Tube problems?

mahoney · Post by **mahoney** » Sun Jul 25, 2004 9:14 pm

I've been noticing lately that the clean channel on my AD-140 is distorting slightly, even on the lowest gain settings. I read somewhere that it could be a problem in the preamp tubes, and to change them out. I decided to double check the tubes, so I warmed up my amp for like 5-7 minutes, and I noticed that the power tube furthest right was not glowing and was cold. The rest were at least lukewarm and orange. This might be obvious, but should I change it out, or is that normal? Any help would be greatly appreciated.

User · Post by **User** » Sun Jul 25, 2004 9:56 pm

"not glowing and was cold" means its no longer a power tube
Basically that says that it is either dead! or not in the tube socket properly (more than likely dead)

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>least lukewarm and orange<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I donÃ¢â‚¬â„¢t know about the AD140 (i have the AD30) but i havenÃ¢â‚¬â„¢t touched the tubes after 5-7 minutes because i know they a so f'in hot, you can feel the heat from a mile away.
Them being Ã¢â‚¬Å“Luke warmÃ¢â‚¬

irish_admiral · Post by **irish_admiral** » Sun Jul 25, 2004 10:16 pm

If your amp is on standby whilst it's warming up, are the tubes always roasting? But ditto to the other comment... if it's on full power, then you should be able to feel it if you wave a hand over it.

Don't tell me the best way, just tell me the cheapest way...

mahoney · Post by **mahoney** » Sun Jul 25, 2004 10:24 pm

Well...maybe "lukewarm" was a little underexaggeration. I warmed it up in standby for about 10 minutes, and they were hot. But still the one was cold. Is there a certain way the tube should be sitting in the socket? Or can it go in any way? One other question, if it is dead (I'm pretty sure it is) can I just change the one, or should I change them all?

mahoney · Post by **mahoney** » Sun Jul 25, 2004 10:26 pm

Also, I've had the amp only for about six months, and I haven't changed the tubes yet.

User · Post by **User** » Sun Jul 25, 2004 10:35 pm

Right, if you havenÃ¢â‚¬â„¢t changed the tubes, then its not biasing thatÃ¢â‚¬â„¢s the problem.

http://www.theallens.theallens.com/Powerampreplace.htm

The tube should be vertical (if you havenÃ¢â‚¬â„¢t taken it out then it will be in right)
EverythingÃ¢â‚¬â„¢s pointing to a dead valve. You "can" only replace one. But its highly advisable to either replace in a pair or in a quad (replace 2 or 4) And when you do replace them you will Need to take it to a tech to be biased.

IÃ¢â‚¬â„¢m still surprised that you only class the valves as "hot", but maybe thatÃ¢â‚¬â„¢s how AD140 are.

Dave

Andy H. · Post by **Andy H.** » Sun Jul 25, 2004 10:47 pm

Sounds very like a dead tube to me too. There is only one way the tubes go in - the pins only seat when properly aligned.
That being the case, as Dave says I wouldn't just change the one. At the very least change the other of the pair. A pair will be the inner two, or the outer two, not the left two / right two.
And yes, get a technician to check the bias with the new tubes. This is just part of the necessary mantainence with a valve amp, although 6 months is not a very impressive lifespan for a tube, unless it has been worked hard. If you pay extra for good quality matched valves they would tend to last much longer then that, but as with lightbulbs it's impossible to predict just when they'll fail.

irish_admiral · Post by **irish_admiral** » Sun Jul 25, 2004 10:53 pm

If you get a new set of matched valves, make sure they are 'dual' matched... better option than single matched.

Anyone know what valves Orange use as stock? Or what valves those Orange branded ones sold on the site are?

Don't tell me the best way, just tell me the cheapest way...

Post by **bclaire** » Mon Jul 26, 2004 12:19 am

Yikes...

I'd bring it back to the dealer where you bought the amp and see what they can do for you. I'd want to know for sure that the tube is getting juice- and not just burned out. Tubes start to wear out from the moment you start using them but that's suspicious for a 6 month old amp!

Billy

Edited by - bclaire on 26 Jul 2004 00:20:12

mahoney · Post by **mahoney** » Wed Jul 28, 2004 8:22 pm

Do I really need to get it biased? I read this from an earlier post.

http://www.orange-amps.com/forum/topic.asp?TOPIC_ID=363

quote:
--------------------------------------------------------------------------------
Hey people,
All our class A amps are self biasing - (AD15's and AD30's). Feel free to change the brand of tubes and
experiment as much as you want!

AD140HTC's are pretty much happy with all brands of EL34's that we have tried with the factory bias setting so
again you shouldn't have any problems swapping out tubes.

AD200B's do need some adjustments for different tubes. Either take your amp to your local amp guy or call your
nearest Orange office for advice.

Hope this helps!!!!

Admin - Orange Amplifiers
--------------------------------------------------------------------------------
I really want to take care of my amp, but I don't have too much money right now. In your opinion, should I take it in anyways? And about how much would it cost to get it biased?

spoonie g · Post by **spoonie g** » Wed Jul 28, 2004 10:37 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Do I really need to get it biased? I read this from an earlier post.

http://www.orange-amps.com/forum/topic.asp?TOPIC_ID=363

quote:
--------------------------------------------------------------------------------
Hey people,
All our class A amps are self biasing - (AD15's and AD30's). Feel free to change the brand of tubes and
experiment as much as you want!

AD140HTC's are pretty much happy with all brands of EL34's that we have tried with the factory bias setting so
again you shouldn't have any problems swapping out tubes.

AD200B's do need some adjustments for different tubes. Either take your amp to your local amp guy or call your
nearest Orange office for advice.

Hope this helps!!!!

Admin - Orange Amplifiers
--------------------------------------------------------------------------------
I really want to take care of my amp, but I don't have too much money right now. In your opinion, should I take it in anyways? And about how much would it cost to get it biased?

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

the ad15 and ad30 are class A cathode biased and need no biasing. the ad140 is class A/B and does. No what someone tells me, I always get my class A/B amps rebiased.

Tube problems?

Who is online