Make/buy rumble/warp filter for pre phono inputs?

Thanks for the concern Albert, but maybe I need to make my situation a little more clear. I have a more-or-less audiophile system, but I don't buy audiophile software. My record collection contains a lot of less-than-pristine rare vintage vinyl (33 and 45), and some of them are unavoidably warped, so this is not an issue about acoustic feedback problems. I am less worried about unadulterated sound with these disks than am about just being able to play them at all without the much worse effects (obvious distortion, compression, and severely limited volume capabilities) of excessive infrasonic modulation on the amplification chain and woofers. I can play the records in question by tracking heavier than normal, but I wouldn't want to do this routinely. What I want to do is make dubs of these onto CD-R with the infrasonics already filtered out before the signal even hits the phono pre-preamp stage. The points you raise are the reasons why I want to make the filter external and easily removable.

Onhwy61 - I will be using Sound Forge on some of these (which has the filter feature you mention) for scratches, but I suspect the results on the warped disks will be superior if the phono pre-preamp never has to deal with the heavy sub-bass modulation in the first place. As for the ADC, the meters on my HHB burner don't seem to register these frequencies' energy very well, but the overall result is poor enough, even when played back at low volumes, that some digital overloading is certainly a possibility. Of course, reducing the recording levels to compensate would reduce resolution and S/N ratio as well. While I haven't yet tried the digital warp filter, I will still want an analog pre-filter, not only for the reasons above, but also for making cassette copies, or just auditioning records in real time without having to digitize the signal and perform "post-production" on the computer.