Hey guys,

I'm wondering if you have a loop pedal and record several loops and have them play back at the same time could this be dangerous to your amp?

My tube amp was making some weird sounds (horrible screaching etc) at prac today and not sure if it was because I was playing over the top of a loop or something...

Should be OK - how are they connected to the AMP - Is it like feedback?
Try playing at a lower volume see what happens

Sometimes a tube amp makes a "horrible screeching noise" when one or more of the power tubes (or a transformer) are starting to burn out. Unless you have a great deal of experience, you should never attempt to probe around the inside of a tube amp (or any amp for that matter), even if it's unplugged because they tend to store up high voltage which can do you real damage. I would suggest taking your amp to a qualified technician if the noise continues (it's possible the amp would need to undergo a process known as "re biasing" if any tubes or transformers are replaced.). Also, it is usually recommended to take special care with a tube amp (allow it to fully warm up - several minutes - before you start playing through it. Also, allow the amp to cool off completely before you attempt to move it - like loading it in your car, etc. - because the tubes are especially fragile when they're hot).

Ok thanks for the advice. I've been playing it since and it hasn't made any more noises. Maybe I forgot to let it warm up...The amp is about 2-3 years old so I might be due for new tubes.

Will keep an eye on it to see if it happens again, I'm usually very careful with it but it does get bumped here and there...

cheers,
James

You only need new tubes if they have a blue glow inside around the anode. Everything except this is ok for a good sound. Some tubes work for centuries.

OK so it's not a tube from a tube amp .... but it's sort of relevant 
http://www.bbc.co.uk/news/world-us-canada-13782651

^ That's awesome, I'd be proud if I hand made something and it worked for over 110 years haha.

Anyway I just opened up the back of my head and had a look, one of my tubes is slightly glowing blue...the amp is still working fine though...Does this mean I should look into replacing just that tube?

James