Interesting, very interesting. My neighbour picked up my DAC in October and I asked for the stock tubes as I had heard his and really liked it. He picked up a set of the black plates as well because Garry really liked them. I was very happy with the stock 6N3. But, since I had these black plates I thought i would give them a try. The black plates are more dynamic, tighter, better resolution and have pinpoint imaging. However, to my ears, they are a bit too clinical thus giving the sound a little too much solid state sound. The 6N3s seem just a little softer and a bit more tubelike which, to me, is a bit more musically satisfying. I will leave the black plates in for a while but I think I will end up going back to the 6N3s.