Tube Phonostage Causing Rumble and Noises


Hello, I am desperate in need for advices and help.

I have a Aesthetix I/O Eclipse (one power supply) that I acquired new in 2009. It started to make the SVS SB16 Ultra subwoofer rumble a few months ago. I sent it back to Aesthetix, they performed a bunch of upgrades and replaced 4 tubes in gain stage one claiming these would help with the noises. 

When I got it back three months later, the rumble got a bit better but it was still there. Then Aesthetix sent me a new set of tubes claiming there were specially selected and tested for low noise. However, they didn’t eliminate the rumble.

Then I played a record to during the test, the unthinkable happened. When the phonostage is idle, there was just rumble. As soon as a signal was passed from the phono, the sub went crazy, it produced some subsonic noise that made the room shake. I then connected the phono to a tube integrated amp and I heard a loud distorted noise through my LS 3/5A.

The strange thing is that I have no issues using the I/O with my Apogee Fullrange without the sub.

I would appreciate any shape or form of advice/help.

Thanks in advance and Happy New Year!

agharion

@mulveling 

“With the Fatboys (both uni and gimbal) the problem is mitigated enough to no longer be a concern.”

Sadly, this is also the Fat Boy — Kevlar 3D printed.

I also have the Esoteric Grandioso turntable.  Same issue when I used the Van den Hul Frog Gold cartridge, so I think it’s the cartridge, which is otherwise lovely.
 

I two huge SVS PB 16 ultras and Bowers 800 (Diamond) to fill a big space and I like to listen loud.

I measured and had an off the charts standing wave peak about 1.5 feet off the front wall.

Regardless of what is picking up the feedback, the base trap solved the issue.

@davetheoilguy 

Interesting - still so many surprises and lessons to be had in this hobby! That's cool you were able to isolate the problem to standing waves, and resolve with acoustic treatments. I *think* the majority of my issue here was structure-borne energy, so that is indeed different (moved rack around a lot trying to avoid the worst of standing waves and structure-borne energy). I've recently had the Frog Gold on the Fatboy here. And agree - it's such a lovely, well balanced cartridge!

@mulveling 

I’d love to say I’m an acoustic genius, but I figured out it was a standing wave because every time I went to look at the turntable to figure out what was going on, the sound would rapidly fade (and my heart would start beating way too fast, which I figured out was relevant later).

A very Heisenberg’s cat situation.  I’d look and the sound would go away.

Eventually it dawned on me that my body was breaking up the wave.  Did a little trial and error and then tests to confirm.

The weird heart rate is a classic symptom of intense subsonics, which I knew from working in a haunted house when I was a teenager.

 

@davetheoilguy - the Frog is relatively high compliance for a moving coil and favours arm's on the lower end of effective mass range, so if there is a problem, it's more likely to be in matching of the arm and cartridge than the cartridge per se.