Pop sound from headphones upon power on.

[Raymond P.]

Hi,


I plugged in a new (to me) 6080 output tube, and then about a second after turning on the Crack (v1.1 w/ Speedball) a quick and loud pop came from the headphones (HD650's). I don't know which side of the headphone the pop came from because at the time it was about 1.5ft away on the table. So, it was loud, but luckily, the headphones don't seem to be damaged. After the initial power-up, everything seemed normal - i.e. the Crack sounded fine.


I know the problem was due to the tube because two other tubes don't have it. So for my own understanding, can someone explain what's happening with the tube and how this defect (I assume it's some kind of defect) interacts with the rest of the Crack circuit to produce the popping noise upon power-on?


Also, would this defect harm the large Speedball board? Is there anything that can be done to the tube to eliminate (fix?) the problem?


A lesson learned here is to try unfamiliar tubes with sacrificial headphones first.


Thanks,
Raymond

[Paul Birkeland]

This could be a number of different things.  I would suggest plugging in a very inexpensive set of headphones, then let that 6080 run for 50 to 100 hours straight, then recheck to see if it's still having the issue.

[Raymond P.]

Thanks for the suggestion, PB.