Well, my intial impressions were that the GBs did some nice things tonally but seemed to have a negative impact on dynamics, leading edge and overall rhtyhm.
Now after listening to them a bit more I think they may be growing on me.
So, I'm going to leave them in for the rest of the week. Then Saturday I will do some side by side, listen, change back to the 7044s, listen to the same music again and try to come to a conclusion.
I think where I'm coming to is that they both sound much better then the stock 5687s but individually they each have some distinct qualities, so it's a matter of preferance. GB5687s more of a traditional tube sound, luscious midrange, sweeter highs. Jan 7044s more modern tube sound, better PRAT, more dynamic.
I'll let you know thoughts after the big shoot out on Saturday...............