Tube Phonostage Causing Rumble and Noises

+1 Could it be that simple? Sounds like a feedback loop.

How loud is your subwoofer set?

When the phonostage is idle, there was just rumble.

Thanks for the feedback. I asked Jim White about the rumble filter and he said it was a bad idea. I set the sub volume at around -20 dB. Crossing over at 35 Hz for the Apogee and 85 for the LS3/5 A. Definitely not loud.

No issue with the rumble/noise playing the DAC (Bricasti M1 Series II).

I am using XLR throughout except the tonearm cables.

I don’t have issues using the I/o with the Apogee. Maybe it’s because the frequency response is 25-25k Hz and the I/O is generating subsonic frequencies under 20 Hz.

One issue with LP records is the need for the RIAA equalization curve. Due to the technical requirements of vinyl record recording, for playback, the RIAA curve boosts bass +20 dB and cuts high treble -20 dB to compensate for the polar opposite frequency adjustments made when the master was cut.  This means that rumble and any imperfections in the record will be magnified.

Over at the Propeller Head Plaza section at Audio Asylum (where geeky stuff is often discussed) a fellow posted some screen shots of spectrum analysis he did on various phono cartridges.  On one set of images, the 20 Hz background noise was about -70 to -80 dB, but when you dropped down to 10 Hz, the background noise increased to -39 to -48 dB.   Therefore, if you are running a subwoofer with a turntable and have a phone preamp & amp system that is linear in the sub-bass, it is very easy to end up with playback problems.

Since the problem persists after tube swapping, I am beginning to suspect there are defective parts in the unit.

when lightning strikes twice, it cannot be just coincidence. Before I acquired the I/O, I got a Rhea Signature. The minute I turned it on, my jaw dropped to the floor seeing the speaker driver cones being pushed all the way out. It was a scary scene. I took the Rhea to a local tech. He did some measurements and concluded the Rhea was generating subsonic frequencies. I informed my distributor about the issue and he didn’t believe me. I took the Rhea to him and he witnessed his diver cones got pushed out all the way. He immediately promised a replacement and I opted for the I/O.

Can anybody offer some information about subsonic frequency coming out of a tube phono that is caused by failed or defective parts?

Thanks.

Thanks misstl. Jim White did mention RIAA curve boost. Jim also said it was impossible to eliminate the rumble to zero although I was assured the rumble was eliminated before I paid for the service. I don’t mind a little rumble but no one can listen to records while the entire room is shaking.

This is most puzzling.