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  • #1

    Bugera help

    Hi all,
    I recently got a deal on a bugera 333xl and was pretty happy with it. Ive had it for about 2 weeks. Just got back from practice which was cut short because the amp just quit making any noise. Being somewhat handy with a meter (but entirely new to tube amps) I thought I would make a couple checks. Tubes light up, power light lights up, standby light illuminates, but no sound. I checked the fuse in the back, which was good. The infamous plug that likes to fail has already been removed and the wires have been soldered to the posts and covered with heat shrink. Ive removed and checked all internal fuses I could find. One of the transformers seemed hot when I removed the head from the case, the other not so much. When I turn off the standby switch it seems to stay on momentarily, and slowly dim through the span of about 5 seconds. Any ideas would be greatly appreciated.
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  • #2
    this site is your friend:

    Tube Amp Debugging Page

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    • #3
      Yes, do the de-bugging page. My first thought is check the speaker and speaker cord.
      Education is what you're left with after you have forgotten what you have learned.

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      • #4
        Wow.... Color me emberassed. It turned out to be the speaker cabinet. Ive never seen a cabinet die like that. After removing the back of the cab, I disconnected the two wires that connect to the jack and ohmed em out and had infinite resistance. All of the wiring is intact, nothing broken, loose, or off and I have no reisitance. Shouldnt I have some measure of resistance through a speaker? Putting my ohm meter across the terminals of each speaker, they all appear to be open, no resistance. What could "kill" four speakers like that? Any ideas?
        Btw, thanks to both of you for responding. Im a newbie in tubeland and your insight and this forum are enormously helpful, thanks for the input.

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        • #5
          Of course a speaker SHOULD have resistance - several ohms of it. But just like a light bulb, they can burn out too. I don't know what speakers were in your cab, but most likely some loud peak killed them.

          If one speaker died and the rest are OK, then the speaker itself is suspect. But if multiple speakers in one cab die at the same time, it is almost never the speakers' fault.

          And one detail - open is not "no resistance." No resistance is zero ohms - a dead short. Open is infinite resistance.
          Education is what you're left with after you have forgotten what you have learned.

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          • #6
            The speakers, I found out, are cheapos, SLM electronics. I guess they were put in some low end Crate cabs. I guess I should check the ohms of each speaker, and see if one or two are bad. My fear is that I have an amp that is going to continue to kill speakers. Never seen this with a solid state amp. Im guessing its uncommon with a valve amp, but is it totally unheard of? I had the master volume set at about 5, I dont think I was driving them particularly hard. A spike makes sense, but I have no idea what to check, or how to check it to see what is actually causing it.
            Btw, I see youre in MI, are you a Lions fan?

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            • #7
              Lions? No. I quit following the NFL when they made it an accountants game with the salary caps. But I grew up in Washington DC< so I root for the Redskins when I see them.

              AMps don;t kill speakers, people do. In fact solid state amps are way more likely to destroy speakers. SS amps can fail and put DC voltage on the speaker, melting the voice coil. Tube amps have no way to do that. But mainly, it is people that put too much through a speaker. It is not the amp's fault it has more power than the speaker can handle.
              Education is what you're left with after you have forgotten what you have learned.

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              • #8
                When you "put too much through the speaker", I assuming your talkin about volume, which "blows" the speaker, right? Resulting in the torn, farty tone? Like if you put 200 watts through a 50 watt cab it would ruin the speaker.
                After checking the speakers in the cab a bit further, two coils have infinite resistance. Anything I should check before simply replacing speakers?

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                • #9
                  Originally posted by DarEch View Post
                  ...Resulting in the torn, farty tone? Like if you put 200 watts through a 50 watt cab it would ruin the speaker.
                  This is just one form of speaker failure, another form is when the voice coil gets too hot and melts into either an open connection or a dead short.

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