Crack/Speedball Help Low Headphone Volume [resolved]

[dpmarriott]

Initial Crack build went great, ran for two months without problem. Installed Speedball, all voltages and resistance correct. Powered up with standard power cord, played great no issue. After an hour or so, powered down to install the upgraded Crack power cord. Lost 80% of volume to the headphone. 6080 tube, larger tube, not lighting up as before. Replaced power cord with standard power cord, same problem. Anyone suggest a root cause & correction? I may have a bad 6080 tube, that occurred by coincidence with power cord change? Bummed!
Don Marriott

[Paul Birkeland]

Does the 12AU7 glow?

[dpmarriott]

Thanks Paul for the response. I powered on and observed two glow dots in the 12AU7 under the top. Unfortunately I also observed smoke coming out of the top vents! Shut down and pulled the plug.
Don

[Paul Birkeland]

Can you post some photos of the build?

Smoke coming out means there was/is a voltage problem, but seeing what smoked might help us point you in the proper direction.

[Doc B.]

Unplug the unit and do your resistance measurements again, along with a visual inspection to see if you can determine what got smoked. Look for crossed leads touching each other and bare wires touching the chassis.

[dpmarriott]

Doc, thanks for your response to my request for help! Love your products! Inspected the backside carefully and found the capacitor on 12U/13U was touching both terminals. Adjusted to eliminate contact, as well as reviewed all other potential interference. Reinstalled on my base, powered up, and now works great again! Back in the saddle! Both tubes glow, headphone volume back to normal, no smoke! Thanks again. This is my first project. Gotta sweat the smallest details!

Don Marriott