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In no real order:
First off, make sure you have fresh power tubes in your amp. A good rule of thumb is to replace them yearly or when you notice the tone isn't as punchy/loud. When you get your new tubes, make sure they have the same rating as the tubes you had. This way you shouldn't need to bias your amp. You should anyways, but you will be in the ballpark. If you're a 'I want every last dripping bit of tone' guy, you should have your amp bias checked at each tube change or learn how to do it yourself. Also, when you replace your power tubes, WRITE THE DATE ON THEM WITH A SHARPIE. This way you'll never forget when they were swapped. If your old tubes sounded just as good as the new ones, then at the next scheduled tube replacement time, put in the old spare tubes and see if they sound better. If not, then wait three months or so and repeat. When the old tubes sound better, get some new ones!
If you put the new tubes in and don't notice a tonal difference, don't get mad... take those tubes you just took out and make those your spares. Carry them with you to practices or gigs, and if you have a tube blow at a bad time you can just plug it in and keep going. Of course, you'll want to replace the full set of tubes asap so they all wear at the same rate, but this will keep your amp running until new tubes come in. When you replace your preamp tubes, MAKE A MARK ON THEM TO THE FRONT CENTER OF THE TUBE. This will help you align them - it can be a real pain getting preamp tubes lined up right. if you don't mind a small mark on your amp, put a little line on the edge of the tube socket to match the tube line.
Driver tubes should be replaced at the same time as the power tubes - they are 12ax7 type (or at or au7) that are usually closest to the power tubes.
Other tubes in the preamp can last a very long time... I've seen preamp tubes from the 60s that were in amps used a LOT still test good on a tube tester. Also, NOS tubes tend to last longer than the new chinese ones. If you're in doubt, buy enough to replace all the preamp tubes in your amp - try them, see if the tone gets better. If not, keep them for spares!
When you change out your tubes, tighten up any loose screws or hardware on your amp. This includes jacks, chassis screws, everything. If a knob feels weird, take it off, retighten the potentiometer underneath it.
Now for the tube amp trouble kit. it's kinda like having a spare tire with air in it - you'll only need one when you DON'T have one in your car. Here's what you should have in yours:
1) set of flathead and phillips screwdrivers sized correctly. Don't strip out bolts or screws on your amp tightening something up!
2) the before-mentioned 'spare set' of your replaced tubes
3) a multimeter. Even if you aren't going to be setting your own bias, one of these comes in VERY handy for testing fuses and making sure that was the problem. Many fuses have those white 'covers' inside - so you can't just look to see if the wire is busted inside. And some have such a small burn/gap that you can't see them. However, your multimeter can. Later on, you can use a multimeter to check bias, voltage in the club you're playing, all sorts of things. Radio Shack sells a cheapie for under $20 that works fine for this. Plus you can use it to test pickups, speaker cab ohms, wiring on your guitar, etc.
4) a potholder. yeah, a potholder. Ever try to yank a hot tube out of your amp? You probably still have burns from it. Use a potholder.
5) spare fuses. At least two of each type in your amp. DO NOT put a fuse rated any larger or of the wrong 'blo speed' in your amp unless you just feel like handing a tech your dead amp and wallet at the same time. It's ok to substitute a smaller rated fuse (in amps) but it will burn up quicker than stock. NEVER and I mean NEVER wrap a fuse in foil to 'get through the gig'. If your amp is blowing fuses, something is wrong - but that fuse blowing is there to protect the amp. Bypass the fuse and instead of a fuse blowing it's likely a transformer or an internal component will blow.
Depending on how often you use your amp, your electrolytic capacitors need to be checked. Usually they last anywhere from 5-15 years, it depends on how often the amp has voltage applied to it, and also how they are rated vs the voltage being run through them. An amp running right on the edge of capacitor voltage rating vs voltage in the amp is going to burn them up quicker. When your caps go, the amp will make more noise, your bass will suffer and the amp will have 'ghost notes' or low tones following everything you're playing... kinda like an out of tune harmonizer.
Use your standby switch! It keeps the high voltage in your amps from slamming into your tubes until they are properly warmed. This is a bigger problem with higher voltage amps than lower wattage ones... Wait at least a minute after turning your tube amp on before you flip the standby to 'on'. When you're done with your amp, flip the standby switch to 'off' before you turn the amp off. This ensures that when you turn the amp on again, it will be in the right position.
If your amp is getting crackly sounds when you adjust a pot, clean em! If you don't know how to do this, you might want to have a tech do it, since you'll have to open your amp up to get to the back of the pots. A way to do it without taking the amp apart is to move the pot back and forth from 0 to 10 and back again, quickly. Sometimes this can clean it up. Sometimes pots need to be cleaned, and sometimes you just need to replace them entirely.
Pete
First off, make sure you have fresh power tubes in your amp. A good rule of thumb is to replace them yearly or when you notice the tone isn't as punchy/loud. When you get your new tubes, make sure they have the same rating as the tubes you had. This way you shouldn't need to bias your amp. You should anyways, but you will be in the ballpark. If you're a 'I want every last dripping bit of tone' guy, you should have your amp bias checked at each tube change or learn how to do it yourself. Also, when you replace your power tubes, WRITE THE DATE ON THEM WITH A SHARPIE. This way you'll never forget when they were swapped. If your old tubes sounded just as good as the new ones, then at the next scheduled tube replacement time, put in the old spare tubes and see if they sound better. If not, then wait three months or so and repeat. When the old tubes sound better, get some new ones!
If you put the new tubes in and don't notice a tonal difference, don't get mad... take those tubes you just took out and make those your spares. Carry them with you to practices or gigs, and if you have a tube blow at a bad time you can just plug it in and keep going. Of course, you'll want to replace the full set of tubes asap so they all wear at the same rate, but this will keep your amp running until new tubes come in. When you replace your preamp tubes, MAKE A MARK ON THEM TO THE FRONT CENTER OF THE TUBE. This will help you align them - it can be a real pain getting preamp tubes lined up right. if you don't mind a small mark on your amp, put a little line on the edge of the tube socket to match the tube line.
Driver tubes should be replaced at the same time as the power tubes - they are 12ax7 type (or at or au7) that are usually closest to the power tubes.
Other tubes in the preamp can last a very long time... I've seen preamp tubes from the 60s that were in amps used a LOT still test good on a tube tester. Also, NOS tubes tend to last longer than the new chinese ones. If you're in doubt, buy enough to replace all the preamp tubes in your amp - try them, see if the tone gets better. If not, keep them for spares!
When you change out your tubes, tighten up any loose screws or hardware on your amp. This includes jacks, chassis screws, everything. If a knob feels weird, take it off, retighten the potentiometer underneath it.
Now for the tube amp trouble kit. it's kinda like having a spare tire with air in it - you'll only need one when you DON'T have one in your car. Here's what you should have in yours:
1) set of flathead and phillips screwdrivers sized correctly. Don't strip out bolts or screws on your amp tightening something up!
2) the before-mentioned 'spare set' of your replaced tubes
3) a multimeter. Even if you aren't going to be setting your own bias, one of these comes in VERY handy for testing fuses and making sure that was the problem. Many fuses have those white 'covers' inside - so you can't just look to see if the wire is busted inside. And some have such a small burn/gap that you can't see them. However, your multimeter can. Later on, you can use a multimeter to check bias, voltage in the club you're playing, all sorts of things. Radio Shack sells a cheapie for under $20 that works fine for this. Plus you can use it to test pickups, speaker cab ohms, wiring on your guitar, etc.
4) a potholder. yeah, a potholder. Ever try to yank a hot tube out of your amp? You probably still have burns from it. Use a potholder.
5) spare fuses. At least two of each type in your amp. DO NOT put a fuse rated any larger or of the wrong 'blo speed' in your amp unless you just feel like handing a tech your dead amp and wallet at the same time. It's ok to substitute a smaller rated fuse (in amps) but it will burn up quicker than stock. NEVER and I mean NEVER wrap a fuse in foil to 'get through the gig'. If your amp is blowing fuses, something is wrong - but that fuse blowing is there to protect the amp. Bypass the fuse and instead of a fuse blowing it's likely a transformer or an internal component will blow.
Depending on how often you use your amp, your electrolytic capacitors need to be checked. Usually they last anywhere from 5-15 years, it depends on how often the amp has voltage applied to it, and also how they are rated vs the voltage being run through them. An amp running right on the edge of capacitor voltage rating vs voltage in the amp is going to burn them up quicker. When your caps go, the amp will make more noise, your bass will suffer and the amp will have 'ghost notes' or low tones following everything you're playing... kinda like an out of tune harmonizer.
Use your standby switch! It keeps the high voltage in your amps from slamming into your tubes until they are properly warmed. This is a bigger problem with higher voltage amps than lower wattage ones... Wait at least a minute after turning your tube amp on before you flip the standby to 'on'. When you're done with your amp, flip the standby switch to 'off' before you turn the amp off. This ensures that when you turn the amp on again, it will be in the right position.
If your amp is getting crackly sounds when you adjust a pot, clean em! If you don't know how to do this, you might want to have a tech do it, since you'll have to open your amp up to get to the back of the pots. A way to do it without taking the amp apart is to move the pot back and forth from 0 to 10 and back again, quickly. Sometimes this can clean it up. Sometimes pots need to be cleaned, and sometimes you just need to replace them entirely.
Pete
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