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

@audio_is_subjective "...or filaments maybe getting damaged in shipping?".

 

Possibly so. No joke. I had a particular 6SN7 tube I was buying from a specific distributor overseas who densely cotton packed, bubble wrapped, and then double boxed quad sets I was buying. No problems for me on any of them, shipped from over seas to me direct. Many drop changes too, along the way. Others, were having issues with the exact same tubes. Nobody could figure out what was going on. They chased it down. Took a while for the manufacturer to figure it out.

Two years later they figured out they were shipping these large boxes of 100 units (or so) well packed, to a US Distributors who was taking them out of those specially packed boxes, and poorly repacking them in other cheap packaging as individual or pairs and sending them out. All the sudden this distribution channel had problems. People blamed the tubes themselves, and yet it was poor re-packing and shipping damage occurring. Recalling photos, the US distributor put NO time, care, $, or effort into the repackaging and boxing.  THIS created a real problem for the reputation of the manufacturer. Was unfortunate, this created other business issues too. 

ASK: 

Ask your tube reseller to explain exactly how they get shipped out or send you a few photos before shipping them out. If they won’t do this, move to a different tube reseller. Best of Luck!

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. 

Tubes are a consummable. use this as an opportunity to upgrade.

PS  I wouldn't own an amp with 24 tubes.  

If they are preamp tubes, they should last 2000-10000 hours depending on the design of the preamp. Obviously there is something wrong.  While I don’t particularly like the sound of JJ tubes, they might not be at fault and I would hope Mac would inspect the tubes they buy before they install or send them out. 
Did you buy the amp new from a dealer? Maybe it needs someone to check it out?

All the best.