problem with ear 834p..... HELP

I am confused, baffled, mystified but most of all concerned. I recently replaced tubes in this phono stage and was very happy with the results. however after two nights of listening i put on the new Derrek Trucks band lp and noticed a considerable difference in volume levels between the two channels.figuring it might be a tube issue i was advised to switch the two outside tubes around to verify the problem (sound reduction would change to other channel w/repositioning of tube)alas it didnt help.so i replaced new tubes with the tubes i had in before and everything was fine. So i thought if i replaced each old tube , one by one,. with new tubes i could identify the bad tube. I replaced the rear tube w/ a new one and again had reduced volume in right channel, eureka, problem solved i had found the bad tube, i thought. i replaced that tube with one of the two remaining new tubes and all was fine i had isolated the bad tube. so i put the last of the 3 new tubes in the front position and to my bewilderment I again had a reduction of volume in the right channel. Now what? what is the possibility of being sent two bad tubes by a very reputable dealer..... none. so i switched the two new tubes front to back and there was no change. The volume reduction remained with the right channel.at this point i was even more confused then u must be reading this. so i called the company who i had bought the new tubes from and ordered three new tubes with the agreement that i would send back the old tubes to be checked and compensated for if they were faulty.Fine, very professional, as this company always is.That is where the problem really began. i put the old tubes back in and played an lp & it seemed fine.I took the album off and was replacing it in the sleeve when i heard air coming from both speakers...... not normal.So i completely disengaged phono stage from all equipment and checked cd playback all seems ok there, no escaping air from speakers. My question, what have i freaking done? seeking any and all advice, associated equipment:sota star sapphire turntable with koetsu rosewood cartridge retipped by V D Hul, DK Design VS1 reference Mk 11 integrated amp. Sony scd 77 es cd player and Von Schweikert Vr-4 Gen 111 hse speakers. thanks in advance