hum

[proud indian]

Hello everybody..... been a long time!!

Well, I got hum from the right channel and took off the tube, put in a new one. problem solved.
So I figured it was the tube, till yesterday. I had put in  a new set of tubes, and after about  70 hrs on them, again the hum started in the right channel. So i tossed out the tube and put in another. Hum gone.

This morning, I was wondering if it was the tube, so I took the one that was humming and put it in the left channel. No problem......the tube is working fine. So what is happening?

Some help required here.

Thanks

shreekant

[boulos]

When the tube from the right channel started humming, did it also hum when you turned on the amp in your next listening session?  I'm wondering if the hum starts after the amp gets hot, it may be a bad solder joint somewhere.

[proud indian]

The amp was on and running for a while. In fact, since I put new tubes in, I ran it through the weekend. Now the tube that is in its place has worked fine.

It cant be a tube problem, but then it should have happened again, which it has not done till now.

shreekant

[Grainger49]

The act of changing the tube seems to clear up your hum problem for a little while.  Two things come to mind.  Either the socket is a little dirty and needs cleaning or there is a bad solder joint on or near the tube socket. 

Heat up all the tube socket solder joints.  Run down where each tube pin goes to and heat up those solder joints.

Then insert and remove the tube a dozen times.  For minor corrosion this will make a better, longer lasting connection.

[proud indian]

Thanks for the inputs. I normally use progold on the pins, but one never knows. I will move then in and out and check if the problem reoccurs.  Then I can work on the solder.

Thanks

Shreekant