Author Topic: Is this the sound of power tubes dying/going bad? (Read 7474 times)

_tom_ · « **Reply #15 on:** June 04, 2008, 08:34:05 PM »

hmm I just put the old TADs back in and theres still a slight burning smell with them. Maybe its always been there but I've never noticed it before.

gwEm · « **Reply #16 on:** June 04, 2008, 09:06:55 PM »

tom, you probably already know this - but check the plates to make sure they aren't glowing cherry red. thats a sure sign they need biasing. the paint on new valves sometimes makes a buring smell.

_tom_ · « **Reply #17 on:** June 04, 2008, 09:07:42 PM »

Didnt know that but the plates appear to be normal. The valves seem to be glowing a normal orangey colour.

Elliot · « **Reply #18 on:** June 04, 2008, 09:41:07 PM »

Sounds like normal power tube burn in then - it is normal for the paint/markings on the tube logos to discolour in the heat.

_tom_ · « **Reply #19 on:** June 04, 2008, 10:28:51 PM »

Odd that the old tubes smell a bit as well though isnt it. Like I said maybe I just didnt notice before. Could be that I've been keeping my pedalboard on top which cant help ventilation. Its on the floor now despite me not having much floorspace to begin with :(

Hopefully that guy will pick up his phone tomorrow so I can get him to bias my amp with the svets in. They're really easy to install (less fiddly than preamp ones!) but I dont know if I feel comfortable with setting the bias. Then again it cant be that hard can it, so long as I dont touch any of the amps internals (except the bias pot with a screwdriver) and use a weber bias rite with a good multimeter?