For the power tubes, any brand of a matched quad will work. So you can go with Sov's, Ei, JJ, etc. Each have their advantages/disadvantages and their diffferent pirce points. Any 12AX7 will work with your amp. More than likely your amp came with Sovtek EL84's and either chinese or sovtek 12AX7's. I personally prefer JJ for everything and go through Eurotubes.com. There are a myriad of NOS tubes that are usually not worth the price unless you are dead set on something. I suggest buying tubes that are affordable as you are supposed to replace them every year or so, depending upon use, to retain the tone. New tubes are fairly cheap (figure around $10 per 12AX7 and around $30 for 4 matched EL84) so it's ok to experiment.
