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Bias question on Carvin tube amp

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  • Bias question on Carvin tube amp

    Hi I'm a new member here and have a question that I hope that someone can help me with concerning the X100B tube head made by Carvin ,its the model put out around 1992 though they have been around since the 1980's this would be the 90's model.
    First of all from the very beginning I had troubles with this amp the volume and bass pots popped terribly and still do, and were doing so less than a year after I purchased this amp from Carvin and along with that I ended up losing a preamp section on the board that had to be rebuilt,at around this time I also put new Groove tube EL34's and all new preamp tubes in it.
    With no prior knowledge of power tubes or preamp tubes I proceeded to order the tubes ,which from my best guess were sorted by how hot they were I got them in a hard rating in other words.
    I replaced the tubes at the same time that I had work done on this amp to repair a burnt preamp section so I know the tubes need replaced but the end result after the repairs and re-tubing it ,and this has been some time ago that these repairs were made,it never again sounded the same in fact I've gone from one processor to the other, effect pedals etc,you name it I've used it!
    Now keep in mind this amp is self biasing but I didn't replace the tubes with the exact model only the same name brand it came with EL34's made by Groove tubes I replaced the tubes with EL34 groove tubes that were rated as hard.
    Considering the amp is self biasing would this make any considerable difference,as far as the fact that I pulled the old tubes out replaced them with tubes of the same make,made by the same manufacturer with the only difference being the tubes are a bit hotter?
    Thanks in advance for any help you guys might be able to offer and sorry if this is a long winded post

  • #2
    Its not "self biasing", its just non adjustable fixed bias. They can be modded to have adjustable bias....I've done it to all of my x-amps. If you use the same rating GT pwr tubes then you *should* be ok bias wise. I'd still check it to make sure, but that's me. I don't trust any of the new production tubes regardless of the "importance" of the painted on label.
    The farmer takes a wife, the barber takes a pole....

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