Digital buzzing sound, both channels, you can set your watch by it

I am utterly stumped here. Every evening at 8:35 p.m. Pacific (0335 UTC for you aeronautical purists) an intermittent buzzing emits from both channels of my system (SP-13 driving pair of M-125s). The buzz returns intermittently and at random lengths of time, then about 9 p.m. this weird pulse ceases. It's not your usual 60-cycle AC hum, either; it's higher pitched, almost like a deliberately attenuated wet pharte.
This is regardless of source. It is independent of cabling, pre-amp and amp-driver tubes, all of which I've swapped out to no avail. It remains the same amplitude regardless of volume setting. The only constant is the timing of it. Starts and quits every night at the same time.
The stereo is on a dedicated 20-amp circuit and my appliances, when functioning, don't perform with that regularity.
I'm guessing RFI, but there are no hams in the neighbourhood and the nearest cell tower is several miles away.
If so, how would one diagnose and eliminate it? Or could it be crawling out of the power xformer on the pole? Someone had suggested street light noise, but the ones around here start up and quit with the daylight, which being near the 49th Parallel means vastly different times, so I've ruled that out. Ditto the next-door house, with whom we share the power xformer; the house has been empty for over a year due to a bank repo.
What could one do to diagnose and address this? Anyone experienced anything similar?

ALIENS!....gotta be ALIENS! ET phoning home???

Check with your Utility company. May be a programed grid transfer going through a noisy switch.

Water or electric meter reporting to the mothership?

skriefal wrote:Water or electric meter reporting to the mothership?

actually this would make sense since it is the same time same channel kinda thing....

Do you happen to have a cell phone on at the time? If so, try turning off the phone during the suspect time period. If you have WiFi, try turning that off as well.

Mike

Any Missile Silos' or Military Installations within 150 miles?

terry37932 wrote:Any Missile Silos' or Military Installations within 150 miles?

Not that I'm aware of, Terry . . . Of course you know how sneaky those guys can be.
It seems there is one device that phones the Mother Ship every day, and that's the electric meter. Gas and water meters only xmit when the readers drive by. Trying to hunt down if this could be the source. The human I spoke with at the utility company wasn't sure what time a day the pulse goes out from the electric meter, but it is on a 24-hour cycle. Supposedly they're sending out a tekkie.
I should add this doesn't happen to my solid-state gear.
Anyway, thanks for the input. Will keep y'all posted.

Well your tubes are definately picking up something. A simple Faraday Cage might work.

Any power storage systems in your area? (e.g., small hyro-damns that run variable-frequency drives to pump water uphill an low demand times.)

Had a similar problem several years ago with AC hum in the stereo.  So I went around the house unplugging one appliance at a time until I got to the refer.  When I unplugged it the hum went away.  Short version:  the defrost cycle was the offender, so I got out the refer manual and reprogrammed the time for defrost cycle and all is well now. Just goes to show how we can take for granted that the manufacturer gives all information regarding their product.  One would not think that a refer would transmit radio/AC interference.  Another appliance to check is the washing machine.  Our newish washer transmits radio interference when the motor is running. Totally screws up AM reception in the house when we do laundry.  Just two things to check.

Hey! That's prime listening time!!

Someone still listens to AM?

No word yet from the electric company on when they might be out to check on the meter xmit cycles.
HOWEVER, and I shoulda done this before starting this thread, I have eliminated the SP-13 pre-amp as the culprit. The interference, whatever it is from, is getting picked up by the power amps, equal levels, both amps. So my guess is that one of the driver tubes is the "antenna."
I'm going to make up some tin-foil shields for them and move the shields around till I can find out and/or isolate the problem.

deepee99 wrote:No word yet from the electric company on when they might be out to check on the meter xmit cycles.
HOWEVER, and I shoulda done this before starting this thread, I have eliminated the SP-13 pre-amp as the culprit. The interference, whatever it is from, is getting picked up by the power amps, equal levels, both amps. So my guess is that one of the driver tubes is the "antenna."
I'm going to make up some tin-foil shields for them and move the shields around till I can find out and/or isolate the problem.

I can't wait to see what is causing this interference, it's like waiting on the next episode of a soap "As the Tube Turns"

10-E-C wrote:

deepee99 wrote:No word yet from the electric company on when they might be out to check on the meter xmit cycles.
HOWEVER, and I shoulda done this before starting this thread, I have eliminated the SP-13 pre-amp as the culprit. The interference, whatever it is from, is getting picked up by the power amps, equal levels, both amps. So my guess is that one of the driver tubes is the "antenna."
I'm going to make up some tin-foil shields for them and move the shields around till I can find out and/or isolate the problem.

I can't wait to see what is causing this interference, it's like waiting on the next episode of a soap "As the Tube Turns"

Me neither. Since it's coming from both amps M-125s at equal levels, with the preamp OFF, I'm guessing it's the front two holes. Will try those tonight and keep you posted. Meanwhile, a word from our sponsors . . .

10-E-C wrote:

deepee99 wrote:No word yet from the electric company on when they might be out to check on the meter xmit cycles.
HOWEVER, and I shoulda done this before starting this thread, I have eliminated the SP-13 pre-amp as the culprit. The interference, whatever it is from, is getting picked up by the power amps, equal levels, both amps. So my guess is that one of the driver tubes is the "antenna."
I'm going to make up some tin-foil shields for them and move the shields around till I can find out and/or isolate the problem.

I can't wait to see what is causing this interference, it's like waiting on the next episode of a soap "As the Tube Turns"

I'd suggest "As the Filament Burns" as a more apt title.

And I too look forward to the next 'episode'. I'm definitely curious as to what may be causing it.

-Pat

I had a similar problem many (many) years ago with an old heathkit amp .  I was stationed at Biloxi AFB and it turned out to be the flightline radar antenna...circling around and around...

What sort of commercial/industrial facilities are in your area?

[EDIT] Wow Deep! I just googled Wallace Idaho. Cool looking area.

Yeah, Wallace is a cool place, esp. in the summer when it doesn't snow so much . . .
I've not solved my daily 8:35 p.m. buzzing sound, and the power company (Avista) have not condescended to a time they might come out and have a look at things.
So I've whiled away the time researching "smart meters," one of which is installed on our house now and possibly concurrent with this noise issue. Quite a bit on them, ranging from the black helicopter crowd worried about health aspects of microwave pulses and Big Brother's monitoring of your refrigerator, to more sensible stuff from ARRL and various other tekkie sites.
Apparently these things operate on two frequencies; 63 kHz and 1.7 to 80 MHz, and report to a receiver on your power pole xformer which shoots a signal down the 3-phase line to tell the utility company how often you open your refrigerator door for another beer, or whatever.
Since Avista has not called back to arrange a service call, I'm wondering if it might expedite matters to wrap the meter head in tin foil or stick a big lead bowl around it.
Since both 63k and 1.7-80m are well beyond human hearing range, I'm also wondering if one of those two frequencies might agitate sometime in the tubes.
Happy Memorial Day to all, and thanks for the thoughts.

Lots of controversy here in Massachusetts about the Smart Meter, too. I'll bet a Mullard GZ-37 that this is your culprit. Wrapping the unit in shielding might solve the problem, at the risk of pissing off the power company. You'd foil their spying -- with foil.

Well, I'll know in about 3 hours if the aluminum foil does the trick.
Of course it's just wrapped around the meter-head. Didn't want to go breaking utility seals and/or electrocuting myself. That could impair a long holiday weekend.
If it turns out this is the cause of the static, the utility will be under FCC regs responsible for dealing with it.
If this fix works I'm sure they'll be out Monday or Tuesday to arrest me.

deepee99 wrote:Well, I'll know in about 3 hours if the aluminum foil does the trick.
Of course it's just wrapped around the meter-head. Didn't want to go breaking utility seals and/or electrocuting myself. That could impair a long holiday weekend.
If it turns out this is the cause of the static, the utility will be under FCC regs responsible for dealing with it.
If this fix works I'm sure they'll be out Monday or Tuesday to arrest me.

I think you ought to wrap your house in foil, that way, you'll keep ALL radio, X-Ray, Gamma Ray, and all the other ray's away!!!!

MontanaWay wrote:

deepee99 wrote:Well, I'll know in about 3 hours if the aluminum foil does the trick.
Of course it's just wrapped around the meter-head. Didn't want to go breaking utility seals and/or electrocuting myself. That could impair a long holiday weekend.
If it turns out this is the cause of the static, the utility will be under FCC regs responsible for dealing with it.
If this fix works I'm sure they'll be out Monday or Tuesday to arrest me.

I think you ought to wrap your house in foil, that way, you'll keep ALL radio, X-Ray, Gamma Ray, and all the other ray's away!!!!

That's any house in Alaska or the Northwest Territories during the summer solstice to keep out solar radiation so you can bl**dy sleep!

This reminded me of a clause I've read on some tag on some gear I once bought. Turns out the FCC REQUIRES any electronics to ACCEPT interference. Below find an attempt at an explanation in "layman's" terms of why this seeming paradox should be.

http://ask.slashdot.org/story/00/07/15/1940242/why-does-fcc-require-the-acceptance-of-interference