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

@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.

The phono stage is fine. It sounds like the subwoofer is way too sensitive. I would disconnect the sub and any crossovers and see how things run. Remember, records always produce a little rumble. If all is back to normal you have a subwoofer problem, if not than you will have to start eliminating units one at a time. Other sources do not produce a lot of very low frequency garbage like a record does and may not excite the problem.