Unfortunately JJ Electronic is the only 6386 tube manufacturer in the world at the moment, and they do not want to match tubes, so I have to buy a lot of them to be able to make nice sets for all the FAIRCHILD work that I do worldwide :
I am more than happy to give you a discount if you can supply me with original new old stock tubes :
It only needs to be two sets of four identical tubes, perfectly matched, none microphonic, and low noise...
Here is a list of all the JJ Tubes serial numbers that have failed on me so far, it seems like year 2014 was particularly bad :
2013:
0342-D
0402-D
0566-D
0664-D
0809-D
2014:
0543-E
0583-E
0427-F
0449-F
0472-F
0548-F
0592-F
0575-F
0405-F
0466-F
0480-F
0430-F
2016:
0812-B
0915-G
2019:
4286-k
4306-k
4875-k
4857-k
You can send your Tubes for testing and matching at POM AUDIO DESIGN if you like.