ok....I was told by a friend that it would be best if I went to a professional to replace my tubes.

I have never replaced tubes before. Is it that complicated ?

Should I take them to a professional ?

power amp or pre amp tubes?

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im not a gear expert by any means, but wouldnt it be like changing a damn light bulb? you screw the old one out and the new one in...

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thats what i would have thought

and that's wrong.

if you need both power tubes and preamp tubes you'll need to have it done by a tech.

the preamp tubes are simply plug-and-play, take out the old ones, put in the new ones and thats it. (leave it on standy before playing first, for a couple of hours for the tubes to get used to getting lit)

the powertubes however need to be biased, which is basically setting up your amp for the powertubes, since all powertubes have slightly different characteritics, sometimes even if you have the same brand/type. Some amps don't have to be biased and have factory tube sets, like Engl, Mesa Boogie and Koch, they have their own sets and their amps have a fixed bias. (you can adjust them if you want, but their factory tubes are selected so they match your amp instantly.)

Anyways, if you need your powertubes replaced, bring it to the amp doc. it won't be really expensive but it's something you just have to do. if you put in other powertubes and fire the amp up your amp might sound either crappy or the tubes will burn out in less then an hour..

preamp tubes are just plug and play. if you don't know shit about the tubes, the small ones are the preamp tubes and the big ones are the powertubes, hehe. what amp are you using? maybe there's better tubes out there for your amp then the stock tubes. (for instance, warmer tone, more gain, etc. better tubes are more expensive then crappy ones but its well worth the price difference.)

What Def said.

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biasing is a factor in powertubes, but usually if you have a matched quartet(or pair or whatever) it should be fine, you can ask a tech... never had to take my 50/50 to a tech, bob at eurotubes told me it'd be plug in and play... same with my buddy's 5150....

mesa, simply restamp other brands tube's, mostly sovteks... you might think, why buy mesa tubes then? the tubes mesa restamps are picked to fit in a certain bias range, to match perfectly with their amps... so if you bought any old sovtek 6l6's to throw in your recto, chances are it may not fit the range properly like the mesa ones.. though you can have someone like bob at eurotubes handpick specific tubes to fit your needs if you do want jj's or something in your amp.

just food for thought, i hear so much knocking on mesa tubes from some people, saying sovteks all the way, or sovteks rock, mesa's suck.

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Mesa restamps chinese tubes.

yes they do, but they mostly restamp russian tubes, like sovteks and svets...
http://store.yahoo.com/mesa/el34sovtek.html
http://store.yahoo.com/mesa/12axtes.html
http://store.yahoo.com/mesa/6l6stsvet.html
http://store.yahoo.com/mesa/elstsvet.html
http://store.yahoo.com/mesa/5881russian.html
http://store.yahoo.com/mesa/5u4recrus.html
http://store.yahoo.com/mesa/6l6stgcrus.html
http://store.yahoo.com/mesa/6bq5elrus.html
http://store.yahoo.com/mesa/elsiemst.html


they only have three chinese tubes...
http://store.yahoo.com/mesa/5archin.html
http://store.yahoo.com/mesa/6v6chinese.html
http://store.yahoo.com/mesa/6l6stchinuse.html

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Matched tubes all draw the same current... it dosent mean your amp will be properly biased. If I take some matched JJ's from Dougtubes.com and throw them in a stock 5150 the bias will still be cold, thus still causing crossover distortion.

Biasing your amp is important, if I just threw tubes in my 5150 I would have never known that it had a blown screen grid resistor.. thus only running three power tube.. which stresses the output transformer. Since the previous owner just "Plugged a Played" he had caused one of the screen grid resistors to blow.

BTW, Mesa's are also biased extremely cold. Chances are if a amp is just plug and play then the bias is set lower to avoid overheating the tubes. Unless you have somone manually set the biad is will NEVER be the same. All tubes draw different currents.

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that's what i ment... alot of more popular amps are biased pretty cold these days. and are pretty ok with most tubes as long as they're matched..

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I bet this biasing shit explains why my sovteks get red when I turn them on.

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When I first changed the tubes in my amps I got to know this:

One of my tubes were completely ruined. Every grid resistor had been burned .

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I think one of my preamp GT12ax7 blew the other night. There's a total of three preamps and two of the three have the nice silver lining inside the top and the other one has turned to a rainbow, kinda burned colour. I noticed a decrease in sound quality as I was playing. I'm going to be ordering some GT12AX7-M from groove tubes and see what they are like.

GT Product List

Anyone else have this happen to their preamp tubes??

Will any damage be caused if I pull out the burned one and play with one less tube??

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That rather depends on the amp if it will work in the first place, but it will definitly affect your output volume or tone.

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while it's on... try lightly tapping the "rainbow tube" with something like the eraser end of a pencil.. if you can here it, you have a microphonic preamp tube...

as for your amp without a tube... i don't recommend it... sometimes on some amps you can pull out power tubes by pairs(outer two or inner two) to half the wattage... but not all amps work like that..
and i don't think it'll work without a preamp tube...

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There's nothing like a good poke to solve the problem.I tried poking my metal master but it didnt sound any better.

Pulling out a preamp tube isent a good idea.

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If you dont know what you are doing.

Well, I fired it up last night (after removing the grill and preamp caps). The two el34's were lit evenly and the three preamp tubes were also lit evenly. I guess i'm wrong and that 'none' of my tubes are blown. I thought that I noticed a change in performance but maybe i'm losing it. Maybe my tubes are losing their edge and may require change soon. My buddy said to pay attention to the fuse(s) as well.

I may have had an off day. It's known to happen.

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i imagine you crank it quite a bit because it's only a 50 watter.. the more powetubes are pushed the better they sound, but unfortunately it's also the faster they go.

if your poweramp tubes are getting old and losing sound you'll notice a few subtle things, like your highs will be a bit more brittle, you'll also lose some low end, a slight volume drop, and kind of an overall "airy" sound.



if a tube blows, alot of the time it'll take a fuse with it... but if a fuse blows you'll know it...

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.... what the hell is that supposed to mean? Running with one less preamp tube is fucking retarded and dont even try to argue.

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What the hell dude i said pulling out a tube isnt good idea if you dont know what your doing.relax

Well, I like to keep my preamp knob to 9 oclock and crank my gain knob to 3 oclock. That's a smooth distortion configuration for my JCM 900. Most of the time, I keep the master volume low for a nice tube sound but everynow and then, I do like to crank it up for some raw power. The problem with volume are the neighbours!

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