Buzzing sound emanating from my speakers when receiver is set to 'phono'

My system developed this issue a few weeks ago after moving cables around and the power cable for the amp became close to the phono interconnect, and parallel to it for a few inches.

I rerouted the phono interconnect & amp power cable to fix the problem.  The phono stage is multiplying the signal by a factor of something like 1,000 so it does not take much electromagnetic interference to do nasties.

I once hooked up a turntable with  an unshielded PBJ and got the local AM station!  That was also a sign of a dirty contact acting like a crystal detector. Google can dirty electronic contacts act like an AM detector.

Amusing (off topic) story, In the early '60s I'd been building a crystal set with my much younger brother when we lived in Worcester (UK), about 10 miles from the BBC Droitwich transmission station.  This is a 500kW transmitter at 200kHz.  Somehow the headphone leads were touching the gas stove that we were working next to, in came the BBC Light Program (now BBC 4).  There was even a design for a transistor radio that used the signal from that transmitter as its power source in some radio hobbyist magazine that I read as a young teenager (1950s).

I have posted this root cause analysis protocol in other posts regarding buzzing or humming and distortion.  If you follow the protocol, you should find the issue.  I have further explained reasons.  I have listed then in my opinion of the order of priority   

1. Ground loop:  Are there multiple ground current paths (equipment plugged into different outlets?  Is the turntable and phono preamp grounded properly or has the existing ground wire become faulty? Connect equipment to different outlets, check ground of turntable and phono preamp. 
2. Electromagnetic interference:  Equipment and connections generate EMI that can enter sensitive phono sections.  Have you recently moved equipment or cable paths … or added a new piece of equipment? Relocate equipment or reroute connections.  Faulty interconnect or cable shielding can permit EMI to enter system.  Check all wires for damage.  Have you purchased a new appliance that is on the same line?  Unplug the appliance to see if the problem resolves.  
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Sorry, hit send by accident. 
 

3:  Insufficient contact at connections.  Clean all contacts.  Check for improper contact os connector damage. 
4:  Preamp ware or damage.  Bad capacitors, tubes, oxidized tube contacts are all potential causes.  DC leakage usually causes popping rather than buzzing, but have the unit checked.   A broken internal wire or poor internal connection can cause the buzzing.  An aging or damaged cartridge can cause the problem.  
 

Hope the protocol gives you some ideas on how to investigate root cause.  Good luck. 

What turntable, cartridge and ohono preamp are you using. This may shed a little more light on the problem. 

Thanks again guys!

:thumbsup: