Hissing at left side

[jack_forge]

Guys, my Crack (+Speedball) got some hissing sound at the left side. Sometimes even got pulsing sound which happened last time when I put Crack too close with my PC speaker.

Usually when I turn on the amp, it hiss only for few second than silent. However recently instead of disappear, the hissing became worst. I changed the output tube but no luck. I don't have input spare tube to try with. Can faulty input tube caused this kind of issue? Or perhaps cracked soldering due to hot temp of the amp it self?

Guys, care to suggest input tube replacement for my old 12AU7A? I need to figure out what's wrong with my Crack. Kindly help me because it's been so long I don't listen from my Crack and it cracking me up.

[jack_forge]

Anyway the hissing sound is more like TV static sound but it can be loud then slowly disappear and then it came back. Tested with no DAC connected, headphone doesn't have problem from other amp, and I removed tested far from wifi router, TV, amp, speaker etc...

[Paul Birkeland]

This sounds like a funky solder joint, so it might be worth it to reheat all the joints in the amp, just to be sure.  Solder melts at several hundred degrees Celsius, and the hottest components in the Crack operate at or under 100C. 

[jack_forge]

This sounds like a funky solder joint, so it might be worth it to reheat all the joints in the amp, just to be sure.  Solder melts at several hundred degrees Celsius, and the hottest components in the Crack operate at or under 100C.

Thanks... I guess need to send back to my friend who help me built the Crack. At the meantime I still waiting for input tube replacement.