Do I Have a Bad Tube????

[Early B.]

Today I changed out the tube in my Bada CDP. On three occasions, after about 20 minutes, the volume slowly fades out and the music can only be faintly heard on the right speaker. I have to "reboot" the system to get things back to normal, then 20 minutes later, it occurs again. This has never happened before. Can a tube exhibit that kind of behavior or should I look elsewhere?

Thanks.

[RuSsMaN]

Dirty pins / socket perhaps.

[madmax]

You could swap tubes.
madmax

[Early B.]

You could swap tubes.
madmax

There's only one tube.

[phipiper10]

Hi Early,

If you do determine it is the tube that I sent you by all means let me know, of course I'll send your money back.

I didn't personally put the one you have in my player after it was tested by tube depot.

I'm no tube expert but is it seated firmly into the pin holes?

[Early B.]

phipiper10 --

Not sure if it's the tube yet. PM sent.

[madmax]

I meant swap in a known good tube.
madmax

[Early B.]

I meant swap in a known good tube.
madmax

Gotcha, will do. I'll report back in a few...

[Early B.]

Put the old tube back in. No problems at all.

I suppose the new tube is the culprit. After consulting with one of our resident audio techies, he suggests the tube probably has a heat related issue since the problem occurs after the tube heats up for a while.

[RuSsMaN]

Did you clean the pins?

(see post numero two)

[Early B.]

Did you clean the pins?

(see post numero two)

How do I clean them? I have some of that Caig stuff, but was reluctant to use it because I don't want to gum up my tube sockets. Not saying Caig does that, but didn't want to take any chances.

[RuSsMaN]

Caig will work fine, and won't do any harm to the socket. Just make sure everything is completely dry before power up.

Apply to a cotton swap or pipe cleaner and give it a whirl.

[reeltrouble1]

FWIW the pipe cleaners Russ suggested do an excellent job with the Caig.

RT1

[Early B.]

OK, I cleaned the pins with Caig and a q-tip, and popped the tube back in. No issues for 1.5 hours. Gonna do some more testing over the weekend and will report back...

[engtaz]

Congrat on the find. It must have drove you crazy. Good music should help the pain.

[Early B.]

Yeah, I think the tube is bad.

I ran my system this morning and it went for over an hour, then the same problem occurred. I had the top panel off and I noticed the fire in the tube was not burning. Somehow it must have cut itself off. It's gotta be some sort of heat issue with the tube itself because my CDP doesn't get hot. This phenomenon has never occurred with a my previous tubes.

[madmax]

Before you clean tube sockets make sure B+ has drained out of the capacitors. It could be very enLIGHTNING if it hasn't. :D

I know you already did it and I didn't think about it in time, sorry. Next time you will think of it...
madmax

[GV#27]

You best give that tube a dirt nap,it sounds like it is NFG.

btw.what did the filament look like before it stopped working?was it brighter than normal?

[Early B.]

btw.what did the filament look like before it stopped working?was it brighter than normal?

I dunno. I didn't see it right before the CDP lost volume.

[mulveling]

I had that happen before. It was an expensive, sweet-sounding Tung-Sol round plate 6sn7 About 30 minutes into a listen, the right channel just peacefully faded out and didn't come back. Visually, I noticed one of the two triodes wasn't lit up anymore. I didn't try using it after that - I figure once a tube shows signs that it's bad, the safest route is to keep it away from expensive gear.

[Early B.]

I revived this old thread because I have some new info about this problem of my CDP petering out after extended play of maybe 1.5 - 2 hours. I still have this problem, but it's not really a big issue because I rarely play music that long. I noticed this problem back in May 2007 after changing out the tube to a Bendix 6385.

Anyway, today I hooked up a brand new amp and the problem has occurred twice already after 30 - 45 minutes of play, so I'm thinking the amp is somehow playing role in this issue. Both the CDP and amp don't appear to be getting too hot.

Can tubes be picky about amps?

Is it a DC voltage leak?

Will I damage my CDP, tube, or amp by continuing to play music?

Thanks.

[RuSsMaN]

You swapped the tube, problem went away, no?

[Early B.]

You swapped the tube, problem went away, no?

Same tube, different amp, bigger problem.

[RuSsMaN]

Yeah, but reading earlier in the post, you swapped tubes, and the problem went away. If so, that pretty much sums it up, right?

[dorokusai]

Why did you put a possible bad tube in another piece of gear? Am I not reading something correctly?

[Early B.]

Yeah, but reading earlier in the post, you swapped tubes, and the problem went away. If so, that pretty much sums it up, right?

Yeah, but the Bendix tube stays because it sounds so good. My question is more about why it's happening more frequently with a change in amp.

[beardog03]

More power trying to go through a bad tube ? ?

The cdp doesn`t put as much through it as the amp ?

[Ricardo]

Or maybe the tube is just going south....faster????? You know tubes can do weird things....I would remove it no matter how good it sounds. Maybe it's time to try the Sylvania gold pins....

[dorokusai]

Maybe its time to get a cheap tube tester.

[RuSsMaN]

Or find another Bendix tube, if you are dead set on it.