Right channel noisy. Help troubleshooting

[denti alligator]

Again, I’m giving up. I can’t see where this is coming from. If I jab every single terminal, plus some of the wires, plus some of the resistors and capacitors and it makes no difference; if I re-flow almost every connection and the right side and it makes no difference; I don’t see what else to do. I guess I could switch out the sockets for the 2A3 tubes and see if it changes channels. I’m getting to the point of frustration—and also totally bummed to be throwing a small NYE party with no music.

[denti alligator]

Happy New Year!

I’ve got my PayPal invoice to send this to you, Paul, but want to give you a chance to weigh in one last time after hearing the recording (posted on previous page). Let me know if there’s any last-minute tests you think might help locate the source of this problem. Otherwise, I’ll pay the invoice and initiate the repair shipment. Thanks!

[Paul Birkeland]

I still believe it's a loose connection with the realistic possibility that when it gets here it makes no noise in my workshop.

[denti alligator]

And most likely it is, but damned if I can’t locate it. Would you suggest trying to swop out the tube sockets? If the noise moves channels, we’d at least know it’s something there.

[Paul Birkeland]

I think if you tried to remove the tube sockets, you'd probably damage one in the process to the point where it would no longer be useful, so you'd be worse off than you are now.

[denti alligator]

Too late, unfortunately. And I have to say, the socket on the right doesn’t look good. One of the pins drops down into the socket all the way. The other socket looks good. I’ve done the desoldering and hardware exchange. I’ll resolder
 after dinner and report back. If the noise moves channels I might as well start by replacing the socket.

[denti alligator]

That was a bunch of work for nothing!  Switched out the sockets and the noise is still in the same right channel.

There’s no way you won’t hear this, Paul. I’m very curious to know the source and am very happy for your help on the way and your repair expertise!

Thank you. I’m paying for the shipping box now.

[Paul Birkeland]

I appreciate your willingness to spend some time on your end before sending it out.

[denti alligator]

I’m very grateful for your patience troubleshooting with me, especially during the holiday week.

[Paul Birkeland]

I finally had some bench time to explore this repair.  The noise was absolutely there, so Denti isn't crazy.  I ended up shorting stages to chase the noise and it was present even with the 2A3 grid shorted on the channel, so that localized it to a very specific spot.  When I was looking around there, I noticed this crazy green corrosion on the tube socket, and I could poke around with my meter and measure some substantial DC voltage crawling around on the surface of the ceramic, so out that went and in went a new tube socket and all is well.

[denti alligator]

Paul,

This doesn’t make sense, because one of the things I did during troubleshooting is to switch out the L and R tube sockets! The sound was still there, but only in the right channel.

I’m totally confused. Though I also have no idea what that green stuff is.

[Doc B.]

Did you perhaps use alcohol to clean the contacts at some point? I could imagine the water content of rubbing alcohol creating the corrosion.

[denti alligator]

No, I only used DeOxit.

And to clarify: I *swopped* the sockets (I didn't replace one). I wanted to see if the noise would travel with the socket. It didn't! Which is why Paul's solution doesn't make sense to me (though if it's quiet, who am I to complain?).

[denti alligator]

The noise was absolutely there, so Denti isn't crazy.

I'm starting to think I am crazy! Seriously. The only thing I can imagine is that I somehow mixed up L and R speaker wires after I swapped the sockets. In fact, if Paul is only hearing noise in the left channel then this *must* be what happened. There is no other logical explanation. The socket was the issue and when I swapped them the noise went with it, but I didn't notice because I had mixed up the speaker wires...

The thing is: I'm pretty sure I didn't mix up the wire. In fact, I tried it on a couple speakers, so I would have had to mix up the wiring twice. Actually three times, because I tested right before packaging it up to send to Paul.

Paul, can you definitely reassure me there was only noise in one channel?

[Paul Birkeland]

I only heard the noise in one channel.  I also mix up speaker wires and RCA plugs when trying to sort stuff like this out, so what you're experiencing is not that inconceivable.