Strange Noise from PrimaLuna DiaLogue One

Thank you all for your feedback. I will be calling Kevin at Upscale Audio tomorrow, but was wondering if any of you had had a similar experience.

Lostbears, I am actually auditioning an used McIntosh MA8900 as we speak. I am very much aware of the limitations of the PrimaLuna in this particular context, but I love the amp dearly, my room is fairly small, and I tend to listen to fairly moderate volume levels. I really have had no big issues with the Elipsa/DiaLogue One combination. But I was indeed curious to see what the Elipsas could do with a solid state amp, and my dealer was kind enough to let me take it for a ride for a few weeks, so I am definitely looking forward to the next few days. Right "out of the box", so to speak (even though this particular unit had a previous owner), I certainly can hear a lot more "ease" and "flow" to the sound, and, ironically, a sweeter midrange and warmer overall tone. It may be foolish of me to jump to conclusions so quickly, but to my ears (at least so far) the Mc integrated sounds more "tube-like" than the PrimaLuna!

@tonediary  Interesting! In my case, it only developed in the last few months. My new speakers are more sensitive than the pair I used to have, so that may be why I did not notice the noise before. I did call Upscale Audio, but their response was "no clue!"... Sigh... 

Could you elaborate on how the noise sounds like on your end?

I do not want to ship it back to Upscale because they are on the opposite coast, the unit weighs 70+ lbs., and I do not feel like spending hundreds on shipping + insurance. I have had my fair share of horror stories with UPS, etc. Also, have not had the greatest experience with Mr. Deal in the past... 

I may be taking it to a local tech to see if they can find anything wrong with it.

tonediary, thank you. That is exactly the same type of noise I get. Your description was perfect. 

Well, the plot thickens.

Long story short, the noise I described earlier is 100% an FM station that is interfering in my system and overall making my life miserable.  

I can now hear it on the McIntosh as well.

The reason why I was *not* hearing it before is because I was only using the digital coaxial input on the McIntosh. Since the Mc has a built-in DAC, I was using a digital coax cable from my Oppo 105 straight to the DAC in the Mc, so we are talking about a 100% digital signal path. No noise at all.

But after a few days, I decided to try my turntable...

The FM noise is back. In fact, I decided to see if the noise was also present in all of the analog inputs. And, yes, it is. However, you need to crank up the amp all the way to +/- 80 to really hear it, and I would never listen at those levels. I am normally listening at 38 - 48. So that is why I did not notice it before, and, regardless, it is a non-issue since the DAC in the Mc is really good, so I do not need any of the unbalanced inputs.

But when using one of the unbalanced inputs with my Pro-Ject turntable, the FM noise comes back in full force. It is like literally listening to the station. It is VERY noticeable at around the 50+ volume level. This is with the following signal path: turntable > phono preamp (external) > Mc unbalanced input. The noise is louder on the right speaker, for some reason.

It gets weirder.

I disconnected the turntable, and brought it closer to the amp. I then used a single pair of RCA's to go straight into the Mc's MM phono input. The radio interference was better (ie: less audible... because the turntable was now in a different location). However, the phono stage was really noisy! NOT the FM/RFI noise I described earlier. Just plain old-fashioned "sssshhhhhhhhhhhhhhh" phono noise.

Then, I tried disconnecting everything analog. All I had was my Oppo 105 and a digital coax cable and the speakers, of course. With this set-up, I switched to the MM / MC inputs (again, with NOTHING connected to those inputs) and turned the volume up. At around the 45+ level, there is a lot of noise! With NOTHING connected! And... the MC input is LESS noisy than the MM input.

What a hobby ours is!

Thank you all for the input and help. The interference seems to be precisely that: interference, and not the fault of the PrimaLuna after all. The problem simply manifests itself differently in each amp, and not surprisingly the tube amp was more sensitive to it.

Last night, I went out to walk my dog. I normally wear noise-cancelling headphones when I do this because the area we live in is unbearably loud. Main avenue, lots of hotels and traffic everywhere.. A nightmare if you are like me and have sensitive hearing... Normally, I leave my house with music already playing in my headphones, so by the time I get out I do not notice the outside world as much. But this time I forgot to turn my portable player on, so the headphones were working in noise-cancelling mode without any music playing through them. As you know, noise-cancelling headphones actually have microphones built-in. Lo and behold, the same interference/noise was (barely) audible through the headphones as well! The microphones were probably picking it up! I have no clue why this damn signal is so powerful and intrusive all of a sudden...

I spent the last 2 days essentially re-arranging my entire system. I THINK (I hope I am not shooting myself in the foot here) I found a place where the turntable is directly connected to the McIntosh's MM phono stage and does not pick-up the interference. Once I placed the table in a different spot (about 2 meters from its previous location, away from the only window in the room), and connected it straight to the MM input (only 1 cable run, no external phono pre-amp), the noise in the McIntosh was gone, and so was the FM/RFI interference.  

Still experimenting, however. I hate the new location I was forced to use for the turntable, but I suppose I will need to live with it, since the alternative would be worse.