Accidentally unplug input tube when it's on

[mahdi8]

Hi Guys, over the week end I accidentally swap the input tube while the power is on. the headphone plugged to it made some crackling noise and I immediately switched of the crack. After I plugged in the input tube I listed to it and everything was fine.

But last night while listening to the crack I notice a ringing noise on the left channel that comes and go every now and then. it lasted only a short while around 5 second and disappear.

I wonder whether this is caused by my mistake unplugging the crack while and do I need to check the crack for anything that might be broken? or my tube has developed micro-phonics?

[Paul Birkeland]

I wonder whether this is caused by my mistake unplugging the crack while and do I need to check the crack for anything that might be broken? or my tube has developed micro-phonics?

A quick check of voltages will give you a run down of how well (or not well) your Crack is operating.

[mahdi8]

Thanks I'd try that. But I think I've narrowed it down to my power tube. it's a svetlana 6as7g. I switched it to standard 6080WA and the noise doesn't happen any more.

[mahdi8]

Is it possible to break the power tube because I accidentally switched the input tube while on? Since the tube is acually a NOS tube I've just bought

[Paul Birkeland]

You're kind of in uncharted territory, as none of us are going to run out and start pulling tubes out of running gear to find out.

Pulling the 12AU7 while the amp is running may or may not damage the tubes and/or amplifier components - and the extent to which any of this happens is probably not consistent if you repeat the experiment.

[mahdi8]

I definitely wouldn't want to repeat my "experiment"

[John EH]

I say yes because I started the amp with no input tube once and got some weird goings on that disappeared with a power tube change.

John