A 75 J bass is the sound of a bass (that and a vintage P) heard on many, many recordings, just doing its job, supporting and not being obtrusive. Of course there were and are those who made their J and P basses stand out, but this was achieved by pushing various 'non-standard' sonic attributes to make it stand out. The 'Ray and ESP, by comparison, are 'modern' takes on the classic Leo designs (yes I know the 'Ray has been around for ages, but it still a more modern take on the P). The LM heads and cabs doing a fine job of reproducing what is put into them (I had an LMll through a Schroder 2x12 and a fine rig it was, more mid focussed because of the cab) so you may be correct in assuming that some more modern pickups in your J will give your sound that X factor that you're looking for. Trying on of the Tech21 pedals might also get you where you want to go. Either way, it'll be a fun journey .