My stereo is haunted!!

Hello Audiogoners,

I’m looking for some serious sleuthing. I cannot figure out what’s going on with my system. 

The basic system is:

  • Bel Canto Ref1000M Class D mono blocks
  • Modwright SWL 9.0 Anniversary Edition preamp
  • Bel Canto DAC 3
  • Either my old Rotel CD player or Cambridge transport to DAC
  • GoldenEar Triton One speakers

I liked the sound. It was just fine. Then, out of the blue, when I started the system, I’d get static that would build up until I got a loud POP out of the right speaker. How loud? My dog is now afraid of my stereo. Well, she’s not that brave…

I have tried:

  • Swapping in various tubes in the preamp.
  • Sending the preamp back to Modwright for a full exam. Done for only the cost of postage- great company. 
  • Switching the channels used for each mono block. 
  • Switching the channel for each speaker. 
  • Switching out the electronics in one of my speakers (parts supplied for free from GoldenEar- great company).
  • Switched in Adcom GFA555
  • Switched in a Dynaco PAS 3 Series II preamp
  • Used all combinations of preamp/amps
  • Switched out all cabling including speaker wire
  • Added a Furman PL-8C to stop line noise
  • Tried a different circuit in my apartment
  • Tried powering off flatscreen TV, Roku, and WiFi router
  • Switched between CD transports and used the Rotel built in DAC to take the DAC out of the system
  • Tried new surge protectors and power line.
  • Tried some medium sized Klipsch speakers I had around.

Nothing has worked. Some things (like the Furman, oddly enough) have added additional hum. 

I’m fine with basic tube noise floor. Not so fine with small booms and hum.  

I’m ready to go back to my Victrola and give up on electronics all together!

Guesses? Things to try? Have a problem like this before? Thanks for any clues!

Given that you have already switched out all stages and interconnects of your audio chain and still have the loud POP, the problem may be coming from external sources. Does the problem repeat later or only on power-up of your system? And to verify my understanding, it is always in the right channel?
You should swap your speaker cables left to right ( at speaker end only ).

If the problem stays in the right speaker - then either the speaker has issues or it is picking up rf from somewhere. Possible speaker issue could be faulty caps or bad solder joint which is more prone to rf.

If the pops go to the left then stereo more likley the problem, or one channel of the stereo is picking up rf.

Typically if you have a one channel problem, you simply swap left and right channels on one component at a time until you find the problem component.

Sources of rf - anything electrical device that has digital control of timer software running - eg fridges and air-conditioning units are a common source, wifi routers, washing machines/driers. Just try switching them off one at a time to see if it helps.

Try having all your digital gear off a separate outlet - even if you have to run a temporary extension cord. Also make sure your wifi fi routers are on a separate spur from the stereo.

Light switches and dimmers with bad contacts are another common source. I periodically turn the mains power off and go through all the power outlets and light switches in the home and clean and tighten up all the wire contacts - you’d be amazed at how bad these get over time.

It is just a process of elimination. Good luck.
I don't have a suggestion but I can relate to the issue because I had a very similar system with annoying sounds. I also had a Modwright Anniversary Ed. preamp like yours with a Bel Canto REF500s amp and Dynaudio Special 40s. I would always hear faint hums/static (no pops) and little 'ping' noises. I tried to ignore it at first but it eventually began to really get on my nerves. I switched cables, moved things around, called my expert friends and so on. Eventually, nothing worked so I sold them and got a Luxman 505UXii integrated and never looked back. Quiet as a mouse. Best of luck to you--I hope you figure out what's going on.