Rauliruegas
Dear Actusreus: probably you don't know how filters works so take a look on internet to learn about other that what Onhwy61 posted.
This is your response? I thought you knew what you were talking about. Sounds like you're simply repeating your analog rhetoric without much scientific knowledge on the subject to back it up. Sorry, but that's not very convincing to me.
It seems to me that the audio signal is always necessarily "filtered" once that stylus and its motor assembly picks it up off the record surface. Open up your phono, line, and power amps and you'll see all sorts of "filters" such as transformers, resistors, capacitors, chokes, etc. I don't doubt that there are better and worse subsonic filter designs out there, just as there are better and worse amplifier designs out there, and I do understand the argument that fewer components in the signal path is more desirable. But after reading countless posts about rumble filters on this forum over the past several years, I still have not seen a convincing argument how a well-executed rumble filter degrades sound except for purist rhetoric. Onhwy61's post is a good start, but I'd like to see more informed responses.
The most popular rumble filter on the market is the KAB filter. It's supposed to be transparent and not affect the signal except for the undesirable ultrasonic frequencies it is designed to filter. I'd like to hear an educated opinion just how this filter degrades the audio signal besides adding another pair of IC to the path.