Jolida jd-502p

I used 5751s in my system to great satisfaction when I was using monitor speakers. I later moved to full size speakers and the system sounded flat. For the larger speakers I went back to the 12AX7 tube and it provided significantly more dynamic performance.

Jedinite24 makes a good point about Jolida in general...other amps I've looked at (and some I've actually listened to) are from VTL (85), Conrad Johnson, Cary, Rogue, and even a Tim de Paravicini EAR thing...all sell for multiples of the Jolida cost, and are they better? I'm not so sure...heresy yes, but really...the 502P sounds amazing.

Everyone likes what they like and if the Jolida makes you really happy why fight it. I say this because I imagine you have heard other makes of audio gear and are not naive. My own thoughts are that there are many better sounding pieces around including the EAR.
I use Chinese amps that are truly giant Killers. I honestly think their sound is about as good as it gets (in my system). They will never garner the respect of the mainstream audiophile community but I don't care and for the price paid they are simply ridiculously great.

I hardly "fight it" (the low cost excellence of the 502P)...I think I celebrate it! (ad nauseum maybe, but I prefer enthusiasm to cool). I use a Chinese Kavent S-33 (before going out of production it was built alongside Vincent stuff) that is a Giant Killer so I'm hip to great things from our Chinese brothers, without whom I'd have paid several times over what my rig cost.

Wilson - I'm a JoLida fan. I used Ei Elite 12AX7s and NOS Mullard 12AT7s with Winged C KT88s in mine. Never tried 5751s. You might want to check out Tube Monger if you haven't already. They have interesting stock and possibly some suggestions for you.