JJ EL84's are $20 for a matched pair
Sovtek 5751 - $10
Electro Harmonix 12AX7 - $10
Philips/Sylvania 12AX7WA - $12
mini review. all listening was done with AMC CD8b -> Outlaw PCA .5m -> MG Head OTL w/JJ EL84's -> Sennheiser HD600
GE 5751 with marking JG-5751WA, writing is rubbed off and pins are dark. I'm assuming this is a NOS tube. I like this... makes the Head sound more tubey than the rest. But, maybe as a result, separation of instruments is not really clear and the tube does not pull as much detail as the rest of the batch. The registers seem pretty even to me with nothing really recessed... semi-lush midrange but highs and bass are still there.
EH 12AX7 - stay away from this! I really didn't like this tube. Soundstage suddenly collapsed and it sounded like everyone (listening to jazz) was really straining to keep up and to keep from creating a disaster on stage. It was kind of funny actually. But, I'd stay away from it. If you want to hear it for yourself, I'll sell it for $5 or so
Keep in mind that I didn't burn in this in for the 10 hours or so like I did the Sovtek and Philips/Sylvania tubes. I really don't think it's going to improve that much if it's actually possible
Sovtek 5751 - I liked this tube too. Soundstage is really wiDE! A lot of detail is presented to you... nice separation between instruments. All registers played nicely and shared tones (even presentation throughout the registers). Ummm... yeah.
Philips/Sylvania 12AX7WA (7025) - I'm not sure about the 7025 thing. Is it a 7025? triodeelectronics says it is... I don't see anything on the tube that says this. Just 12AX7WA... does the WA mean 7025? Well, to get on with it, I really liked this tube as well... it's probably my favorite out of the bunch. Soundstage is not as wide as the Sovtek 5751, but the level of detail presented is probably even greater. There is also more of a slam in the bass... much more defined than the GE tube. Midrange and high registers play nicely too. This tube really puts you closer to the stage... almost Gradoish with Senn's, kind of weird, but I really liked it. I'll have to listen to more music with this one and compare it to the GE and Sovtek more. Probably less emotional than the GE because of less tubiness, but... I don't know. I really haven't formed a total opinion of these tubes yet and won't 'till I hear the Sylvania 5751 triple-mica black plates!
Okay... that's it for now. I've really only listened to about two-three different artists and three-four songs on each tube, so keep that in mind.