Tube Phonostage Causing Rumble and Noises

Hi dmguragno, thanks. I just moved the phono power cord to another receptacle.

I had an experience that a defective receptacle caused my power amp to overheat.

@agharion

If your rumble occurs with needle out of the groove, that is not turntable feedback! And it does indeed point to the Io Eclipse as a culprit for generating this unwanted LF noise. The needle has to be in groove to test for table feedback issues. I used the needle in groove, at rest, to test many many times in my "problematic" small room rig.

It’s a lot of money to have invested in that Io. I’d try to borrow another phono stage to really nail it down to the Io. Heck, maybe buy a Hagerman Trumpet MC - it sounds great for the money ($1289), might surprise you, works with almost any cartridge, won’t cause this horrible noise, and is handy to have around as a backup and sanity check.

But yes, the KAB rumble filter should "fix" this problem, but if it’s being generated by the Io I wouldn’t keep that phono stage in there regardless. My problem in my small room rig was feedback based, and the KAB did indeed resolve it (I went through 2 of these KAB’s actually; the 1st unit was defective) - though I don’t feel it’s quite 100% "sonically transparent" as claimed. However it is indeed good, and FAR better than dealing with the issue you describe. In the end my issue bugged me enough that I vowed to resolve the feedback issue itself, and eventually did. I now run happily without the KAB filter. I don’t think with all you’ve invested, you should tolerate a phono stage generating rumble. The fact that the company sent it back like this is a huge strike against.

And just philosophically, I don’t consider tubes capable of producing up to 80dB of phono gain without inviting massive noise issues. That’s why everyone else uses a JFET stage or SUT for MC gain. I’m sure it’s a nightmare selecting and re-selecting low noise tubes.

Hi mulveling, thanks. I will certainly look into the Hagerman.  If I can’t resolve the problem, getting the Hagerman at $1289 sounds like a good option.

I was interested in the Pass Labs XP-27 but the price is way up there. From my experience with Pass, they offer superb customer service. I have their XVR-1 crossover. The balance started to skew to the left a couple of years ago. They replaced the 4 attenuators but the problem came back after a few months. The took it back two more times and the same problem still persisted. They took it back for the fourth time and arranged for me to ship it directly to Nelson Pass. Nelson fixed it in less than a week. I only paid for the attenuators ($60) and first time shipping. They didn’t charge me anything after that. That’s good service.
 

I’m curious if you have a hot spot and the turntable is sitting on the peak of a standing wave.  
 

I would try to move the turntable forward off the wall or just anywhere.  Also consider bass absorption on the front wall.

i had not a rumble, but a low, loud, buzz (or hum!? No clue what he right term is) that would gradually appear (especially listening to “sticky fingers” Riling Stones)  if my volume was too high using the turntable.  It wasn’t coming off up the turntable, either.  This is a super-isolated VPI Avenger Titan, siting on a 3 inch slab of hardwood with rubber feet, sitting on a Symbol Audio table.

i read somewhere that the cause could literally be sound vibrating the stylus or cartridge.

I had extra GIK bass trap panels and lined one up right behind the audio cabinet, just sitting on the floor with about two feet sticking up so it absorbed the “bounce” off the back wall.  Immediately went away.

i then did a cleaner install.

i had not a rumble, but a low, loud, buzz (or hum!? No clue what he right term is) that would gradually appear (especially listening to “sticky fingers” Riling Stones) if my volume was too high using the turntable. It wasn’t coming off up the turntable, either. This is a super-isolated VPI Avenger Titan, siting on a 3 inch slab of hardwood with rubber feet, sitting on a Symbol Audio table.

i read somewhere that the cause could literally be sound vibrating the stylus or cartridge.

I had extra GIK bass trap panels and lined one up right behind the audio cabinet, just sitting on the floor with about two feet sticking up so it absorbed the “bounce” off the back wall. Immediately went away.

i then did a cleaner install.

@davetheoilguy I recently started playing with VPI turntables, and really love them BUT they are more susceptible to a ~ 100Hz resonance, in my experience. I first perceived this as a background rumble / hum / buzz which became more pervasive with higher playback SPL, and thought it was a ground loop - but upon further investigation, confirmed it was indeed feedback!

It’s a combination of the plinth and tonearm. I’ve experienced it with Aries 3 and Avenger Reference, on a Critical Mass Systems rack and Platinum filter. In my case, the issue got FAR worse with the 10" 3D arm wand. With the Fatboys (both uni and gimbal) the problem is mitigated enough to no longer be a concern. The 10.5i metal arm is actually quietest of all (its problem resonance is much higher in frequency but also much lower in level), though the Fatboys do sound better overall. The original 3D arm was just unusable in my small room. In fact, at a high enough volume it could be triggered into runaway feedback - fortunately I’m quick on the mute button! You could destroy your speakers otherwise.

I’ve read a couple other instances of this issue with the original 3D arm, but it doesn’t seem to be well known overall.

With my Clearaudio magnetic bearing (CMB) decks, there are no problems with 100Hz (drum beat like) frequencies, but they can be hell at subsonic frequencies (visible woofer flapping), unless you have truly excellent support underneath them.

Again, I don't think any kind of table feedback is OP's issue since he says it happens with needle out of groove. The cartridge coils form part the "constrained" layer between vinyl groove / cantilever on one side, and damper / suspension on the other side. When stylus is lifted out of groove, it cannot generate signal.