Jolida jd-502p

Thanks everyone for your responses. I did get a chance to
hear a pair of RCA JRC- 5751WA the sound was was nice and open with a good sound stage and nice separation but very little bass.In other peoples experience do the 5751's typically lack bass. Is there another tube that I might try to get a little more bass?

Jedinite24
I am still not settled on what 12ax7 to use. Shortly after this thread my phono pre had to go to the shop. It was and still is my only source and does double duty as my preamp . I did not get to listen to any music other than through my tv.Now that it is back I hope to get this sorted.So for now I am using some sovteck 12ax7 the tung-sol that came with it and a rca jrc 5751wa of those I think I like the sovteck best.

I bought my 502 used here and the person I bought it from did not say if it was upgraded and I did not ask.So shrot of opening it up I have now idea how to tell.Sorry I could not be more helpful.

Mechans
Thanks for you response. The Jolida jd502p is a tube power amp, my phono pre is a PS Audio GCPH and is solid state.The sovtech I am using is an LPS and it came from the previous owner so I don't know if it is an early or a recent production tube.I believe I read somewhere that the ones from the eighties were the more desirable ones.