Lee Jackson Metaltronix Amplifiers

[patiam69]

So i bought some sylvania 6ca7's , I was told they were not a perfect match but pretty close, i stuck em in my 501 and let them warm up then started playing to see how they sounded, well they sounded good and started sounding even better then the volume dropped, i looked at the back and 1 tube was red hot, i immediatly turned off the amp , grabbed my fan to cool the tubes down.

My question is after a tube does that is it shot or did it just burn some life off of it? everything from playing to the fan happened in under a minute. if the one tube is shot i have no problem eating that money because i am thankful i didnt fry my amp.
Anyone else have probs w/ red hot tubes????

[ClassX]

Ya ,,tubes should never get Red Hot,,They should all have an even tempered glow to them,,being able to see the inside plates ,,with the glow at the bottom and top of the tubes,,

My guess is that tube is history,,as well maybe the others to,, because a ClassAB 4 tube setup is like a V-twin engine,,think of the each side of the V as 2 cylinders(tubes),AB amps are push pull amps 2 tubes pull while 2 tubes push alternating with each cycle,,

You said you were told they they were not a perfect match,,but they were close ,,my guess not close enough,,unless you have a matched set ,,you may run into this problem again,,

And there is always the possibility that that the tube in question was just a bad tube from the get go,,,

In another post you state,,,,
right now im running the 6550 tubes, w/ mullard and buble boy preamps w/ a chinese tube in the inverter.

If this is so and you put in 6ca7's,,did you switch the bias to the EL34 position,,and also when the tubes are in question about being matched ,,best to have it biased by a qualified amp tech,,,,

I love the 6550's in my VL-502,,,

Keep on aRockin',,,,