*update* so i got the extensions adapters and im finally able to use 6sn7 now! was well worth it. Got 4 pair to try out, really loving the Ken-Rad with Brimar 5r4gy so far, its clear, very clean bass, natural vocals and a sense of space ! i might do a comparision thread.. been switching rectifiers (RCA 5r4g, Brimar 5r4gy, Sophia 274b, RT 5R4GYS and Fivre 5R4gy) so far my favorites are the Brimar 5R4GY and the RT 5R4GYS, seems to always get back to those 2 for some reason, the Brimar has an obvious step up in vocals compared to the other Rectifiers! and the RT has a fairly linear frequency response with a nice organic grain sound with good bass!! I did like the RCA too, but i find it to be close to a solid sate sound, although very nice, sounded too dry and not engaging enough for me. @filip sebastian youll have to try out yourself! what do you listen to/ what are you looking for? look for Brimar, Sylvania, Ken-Rad, RCA, Tung-Sol, GE.