Can Speakers kill an amp?

[DCWalt]

I'm having a serious run of bad luck with audio gear lately. My setup is nothing special. In fact i'm sure a lot of you would cringe at it but it's worked well for me considering my overall lack of funds. But lately i've been going through amps like candy.

 

To get it out of the way my speakers are a mix of semi-homemade and goodwill speakers. I have a Boss Acoustimass 7 that I picked up at goodwill years ago and some Dual (Walmart brand) automotive speakers in a homemade box. My amp goes into the sub then out to the speakers.

 

At first I was running a reasonably nice home theater receiver (another goodwill purchase) until one of the channels died after a few years of use. Having no money I grabbed a random 80's radio shack amp that we had laying around. It worked fine for a year or two but the audio quality left something to be desired. It had absolutely no treble. This Christmas I wanted an "upgrade" so I ordered a $35 stereo amp from amazon. a channel died almost immediately (not sure if it was the same channel that died on the first amp) so I returned it and order what appeared to be a much better quality amp for $50. It was a random off brand Chinese thing that I couldn't find any information on outside of the amazon listing but it was cheep and had nice features. it worked more than fine for about a month then started having crazy power issues. It did weird things to the wall wort, would go on fits where it just blasted out static and then today it died.

 

I've decided to stop messing around with super cheep amps. Right now i'm looking at the Yamaha A-S301 with the intention of upgrading my speakers later on down the line but before I hook my current speakers up to it I want to make sure they won't kill it.

 

I don't know if my speakers where the reason for the death of three amps or if it was just the fact that they where three super cheep/used amps. Any advice?

[Ithanul]

I found the manual for the Boss speakers.

 

These seem to be some old style ones that go straight to a receiver.

By the manual there is mention of 8 Ohm or less for where the speakers should hook to the posts.

 

Ok, I found where their compatibility is at in the manual.

10 to 200 watts per channel and 4 to 8 Ohm impedance.

https://www.manualslib.com/manual/445949/Bose-Acoustimass-7.html?page=11#manual

 

Also, never go cheap on amps, that is just asking for headaches as those are the power house heart of driving a speaker.

[orangecat]

Is the sub and the front channels running off the same speaker output in parallel? If so it's likely that the subs and the front channel speakers are putting too low an impedance on the amp. For example if your amp is rated for 50 watts per channel @ 8ohms and you have 2 8 ohm speakers in parallel connected to the output you will end up with a 4ohm load on the terminal that the amp may not be designed to handle. I assume those subs are 4ohms (because most subs are) and if you happen to have 4-6 ohms in parallel with those subs you'll end up with a pretty low impedance probably around 2 ohms. Most amps can run 2 ohm speakers unless they're car audio amps as under 4 ohms is rare in home audio. Same thing goes for to high an impedance. If the impedance gets too high the amp must deliver more current to properly drive the speakers and it will put more stress on the amps IC or transistors causing them to die sooner.

[DCWalt]

4 minutes ago, Ithanul said:

I found the manual for the Boss speakers.

 

These seem to be some old style ones that go straight to a receiver.

By the manual there is mention of 8 Ohm or less for where the speakers should hook to the posts.

 

Ok, I found where their compatibility is at in the manual.

10 to 200 watts per channel and 4 to 8 Ohm impedance.

https://www.manualslib.com/manual/445949/Bose-Acoustimass-7.html?page=11#manual

 

Also, never go cheap on amps, that is just asking for headaches as those are the power house heart of driving a speaker.

yes, those specs are on the back of the sub. I theory everything falls into those specs but what about weird stuff with the speakers just getting old? Could the circuitry in the sub degrade and cause problems? There's also a rats nest of wires in my speaker box... Though, I would assume if there where anything shorting out in the box that the speakers would go out and they haven't.

[DCWalt]

4 minutes ago, Kilobytez95 said:

Is the sub and the front channels running off the same speaker output in parallel? If so it's likely that the subs and the front channel speakers are putting too low an impedance on the amp. For example if your amp is rated for 50 watts per channel @ 8ohms and you have 2 8 ohm speakers in parallel connected to the output you will end up with a 4ohm load on the terminal that the amp may not be designed to handle. I assume those subs are 4ohms (because most subs are) and if you happen to have 4-6 ohms in parallel with those subs you'll end up with a pretty low impedance probably around 2 ohms. Most amps can run 2 ohm speakers unless they're car audio amps as under 4 ohms is rare in home audio. Same thing goes for to high an impedance. If the impedance gets too high the amp must deliver more current to properly drive the speakers and it will put more stress on the amps IC or transistors causing them to die sooner.

I don't know how many ohms the sub is but I do know it's two small subs in one box. weather or not they're in parallel i couldn't tell you. The automotive speakers I assume are 4ohms. I put this set up together almost ten years ago. I'm struggling to remember much about it. I do remember putting a cross over filter on the automotive speakers... thinking back i'm not entirely sure though. what ever it was just looked like a capacitor in nice sleeving. if something went wrong with them or if there where a short somewhere i would assume the speakers would have gone out and they haven't.

[orangecat]

1 minute ago, DCWalt said:

I don't know how many ohms the sub is but I do know it's two small subs in one box. weather or not they're in parallel i couldn't tell you. The automotive speakers I assume are 4ohms. I put this set up together almost ten years ago. I'm struggling to remember much about it. I do remember putting a cross over filter on the automotive speakers... thinking back i'm not entirely sure though. what ever it was just looked like a capacitor in nice sleeving. if something went wrong with them or if there where a short somewhere i would assume the speakers would have gone out and they haven't.

Ok so with all the information I have right now it seems that the subs might be 4 ohms each and running in parallel down to 2 ohms. If you have a 2 ohm load in parallel with an 8 ohm load your amp will now see a very low 1.6 ohm load. I know for a fact no 35$ amp can handle a 1.6 ohm load. So what's likely happening is your overloading the outputs with a low impedance. If you wanna fix this you can try wiring up the subs in series into an 8 ohm load and then when you run them in parallel with the front speakers the amp will be running a 4 ohm load that the amp will likely be much happier with. Also I doubt there's anything wrong with the crossover but it doesn't hurt to check. Since it's only been about 10 years since you built that I doubt the capacitors in the crossover have been damaged unless you put too much power through them. Just give them a quick visual check to see if there's any bulging.

[DCWalt]

2 minutes ago, Kilobytez95 said:

Ok so with all the information I have right now it seems that the subs might be 4 ohms each and running in parallel down to 2 ohms. If you have a 2 ohm load in parallel with an 8 ohm load your amp will now see a very low 1.6 ohm load. I know for a fact no 35$ amp can handle a 1.6 ohm load. So what's likely happening is your overloading the outputs with a low impedance. If you wanna fix this you can try wiring up the subs in series into an 8 ohm load and then when you run them in parallel with the front speakers the amp will be running a 4 ohm load that the amp will likely be much happier with. Also I doubt there's anything wrong with the crossover but it doesn't hurt to check. Since it's only been about 10 years since you built that I doubt the capacitors in the crossover have been damaged unless you put too much power through them. Just give them a quick visual check to see if there's any bulging.

The new amp I'm looking at is the Yamaha A-S301. It has a sub-woofer pre out. There's a rather nice Polk 12" powered sub on sale on newegg right now. would it be reasonable to assume if i simply removed the Boss sub from the equation and just ran the amp to the speakers with a powered sub doing it's own thing that that would fix my problem?

[Enderman]

Idk why you bought those cheap crappy amps, you can buy high quality stereo or AV receivers on craigslist for the same price from high quality brands like sony or yamaha or whatever.

These receivers have protection that will prevent them from getting damaged from shorting or overheating.

[orangecat]

1 hour ago, DCWalt said:

The new amp I'm looking at is the Yamaha A-S301. It has a sub-woofer pre out. There's a rather nice Polk 12" powered sub on sale on newegg right now. would it be reasonable to assume if i simply removed the Boss sub from the equation and just ran the amp to the speakers with a powered sub doing it's own thing that that would fix my problem?

Yes that would fix the problem. From what I can tell the issue is that you're running a too low of an impedance on your amplifier. If you remove the 2 ohm sub from the equation you'll be fine as is but you won't have a sub for any real bass. If you buy an amp that has a subwoofer pre out and you buy a powered sub as long as your speakers are still 8 ohms and the new amp can easily handle that you should have no problems. So just make sure that wherever speakers you plug into the new amp are between 4 and 8 ohms and don't add any more speakers off the back. Since you'll have a powered sub you can just use the sub out to run a powered sub.

[DCWalt]

3 minutes ago, Kilobytez95 said:

Yes that would fix the problem. From what I can tell the issue is that you're running a too low of an impedance on your amplifier. If you remove the 2 ohm sub from the equation you'll be fine as is but you won't have a sub for any real bass. If you buy an amp that has a subwoofer pre out and you buy a powered sub as long as your speakers are still 8 ohms and the new amp can easily handle that you should have no problems. So just make sure that wherever speakers you plug into the new amp are between 4 and 8 ohms and don't add any more speakers off the back. Since you'll have a powered sub you can just use the sub out to run a powered sub.

Thank you for you help. I actually ended up ordering the Yamaha A-S501. It seems to be a rather beefy amp and it has a switch for selecting between low and high impedance. I'm going to crack open the speakers for the first time in a decade and see how I wired the tweeters in... I hate fixing things my teenage self did 

[orangecat]

1 minute ago, DCWalt said:

Thank you for you help. I actually ended up ordering the Yamaha A-S501. It seems to be a rather beefy amp and it has a switch for selecting between low and high impedance. I'm going to crack open the speakers for the first time in a decade and see how I wired the tweeters in... I hate fixing things my teenage self did 

No problem. I would just recommend if you plan on running the subs you have now get a second amp for them. They seem to be wired down to 2 ohms and there's no way to pair them with a 8 ohm pair of speakers and have a happy amp. 1.6ohms is very low and just about no amp will be happy with that. You could also wire the subs in series to be 8 ohms then when you run them in parallel with the speakers the amp will see 4 ohms and if the new amp can handle that you may be able to get away with that but i wouldn't recommend it as it would be best to run your subs off a mono source. If you put them in stereo it could damage the amp when a current starts to get induced into the other channel when it shouldn't.

[orangecat]

BTW if you ever need any help feel free to send me a message on the forum.