Can Not Changing your Amp Tubes Cause Damage?

[7th Hell]

HEY!

I'm a little curious as to how often you should change your amplifier tubes. I often read that power tubes need to be replaced if they become microphonic or have poor sound quality (no highs or lows). I also hear that the preamp tubes just need to be functioning. Some guys say 6 months to 1 year inbetween changes- and others say wait until you notice any problems.

I'm just wondering if you could actually do some damage to an amp by not replacing tubes often. Guys- give me some knowledge! THANKS!

 

[mrid]

Re: Can Not Changing your Amp Tubes Cause Damage?

As long as they're functional, you're fine, but if the tubes go south, you might run into some problems. Hopefully, your amp will simply blow a fuse when the tubes go bad.

 

[sanrafael]

Re: Can Not Changing your Amp Tubes Cause Damage?

Although tubes might go bad in a number of ways depending on how you treat your amp (Please do not throw it across the stage!), usually they just cannot put out the current anymore; bad sound, low power, but no damage to the amp. Tubes should last for years, but some guitar amps squeeze out every watt possible, and that might shorten the like of the ouput tubes (the big ones). The small tubes really should last a long time even if you leave the amp on al lthe time.

 

[7th Hell]

Re: Can Not Changing your Amp Tubes Cause Damage?

Thanks, guys! I did some more research online and found a very informative link- it was from the bad Fender Hot Rod thread, so +1, mrid!

http://studentweb.eku.edu/justin_holton/tubes.html#tubefaq

 

[Gearjoneser]

Re: Can Not Changing your Amp Tubes Cause Damage?

It's kinda like driving your car when it needs a tuneup and oil change.
For a few bucks you get much better performance.

 

[Simon_F]

Re: Can Not Changing your Amp Tubes Cause Damage?

I once had an EL34 power tube fail in my JTM60 combo. Fortunately it was during a rehearsal. It was obvious because the volume suddenly dropped a lot. Looked in the back and could see that one power tube had stopped glowing. You don't want that kind of thing happening mid-gig, which is why you need to change them before they die.

Pre-amp tubes I believe give more indication they are on the way out - various pops, hisses and wheezes for some time before they fail.

 

[Pandemonium]

Re: Can Not Changing your Amp Tubes Cause Damage?

No, but caps are another story.

 

[Kent S.]

Re: Can Not Changing your Amp Tubes Cause Damage?

As long as they're functional, you're fine, but if the tubes go south, you might run into some problems. Hopefully, your amp will simply blow a fuse when the tubes go bad.

On this note, if your amp doesn't have a B+ fuse then have a tech install one for each push/pull pair, the reason is that if the tube shorts when it goes,and tries to draw more current from the supply the fuse will go rather than the power supply burning up because it's limit has been exceeded. Most modern tube design (50~100 watters) have these. Speaker fuses aren't a bad idea either, if a speaker coil shorts the fuse goes before it blows the output tranny, short circuit,major low impedance, major current draw, or if those are set up properly if to low a load is connected, and the amp is pushed to herd ... same thing ... it blows instead of something else. Fast blow for speakers, fast blow for B+ fuses, and slow blow for power supplies is normally what is preferred, but always replace fuses with the same type and rating ... I know, but I had to say it...

 

[beandip]

Re: Can Not Changing your Amp Tubes Cause Damage?

My old Gibson GA-30 is from 49 (or so my grandpa says, who knows) and still uses the original small tubes. RCA something or another. Anyone tried that new thing from GT? it goes in a 6L6 slot but uses a EL84 tube. You drop the amps power by 70% I'm thinkin it's kinda like a Powerbrake or something.

 

[Kent S.]

Re: Can Not Changing your Amp Tubes Cause Damage?

My old Gibson GA-30 is from 49 (or so my grandpa says, who knows) and still uses the original small tubes. RCA something or another. Anyone tried that new thing from GT? it goes in a 6L6 slot but uses a EL84 tube. You drop the amps power by 70% I'm thinkin it's kinda like a Powerbrake or something.

Haven't seen it, powerbrake, nah, I'm thinking it reranges your bias and/or supply and is just an adaptor, I've seen the plug in S.S. rectifer that they (I think it's them) have that allows you to replace a tube rectifer (full wave only I believe) with a S.S. ... Helps to tighten up some amps ...If only it were as easy going the other way ...

 

[beandip]

Re: Can Not Changing your Amp Tubes Cause Damage?

Well, I'm thinkin it does about the same thing. Lets you get that Cranked UP sounds w/o having the cops come to your door.