STAX SRM-1 / MK-2 problem

[ATHome]

Hi there, I've got a strange and somehow annoying problem with my STAX SRM-1 / MK-2 (B Series).

Sometimes, in about 3 to 4 cases out of 10 after switching it on in an cold state, I hear a strange clicking / buzzing noise on my Lambda on the left channel only. It's definitely faster or more often to be directly related to 50hz AC noise problems and it sounds more like a "ticktickticktick" kind of noise. This noise doesn't change if I make the amp louder and if it occurs, it's stays for about half an hour and slowly fades out, until the amp is heated up regardless of switching the amp on and off.

Sometimes I also get a very distorted left channel which can happen anytime, even if the amp was running some time without trouble. You can still alter the loudness of the distorted channel with the volume knob. Switching the amp on and off a couple of times fixes that problem. I've changed the R101, R201, R102 and R202 to ones with the same value as before in order to fix that, but I don't know if it has done the job by now. For the moment that problem is gone. I mentioned it, because that might be somehow related to the other problem.

I've also changed the capacitors about 1 year ago to fresh new ones and the problem didn't occur back then. Both problems are not related to the source, because unplugging the cinch inputs or changing to another source doesn't help.

As I don't really understand much of electronics, my pal (Cynric here on Head Case) helped me with all the information and fixing attempts so far (thanks for that ), but he is running out of ideas what might be the cause.

So did anyone of the STAX Gurus here had a similar problem or has an idea what could be tried to fix that?

Thanks in advance,

ATHome

[nikongod]

This is very unusual. When I clicked this post to view it, an ancient AOL looking display came up. Very weird.

[manaox2]

Could it not be a parasitic charge caused by dust or something in the headphones? Have you tested with other phones?

[ATHome]

Could it not be a parasitic charge caused by dust or something in the headphones? Have you tested with other phones?

I could test that later, could be possible. But I guess that wouldn't explain why it is gone when the amp is warm

[spritzer]

First thing to do is swap the channels inside the amp so if the issue moves over to the right earpiece then it is the amp. Well that or try another set...

[ATHome]

I'll try another Headphone first, if it happens there as well, I can be sure it's the amp. I'll report back

EDIT: Just noticed: If I plug the Lambda out while the amp is on, the ticking noise stays for a very short while, with no connection to the amp. So it must be dust, I think.

Anything you could do against dust?

EDIT2: Took the headphone apart and tapped a bit against it while upside down, seems like it has fixed the problem for now. So there is just the distortion problem left with the left channel. Got to keep an eye on that if changing the resistors helped