I bought my amp used so Im not too sure about the pre-amp tubes, Im 99% sure they are stock mesa 12ax7's. But I recently replaced my power tubes, I just bought mesa boogie tubes. I wasnt sure what else to get, but Im very happy with them. I love the sound of my amp.
NOS RCA and Sylvania 7025 preamp tubes, Chinese Mesa Power (6L6gc) tubes. Have tried several brands of power tubes, including Winged C's and just couldn't justify the cost compared to the tone.
All Mesa's for me, except for one 12ax7 the tech had to replace, he put in a 12ax7WC. The other preamps are the originals I believe and the power tubes I bought new.