Hi @Cooky,
I too previously owned a 52 but with an olive 250.
However, I had the opportunity to purchase a preloved non dr 500 at a very good price, which I did. I then had it serviced and ran it with my 52.
As good as it was I never really settled with it as I knew the logical thing was to pair it with a 552, which I did purchasing preloved and had it serviced.
Happier that I had now regained the synergy between my amplification though at a higher level, I was now content … not at all.
There was now a new itch to scratch, the dr upgrade…and so it goes.
Yes, I did get them both the dr upgrade…and so it goes.
Did the olive & black boxes work together, of course they did.
But there is always…what if.
I am sure you are aware of this, as I was, but it’s that itch!
As I’ve heard a fellow member say very often, ‘resistance is futile’.
Personally I wouldn’t change the 52 unless I was prepared to change the 135s for a black box power amp at some point.
I also have an LP 12 , and with respect @Dan_M , that is one heck of an itch !!
Dedicated mains supply, very cost effective upgrade.
Recently, I’m recognising the benefits of room treatment maybe that’s worth exploring.
Just thought, don’t think you’ve said what part of your music replay your not happy with or would like to improve?