Phono Preamplifier Circuit Board MM RIAA Preamp HI FI Amplifier with Subsonic Filter for Vinyl Record Player Turntable Rumble|Amplifier| - AliExpress
Lafayette PK-444 Stereo Rumble Filter (page 1) - Other Turntables - Lenco Heaven Turntable Forum
The Art of electronics - exercises - Additional exercise 3 of Chapter 1. Design a "rumble filter" for audio. It should pass frequencies greater then 20 Hz (set the "-3 dB" point