@stievus
If these recordings give you rumble as you describe, then it must be your deck. (My humble opinion...) I am still using a Pink Triangle Export Gti
I have a number of exceptionally quiet records, some listed above, which in my opinion exonerates my decks.
I have thought about it some more, and two of the records I mentioned as noisy were not recorded in purpose-built studios. For one recording, local streets were shut down to reduce traffic noise, but obviously there is a limit to restricting noise in a big city. Another contributor mentioned hearing London tube trains on records.
Big cities are inherently noisy, though usually quieter at night. I was camped south of Sydney, and in the middle of the night became aware of very faint, periodic subterranean rumblings, each lasting about a minute. Turned out it was the sound of underground coal mining machines, being transmitted through kilometers of solid rock. The machines are so-called "continuous miners" but they stop to unload when they have chewed about 100-tons, in order to unload. Hence the minute duration!
That and the London underground got me thinking about the Sydney Opera House where the live recording of Mahler 2 was made. It has to contend with trains and traffic on the Harbour Bridge, plus constant ferry movements, the occasional cruise liner being moored, a double-helix underground carpark, freeways, helicopters, etc.
Around the time the recording was made, massive Tunnel Boring Machines were boring under the harbour. Against this backdrop, the venue is amazingly quiet but to very sensitive microphone?
By the way, the Achromat platter mats I use are directly descended from Pink Triangle which is one of the reasons I got them!