When I bought a 15 year old unserviced 500 I was a bit underwhelmed. I initially put it in my racks with the head and ps both on bottom shelves of adjacent stacks with the Burndys on the carpet. My first attempt to improve matters moved the 500 ps up to the 4th shelf just above a 555ps, this put it higher than the 552 on the clean stack but got the Burndys off the carpet and there was some improvement but when I sent the 500 off for DRing and a service and put a 250-2 in place of the head unit the boogie (or swing or whatever) returned to the system despite the ps in the 250. I had great expectations for that service after that but upon its return the system with the 500 lost its boogie again. Now I couldn’t blame the lack of service it was time to experiment, I moved the 552 up a shelf, swapping it with the CDX2 (which the 555ps powered) and the life came back into the music and I finally started to get the point of the 500. My guess is the 552 didn't appreciate the 500ps on a higher adjacent shelf.
When I went to a NDS to ND555 comparison event recently (I already had the ND555 but had never lived with an NDS) the system had been set up by Jason from Naim and I noted that the 300 ps was lower than the 252 in the adjacent stack. As for the comparison the music just made more sense on the 555.
Your 135s don’t have external ps but do make sure your 52 isn’t near any big toroids, try it on the top shelf if not there already and while your’e at it when taking signal from a ps use the sockets nearest the input/dc out, in your case the Burndy.
