|
|||||||
| Home | Forums | Rules | Articles | Store | Gallery | Blogs | Register | Donations | FAQ | Calendar | Search | Today's Posts | Mark Forums Read | Search |
| 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 |
16th September 2005, 02:28 PM
|
#1 |
|
diyAudio Member
Join Date: Jul 2005
Location: southern us
|
120 Hz Buzz Unplugged
I happened to place my ear close to my Khorn this morning and heard a faint 120 Hz buzz. Odd because my entire system's power is switched on an off from a single source, a rack mounted PS filter.
A monoblocked SE EL84 amp powers the speaker, so I pulled the PS cord and input cable, still buzzes. If I disconnect the speaker wire from the amp the buzz stops (if this didn't stop it I'd have my ears checked). Question is, how can an amp, disconnected from any 120 v power supply and source generate a 120 Hz buzz when connected to a highly efficient speaker like the Klipschorn? Do I need an exorcist? Maybe my home was built on a burial ground? Any ideas, suggestions? dr._sleep |
|
|
16th September 2005, 02:49 PM
|
#2 |
|
diyAudio Moderator Emeritus
Join Date: Jan 2003
Location: Near London. UK
|
Bell, book, and candle?
Sounds as though the output transformer (which is a coil) is picking up a stray magnetic field and passing it to the loudspeaker. Now, the more interesting question is, "Why is it 120Hz and not 60Hz?" I'd suspect that there's a transformer or motor (or perhaps even a fluorescent light) nearby that is saturating and leaking 120Hz. You'll have to go round switching things off. Possibly by candlelight...
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference... |
|
|
|
16th September 2005, 02:59 PM
|
#3 |
|
diyAudio Member
Join Date: Jul 2005
Location: southern us
|
I didn't have time this morning but I'll put my oscilloscope on it to check the frequency. It was not a hum that was audible, but it could be harmonics of 60Hz through the tweeter and/or midrange horn.
I do have a dimmer switch in the room but it is 20 feet from the amp. Nothing else was powered up nearby. thanks, dr._sleep |
|
|
|
16th September 2005, 03:14 PM
|
#4 | |
|
diyAudio Member
Join Date: Oct 2003
Location: Denmark, Viborg
|
Quote:
Hmm, a light dimmer, the No. 1 on the top 10 of nasty little buggers that causes noise on the mains. Try switching off the dimmer and see if the problem persists. Magura 
__________________
Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com |
|
|
|
|
| Thread Tools | Search this Thread |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Blackgate cap leg is unplugged help | milen007 | Parts | 9 | 24th April 2009 02:21 PM |
| Melos triode and computer as source: BUZZ BUZZ BUZZ | zigo3 | Tubes / Valves | 4 | 28th November 2007 02:11 AM |
| What if the speaker becomes unplugged? | aletheian | Chip Amps | 2 | 9th April 2006 03:48 PM |
| pre hums - even unplugged! | Bill*B | Tubes / Valves | 14 | 18th November 2005 01:22 AM |
| A-75 buzz | Dave Varner | Pass Labs | 3 | 15th February 2002 01:30 PM |
| New To Site? | Need Help? |
