What is causing me to blow speakers?

[Lowerleftcoast]

I recently had my main three amps serviced, and at the time I had speaker line outs that defeat the signal to the internal speaker installed in two of the combos.

1961 Ampro
1960 GA-6
And the third amp is a _______?

A green beret, an et 65, an eminence 15, and an EV all bit the dust.

Let's hear more of the story...
Of the three amps, are any of them solid state or have a solid state power section?

How did the speakers sound the day they died?

Did the 1961 Ampro damage the onboard speaker? Did this speaker get plugged into a different head?

Did the 1960 GA-6 damage the onboard speaker? Did this speaker get plugged into a different head?

Did each one of the three amplifiers damage one or more speakers, or did one amp damage all of the speakers?

The shock brothers are assuming there was DC on the speakers which caused the damage. It is more common for a solid state amp to have DC on a speaker jack. It is less likely a tube power section will have DC but it is possible.

The 1960 GA-6 is a tube amp.
Is the 1961 Ampro a tube amp with a tube power section?

Do you have a multi-meter?

 

[2L man]

Measure if there is DC voltage on output jack output? If they are tube amps I don't know the mechanism what would make any?

 

[2after909]

1961 Ampro
1960 GA-6
And the third amp is a _______?

The third amp is just another amp I had serviced. I haven’t used it. I haven’t plugged it into the cabs or the speakers in the two combos. I’m sorry I mentioned it.

Let's hear more of the story...
Of the three amps, are any of them solid state or have a solid state power section?

There are two amps in question. Both are tube amps.

How did the speakers sound the day they died?

After they blew they all sounded normal, and basically good. But on all of them there’s an intermittent crackle/rattle and they fart out/sonically collapse intermittently. I don’t know how to describe it better than that.

Did the 1961 Ampro damage the onboard speaker? Did this speaker get plugged into a different head?

Yes. But I can’t be certain that speaker was in perfect shape to start with. It’s a 60 year old jensen. This speaker did not get plugged into a different head.

Did the 1960 GA-6 damage the onboard speaker? Did this speaker get plugged into a different head?

Yes. After having a green beret in this amp for a decade, it blew after the mod. This interval speaker did not get plugged into a different head.

Did each one of the three amplifiers damage one or more speakers, or did one amp damage all of the speakers?

Of the two amps in question, I don’t know. Speakers in three cabs blew - an EV from the 80s that I don’t have a lot of experience with (and could’ve been blown already), an et65 that had been in great shape, and an eminence 15 that was in like new condition. Both amps were plugged into all three of those cabs.

The jensen in the Ampro and the green beret in the gibson are blown too. But no other amp was plugged in to those speakers.

The shock brothers are assuming there was DC on the speakers which caused the damage. It is more common for a solid state amp to have DC on a speaker jack. It is less likely a tube power section will have DC but it is possible.

I have a rehoused valve jr with a partial solid state section but I haven’t used it. I have an 80s aria solid state amp and I did try (and blow) the speaker in it, but I didn’t turn the head on.

The 1960 GA-6 is a tube amp.
Is the 1961 Ampro a tube amp with a tube power section?

Yes.

Do you have a multi-meter?

Yes.

Basically, the situation is that I had two amps modded for an external speaker out. I tried three different 1x12 speaker cabs with each of the two heads. All three speakers blew. The two internal speakers in the combos also blew. BUT the EV and maybe the Jensen might’ve had problems already.

That’s really all I can think to tell you.

 

[ficelles]

The third amp is just another amp I had serviced. I haven’t used it. I haven’t plugged it into the cabs or the speakers in the two combos. I’m sorry I mentioned it.



There are two amps in question. Both are tube amps.



After they blew they all sounded normal, and basically good. But on all of them there’s an intermittent crackle/rattle and they fart out/sonically collapse intermittently. I don’t know how to describe it better than that.



Yes. But I can’t be certain that speaker was in perfect shape to start with. It’s a 60 year old jensen. This speaker did not get plugged into a different head.



Yes. After having a green beret in this amp for a decade, it blew after the mod. This interval speaker did not get plugged into a different head.



Of the two amps in question, I don’t know. Speakers in three cabs blew - an EV from the 80s that I don’t have a lot of experience with (and could’ve been blown already), an et65 that had been in great shape, and an eminence 15 that was in like new condition. Both amps were plugged into all three of those cabs.

The jensen in the Ampro and the green beret in the gibson are blown too. But no other amp was plugged in to those speakers.



I have a rehoused valve jr with a partial solid state section but I haven’t used it. I have an 80s aria solid state amp and I did try (and blow) the speaker in it, but I didn’t turn the head on.



Yes.



Yes.

Basically, the situation is that I had two amps modded for an external speaker out. I tried three different 1x12 speaker cabs with each of the two heads. All three speakers blew. The two internal speakers in the combos also blew. BUT the EV and maybe the Jensen might’ve had problems already.

That’s really all I can think to tell you.

I'm just going to put this out there... are you sure it's the speakers and not the amps? Maybe check out the speakers with a known good amp. Two amps and a lot of apparently-blown speakers, maybe the amps are what's gone wrong.

 

[2after909]

I'm just going to put this out there... are you sure it's the speakers and not the amps? Maybe check out the speakers with a known good amp. Two amps and a lot of apparently-blown speakers, maybe the amps are what's gone wrong.

Worth a shot. I have another head I can try with the speakers.

 

[ficelles]

Worth a shot. I have another head I can try with the speakers.

I'd also try different guitar cables, speaker cables, power cables, power outlets etc just to make sure it isn't some other common factor.

 

[Peegoo]

Yeah, this is a puzzling one.

It's impossible to taste a chocolate cake just by looking at the pictures

 

[JustABluesGuy]

After they blew they all sounded normal, and basically good. But on all of them there’s an intermittent crackle/rattle and they fart out/sonically collapse intermittently. I don’t know how to describe it better than that.

The speakers sounded good “after” being blown? This is confusing. Crackling (and/or cutting out makes me think of dirty pots or possible cold solder joints in the amps.

 

[Winky]

I'd definitely get new tech. That little crimped plate he used to mount one of the jacks is beyond awful workmanship. If that is an example of his work, then he probably has no clue what he's doing. As a minimum, he does not care at all about the quality of his work.

 

[PhredE]

Good advice in the above.



In a similar vein of Lowerleftcoast and ficelles..

Along with those possibly-not-so-obvious hardware / equipment issues, is it possible you're playing tunes requiring a fuzz pedal run wide open into your amps which are also running at or near max?
That level of distortion *can* (not necesarily 'will'..) ruin a perfectly good guitar speaker even with a hefty power rating. If you ARE playing that sort of tunes, you'll want a big speaker with a very large ceramic magnet whose size is almost as large as the basket itself -- preferably vented (eg; can handle the extreme waveform(s) and dissipate the heat ok).

(..I know, I know.. but I had to at least pose the question)


What kind of speaker cable are you using? That's one thing I'd check right away. Reversible speaker leads will just make the speaker move in 'reverse' (move backward instead of forward essentially). It might sound weird but should not harm anything. Easily fixed if that is a problem.

I also agree you should keep checking all the other parts of the chain before doing any speaker swaps or spending money on the amps. There has to be some other missing part of the puzzle that hasn't yet been identified. I've had dirty jacks on pedals produce a similar set of sonic anomalies which *appear* to manifest as another part of the amp->cables->pedals->cables->speaker chain. Clean your cable ends and jacks on all attached devices too. If you have a DMM, you can check connections/continuity for every cable too.

Double check every and all parts of that chain

 

[printer2]

I have the ET-65, I have a hard time with a 6V6 amp blowing it. I would have said (given the different amps and the same issue) that it would be time to check the speaker cable but that seemed to have been done. Check the continuity of the new jack to the chassis ground when the cable is plugged in. If the secondary is not tied to the chassis the secondary will float on its own and can end up with a high voltage on it (capacitance coupling). A high enough voltage can punch through the voice coil insulation and then a short causes a hot spot and things go from bad to worse. You may have to do an autopsy on one of the speakers (or another cheap speaker you can try with the amp and see if it blows).

 

[Mowgli]

1. Most amp techs check their work and then “push” repaired amps to be doubly sure their repairs are satisfactory before releasing them. Ask your tech if he/she did this and how hard he pushed it?

2. Most repairs come with warranties ~ 30-60 days. If they are still covered by the warranty take them back and have the tech use a similar wattage speaker of his own to see what happens to his speaker or have him put the output on a scope (see below).

3. Distortion produces square waves and the RMS (root mean square) power of this is ~ a little more than twice that of sine waves. So a distorted output from a 15 watt amp shouldn’t come close to frying a 65 watt speaker.

4. Bass guitars that are played with “slaps” can result in ridiculously high transients which, when fed direct to PA systems, can occasionally blow PA or badly chosen bass speakers. I don’t think that’s the case here.

5. Transformers work via induction from AC (current); AC in the primary windings induce AC in the secondary windings. DC doesn’t cause induction so DC is, in essence, “blocked” by transformers (and capacitors). As such, DC from an isolated circuit as this one “appears” to be is unlikely.

6. Polarity isn’t a relevant issue.

7. Something isn’t adding up. When this happens, restart with the basics. Rule out easy things; speakers work with known good amps, noisy or poorly tracking pots/pot contacts, cable continuity with different positioning of the cables (especially at the jack junctions), etc.

I once had an incompletely inserted patch cable into one of my pedals on the pedal board. This transient connection made it sound like my amp was cutting in and out. After plugging directly into the amp and everything working fine regarding the amp, I ruled out everything distal to the pedal board. That’s when I found the problem.

8. If it’s under warranty start with a revisit to the tech per above.

9. Otherwise have the tech or another tech put the output on a dummy load, feed a 1kHz sine wave into the input and look at the output on a scope. A DC (current), if present along with the sine wave, will alter (i.e. bias) the output off the normal baseline. If something else is wrong it should show up.

Good luck.

 

[King Fan]

I see two red flags. One, your tech worked on your amps and they started literally killing speakers left and right. Two, you heard your tech say your low-powered amps were more likely to blow high-powered speakers than low-powered speakers. I hope to goodness you misunderstood (or he mis-spoke) on that second one. But even just the first one says you need a diagnosis, a full checkup, and a **second opinion.** Best in town or not, I'd get any other competent tech to look into why you're suddenly blowing speakers. This is a DIY forum, so folks are suggesting DIY tests and fixes, but even these smart guys are puzzled, so I'd say unless your name is Keen or Aiken or Blencowe, this isn't a DIY problem. Hang in there.

 

[slider313]

After they blew they all sounded normal, and basically good. But on all of them there’s an intermittent crackle/rattle and they fart out/sonically collapse intermittently. I don’t know how to describe it better than that.

I think you may have blown output transformers and not speakers. If your "tech" wired things wrong he may have left the speaker out "open", which means your output transformer is not seeing a load.

 

[2after909]

I think you may have blown output transformers and not speakers. If your "tech" wired things wrong he may have left the speaker out "open", which means your output transformer is not seeing a load.

Whoa

 

[kilroy6262]

"What is causing me to blow speakers?"

Obviously it's your crack addiction.

Ba dum Tssss..

 

[steeve]

I recently blew a couple speakers in two combos and a couple in two different cabs. Pretty pricey problem. A green beret, an et 65, an eminence 15, and an EV all bit the dust. It’s not like I’m a newbie either. I’m 49 and I’ve never blown speakers in my life, and suddenly I’ve blown 4. Could it be the power in my house? I do not have a brown box. My studio power conditioner shows I’m fluctuating between 116 & 117. The only thing that’s different is I recently had my main three amps serviced, and at the time I had speaker line outs that defeat the signal to the internal speaker installed in two of the combos. Is there something to test for or check for?

Sounds like one of your speaker lines is getting into the chassis ground.....

 

[printer2]

I think you may have blown output transformers and not speakers. If your "tech" wired things wrong he may have left the speaker out "open", which means your output transformer is not seeing a load.

Whoa

Which is why you have to check your amp, cord, speaker with known good ones to know where the fault really is. Does not need to be cranked but enough to know if the piece is healthy. When you have multiple failure points you have to confirm each piece to make sure they work.

 

[printer2]

Sounds like one of your speaker lines is getting into the chassis ground.....

???

 

[tubeToaster]

Make sure you are using speaker cables and not instrument cables.