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rapedbyape
New member
...How can you tell when the tubes in an amp have worn out? Do they just stop working, or begin sounding bad, or what? APologies for my lack of knowledge.
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SteveK
New member
Depends on tube type and location. If it's a preamp tube (the smaller tubes) you will notice loss of gain, and/or an increase in distortion when trying to play clean. Power tubes generally start sounding weaker, less depth and girth to the tone and volume. Of course tubes can and do also fail catastrophically, usually at a gig, or in the middle of recording a truly one-of-a-kind solo that you know you'll never be able to duplicate 
If you notice that the amp just doesn't sound right to you, check the tubes and try replacing them one at a time in the preamp section. Preamp tubes generally last much longer than power tubes though, and while some players replace their power tubes on a regular basis depending on how often and how hard the amp is played, they tend to leave the preamp tubes alone unless there is a problem. If you replace the power tubes, make sure that you have a qualified tech or experienced friend bias them correctly if your amp requires it. Also, especially if you are in a gigging situation, make sure you carry replacement tubes in your gig bag...you never know when you might need them. 
If you notice that the amp just doesn't sound right to you, check the tubes and try replacing them one at a time in the preamp section. Preamp tubes generally last much longer than power tubes though, and while some players replace their power tubes on a regular basis depending on how often and how hard the amp is played, they tend to leave the preamp tubes alone unless there is a problem. If you replace the power tubes, make sure that you have a qualified tech or experienced friend bias them correctly if your amp requires it. Also, especially if you are in a gigging situation, make sure you carry replacement tubes in your gig bag...you never know when you might need them.
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rapedbyape
New member
Thanks for the information, although to be honest I don't really have a clue about the innards of this amp (pre-amp/power tubes etc.), so I'll probably just take it to the shop. All I know is that it's a Laney Tube Fusion 200, and that both the drive and gain channels have started sounding very gritty and abrasive with distortion turned up.
jimistone
long standing member
I have a fender hot rod deville and it started sounding really bassy, I had to turn the bass tone knob almost all the way down to get a decent sound. It was just dull sounding. A friend of mine, who is very knowledgeable said it sounded like it needed a new set of power tubes. I put a set in and it sounded like it was supposed to.
Outlaws
New member
I had a Blues Jr. and it sounded like a freight train when I turned it on. Got new power tubes and it was solved. Scared the hell out of me though.
Buck62
噛んでくれ
Outlaws said:
Often, you will hear a faint "crackling" sound before it gets to the extreme of sounding like a freight train. But most people either don't hear it at that early stage or simply dismiss it as cheap cable, bad connection or a noisey pickup.
The best way to tell if your tubes are starting to go is to turn on the head with nothing connected to it... no guitar, no speakers, nothing. If you hear noises, one or more of your tubes are on the way out. We just had it happen to a guitar player who recorded with us over the weekend with his Marshall JCM2000 head. The thing was crackling like a hamburger on a grill before anything was even connected to it. Definitely a bad tube. The crackling was audible in the recording, so his JCM head was unusable for recording. Fortunately, I had a backup amp, so the session was saved.
Whoopysnorp
New member
Buck62 said:The best way to tell if your tubes are starting to go is to turn on the head with nothing connected to it... no guitar, no speakers, nothing. If you hear noises, one or more of your tubes are on the way out. We just had it happen to a guitar player who recorded with us over the weekend with his Marshall JCM2000 head. The thing was crackling like a hamburger on a grill before anything was even connected to it. Definitely a bad tube. The crackling was audible in the recording, so his JCM head was unusable for recording. Fortunately, I had a backup amp, so the session was saved.
Doesn't this damage tube amps though?
Buck62
噛んでくれ
Whoopysnorp said:
How would that be?
Do you think a technician hooks up a head he's working on to a matching cabinet when someone brings it in for repair?
I doubt it.
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boingoman
New member
Buck62 said:
Actually it's true. Tube amps need to see the right impedance to stay healthy. Firing up a tube amp with no speaker load on it can smoke the output transformer fast. Also the power tubes, and a few other bits, if you are unlucky. Any tech working on a tube amp will definitely hook it to a cab or load for any kind of test that has to do with the outputs, if the amp is on.
It's usually no biggie if there is no signal going through the amp, but it's way better to play it safe.
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Protube2004
New member
The rules I have always followed are these,If you use the amp 3-5x a week and for 2-4 hours each time,Replace the Power Tubes every 6 Months and The Preamp Tubes Once a year...I have been doing that with the same Randall 100 Watt Protube2000 All Tube(obviously)since 1992 and the ONLY problem I have EVER had was a faulty tube blew ONCE and I noticed the amp wasn't as loud BUT it kept on for the rest of the night.The PT2000 has an open grill in the front so you can keep your eye on those Hot Bulbs...You never know,so it's great to be able to see.....BTW,it's always BEST to have an Authorized Service Center Bias and Adjust whenever you replace the tube!
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boingoman
New member
I feel compelled at this point to say that the amp in question, the one with the problem, is a hybrid with a solid state power amp.
It has no power tubes.
That pretty much means this guy's problem is limited to his preamp tubes, if it is even a tube problem.
It has no power tubes.
That pretty much means this guy's problem is limited to his preamp tubes, if it is even a tube problem.
ecktronic
Mixing and Mastering.
Dont touch the inside of a tube amp unless you know what you are doing. They carry high charge even when switched off. So be carefull and dont die.
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bradthefattest
New member
just wonderign while on the topic, approximately how much would it cost to get an amp rebiased, the one i need it done on hs 4 12ax7 tubes, and 4 el84 tubes.
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1kidc
New member
One other rule of thumb - Class A amps (vox - matchless) go through tubes MUCH faster than a Class AB amp (fender-marshall). Reason being that tubes in class AB amps are only full on when there is signal present. Class A amps are at full power all the time.
Often it takes a while to notice they are dying but when you re-tube its unbelievable how obvious it is! I just re-tubed my pair of Gibson goldtones one at a time and A/B'd them (no pun intended) and the difference was AMAZING!
Often it takes a while to notice they are dying but when you re-tube its unbelievable how obvious it is! I just re-tubed my pair of Gibson goldtones one at a time and A/B'd them (no pun intended) and the difference was AMAZING!
