|Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum|
Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
||Thread Tools||Search this Thread|
|24th September 2007, 10:06 AM||#1|
Join Date: Oct 2006
Loudspeaker noise from 300B
Hello to all,
I have a strange problem. I have already tried to search for this exact problem with little results.
There is a small speaker buzz arriving from both channels of my 2A3/300b amplifier.
There is no mains power to amplifier (and there is still this buzz).
The grounding looks okay (There wasn't this problem before).
No lights are present, no cellular telephones, WiFi is disconnected etc... No AC connected...
Is there a problem with the ouput transformers? How can I check without sophisticated equipment?
Please ask questions because it is difficult to write all important details. Thank you for your help.
Kind regards to all!
|24th September 2007, 04:00 PM||#2|
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Try disconnecting the mains and all signal leads from the amplifier.
Next try disconnecting the speakers from the amplifier and shorting the speaker cables together at the amplifier. (No, I'm not kidding) If you still hear a buzz that indicates that you have a strong magnetic field in that area of your listening room. This indicates that your speaker wiring is acting as a loop (equivalent to a single turn on a transformer) and picking up induced voltages. Suspect nearby electrical appliances (fluorescent lights, big transformers used for low voltage lighting e.g quartz halogen lamps, hot water heater, high current mains wiring, etc..) I have run into this problem a few times over the years with highly efficient speaker systems.
If the pick up does turn out to be magnetic twisting the speaker cable conductors (making a twisted pair) should help.
"Extraordinary claims require extraordinary evidence." - Carl Sagan
|Thread Tools||Search this Thread|
|Thread||Thread Starter||Forum||Replies||Last Post|
|Low noise transistor and noise figure||Real_Macgyver||Solid State||28||27th July 2012 09:42 AM|
|DIY loudspeaker vs. factory built loudspeaker||keyser||Multi-Way||83||16th May 2011 12:27 PM|
|Noise - 6J5 - 71a -300B amp||hal3101||Tubes / Valves||14||3rd November 2008 04:42 PM|
|FS: for 300B (JE Labs 300B SE) builders||cartman||Swap Meet||2||29th October 2008 01:13 PM|
|* 35 watt * 300B SE = super 300B + Class A2||rick57||Tubes / Valves||4||13th July 2005 04:18 PM|
|New To Site?||Need Help?|