how do i know when to change a tube

[ErikH]

Re: how do i know when to change a tube

If it's brand new, you're fine. If you got it used and the previous owner is not sure when it was last retubed, then go ahead and retube it, pre-amp and power tubes. Then go from there. A retubing depends on how often the amp is used, how hard it's pushed, the elements it's used in, etc. Playing it at home in the garage once a week or so doesn't warrant frequent tube changes, probably every year or two, again depending on how hard those power tubes are pushed. Played loudly in a smokey bar 5-6 nights a week will warrant more frequent tube changes. And again, listen to how it sounds with fresh tubes. When it doesn't sound like that anymore, then it's most likey time for a change.

[DesertRose]

Re: how do i know when to change a tube

Usually there will be those red lights glowing in the tubes.
Think when they're outta action those red lights will not lid up I guess.
Prolly thats one way to tell that a tube is busted

[Chaos]

Re: how do i know when to change a tube

I'm a highly qualified electrical engineer and it's not the volts that kill, it's current. As little as 100mA is enough to kill!!!!

Correct. Current is what kills you, however 100ma would have little affect on contact with unbroken skin.

Most likely you'll injure yourself when your hand smacks something hard as you instinctively jerk it back after you accidentally short a cap.

[motorboy29]

Re: how do i know when to change a tube

Right, so i got it used and the tubes are kinda old-lookin and black on the bottom... I prolly need to change 'em. Please tell me its easy... like changing light bulbs or somethin. Also, what ones do I need and where do i get them and poss. instructions on how to do it.

[marvar]

Re: how do i know when to change a tube

My advice is to take it in to a electronics or amp tech- changing the tubes is no big deal-however-setting the bias takes some knowledge of the inner workings of an amp-at the same time, he will probably give a look at, and inform you of any things amiss- which could lead to problems in the future- go aead and eat the cost- but don't let them overcharge you for tubes! You can even buy your tubes somewhere else and let the tech install them for you.
at least your amp will get a clean bill of health, and you will be in good shape.

[Buckeyedog]

Re: how do i know when to change a tube

Dude it's very easy. What are the power tubes.....el84's?? el84's? Or 6l6's??
If they are el84's, I'd recommend JJ's. El34's, I would suggest SED's. 6l6's could be SED's or JJ's. Also see the other "pre amp tube" threads, there's all kinds of good stuff in there. Don't worry about killing yourself just changing tubes. Pretty much if you take the chassis out and are fooling around in there is where you have to worry. Just gently grab the tubes and rock them back and forth and slowly pull them out. Line up the new ones and put them back in.

[motorboy29]

Re: how do i know when to change a tube

Right, the current tubes are 6L6S's,Marvar how much are we talking here... like fifty bucks? and, where do I get this stuff, are there internet sights? BTW I cant even find the goddam pre-tubes