Phono-pre: subsonic filter on or off ?

It also depends on what frequency the cut off is omplemented. If at 70Hz, then you are definitely losing something with it on. In which case I would leave it off unless your woofers are pumping hard from rumble.

If it cuts off at 30Hz or below then it may not make much difference leaving it on all the time

Ptm,
I've never seen rumble filter adjustable. It's mostly oriented on sub-sonic frequencies of a large amplitude. Hence the alternate name is SUBSONIC filter.
SUB-SONIC means UNDER-AUDIABLE.

Actually, subsonic means 'under the speed of sound'. The proper term is Infrasonic. We don't say sub-red for infra red do we?

Also, Carver produced an infrasonic filter that automatically adjusted its cutoff properties to the low frequency content of the recording and the turntable's inherent rumble or lack of.
Salut, Bob P.

INFRA -- SUB
ULTRA -- SUPER

are synonims
as well as SUBSONIC or INFRASONIC.
Technically you can say SUB RED but it's not common.

Not only Carver produced the infrasonic dynamic filter. I've seen that in works of many different electronics designers adn Carver probably not the first implementing this circuit.

Marakanetz, Infra and Sub are NOT synonymous. neither are Ultra and Super.

Ever heard of super violet? SUB-Sonic has always been used for the speed of an object being lower than the speed of sound and never for UNDER-AUDIABLE, whatever that is. If you meant audio or audible, then that is not synonymous with sonic either. Sonic has to do with sound, not audibility.

Infra and ultra have always been associated with frequency, low and high, of vibration, sound and light, among others.

Perhaps this is a second language thing.

respectfully, Bob p.