Thanks for your responses. I did some more testing to locate the problem. The low frequency signal seems to be generated by the phono pre amp (VALVET soulphono MM/MC tube phono amp). With the phono pre amp hooked up to the pre-amplifier (Krell Evolution 202), without the turntable connected the woofers go crazy when I turn up the pre amp volume.
Low frequency problem while playing vinyl
Has anyone experienced (and knows a cure for) a very low frequency problem while playing records. Just recently I hooked up two old turn tables, Linn LP12 (1980s) and Dual 704 (1980) in my system and the woofers of my speakers are almost jumping out of the speaker cabinets while I am listening to a record. Displacement at least 0.5 inch if not more and the keep "pumping". Needless to say that I didn't experience this issue years ago when I used to play records regularly.
amps: Krell Ev202/350MCx
speakers: Thiel CS7 + smart sub
phono amp: Valvet
amps: Krell Ev202/350MCx
speakers: Thiel CS7 + smart sub
phono amp: Valvet