I was working on a JVM the other day, and in the V1 position there was a JJ ECC83s with silver plates much like the famed chinese silver specials. The tube was labeled Marshall vlve00067, which I found out to be a low noise low microphonic graded tube. The tube was very quiet, with literally zero microphonics when tapped. It seemed to sound good in this amp, I know there have been some issues with noise/feedback with these amps. I am wondering if marshall got JJ to do a special run of these tubes for the JVM line as I have not seen them in other newer marshalls I have worked on. Any body have any info on these??