How easy is it to damage my amplifier or speakers?

A

Aki565

New member
Hi! I have never been good in electronics so I would like to hear some opinions from you about a situation where I left my audio system in a room with a bunch of drunk guys and they started using it when I left the room for some time.Now I am worried that they did some damage to it.

It happened a few days ago that I had to leave these guys alone for about an hour. This set up consists of a mixer that sends the signal to the amplifier which has 4 speakers conected to it in a parallel way,so a cable with speakon connector runs into 1 speaker and from that speaker a cable goes to the 2nd one. When I left the room the mixer power was unplugged , the amp was turned off and the cable was disconnected from the first speaker (the other end still connected to the amp) on both channels.
These guys were drunk and they know absolutely nothing about electronics or amplifiers or speakers or what is safe to do with stuff like this and what is not so I am worried that they abused my stuff. While I was away they somehow managed to plug the cable back to the speakers , plug the power cord back to the mixer and they turned on the amplifier and turned up the volume.
When I got back after an hour they immediately turned it off. Unfortunately since that time I did not have a chance to test if it sounds different than before. but it really bothers me.

So my main queston is , how likely is it that they damaged something in the amp or the speakers when they plugged these together somehow and turned up the volume?
I don't really know how easy it is to damage these stuff or what means real danger to them. for example I can imagine a scenario where they turned on the amp and had no sound. Then they managed to plug in the mixer , turned it's volume to the max because they still had no sound. After that they found the cables hanging from the amp and tried to plug in the speakon to the speakers trying to fit it in place not knowing how to do it , turning it left to right with the volume still to the max till finally they locked it in place somehow. I don't know how they did it exactly cause noone told me but I'm sure it was something like that. Could they cause damage that way?
The thing that bothers me the most is that my amp has some problem with it's fan. 90% of the time when I power it on the fan does not spin nicely. It spins making a horrible crackling noise as if it was about to fall apart. I think it is because of dust mainly. When this happens I gently stop the fan for a sec with my hand and then let it spin again. I do this for a few times(2-4) and after that it spins normally pretty quietly. So it is almost certain that when they turned the amp on the fan acted badly again and they did not fix it like I do all the time. So they used it with the fan being unstable and I am worried that it does not cool the amp well enough this way. When I arrived I wanted to check for burnt smell but I could not because the guys smoked so much in that room.

So could you please give me your toughts about this whole situation? I don't know what type of protection is in these kind of amps and speakers if there is any at all. How likely is that they damaged something? And what signs of damage should I look for when I will have time to check my system? I know I am a noob in electronics but I really don't know if I am overreacting it or not so please don't be too harsh with me. And I'm sorry if my english is not too well I'm not a native speaker.

My devices are pretty basic stuff but I really love this system and it served me really well for many years now.
The amp is a Konig AMP10000-KN with 2x 500 W. this one here PA-AMP10000-KN - König - PA amplifier 2x 500 W - Electronic Discount.be
2 of the 4 speakers are Omnitronic DX1022 10" Passive 200/400W. this type Omnitronic DX1022 10" Passive DJ PA Speaker- 400 Watts.
The other two are a pair of a different type but they are also 200/400W speakers but with larger woofer. And the mixer is a behringer Xenyx 802 like this Behringer XENYX 802 Mixer | Musician's Friend.
 
If they damaged it, you should be able to hear it, or a channel will be out, or something like that. It sounds like you're more pissed off at their rude behavior, and this is driving your animus. Your English is quite good, actually--at least as good as the average posters here (ha ha . . . ). Have that cooling fan fixed ASAP though, and when you set up and check your gear, listen for humming, a channel cutting in and out, etc. Fix the fan!
 
What TimN says ^^^

Replacing the fan should be a relatively cheap and simple job, and is worth doing for peace of mind. Alternativly, you may be abe to get a few drops of oil onto the rotor if it's accessible.

Does they system still work? Is there any difference between before and after? If not, then you are fine. If yes, is it really a difference, or are you imagining it?
 
Maximum output power at 4 ohm: 2x 500 W Watt
Rated output power at 4Ohm: 2x 225 W Watt

That ^ is an odd way to specify an amplifier! I would bet it can only put out a genuine 225W into 4 Ohms and the 500 figure is peak.
Then the speakers are 8R and will thus absorb only 125ish watts apiece, well within their ratings. Bottom line, I doubt any damage has been done. The fan IS a concern but the amp should have other thermal protection because fans stop or get covered up.

Re-rig the setup as soon as you can and play some clean, high level music through it, classical or jazz/big band. Distorted Rock is going to tell you nothing. My bet is all will be fine.

Clean the fan with a brush and vacuum cleaner and is it is still sticky try a squirt of WD-40. But yes, get it replaced ASAP.

BTW! H'horse trotting out! THIS^ is why I am almost alone in saying that PA speakers should be rated well over the amplifier's output. The received wisdom is that 400W speakers need 800+ amps. Well fine in the right hands but there will always be drunken t***s!

Dave.
 
ecc83 said:
The received wisdom is that 400W speakers need 800+ amps.
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The received wisdom comes from pretty reputable sources. This is a good article from Crown:

How much amplifier power do I need?

ecc83 said:
Well fine in the right hands but there will always be drunken t***s!
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Most of the time, systems with that amount of power are in the right hands. They are generally not used in domestic situations.

But yes . . . there are always drunk or otherwise out of control people who can do bad things to gear . . . but they are comparatively rare; rare enough for me not to change the received wisdom. I wouldn't compromise the optimum power relationship between amp and speaker on the basis of yobbo risk. Instead I would minimise yobbo risk by not leaving it unattended and making sure only I or someone else equally able used it.
 
Actually Gecks' I go the other way on domestic "hi fi"!

The enthusiast will be listening very intently and even if the amp is 100% over the speaker rating he will be well aware of any distress to said speakers.

My view for PA is perhaps a simplistic one but then House PA is rarely installed by an acoustician* !
Decide on the SPL you wish to achiever. Buy speakers that can produce that SPL (with headroom based on budget). Buy amplifiers that match the sensitivity of the speakers for THAT SPL.

*NOT! That I claim any such qualification!

Dave.
 
I always thought sending distorted clipped square signals to speakers was worse than a clean signal well over the speaker's rating.
 
I would think its definitely possible that the inputs on the amp got overloaded if they had cranked gain and ouptut controls on the mixer (what was the input to the mixer?)

Note: OP said he has the 8 Ohm speakers wired in parallel, so the amp is seeing an approximate 4 Ohm load. At least speakon's don't short out when plugging them in - if everything was cranked, that coudl hurt the speakers.
If the OP's sound is not good now, is it possible the amp overheated due to the fan issue? (yes, I think)
 
Modern solid state amplifiers are pretty well protected. Even if the fan is not working it will go into thermal shutdown when the temperature of the output transistors heat sink(s) reach a per-determined temp. A lot of them also protect the speakers, by throttling output if the wave form is distorted or clipping (Mcintosh calls it power-guard, others have their own name for it).

Turn it all on and give it a listen.
 
Thank you all for the answers!
I can check how it sounds next weekend but not before.

mdainsd said:
Modern solid state amplifiers are pretty well protected. Even if the fan is not working it will go into thermal shutdown when the temperature of the output transistors heat sink(s) reach a per-determined temp. A lot of them also protect the speakers, by throttling output if the wave form is distorted or clipping
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And are they protected against plugging in speakers when the amp is on , input is being sent and volume is up?
I don't know if my amp has any protection at all. The manual says nothing about it of course.
http://www.sunelectronics.gr/extra/manuals/MANUAL_PA-AMP_COMP.PDF
But what it says is "Make sure the amplifier is switched off when connecting or disconnecting any cables of the system equipment."
which makes me worry.

mjbphotos said:
I would think its definitely possible that the inputs on the amp got overloaded if they had cranked gain and ouptut controls on the mixer (what was the input to the mixer?)
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It was a notebook with an external soundcard plugged into it which has RCA outputs. If they overloaded the amp input does that mean it is damaged now or can it handle it? and what signs are there if it is damaged because it got overheated?
And yeah I am glad that at least they did not short the wires because the speakon connection did not let them.

ecc83 said:
Maximum output power at 4 ohm: 2x 500 W Watt
Rated output power at 4Ohm: 2x 225 W Watt
That ^ is an odd way to specify an amplifier!
Re-rig the setup as soon as you can and play some clean, high level music through it, classical or jazz/big band. Distorted Rock is going to tell you nothing.
Click to expand...

That specification may be odd but it is taken from the manual of the amp.
Allright I will test it with some loud but clean music. Do you have any recommendations?
Do you have some recording that you love to use to test PA systems?

TimN said:
If they damaged it, you should be able to hear it, or a channel will be out, or something like that. It sounds like you're more pissed off at their rude behavior Have that cooling fan fixed ASAP though, and when you set up and check your gear, listen for humming, a channel cutting in and out, etc.
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You are right. I am really pissed off about this whole situation. And I won't let my system alone again with people like them.
I didn't think they would even plug in the speakers and mixer and use it behind my back.
when I'll test if it is ok I'll listen for everything you listed, thank you.

TimN said:
Your English is quite good, actually--at least as good as the average posters here (ha ha . . . ).
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well, thank you for saying that. :rolleyes:
 
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