My combo amps keep blowing speakers?

destroyerrock

TDPRI Member
Joined
Mar 23, 2021
Posts
53
Age
17
Location
Las vegas
So I have a handful of amps, and i have found an issue specifically when i run combo amps. they keep blowing/damaging speakers! I cant figure out any real reason. One is a carvin belair, 50 watt amp thats damaged a few WGS g12c's, even with two 75 watt speakers in it. the other is a vintage Maestro amp that i put an eminence legend 1518 150 watt speaker in. this maestro amp is rated around 15-20 watts i would assume. its starting to get the nasty noises on certain notes too. any adivice? they dont seem to blow when i run them into speaker cabnets.
 

Mike SS

Poster Extraordinaire
Joined
Aug 9, 2012
Posts
9,176
Age
66
Location
Nebraska
The issue could be clipping. When an amplifier is pushed to the max of it's output volume, it can cause the amp to overstress the voice coils of the speaker, heating them up, and causing them to blow.
When you run cabinets, are they the same ohm rating? A higher ohm rating would drop amplifier out put, which would help eliminate clipping, without too noticeable a drop in volume.
I am not an expert by any means, but these are just a few thoughts.
Hopefully a more knowledgeable person will weigh in:D
 

destroyerrock

TDPRI Member
Joined
Mar 23, 2021
Posts
53
Age
17
Location
Las vegas
The issue could be clipping. When an amplifier is pushed to the max of it's output volume, it can cause the amp to overstress the voice coils of the speaker, heating them up, and causing them to blow.
When you run cabinets, are they the same ohm rating? A higher ohm rating would drop amplifier out put, which would help eliminate clipping, without too noticeable a drop in volume.
I am not an expert by any means, but these are just a few thoughts.
Hopefully a more knowledgeable person will weigh in:D
the carvin has an impedence switch that i match to whats put into it, and the maestro has an 8 ohm speaker which im pretty sure is the right ohms, im not sure if it is clipping but i do have a tendancy to dime the volume from time to time
 

destroyerrock

TDPRI Member
Joined
Mar 23, 2021
Posts
53
Age
17
Location
Las vegas
IT'S POSSIBLE that you have a warped baffle, and your speakers aren't mounting true/flat. If the speaker frame is bent or twisted, it can cause voice coil rub, which will eventually destroy any speaker, regardless of power.
i didnt think of that, could that also be caused by uneven tightness of the bolts holding a speaker?
 

vintagelove

Tele-Meister
Joined
Oct 18, 2014
Posts
453
Location
NY
I would definitely check for cabinet vibrations and speaker mounting issues.

I recently went through this myself. I had to add weather stripping to the head in a combo to stop the buzzing/"distortion". Sounds perfect now.
 

King Fan

Poster Extraordinaire
Ad Free Member
Joined
Jan 1, 2013
Posts
8,001
Location
Salt Lake City
I would definitely check for cabinet vibrations and speaker mounting issues.

I recently went through this myself. I had to add weather stripping to the head in a combo to stop the buzzing/"distortion". Sounds perfect now.

This is interesting. As we'll all agree, cabs don't blow speakers, so combo v. extension shouldn't matter. I'm impressed by the good ideas folks suggest here for how it could seem cab-specific -- bad wiring, impedance, or warped baffle, etc. The baffle deforming the speaker enough to deform the voice coil (or at least cause rub) is a great idea.

But are we sure the speakers are actually blown? You mention nasty noises on certain notes. A nasty cab buzz can sound a lot like a torn speaker and can have a dozen causes from hardware to voids in plywood. And combos do have one other bad habit that separate cabs don't. The speaker vibration can actually cause a mechanical, sympathetic vibration inside the chassis (a wire, a component, a screw or bolt or metal fitting, anything) *that gets amplified* and sounds like speaker or cab buzz.

The fact this happened to speakers well within their wattage specs (in one case, way-y-y within) would make more sense if they weren't actually blown.
 
Last edited:

dan40

Friend of Leo's
Joined
Aug 19, 2015
Posts
2,687
Location
Richmond Va
i didnt think of that, could that also be caused by uneven tightness of the bolts holding a speaker

When installing speakers, it's important to not tighten them down to far. Just barely snug is all they need and excessive tightening can definitely warp the frame. I have to be careful with this myself because I'm use to tightening things down much more when working on cars and others such things.
 

Wally

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
41,551
Location
Lubbock, TX
So I have a handful of amps, and i have found an issue specifically when i run combo amps. they keep blowing/damaging speakers! I cant figure out any real reason. One is a carvin belair, 50 watt amp thats damaged a few WGS g12c's, even with two 75 watt speakers in it. the other is a vintage Maestro amp that i put an eminence legend 1518 150 watt speaker in. this maestro amp is rated around 15-20 watts i would assume. its starting to get the nasty noises on certain notes too. any adivice? they dont seem to blow when i run them into speaker cabnets.

Plus one with the concern over improper installation. I use diagonal a tightening pattern with light torque.
Do you run distortion pedals…fuzz pedals? Square wave distortion will age a speaker because the speaker has reduced cooling time when dealing with such signals.
 

PhredE

Tele-Afflicted
Joined
Sep 25, 2017
Posts
1,901
Location
Suburban PDX, OR
its starting to get the nasty noises on certain notes too.

I am a little unclear as to the circumstances in which you are noting the problem(s) or not.
Is it isolated to a single amp? A single speaker cabinet? In any case, in the past when I have experienced something similar (I should note that I have built my own for the last several years.. so the workmanship is suspect!..) anyhoo, what was going on was this:

I run a separate head into one (or more) of several separate speaker cabinets. At home, I usually have them in the same room and swap them around on the fly. One day I was noticing some big 'buzz' type splatting at the speaker when I play at or around one particular note (can't remember which, but it was a note or chord having a low note). So, I very systematically went through each speaker and cinched down any attached part - checking the speaker itself, the rubber feet, the handle, the interior screws even (although I build with screws and glue), etc. << That, solved the problem. The tricky part was that because they were in the same room together one could sympathetically vibrate even if it was another speaker causing the initial problem. So, checking everything in the amp and every speaker cabinet for loose fitting parts. Even check other things in the room if you have to. I'd wager a guess you aren't punishing the speakers enough (even if mounted semi-wonky..) to cause real damage. My hunch is, you are getting vibrations from something loose <somewhere>

Good luck.
:)

Edit: The real work will be in isolating which component is the real cause of the problem. You may have to move amps/speakers out to a different room to test each one.

Edit(2): Have you checked DC resistance across the speaker connectors for any of these speakers? If you have a digital multimeter it's real easy -- takes about 10 seconds.
You should get something like 6.5 ohms to 8.0 ohms for a nominal 8 ohm speaker.
The other thing is since you are using tube amps, check for microphonic or wonky tubes (and even other components as well). Safety first of course!
 
Last edited:

Telenator

Doctor of Teleocity
Vendor Member
Joined
Sep 19, 2005
Posts
14,617
Location
Vermont
I have seen PA speakers blow from being rated too high for the power amp. 300 watt speakers on a system that only puts out 200 watts.

The sound gets a bit distorted when there isn't enough power pushing the speakers. And sometimes the speakers blow
 

bebopbrain

Tele-Meister
Joined
Feb 5, 2021
Posts
408
Location
New York City
I have seen PA speakers blow from being rated too high for the power amp. 300 watt speakers on a system that only puts out 200 watts.

Be aware that amps are rated for the biggest the sine wave they produce and a square wave has twice the power. So the 200W PA can distort and put out 400W which might explain what happened.

Rock players have been making square waves since before Link Wray. Any appropriately rated guitar speaker will handle square waves. Bass speakers ... it depends.
 

Telenator

Doctor of Teleocity
Vendor Member
Joined
Sep 19, 2005
Posts
14,617
Location
Vermont
Be aware that amps are rated for the biggest the sine wave they produce and a square wave has twice the power. So the 200W PA can distort and put out 400W which might explain what happened.

Rock players have been making square waves since before Link Wray. Any appropriately rated guitar speaker will handle square waves. Bass speakers ... it depends.

So true about bass speakers. I friend of mine used to go through them all the time.
 
Last edited:

destroyerrock

TDPRI Member
Joined
Mar 23, 2021
Posts
53
Age
17
Location
Las vegas
This is interesting. As we'll all agree, cabs don't blow speakers, so combo v. extension shouldn't matter. I'm impressed by the good ideas folks suggest here for how it could seem cab-specific -- bad wiring, impedance, or warped baffle, etc. The baffle deforming the speaker enough to deform the voice coil (or at least cause rub) is a great idea.

But are we sure the speakers are actually blown? You mention nasty noises on certain notes. A nasty cab buzz can sound a lot like a torn speaker and can have a dozen causes from hardware to voids in plywood. And combos do have one other bad habit that separate cabs don't. The speaker vibration can actually cause a mechanical, sympathetic vibration inside the chassis (a wire, a component, a screw or bolt or metal fitting, anything) *that gets amplified* and sounds like speaker or cab buzz.

The fact this happened to speakers well within their wattage specs (in one case, way-y-y within) would make more sense if they weren't actually blown.
the carvin, im 99% sure that speaker is blown, it sounds like theres beans being shaken on certain notes, and it does it running the carvin or my marshall origin head, so i dont think its the carvins electronics at play
Plus one with the concern over improper installation. I use diagonal a tightening pattern with light torque.
Do you run distortion pedals…fuzz pedals? Square wave distortion will age a speaker because the speaker has reduced cooling time when dealing with such signals.
no pedals here, too busy spending the money on more guitars and amps
I have seen PA speakers blow from being rated too high for the power amp. 300 watt speakers on a system that only puts out 200 watts.

The sound gets a bit distorted when there isn't enough power pushing the speakers. And sometimes the speakers blow
ive ran a couple 5 watt amps through the eminence 1518, sounded perfect (not just rattle free, but just in general, i love 15s), not sure why it wouldnt hsve issues w that but is with the 15 watt
 

destroyerrock

TDPRI Member
Joined
Mar 23, 2021
Posts
53
Age
17
Location
Las vegas
I am a little unclear as to the circumstances in which you are noting the problem(s) or not.
Is it isolated to a single amp? A single speaker cabinet? In any case, in the past when I have experienced something similar (I should note that I have built my own for the last several years.. so the workmanship is suspect!..) anyhoo, what was going on was this:

I run a separate head into one (or more) of several separate speaker cabinets. At home, I usually have them in the same room and swap them around on the fly. One day I was noticing some big 'buzz' type splatting at the speaker when I play at or around one particular note (can't remember which, but it was a note or chord having a low note). So, I very systematically went through each speaker and cinched down any attached part - checking the speaker itself, the rubber feet, the handle, the interior screws even (although I build with screws and glue), etc. << That, solved the problem. The tricky part was that because they were in the same room together one could sympathetically vibrate even if it was another speaker causing the initial problem. So, checking everything in the amp and every speaker cabinet for loose fitting parts. Even check other things in the room if you have to. I'd wager a guess you aren't punishing the speakers enough (even if mounted semi-wonky..) to cause real damage. My hunch is, you are getting vibrations from something loose <somewhere>

Good luck.
:)

Edit: The real work will be in isolating which component is the real cause of the problem. You may have to move amps/speakers out to a different room to test each one.

Edit(2): Have you checked DC resistance across the speaker connectors for any of these speakers? If you have a digital multimeter it's real easy -- takes about 10 seconds.
You should get something like 6.5 ohms to 8.0 ohms for a nominal 8 ohm speaker.
The other thing is since you are using tube amps, check for microphonic or wonky tubes (and even other components as well). Safety first of course!
with the carvin, it has the issue running the carvin or connecting it to a marshall origin head. not sure ab the maestro, i havent tested it. im fairly sure its not a tightness thing, i make sure everything is very tight (sometimes too tight, why i worried ab the mounting them too tight) no multimeter at the moment, but ill try the different room testing
 




Top