It is a good idea to purchase a vintage tube pre-amp.

I've owned a melos 222 preamp for about 20 years. I had it looked at last year and upgraded some switches, the volume pot, umbilical cord, added an IEC, etc., to great result. Although it's not the level preamp you're looking for, my point is that it's worth upgrading old quality equipment, if you like it.  

After I purchased a 2nd Accuphase C275V, I find that it grade in sound is unable to compare with the pre-amp. I owned more than 30 years ago.  The problem is the old tube amp. has problem occasionally which required maitenance which is trouble some for me for I am not an engineer. Without comparison, you don't know how good my old tube is. The SS's slim and lean sound reproduction makes me tasteless.

Also, thanks for all of you for your kind response and help or suggestions. Best wishes for you to have pleasant listening too.

The classic SP-15 is a classic ARC pre & cherry ripe for high end mods imho. Bare is mind, it is quite old, so unless you find one already refurbed unit, I would look for a stock example in good nic & save up for a refurb incl: higher end caps, some nice WBT rca jacks, Furutech IEC & some nice matched NOS tubes. The only caveat is you’ll need single ended cables. Also, the included phono stage is ok, but i’d look for something like a 2nd hand ARC PH3 SE if you want a decent matching phono stage.

For $3000, a PH-3se phono stage and an LS-16 line stage might be better than an SP-15, don't ya think?