Cause of blown speaker

[newfuture]

Motor boating is often cause by a capacitor gone bad in the amp. It might still happen with the volumes completely off so be careful!

^^^

I've had an amp blow a speaker with nothing plugged into the input and the volume on the amp completely off. Heartbreaker is it was a vintage JBL d120 I'd just brought back from having reconed. In that case it was a tube amp with a phase inverter tube that had gone microphonic, but the concept that an amp doesn't have to have an input to cause grief if it has a fault still holds.

On the positive side, if you're getting proper DCR readings off the scraping woofer, you can probably still use it to test this amp until the amp's been repaired and a new driver can be safely installed.

I don't suspect your issue is in the bass at all, and am near 100% sure it's not in the octave box.

 

[Milo Spleen]

new gear is always fun to think about!!

I didn't know what GAS was until I showed up here.

 

[Matt O]

I would have a hard time trusting that amp again, even if I figured out what happened.

I feel the pain, brother. Just two days ago I dusted off my very old SVTIII pro that I got when they were first introduced. Had it stored for a few years. Plugged it in, powered it up and POP POP POP POP!!! and then smoke. Hadn't even taken it out of mute yet. Cracked it open and saw that some resistors had failed, maybe a cap or two, too. It was time though, that thing put up with a lot over a couple decades. I'll give it a viking funeral!

If I were in your shoes I'd be eyeballing a new Rumble V3 combo... Best of luck whatever happens.

 

[bassmeknik]

I would have a hard time trusting that amp again, even if I figured out what happened.

I feel the pain, brother. Just two days ago I dusted off my very old SVTIII pro that I got when they were first introduced. Had it stored for a few years. Plugged it in, powered it up and POP POP POP POP!!! and then smoke. Hadn't even taken it out of mute yet. Cracked it open and saw that some resistors had failed, maybe a cap or two, too. It was time though, that thing put up with a lot over a couple decades. I'll give it a viking funeral!

If I were in your shoes I'd be eyeballing a new Rumble V3 combo... Best of luck whatever happens.

People like me live to find nice quality amps in damaged condition, most likely it is repairable to like new condition (electrically) so think about posting it here for sale on TB, you will need supporting membership (currently only $4 per month). I am interested...

 

[Matt O]

People like me live to find nice quality amps in damaged condition, most likely it is repairable to like new condition (electrically) so think about posting it here for sale on TB, you will need supporting membership (currently only $4 per month). I am interested...

I'll give it some thought. It's totally repairable, I just haven't any use for it anymore. Keep an eye on the classifieds, or I'll give you a shout if I post it for sale.

Cheers!

 

[BAG]

This is an amp that I use once a week at church, mainly as my monitor. I run through the system for FOH. I don't use this amp for regulars gigs, etc and just leave it at the church. Pretty convenient so far, but, hey, new gear is always fun to think about!!

That's the right attitude!

 

[Engle]

I would have a hard time trusting that amp again, even if I figured out what happened.

I feel the pain, brother. Just two days ago I dusted off my very old SVTIII pro that I got when they were first introduced. Had it stored for a few years. Plugged it in, powered it up and POP POP POP POP!!! and then smoke. Hadn't even taken it out of mute yet. Cracked it open and saw that some resistors had failed, maybe a cap or two, too. It was time though, that thing put up with a lot over a couple decades. I'll give it a viking funeral!

If I were in your shoes I'd be eyeballing a new Rumble V3 combo... Best of luck whatever happens.

If think it's better to run amps every once in a while. If you let them sit for too long, capacitors can dry out and things go bad. (Conversely electronics that never get turned off for years will often fail when they are shut down and restarted)

My Peavey Centurion head is still going strong. I bought that in 1979, but it never sat unused for more than a year. I think it's going to be relegated to being a keyboard amp.

 

[bassmeknik]

If think it's better to run amps every once in a while. If you let them sit for too long, capacitors can dry out and things go bad. (Conversely electronics that never get turned off for years will often fail when they are shut down and restarted)

My Peavey Centurion head is still going strong. I bought that in 1979, but it never sat unused for more than a year. I think it's going to be relegated to being a keyboard amp.

As a 1979 model amp its capacitors are now well beyond their expected service life and the amp should be recapped. If you know how to solder it is not that hard to DIY. Just be sure the caps are discharged before putting your hands on them....

 

[Matt O]

If think it's better to run amps every once in a while. If you let them sit for too long, capacitors can dry out and things go bad. (Conversely electronics that never get turned off for years will often fail when they are shut down and restarted)

My Peavey Centurion head is still going strong. I bought that in 1979, but it never sat unused for more than a year. I think it's going to be relegated to being a keyboard amp.

Good advice there. Keep rocking that Centurion!

 

[Old Garage-Bander]

As a 1979 model amp its capacitors are now well beyond their expected service life and the amp should be recapped. If you know how to solder it is not that hard to DIY. Just be sure the caps are discharged before putting your hands on them....

I agree about the need for recapping. I will respectfully disagree that just knowing how to solder will make it an easy job. There are many degrees of knowing how to solder. If the OP is a beginner he or she may be getting in over they're head. That being said, there is no better way to get better at something than to jump in and try. And if you mess up, keep trying until you get it right. Just as important as knowing how to solder is knowing how to unsolder.
Done wrong and you can damage circuit boards. Also be aware that some caps have a polarity. If you put them in backwards they can release the smoke rather violently. Even to he point of spewing capacitor goo all over very thing else. Some power supply caps have multiple sections, so you need to be sure you get the right section to the right part of the circuit. Definitely discharge all caps before attempting to remove them. This can be done by shorting the leads with a piece of wire. On big caps you might get sparks and bangs. A better way is to discharge them with a resistor in series with the shorting wire. This will discharge the cap more slowly and avoid the big flash, bang. The larger the resistor, the longer it will take to discharge the cap. I'd say try something in the 100 to. 500 ohm range.

 

[Engle]

I agree about the need for recapping. I will respectfully disagree that just knowing how to solder will make it an easy job. There are many degrees of knowing how to solder. If the OP is a beginner he or she may be getting in over they're head. That being said, there is no better way to get better at something than to jump in and try. And if you mess up, keep trying until you get it right. Just as important as knowing how to solder is knowing how to unsolder.
Done wrong and you can damage circuit boards. Also be aware that some caps have a polarity. If you put them in backwards they can release the smoke rather violently. Even to he point of spewing capacitor goo all over very thing else. Some power supply caps have multiple sections, so you need to be sure you get the right section to the right part of the circuit. Definitely discharge all caps before attempting to remove them. This can be done by shorting the leads with a piece of wire. On big caps you might get sparks and bangs. A better way is to discharge them with a resistor in series with the shorting wire. This will discharge the cap more slowly and avoid the big flash, bang. The larger the resistor, the longer it will take to discharge the cap. I'd say try something in the 100 to. 500 ohm range.

Good advice. I trained as an electronics tech, so the job is well within my capabilities and I have done it before on other amps.

However this Peavey isn't making a lot of noise or performing poorly at all. I just have other amps I like more.
The Centurion isn't worth a lot to sell and has some sentimental value to me, so I'll keep it parked at my drummers place and/or have it ready for keyboard use at my house. If it were to fail some day, I would likely repair it myself, but I don't have time or the need to replace the filter caps now.