@clearthinker , no wonder. I owned two Linns over the years and they have to be the poorest suspended turntables made. Very unstable. The problem was they were a great sounding turntable for relatively reasonable money at the time. I got rid of my last one in 1981 and never looked back.
False clearthinker. There is loads of low frequency noise in the environment that is transmitted to the turntable. Don't believe me? With your turntable on, place the stylus down in the run out area and turn the volume all the way up. Keep an eye on your woofers. Have a friend or significant other turn on the washing machine and watch what happens. Have them walk around the room, jump up and down. You will hear your furnace light up and your AC compressor start up. You might even hear cars going up your street. A severe earthquake is just visible evidence of a wave traveling through the ground. The earth is quaking all the time at levels you can not feel, but your cartridge can and if you have a good system you will see it in the woofers.
Currently, the way my Sota is set up if you do the same experiment, and I have, all I ever get is a little hiss from the phono stage and I have boosted subwoofers. With the high pass filter off my system will go right down to DC. I can hammer the side of the plinth and you can not hear a thing and I mean hard enough to dent the wood if I did not have a wooden block in the way. Try that with your table but you might want to turn the volume down first and be ready to catch the tonearm. Like the earth quake this is a severe example. People do not normally hit their tables with hammers but you will see in your woofers how plenty of noise you can't hear makes it's way into your system via the turntable and it does not matter how much the turntable weights, this is just lay intuition.