(SOLVED) Very loud "snap" seconds after turn on

[rmryan]

My Crack has been working great, right off the bat, and I wouldn't have even noticed this issue at all if I hadn't happened to have the headphones on one day when I turned the amp on.  Within a second or two of applying power, there was an extremely loud, sharp, quick "snap" in the left channel only.  Volume was turned all the way down, so not volume dependent.  Didn't think too much of it, but happened again today when I had the headphones on again.  I normally do not have the headphones on when I turn the amp on.  The snap is loud and intense enough that I would worry about my hearing and maybe even my HD600's.

All resistances and voltages are good, including the initial tip/ring voltage on the jack (climbs to 9.0V and drops back down).

The amplifier sounds wonderful under all other circumstances, with no static, buzzing, crackle at all, absolutely no problems.  I love it.

Now what's wrong with it?   

Rich

[Paul Birkeland]

Tell us about what you used for flux/solder.  I've seen some plumbing fluxes create temporary bridges between terminals, which will conduct during startup, snap, crackle, then fizzle out until the amp cools off and is turned back on again.

Otherwise, I'd be looking for loose connections and/or parts touching that should be.

-PB

[rmryan]

Wow, PB.  Fast reply.  Thanks much.

Solder is a standard 60/40 lead/tin I've had around for years.  Used in previous SEX kit.

I will go over the whole thing with my magnifying "cheaters" on this coming weekend.  Maybe reflow some connections as well.

I did get some hot solder on one of the LED's while soldering A3.  Looks messy, but seems to be working okay.

Rich

[rmryan]

Well, I don't want to speak too soon, but I think I'm all set.  The transformer mounting screw that ties directly to the ground bus was a bit loose.  I gave the whole thing a look over, tightened all of the screws, didn't find anything obviously not connected or connecting when it shouldn't be.  Then I plugged in my iphone ear buds as a sacrificial lamb and tested.  No snap.  Tested 8 or 9 more times  and then plugged in the Sennheisers.

Thanks for the assist PB!

Rich