Strange preamp tube problem

  1. #1 by Markku Mäkinen on 03-12-2018
    Markku Mäkinen's Avatar
    Posts: 1

    Strange preamp tube problem

    I have a bugera 6260 bought it second hand. It sounded like there was something wrong with preamp tubes, not enough gain basically. I installed new set of tungsol 12ax7. But the sound went even worse, just very distorted, blurry, broken sound and when i add more gain it just gets overly compressed and cuts off. From here it gets strange, I tried different tubes in V1 and to my suprise, only that old original tube from V1 works. With that exact tube the amp works. Gain doesnt go where it suppose to but this way it kinda works. If i put any other tube in V1 it doesnt work at all. I opened the amp and checked the V1 socket, seems to be ok. No bad solder as far as i can see. Any idea why this happens? I also have 6262 amp and i love the sound of that amp, i prefer it over my mesa/boogie mk3 when it comes to metal sound.