JJ preamp tubes - repeated problems


I purchased an amplifier that came with stock tubes made by JJ.  There were problems with the amplifier so I replaced some tubes and then figured out it was the pre-amplifier tubes and small tubes. The manufacturer in this case who is McIntosh did send me replacement tubes and they worked for a month or so and then began to crackle. Now I have to figure out which of the six small tubes is creating a problem. 

I'm curious to know if manufacturers test the tubes that they use in the amplifiers before they ship them out? Maybe they test fine and then go bad within a month. I'm very suspicious they don't bother testing their tubes.

Judging by the process to test individual tubes and when you have 24 tubes on an amplifier I can understand them not giving them much attention during the manufacturing process. Maybe they expect people to replace all the tubes just like the power cords they send out.

 .Many replace the stock tubes immediately with gold lions which seems like an easy choice. Maybe manufactures do test their tubes and they're just using a poor manufacturer. 

Do others have tube problems with McIntosh amplifiers?

emergingsoul

Showing 4 responses by samzx12

I had a preamp JJ 6922 go bad at about 100 hours.  Heard a crackling and then the left channel went silent. Popped the top on the preamp and the top of the tube was completely burned out.  When I went to pull the tube the glass completely disintegrated. 

@immatthewj no I didn’t say it practically caught fire. The tube went bad and the top of the tube was very discolored and when i went to pull it out the glass crumbled. I sent you a PM.

I replaced both tubes left and right channels and preamp plays just fine.