A worse feeling than burning out your amp?


Last night I was planning to get back into making digital music and began setting up my laptop with the necessary software. I had my audio cable (1/8" connector) plugged into my Macintosh, which was playing mp3s. The laptop was ready to go, so I unplugged the cable from the Mac without turning the amp off, which I've done dozens and dozens of times before; BIG mistake. I heard a very loud buzzing sound that lasted about a quarter of a second, followed by a loud pop. I went over to the amp and could smell electronics burning. I turned the amp off and back on, after which I noticed that sound was only coming out of the left channel and it was very broken and full of static. Also, it doesn't matter which input is selected, it plays all sound coming from all inputs now. This integrated NAD C 340 amp is no longer good as a preamp either. What a horrible feeling, but it could have been much worse (my speakers could have blown out!).

Has anyone ever done something similar to their amp and attempted to fix it? I'm at least going to open it up and have a look before I trash the thing. The only bad part about all of this is having to wait several months before I can afford to replace this unit. For now, it's back to the old mass market Kenwood receiver....
jwglista
Yes, twice I was fooling around with speaker cables and used some cheap banana plugs on the speaker end. Playing music loud must have loosened the bananas and they crossed blowing a channel in an amp. I did it again about a month late to another amp. Cost about $100 per amp to fix all for not spending a few extra seconds to make sure the bananas were in there tightly.

Happy Listeing.
I started doing a minor touch up to the lid of my new c-j 17LS II which started out as a small dot. After improper paint colour matching and thinner, I now have a bigger spot the size of an orange.
Oy! My sympathies for the loss, but I'm sure it's not a total loss. I've spent too many years with tube components so now I always shut down everything before making swaps. I have made a similar mistake once before. A 2A3 amp I owned had a socket that allowed the tube to be put in off of it's proper orientation (some of the earlier, cheaper sockets do). It becomes a visual task to allign them and with four pins would seem a relatively simple one. Guess my eyesight isn't what it used to be. I put in the tube the wrong way and upon turning on the amp promptly fried a resistor. No big deal as the maker is a friend who lives nearby so I was able to bring it to him the next evening to swap out. He had since started using the sockets that only will allow insertion in the proper orientation.

Marco
Yes well it's good to know that I'm not the only that has made such a foolish mistake. I never thought that pulling a cable out like that could fry something. I do think that it's the preamp that is toasted, so I'm going to open it up and look for any burnt components. If it's just a resistor, I may be able to apply my mediocre soldering skills and replace it. I only paid $90 for this amp on EBay, which is one of the reasons I said it could have been much worse. Either way, it's not worth my money to bring this into the shop. I was saving up for a new DAC, but my funds will have to be diverted towards a new amp (unfortunate, because I really need a better CD player or DAC).
Been Their, done that, sucks. Slim chance its just an internal fuse, but I bet you blew one channel.
What does it mean to "blow a channel?" Does this mean a blown capacitor, resistor, or the entire electrical path?
I had some young female relatives visiting a few years ago who took it upon themselves to turn on 'the cool looking stereo' while we were at work. at the time a classe ca 200, ML sl-3's, audio research ls-3, cd player setup. it was common practice for the wife & I to utilize the mute switch on the ls-3 when switching sources and while warming things up. I probably don't need to say more but I take the blame for it. It's great being your own worst enemy. I find humor in it anymore.
Bust a brand new cartridge while installing it and you know what real clumsiness is all about. Do it more than once and you know you're a prime candidate to apply for the job as the village idiot.
I've burned out mine once (Audio Refinement Complete), when my 2 year old son disconneted the right speaker from the amp. I turned on one of my favorite CDs, cranked it up, and about 30 seconds later, the sound cut out and my amp was slightly smoking. Good news was, my local hi-fi shop (Sound Environment, Omaha, NE) did a warranty repair AND gave me a loaner amp while my amp was being repaired. The slightly higher price I paid for buying locally was well worth the service I got in return. Gil
Well I took the amp apart and noticed an area of smoke build up on the top of the cover right above a big capacitor (there are 2 of these in the amp, I'm assuming one is for each channel). I don't know much about electronics so I don't know if it would be worth my time to try and fix this. I also don't know if a burned out capacitor would explain why the amp plays all sound from all inputs at the same time, regardless of which input is selected. That sounds like something in the preamp got fried too....
Hi I just happen on your problem. I have a Denon poa 2400 power amp thats been a problem from day one.That was ok while it was under warranty but it's not now.I turned the system on to listen to a new set of speakers as I turned up the volume (to about 1/3) the amp went up in smoke I had to unplug it as I thought it would start a fire.It should be noted that it only had about one hours time on it scince it came back from being repaired at Denon ($300)To make a long story short Denon blew it up five/six times then sent it back to me and said they could not fix it.I think I will try Rotel now as I'm not very happy with Denon
A worse feeling-

Getting some new gear from UPS (read OOPS) and discovering it has been broken in shipping. You never even get to try it and then have the hassle of contacting the seller and working out a resolution or freight claim while the broken gear sits silently in the corner mocking you for using UPS.
I ALMOST did some major damage after swapping inter connects, I forgot to turn on one of my amps (the 2 channel main) scratched my head and turned volume way up to see if I could hear any noise in speaker...went for the power buton and at last second remembered to turn down volume....that scared the hell out of me and I didnt even do anything...but man it was close.
P.S. I am going to keep a better eye on bananna plugs!
From your description it sounds like you lost the ground connection through your interconnect cable, leaving just the "hot" connections on both channels. This will cause most amplifiers to oscillate, often resulting in damage to the speakers, or amp, or both. It would be nice to think that the internal fuses had protected your NAD amplifier, but the fact that some parts overheated suggests otherwise. If you're feeling adventurous, you can check for blown fuses and replace any you find, and try it again. Otherwise, a visit to your local audio hospital is called for.

Note that this problem may occur again with the same front-end gear, regardless of what amp you are using. Losing both ground connections is rare with separate interconnect cables, but becomes more of a problem with “Y” cables - especially with mini-plug connectors. Check your cable carefully and replace it if you think it might be bad.
Chadnliz, i did not know that was a condition that we need to avoid (turning on amp when voulme is turned up). i will keep this in mind.

i have fried a pair of channels when i ran built in test tones on an avr. rear speakers had been modified and i'm not shure what the ohm load was. i'm still looking for my multimeter to this day. good thread.
I cant say it would be a problem. I hope that it wouldnt but I had the fear in me all the same, the amp was under the Processor and I just didnt notice, but I had turned volume all the way up to try to hear that tiny bit of noise I get when it is up without material playing. that being said I am still glad I caught my mistake.
Oh the banana plugs eh? I almost fried my ML 27.5 years ago when they touched one another due to a heavy gauge speaker cable attached to them that was stepped upon.Thanks God they auto protect on the Levinson did a superb job.Speaking of UPS,I will say this about Fedex.They dropped my shipment on transit.I realized the problem the minute I picked up the box,as I felt something moving loose inside.Well after a visual I realized the transformer of the Tice Titan was broken off and was just held by the wires.I FIXED IT MYSELF after I gave up on them.They just didn't do anything about it.Nothing at all.
For your NAD Jwglista,aren't you overreacting a little.I mean you said it yourself that it was bought used for 90$.I wouldn,t worry about it that much.A good excuse to upgrade to something better.
Sorry if I come hard on you.My opinion anyway.
Best
George
Yioryos, yes it is a good excuse to upgrade my amp. The thing is, I was going to upgrade my DAC which was a bit more necessary, but now I have no choice but to buy another amp (I'm using a Kenwood receiver right now).
I used to run a line from my G4 to an Audio Experience. Upgraded the cable - not far; audio research and grado extension. A couple of days go by, I turn off my Marantz Mono's I have at the time, go to unplug the extension and I get ELECTROCUTED. The mini-jack on the G4 shorts along with the ethernet port. Reversed polarity between two different sockets? Something in the G4 not grounded? G4 DC to Preamp AC or the reverse? MP3's are the end of the world. Now I only listen over headphones.