Hi everyone, I'm having an issue with my new built RR763. The amplifier starts to distort at a very low level, between 1.5-2 The signal (a 0.2V 5000Hz sine) is clean in V1A grid and plate, V1B grid and plate until after the .047 coupling capacitor, from then on the matter gets complicated for my skills because the signal is affected by both pre volume and master volume (trainwreck type-3) or NFB. I also disconnected the NFB (and the master volume too) but nothing changed. Anyway, this is my voltage chart: B+ : A 510V, B 508V, C 501V, D 486V V1a: plate 327V, grid 0V, cathode 2.35V V1b: plate 324V, grid 0V, cathode 2.40V V2a: plate 273V, grid 71V, cathode 115V V2b: plate 271V, grid 76V V3: plate 513V, grid -61V, screen 513V V4: plate 514V, grid -61V, screen 514V 387VAC from the PT (Hammond 290D2EX) 218 after the 1N4007 diodes. Any advice, help or indication is very welcome. Thank you.