare. I would have to assume, based on the given info, there was some fault due to improper installation of the cable. Hanging strands or something. Again, not an electronics guy, but if you did have a poor faulting install, the amp is probably not damaged. Bust the fuse certainly may blow, doing its job. And further, depending on the fault location, the fuse could blow whether or not the ground is continuous. My bet is your macheen iz fine. Of course, it is also possible your macheen was called home during this short period of time. But the mathematical possibility chance is pretty small. Interested in what you find out. Lars Lars, I think you are correct. The phrase "open" and "no resistance" are being used incorrectly. That is why this is confusing. Edited March 25, 2015 by PrestonTom Quote Link to comment Share on other sites More sharing options...
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