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Power Tube Meltdown

post #1 of 7
7/24/11 at 12:05am
Thread Starter 

You know I was just warming up my amp, nothing out of the ordinary, when I hear a horribly loud pop from my headphones sitting on my desk. At first I thought I might had just been hearing things but when I put them one the right driver is quiet and out of the corner of my eye the power tube on my La Figaro 336 looks like a Jacob’s Ladder with wisps of red filament falling to the bottom of the tube.  To say the least this gave me quiet the heart attack.

Anyways the tube is dead but I wanted to ask if you guys think this did any damage to the amp and more importantly my new AH-D2000 that are less then a week old? I’ve plugged them into the ipod and they sound fine and I've even used my ohm meter and the resistance is even on both sides but I'm cautious. I find it odd that my DT880 get a blown driver not long before this power tube goes critical and I don’t want this to happen to my new 2000.

Also, if anyone has any recommendations on a power tube I’m all ears.
 


Edited by DJ McFinnigan - 7/24/11 at 12:15am
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post #2 of 7
7/24/11 at 12:27am
Do you have another tube handy? That's the easiest way to check.

However, it is possible that something failed inside the amp causing the tube to die. Usually happens when a filter cap in the power supply dies.

So maybe open it up - carefully - and don't touch anything inside. Some capacitors retain a charge. Look for obviously blown components or any capacitor that is bulging. Hmm, why don't you take a photo and post it here? It's also possible that a failed tube took out some other stuff.
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post #3 of 7
7/24/11 at 12:43am
Thread Starter 

I do have other tubes I just don't have any power tubes. I can see through the grates of the bottom of the amp and I don't see anything that screams broken but it's to dark so I'll have to wait until morning to take a picture. Sorry, other than typical cleaning and maintenance of an amp I don't know much else. Cars I know, amps not so much lol

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post #4 of 7
7/24/11 at 1:20pm

I suggest to test any new tubes for leaks and shorts before you use them on your amp.

 

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post #5 of 7
7/24/11 at 7:15pm

Check the gain tubes as well. 

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post #6 of 7
7/24/11 at 7:55pm
Thread Starter 

After opening the amp up there wasn't anything inside that suggested that something had gone wrong, everything looked as new as it did when it came off the line. The AH-D2000 sound fine too after listening them for a couple hours straight off the ipod, so the only thing I've lost is the stock power tube which isn't so bad now that I think about it. It did give me a reason to buy something better than the crappy stock tubes. They should be here by the end of the week so we'll see if the stock tube has done any damage I can't see when the replacements get here.

 

Update: Yep was just that crappy tube. Got my new RCA tube and the amp sounds so much better than before, gives it a much better bass impact. Guess that's why everyone always says "replace the stock tubes asap" lol


Edited by DJ McFinnigan - 7/27/11 at 6:28pm
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post #7 of 7
7/24/11 at 8:07pm

You really need the service manual and the schematic to do some checking.

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