Slight Hum With Crack and Speedball ... 6080?

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I finished my Crack with Speedball mod. Sounds great BUT there is a slight hum that is independent from the volume. When I tap 6080 or the chassis, the hum changes and can become more or less. Can the problem be the 6080? I checked my soldering connections and all seem good.

[Paul Birkeland]

It's possible that it's the tube, but it's a lot more likely to be a solder joint that needs to be reflowed. 

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Thanks for the quick response...can you suggest which solder joints to check?

[Paul Birkeland]

I would just reheat all of them except the power switch and the joints on the 9 pin socket with the LEDs. 

You can also plug an inexpensive pair of headphones into the amp and poke around the circuit with a wooden chopstick to see if poking a specific spot dramatically changes the noise.

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Hi...I re soldered some of the joints after poking around with a wooden stick. I still have the same problem. Can you suggest a reputable store where I can purchase another 6080?

Thanks,
Rob

[Paul Birkeland]

How long have you let the amp run?  Sometimes this kind of noise is related to a dormant tube needing some time to be reawakened.  If all your voltages are spot on, I would let the amp run without turning it off for four or five days, then see if things have settled down.

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Hi Paul,

I'll try that, though the amp has been running for many hours, probably if I add all the hours up, about 20 hours. Regardless, I have been a tube guy for 40 years with my Fender, Ampeg, and Mesa Boogie amps, and it really sounds like its a tube issue, though I am not an expert.

Still would like to know where to get an extra tube even as a spare.

Thanks,

Rob

[Paul Birkeland]

The vendors who you would go to for your Fender, Ampeg, and Mesa amps will likely have some 6080s around.