Crack producing noise? (not from headphone)

[revolverxz]

Sometimes I can hear the crack (I think it's the power tube) making a hiss type of noise. I can easily hear it when I move my head close to the amplifier, but sometimes it's loud enough for me to hear the sound just by sitting next to it. Is it a solder problem or a tube problem?

[Doc B.]

Make sure your capacitors are all mounted correctly, with the stripe in the proper position.

[revolverxz]

I think I have the stripes in the proper position. Here's a picture of the crack

[revolverxz]

I did notice that the 2 brown ones are slightly  touching the wood base. Could that be the source of the noise?

[Doc B.]

No, that's not really a problem. But if they were mounted backwards they could vent, which makes a hissing sound and usually a mess under the chassis. It would be helpful if you could narrow down where in the chassis this hiss is coming from. Airborne amp noises are usually a hum or a buzz from a loosely mounted power transformer or arcing sounds from a loose connection.

[revolverxz]

It sounds like the hiss is coming from the big tube(power tube?). I sometimes hear it on my headphones. The hiss goes away for a few seconds when I tap the chassis or the power tube.

[Doc B.]

OK, sounds like the tube is the problem. Is this a recent build?

[revolverxz]

Yes I finished building it last month (around april 7) and I started hearing a hiss after a week or something(don't remember exact number).