Hey guys

At band today, my Bugera 333 suddenly lost a lot of volume, and I noticed a small amount of smoke (it looked more like dust though) coming from the top of the speaker grill. I killed the power, just incase it was a transformer problem. I tried turning it back on again, which worked fine, all the tubes lit up, the fuse didn't blow. However, when In started playing again on the clean channel, I noticed a volume drop, and the speaker sounded very fuzzy and crackly. The speaker coils were hot to the touch after this.

Is this characteristic of a blown speaker? I've had the amp less than 6 months and it's already been repaired because of poor bias and an internal connector failure. The amp is used for a solid 6 hours a week, with the volume at about 9 o'clock, so it's nowhere near its operating max. The speakers in the cab are twin 12" Bugera speakers rated for 70W each, operating in series (they're both 8 ohm speakers)

What is the best course of action to take here? If its a blown speaker (just the one), can I run the amp with just the one (obviously setting the output impedance to 8ohm on the amp), and make sure the master volume is kept low? I need to make it through 3 or 4 more practices before I have time to send the amp away for repair.

If the worst comes to the worst, what are some good replacements? Ideally I want to spend as little as possible, and I would prefer replacement speakers as opposed to buying/building an external cab since transportation space is very limited.

Cheers in advance
Blown tube?
Quote by durhamdynamo
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Honestly that does sound like every time I've ever blown a tube. When I blew a speaker the sound just got kinda warbly and distorted.

That's a 212 right? You're saying one of the speakers is doing this but the other isn't?
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I can't tell if it's one or the other because I haven't tried both yet, all I know is one was much hotter than the other, and the smoke was coming from an area where there are no tube sockets. All the power tubes are fine, and they were replaced very recently too, so it's not them. The fuse didn't blow either, and last time a tube went on me it did, so I'm not sure its a tube either. It affects all the channels so I assume it's the first preamp if it has gone. It is definitely most noticeable on clean though (for obvious reasons). It sounds like a very patchy breakup, almost like a fuzz that's being underbiased, and blended in and out of the signal.


I haven't tried each of the speakers on its own yet because I don't have any 9v batteries lying around, and I wanted to make sure that if it is the speakers, I haven't damaged the output transformer in the same hit. If its definitely safe to roll, I'll connect up each speaker by itself and try it.
Last edited by Dan_5893 at Oct 2, 2011,
Unfortunately I don't. All of my guitarist friends use combos like me. I'm looking around the net and currently the idea of the blown preamp tube is striking me as most likely.

I may just take it down to my local music shop on Thursday and see what they make of it.


Ok, I'm going to try using just one speaker at a time. This should yield results.


Yep, the right speaker is still working fine, so I think it's the left speaker that's bitten the dust. I'll try that tomorrow when I get back from Uni and have time to, since it's quite late here now. If the worst comes to the worst, how safely can I use a 70W speaker with a 120W amp? I'm pretty sure as long as I keep the master volume low enough, I should be good to go?
Last edited by Dan_5893 at Oct 2, 2011,
Bugera speakers are not very good. Look for some used speakers in your area on Ebay,Gumtree, ect..
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Ok, It's definitely a blown speaker. I got around to testing the second speaker today, and its very hissy and fuzzy. I can run the amp with just one speaker fine though, so I may just have to do that for a while and watch the volume.

I have the opportunity to get hold of some H&H Invaders for cheap though, has anyone had any experience with these speakers? For $95 each they seem reasonable, and I can get them from a local amp tech too so there will be no shipping fee involved.

If anyone can suggest an alternative to that, then that is also welcome. I've looked at Warehouse Speakers but the shipping cost will be quite high on a pair of their British Leads or indeed any of their speakers because I'm in Australia.