what do tubes sound like as they are dying?

[shatteredsquare]

I was breaking in some new speakers at the rehearsal space, running a studio pre through a 20/20 in stereo. I play a lot of metal and palm muted drop D, and when I would hit the open D palm mute and let the bass resonance ring, I would get a crackle come out of the speakers. Did this for a while and walked around the back of the rack to hear the studio pre reverb spring having a effing seizure (I had the 20/20 cranked at 4 o'clock).

So with all this vibration it sounded like my power amp then took a dump and died (crackles and pops and wavering output), and from then on every note i played had this pitch shift to it, it sounded like a ring mod effect that would not go away. The power amp was also humming like crazy without playing. Is that the sound of dying/roasted/shaken/shorted tubes?

 

[Jackie]

Yep, this sounds like your tubes are waving bye bye.

 

[MesaGod666]

www.eurotubes.com

that is all

 

[shatteredsquare]

is there any damage that can occur (output transformer or other) from running tubes to absolute failure?

 

[kdorsey]

Personally, I've never experienced any speaker damage from a tube failure. It usually just got quiet, fizzly, or silent. But if the right conditions occur, transient spikes are possible...assuming we're talking power tubes. I sound like one of those TV drug commercials, eh? Maybe one of the gurus wants to chime in here with techno-details?

 

[shatteredsquare]

not really worried about speaker damage, i've got a k100 and a V30 on either side of a stilletto slant...more worried about transformer damage from a tube dying or shorting, and all of a sudden 120v is going straight to the OT without any valves in the way. im not up on all the electronic workings of the insides, i just don't want to really mess it up, it's kind of fun to make noise with dying tubes.

 

[zodiac272]

i think usually what could happen is you will blow a fuse or take out a resistor. I can't imagine frying a tranny. Unless you can find and swap out the toasted resistor, that means a trip to a tech and at least $100 to do it for you. I would suggest a re-tube, and invest the $100 bench fee you will save and put it in new tubes.

scott