CodudeWas wondering the same thing. In a review listed here they say yes, great improvement. But it is mentioned that you need a 6922 adapter. However in the description listed here and elsewhere a 6N3 is used which I've heard means no adapter is needed. Does anyone have any experience with this?
CodudeChanged out for the 5670. Sounds great, boosted the volume just a bit. I have used the 4xx,6xx,dt 770,880,990.....but.....surprisingly....I enjoy my m50x and m40x the most on the tube amp.