Clicking sound from right speaker

Last night, upon powering up my system, after the time delay was complete, a clicking sound could be heard from the right speaker. It was not at any specific interval. I powered down after 30 seconds or so. I decided I'd try powering up again but only after switching it from triode to UL mode. The next time everything powered up with no sound at all until I hit the play button on the CD player and music started.

I checked and adjusted the bias last week even though everything was OK at the time.

I will try duplicating the problem when I get home from work today but if anyone has any ideas please let me know.

Dogstar wrote:Last night, upon powering up my system, after the time delay was complete, a clicking sound could be heard from the right speaker. It was not at any specific interval. I powered down after 30 seconds or so. I decided I'd try powering up again but only after switching it from triode to UL mode. The next time everything powered up with no sound at all until I hit the play button on the CD player and music started.

I checked and adjusted the bias last week even though everything was OK at the time.

I will try duplicating the problem when I get home from work today but if anyone has any ideas please let me know.

There are many sorts of 'clicks':

a) One that starts or ends with a low buzz - typically a leaky capacitor, or one that is self-discharging when it should not.

b) click followed by something of a 'breath' - also a capacitor that reaches a certain level of charge then shorts.

c) Pure (light) click, no approach or follow-on - look after your small-signal tubes.

Some times you can cure a clicky small-signal tubes by giving it a sharp rap absolutely vertically on the pins onto a hard (wooden) surface. What can happen is that the plate coating flakes off and falls across the grid. Rapping it makes the flakes drop to the bottom.

Naturally, whatever it is will be confined to the right speaker. And if it does not show up in UL, but does in triode, you have limited the components yet more.

Best of luck with it.

I'm happy to hear that hopefully the problem is only a 12AU7 tube. Right now I'm using Tung Sol 12AU7's that probably have about 2000 hours of use. I'm using Genelex Gold Lion KT-88's and GZ34 everywhere else. These have about 300 to 400 hours on them. I will try tapping on the installed tubes as suggested before I swap out any other tubes. I do have a few spare 12AU7's if the problem occurs again.

Serialize your dual triodes with a Sharpie then move them to see if the click moves with the tubes. Why not isolate the problem to the tubes--if that's where the problem resides--before resorting to banging on them.

So far since switching to UL mode I haven't been able to duplicate the clicking sound. Even after switching back to triode mode.

Between audio and guitar amps I have about 12 tube amps. I'm not a tech but I've found that when you start getting weird noises in a tube amp it's almost always a tube.

Thanks if it happens again I will probably change out the tubes.

OK...so eickmewg was generous and offered to send me a socket adapter and 6SN7 tube to try out in the center position of the PCB. Before powering up I decided that I should also re-bias the output tubes. My first impression was that the 6SN7 tube the upper frequencies smoother and the lower frequencies more defined. Prior to trying out the 6SN7 tube I was running TungSol 12AU7's, Genelex Gold Lion KT88's and a Genelex Gold Lion GZ34.

This morning I decide to give my Mythologies by Patricia Barber CD a listen so I powered up all my components and let them warm up for a few minutes. While I was in another room I thought I heard what sounded like a lawnmower engine. The sound lasted for maybe 2 or 3 seconds. I live in a house on one acre and many of my neighbors ritually mow their lawns on Sunday mornings so I didn't give it much thought. As I walked into the listening room I heard the sound again and that's when I realized the sound was coming from my sound system.  I powered down and decided to give the amp a while to cool off before checking it again. About an hour later I decided to take all the tubes out and re-tension the contacts as well as swap out the positions. I also swapped out the rectifier tube for a Webber WZ68 SS rectifier. I re-biased again and the sound came back. It was actually a hum. This time I noticed it was coming from both channels. So I took the 6SN7 tube and adapter out and replaced it with a 12AU7 tube and this time I have complete silence from the system until I play music.

At least I solved the initial dilemma...too bad the 6SN7 didn't work out.

There is something loose in the adaptor, the adaptor socket or the amp socket relative to the adaptor.

just to be sure is it necessary to re-bias the output tubes if i change out the driver( PCB ) tubes?

Dogstar wrote:just to be sure is it necessary to re-bias the output tubes if i change out the driver( PCB ) tubes?

Not normally.