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weird tube issue

F

flakeh

Inactive
Apr 21, 2007
2,492
4
Ontario, Canada
#1
Well, After I noticed that only 3 of the 4 poweramp tubes in my YBA200 were glowing, I thought I had a blown tube, or something fried. I took out the 4th tube, and switched its position with the third one, and voila, it would glow. When I moved the tubes back into there regular position, the 4th one would not glow. Also, only the first and now fourth tube glow blue. Is this bad? good?

Is this some wacky tube problem? Do I need new tubes?

For the record, the tubes are 2 Svetlana 6550c, 1 sovtek 6550c, and one winged c 6550. This is how it came from the guy I bought it from. It appears its the Sovtek that is glowing only in certain positions.

What say you?
 
#3
Hard to say without looking at the amp, but I'd say your first step, assuming there are no other major issue (bad/lack of sound), would be to get a new set of tubes.

Your best bet by far is thetubestore.com, they're in Ontario and will get them to you fast and for a good price!

Also, the blue glow is not necessarily bad, it's just gas in the tube. Different tubes will glow to different degrees, so with three different kinds of tube in there it's not surprising that they're glowing different.
 
#4
megadan said:
Hard to say without looking at the amp, but I'd say your first step, assuming there are no other major issue (bad/lack of sound), would be to get a new set of tubes.

Your best bet by far is thetubestore.com, they're in Ontario and will get them to you fast and for a good price!
Click to expand...

i was thinking of a retube, but I'm short for cash. I'm not noticing anything bad, except a little bit of high hiss, which I isolated to the power amp. So maybe a retube is in order. Maybe some KT88's?

Man, Thetubestore is just an hours drive away, sweet!
 
#5
could be the tube socket on the fourth socket, or the tubes themselves. get them all tested, replace any ones you find that are bad. obviously if it's glowing blue than it's running hotter than if it's glowing orange or red. probably needs to go to a tech, which as I know intimately, sucks if you are low on cash.
 
#6
amos said:
could be the tube socket on the fourth socket, or the tubes themselves. get them all tested, replace any ones you find that are bad. obviously if it's glowing blue than it's running hotter than if it's glowing orange or red. probably needs to go to a tech, which as I know intimately, sucks if you are low on cash.
Click to expand...

Its only that one tube that doesn't work in that socket. All the other tubes will work with that socket perfectly. I moved the tube in question form V7 (4th socket) to V6 (3rd) and it now works fine. But only 2 of the four tubes glow bright. These are the svetlana's. They all are at about the same temperature, So I am not concerned about that.

being low on cash sucks. I got payments to make. Cell phone bills and financing on my amps and whatnot. Meh. I'm glad I have a job.
 
#7
Yeah, just be thankfully you don't have to borrow money from your Dad to fix your amp. I have two interviews this week...wish me luck.

If there are any music shops in which you are friendly with, and have an amp tech there, take your tubes out, take them down and have them tested. They shouldn't charge for it.
 

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