Hi plaurids,
thks for super-detailed reply
ok.. probably now I got it... this R20 value change make sense togheter with CCS mod, without not (confirmed?)... I thought was useful to have better control/stability when setting balance/offset (in any case if the resistor is on the bottom side the add another in parallel is very simple soldering it in place)
differences between 6SN7GTB (Tung-sol at the moment, those quite tall) and 6CG7? Well, at the begining I used RCA Clear Top and GE, both 6CG7... RCA are considered super-top but I found them too cold, GE are better but... then I tried Sylvania GTB, better but I have always found Sylvania good but nothing special... then the Tung-sol, those always gave me the feeling to be too much clear, with not enough body in low end... and this time was the same until... until I placed below the energizer three ceramic cone (those used in industry to clean metals), one in the front and two in the back, and that changed the sound quite noticeably, for the better of course (that transformer screwed onto the pcb will make sense from an industriele and cost point of view...but it's not a good job, imho)
I also changed the fuse holder by putting a tinned copper one size 5x20 and fitted a Gustard fuse... another positive change in sound (note that I was quite skeptical about the fuses)(require burn-in and has a dircetion of flow... yes I know, I didn't believe it either)
the power cable made with Supra Low-rad 2m long, I didn't notice any changes from another industrial shielded cable I was using previously, I'm just more comfortable about the noise shielding (the DIY cable with triple choice for shield connection)
any experience with 6CG7 from Mazda or Matsushita?