crackly/fizzy sounds in 1 channel after 100 hrs or so of playing... [solved]

[aroide]

Hi all,

My BeePre (stock + output cap mod) has been happily playing music for 100 hrs or so with no issues.  The last 2 times I powered up and listened, I heard a crackly/fizzy sound for a few secs in 1 channel.  It happens after 15 minutes or so of warmup.  Music keeps playing and it is about the same ave vol as the music.  It may happen twice in the first 30 min, then never comes back after its fully warmed up to a steady state (aka the aluminum is HOT).

I never heard this in the past.  Is this a normal tube thing? Could it be related to tube breakin?  I recall reading something somewhere about stuff burning off the cathode. I'm a newbie to tubes.

If it keeps happening I'll swap 300Bs in L and R and see if it follows.

[Paul Joppa]

It seems likely that there is an iffy connection that takes 15 minutes to get hot enough to make it go bad, then as it gets hotter it reconnects. So, same song 99th verse, re-flow all the solder joints as a starter.

Yes of course you can reflow only some of them. But if that doesn't work, you'll just get the advice to reflow the rest!

[RPMac]

I've had this problem. It has been the tube not making good contact in the socket. Rock the tube in the socket and it clears up.

[Grainger49]

If that helps, you know the routine, in and out and in and out....

Momma has a squeeze box Daddy doesn't sleep at night.

The tube and socket gets cleaned by the friction.  If it isn't cured try a cleaner.  Look here:  http://bottlehead.com/smf/index.php/topic,2408.0.html

FAQ#2.

[aroide]

Thanks for the tips.  I'll clean the pins and socket and see how it goes...

Nudge Nudge Wink Wink Say No More 

[aroide]

That was it... after cleaning tubes, no more crackles and fizzy sounds.  Thanks all!

[johnsonad]

I tighten up the sockets with a pair of pliers.  The UX4 sockets get loose from time to time, even when new.