[kayla]

Alright, so last night at practice, i moved my guitar amp and as i sat it down (yes it was plugged in), i got this loud terrible cracking and popping sound and then everything sounded horrible. my fender cleans sound horrible and my tube screamer sounds like ass.

i need to trouble shoot, i dont know how to tell if a tube is blown or there is a wiring problem or speaker problem. i have noticed over the last month or two i have been getting feed back and squealing.

so if anyone has any tips that would be great. i'm running a fender hot rod deluxe 40 watt tube.

oh ya, and i have a gig tonight and my amp sounds terrible.

thanks!

- kayla.
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`( f e n d e r)`

[Dark Soul]

I'm no expert, but since you have a gig tonight, I thought I'd share what I know.

A tube that's blown or about to blow can cause the problems you're describing. When you play with a tube amp it's always a good idea to have a spare set of tubes on hand at all times in case you blow one. If you don't have any, I'd suggest going out ASAP and getting some if you can even if that's not the problem this time. Vacuum tubes are kinda like light bulbs: they don't last forever. Sooner or later, your tubes are going to go, and if it happens during a show, you're screwed if you don't have a backup set.

Replace the tubes and see if that solves the problem. If it doesn't, it's most likely a problem with the guts in which case you need to get it to someone who can hunt down the problem and fix it unless you think you can check it out yourself. Sometimes what I'll do when I have a problem with something electronic is carefully take it apart, have a look and see if anything looks amiss. Even if you're not an amp repairing master, you can look for loose or disconnected wires or any other sign of something not looking right. Sometimes you get lucky and it's as simple as reconnecting a wayward wire.

Of course, the best thing to do is take it to the god of repair, Ken Oyler, at Gigbox Music and beg him to check it out today sometime if he can.

Hope this was some help to you.
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"This above all: to thine own self be true."
~Polonius, Shakespeare's 'Hamlet'

[kayla]

Thanks! i'm hoping that its just the tubes, i know the tubes were fairly new when i purchased the amp a few years ago. so they are probably about dead. i did take the back off the amp last night, checked connections and soldering to see if something came loose, but didn't seem to see anything.

how hard is it to replace a tube? i've never done it. maybe i will buy a set of tubes tonight and try it. hmm.

- kayla.
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`( f e n d e r)`

[Dark Soul]

It's not hard. Like replacing a car headlight. They come out fairly easily, just make sure you don't touch the glass with your skin. Any dirt or oil on the glass can cause a hot spot which might make it go bad prematurely. Only problem is, I have no idea where you'd get a set on short notice. I usually order mine online. Ask around. Maybe someone on RP has a set they'd sell you. Might want to try borrowing an amp for the gig until you get yours taken care of.
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"This above all: to thine own self be true."
~Polonius, Shakespeare's 'Hamlet'

[kayla]

alright, i should be able to handle it. i will buy some online, luckily i will be able to borrow an amp for tonight. thanks for your help!

- kayla.
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`( f e n d e r)`

[VENTGtr]

Whoa. Wait one second. There's a difference in tube types and replacement.
Preamp tubes you can just swap out. Power tubes need to be biased. If you're not sure how to do that, don't screw with the power tubes (And DON'T try to bias them yourself without knowing how. It can wreck the amp if they're not biased, or not done properly, and, potentially, kill you via happy-happy fun-time electrocution trying. May also need to let the power dissipate from the Power Tubes.

If you have any preamp tubes, ya, give them a try. If it's still doing it, call someplace and explain that you need it tonight.

MIGHT even just be a tube that got loosened a little, if you're lucky.

NOTE: If you order online from, say, Tubedepot.com, contact them first and tell them what kind of tubes you need and for what amp. They'll handle the bias part to your specs (If you want it a little high, low, whatever).
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DaveP.

"You must be this beautiful to ride the Quagmire."

[kayla]

[VENTGtr]

You bet. The one downside to tube amps. I know HOW to bias, but hugely prefer not to. Not sure what kind of tubes are in these Ffor power tubes (6L6, I think?).

For what you're playin', possibly Mullards, for the pre.

I don't have any amps using 6l6s, so not sure who all makes them, but I've heard SED's are great, though might be more expensive than some others.

I, generally, use JJs all the way around nowadays but in the pre, Mullards are really nice, I just need something more "modern" sounding.

Stay away from anything TAD, in my opinion.
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DaveP.

"You must be this beautiful to ride the Quagmire."

[bassist_25]

[VENTGtr]

Yep. I have a Tech21 GT2 sittin' there in the event it all goes wrong. Great in its own right for the Mesa and Marshall type sounds, but the Blonde is better for Fender-y.
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DaveP.

"You must be this beautiful to ride the Quagmire."

[Dark Soul]

I've never heard of biasing tubes before, hence the carefully placed "I'm no expert" at the beginning...lol! Sorry about that Kayla. I knew you could just replace the preamp tubes, so I thought the power tubes worked the same way. Geez, what a pain in the ass. I guess if you blow a power tube at a gig you're screwed no matter what.
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"This above all: to thine own self be true."
~Polonius, Shakespeare's 'Hamlet'

[VENTGtr]

Best option is to have a spare set, preferably an old set that is still good, hence yu know the bias is within a working range. From there, have the singer quickly remove the tube in question, replace...the tube...maybe the singer...
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DaveP.

"You must be this beautiful to ride the Quagmire."

[Dark Soul]

LMAO!!! Great idea! If the singer gets fried...suddenly it's Karaoke Night!

Thanks for the info about biasing. I just read an article online about how to bias tubes and stopped about halfway through. No way do I know enough to do that. I need to get a spare set of tubes for my 5150 sometime soon and I think I'll let someone else do all that biasing crap. That's cool that Tubedepot.com will do it for you. I'll check them out.
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"This above all: to thine own self be true."
~Polonius, Shakespeare's 'Hamlet'

[VENTGtr]

It's actually not hard, and there these cool things that you can plug directly in to the tube socket that make it even easier (No idea what they cost or are actually called) so don't need the multimeter.

BUT, ya, even at that, I prefer not to do it.
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DaveP.

"You must be this beautiful to ride the Quagmire."

[bassist_25]

Not all tube amps require biasing. Every Mesa/Boogie amp has a fixed bias. I believe that some Fenders are fixed bias amps as well. The idea is to get a matched set of tubes. Some people have had fixed bias amps modded, however, in order to be able to use a wider selection of tubes.
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"He's the electric horseman, you better back off!" - old sKool making a reference to the culturally relevant 1979 film.

[metalchurch]

I love tube amp,. they're a tinkerer's dream and nightmare at the same time, yet we keep coming back for more...why is that? LOL
Best of luck, try what VentGtr said, after that look into a reputable repair tech and settle for nothing less.
I've always had Mike Z do my Marshall and Engl for me. I can dig up his #, or you can contact Terry @ Guitarsnstuff. I actually just dropped off and picked up @ his place. Anyway he does great work and his labor rate is reasonable.
I always want to try the Altoona guys, but never did. If you end up taking it to a tech, whoever that may be, please post a follow up.

[lonewolf]

Kayla, the problem doesn't sound like your power tubes, so I wouldn't mess with them...they generally last a lot longer than the preamp tubes anyway.

I have a few good 12ax7 preamp tubes if you'd like to use them to test it.
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...Oh, the freedom of the day that yielded to no rule or time...

[StumbleFingers]

Here's an article on some of the various bias types:

Tube Amp Bias

But ultimately it comes down to knowing what your particular amp requires. Your Hot Rod Deluxe should be biased when you replace power tubes. My gigging amps are cathode biased Vox-style amps, so they pretty much bias themselves. Which is fortunate, because they eat a lot of power tubes.

Preamp tubes can affect your tone a fair amount. It's fun to experiment with different ones to see what you like and they're relatively cheap so you can build up a nice collection without breaking the bank. If you like how your amp sounds now, just keep using what's in there. If they're the stock tubes they should be easy to come by.
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Back in black, I need a snack...

[PanzerFaust]

Great onfo on the link...
Thanx.....

Makes me want to try new tubes in the JCM-800's


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