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More Mesa Boogie problems

#21
Instead of changing all of the tubes at one time, try changing them one at a time. Start with the preamp tubes. Replace the first preamp tube with a new one. If this does not cure the problem, put the first one back in, and exchange the second one for the new one. Proceed through the whole row of preamp tubes.

If this does not cure the problem, take the amp to a qualified technician.

You might also download the manual for your amp from the Boogie site. It will answer many of your questions.
 
#22
Psycho Bass Guy said:
Wrong. You've said it before, and I've corrected you before. While modern tubes may not equal the quality of old stock counterparts, they are nowhere near this unrelaible. On the contrary, 90% of porblems with tube amps are NOT the tubes themselves.
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Perhaps I should clarify: 90% of the time users complain of a problem with a tube amp, the symptom is caused by a bad tube.
 
#23
GeneralElectric said:
I only swapped tubes due to filament rattle from a pair of the JJs...:hmm:
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If you don't know how to properly replace and rebias tubes, then don't. I'm not convinced your initial problem was filament rattle. Filament rattle is barely audible at its worst.

GeneralElectric said:
I swapped out the preamp tubes.

Turns out two of them were shot. I just swapped the whole lot of them for the JJs.
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How did you determine this?

Benjamin Strange said:
Perhaps I should clarify: 90% of the time users complain of a problem with a tube amp, the symptom is caused by a bad tube.
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Still wrong. Many people mistakenly attribute problems to tubes simply because that's the BS they've been sold, but that doesn't mean that the tubes are actually at fault.
 
#24
Psycho Bass Guy said:
If you don't know how to properly replace and rebias tubes, then don't. I'm not convinced your initial problem was filament rattle. Filament rattle is barely audible at its worst.
Click to expand...

I was hearing a rattling noise from the amp head, and not from the speaker. Tapping the tubes, some of them sounded like an old school telephone. After I replaced the tubes, the rattling stopped. It was the two power tubes all the way on right by the XLR jack. Since I didn't have replacement JJs, I just swapped all of them for replacement Mesa tubes which I had, as well as new Mesa preamp tubes which I bought yesterday

Problem solved?

How did you determine this?
Click to expand...

They were blackened on the inside, and when I replaced those with JJs, it sounded fine. I just swapped out all the preamp tubes back to the JJs it came with so I had matching tubes.
 
#25
Psycho Bass Guy said:
Still wrong. Many people mistakenly attribute problems to tubes simply because that's the BS they've been sold, but that doesn't mean that the tubes are actually at fault.
Click to expand...

I'm not disagreeing that there are many things that can and do go wrong with tube amps, but I am saying that tubes are oftentimes the most fragile part of an amp, and often go bad due to vibration, breakage, or other factors. After working at Boogie, and working in the MI industry for many many years, what I've seen is many people suffering from issues that are strictly based on faulty tubes. Microphonics, excessive noise, etc. - much of these problems can be solved simply by changing the tubes. Mesa's customer service department (as I'm sure every manufacturer's service department) is flooded with calls every day from people who are experiencing tube problems, which are very easily fixed.

Methinks that in the case of a tube amp, if it's experiencing problems, the tubes should be the first thing to be looked at in the process of diagnosing what's wrong with it.
 
#26
GeneralElectric said:
I was hearing a rattling noise from the amp head, and not from the speaker. Tapping the tubes, some of them sounded like an old school telephone. After I replaced the tubes, the rattling stopped. It was the two power tubes all the way on right by the XLR jack. Since I didn't have replacement JJs, I just swapped all of them for replacement Mesa tubes which I had, as well as new Mesa preamp tubes which I bought yesterday

Problem solved?
Click to expand...

That's NOT filament rattle. That's just loose glass. As long as it's the glass rattling and not the internals (microphony) it doesn't hurt a thing. If the noise bothers you, shock isolate the head. It really needs to be shock isolated anyway.

They were blackened on the inside, and when I replaced those with JJs, it sounded fine. I just swapped out all the preamp tubes back to the JJs it came with so I had matching tubes.
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Preamp tubes shouldn't burn up like that. You need to get that looked at.
 
#27
Benjamin Strange said:
I'm not disagreeing that there are many things that can and do go wrong with tube amps, but I am saying that tubes are oftentimes the most fragile part of an amp, and often go bad due to vibration, breakage, or other factors. After working at Boogie, and working in the MI industry for many many years, what I've seen is many people suffering from issues that are strictly based on faulty tubes. Microphonics, excessive noise, etc. - much of these problems can be solved simply by changing the tubes. Mesa's customer service department (as I'm sure every manufacturer's service department) is flooded with calls every day from people who are experiencing tube problems, which are very easily fixed.

Methinks that in the case of a tube amp, if it's experiencing problems, the tubes should be the first thing to be looked at in the process of diagnosing what's wrong with it.
Click to expand...

Many people mistakenly attribute problems to tubes simply because that's the BS they've been sold, but that doesn't mean that the tubes are actually at fault.
 
#28
Psycho Bass Guy said:
Many people mistakenly attribute problems to tubes simply because that's the BS they've been sold, but that doesn't mean that the tubes are actually at fault.
Click to expand...

I can agree with that to a degree. This does not negate the fact that most problems that people experience with tube amps can be easily fixed by replacing a faulty tube. I merely state that statistically speaking, 90% of the time people are having trouble with their amp is because they've got a bad tube, that's all. I suggest that the original poster look into that first, before he takes it in.
 
#29
Psycho Bass Guy said:
That's NOT filament rattle. That's just loose glass. As long as it's the glass rattling and not the internals (microphony) it doesn't hurt a thing. If the noise bothers you, shock isolate the head. It really needs to be shock isolated anyway.
Click to expand...

Its in a Mesa Boogie Sus-4 rack space that it shipped in and weighs a ton. Any advice on it being better shock isolated?


Preamp tubes shouldn't burn up like that. You need to get that looked at.
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Will do. They're not all the way blackened, just the top most area. But you're right, that shouldn't be happening.

I haven't had this happen to my other tube amps before.:hmm:
 
#30
GeneralElectric said:
Its in a Mesa Boogie Sus-4 rack space that it shipped in and weighs a ton. Any advice on it being better shock isolated?
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I think you've already got it in the safest case you can get. I once dropped my tube rig down a full flight of stairs (17 steps), and then through a solid wood door. Only one tube out of 20 went bad.
 
#34
Benjamin Strange said:
This does not negate the fact that most problems that people experience with tube amps can be easily fixed by replacing a faulty tube. I merely state that statistically speaking, 90% of the time people are having trouble with their amp is because they've got a bad tube, that's all. I suggest that the original poster look into that first, before he takes it in.
Click to expand...

Even with the ultra-cheap tubes Mesa sometimes rebrands, this isn't true. I've seen some absolutely terrible tubes that were supposedly "tested" by Mesa that were absolute junk, but lots of Mesa's that I've seen had terrible solder connection issues that a preamp tube swap would "cure" only to resurface later. Things like that would be blamed on the tubes, when it was the amp that was at fault. It's irresponsible to suggest an end user replace tubes as first course of action.

GeneralElectric said:
Its in a Mesa Boogie Sus-4 rack space that it shipped in and weighs a ton. Any advice on it being better shock isolated?
Click to expand...

That's a very good case and should do exactly that. Try putting foam under it.

Will do. They're not all the way blackened, just the top most area. But you're right, that shouldn't be happening.
Click to expand...

Sometimes, black marks on the tops are normal. Was that your sole criteria for determining that they were "bad?"

I haven't had this happen to my other tube amps before.:hmm:
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The Bass 400+ is rare in that it is not in head case, which would in itself provide a small degreee of shock isolation. The bottom is metal and screws that attach directly to the chassis which transmit vibration VERY easily.
 
#39
GeneralElectric said:
These were new Mesa 6L6 tubes, and new Mesa 12AX7 preamp tubes. I don't know how to check if they're properly biased or not.

I'm using 2 8 ohm cabs plugged into the 4 ohm speaker jack outs.

Nothing is being run through the effects loop and the slave and effects knobs in the back of the amp are both at 0.
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Is that how this amp works? two 8 ohm speakers get plugged into the 4 ohm slots? If you are running 1 (8)ohm cab obviously it gets plugged in 8. I would say you plug both of your 8 ohm cabs in 8 slots and the amp makes it a 4ohm load automatically.
 

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