Preamp started buzzing/hum just today

[tightplatonic]

Something weird happened, today I was playing a record and it was fine, then I went out and when I came home and put on another record, there was a very loud hum/buzz coming from the speakers as soon as I turned on my turntable - I go through a phono preamp (project phono box se)

I plugged the turntable direct into my amp's phono input and there was no buzz, and tried another external phono preamp and no sound.

It sounds like a grounding problem, but can something like this suddenly just go on a phono preamp? Should I open it up and see if something is loose, I don't know much about these things.

[analogaudio]

Start with the simple stuff, is the TT ground wire in place?

[tightplatonic]

yup..the ground wire was in place, I didn't move anything, tried to unattach and put it back the same thing. It's weird it would suddenly stop working.

[steve195527]

could be a dry joint,if its out of warranty what have you got to lose by taking a look:-even if you can't see anything obvious you save the repair man the job of taking it apart so you should get it fixed a bit cheaper

[tightplatonic]

yeah I might as well try..what is a dry joint and what should I look for?

[steve195527]

yeah I might as well try..what is a dry joint and what should I look for?

A dry joint is a soldered joint that isn't making proper contact for want of a better description:-sometimes they look "dull" as solder hasn't run properly or you mat see what looks to be a hairline crack in the solder around the components leg

[tightplatonic]

ah i see, thanks very much. I'm gonna open it today and see, hopefully it's simple to fix. I have a soldering iron actually!

[tightplatonic]

so I opened it up expecting to see a loose wire where the ground post is, but there is no wire, the post just attached to the body which I guess is how it grounds.

Anyway I noticed when I was touching the unit the hum went away, so I just put it back together and tightened the screws well and the hum went away, oddly enough. Not sure how. Weird things happen to my electrically though.