Caller ID was no heelp

[Enzo]

I was working on a fender tube amp, a little Pro Junior. Cool little amp. I noticed it had a new symptom. At a low level, but easily heard when turned up, it made a steady merp merp merp merp sound. I quickly decided it had to be external - no trem or anything in the amp that was cyclical. And moving my hand around affected it.


REcently I bought a new desk phone for my bench. These days they are all cordless things, not that I need to wander around on the phone. But I also wanted an answering function. SO I got a basic AT&T unit. does answering, caller ID. It was the guilty party. Touching it made a difference. I picked it up to experiment, and that activates the backlight for the LCD screen. Wow, that introduced a whole additional symphony of noise. I got a flat screen monitor for my computer, so that got the very noisy CRT off the bench, but now I have this. Oh well, at least I know about it now.

The electrical noise environment is dynamic and all around us. It pays to keep it in mind.

[The Dude]

The electrical noise environment is dynamic and all around us. It pays to keep it in mind.

No doubt true. What I'm curious about is did this happen with the amp apart or together and/or did it go away when the amp was together and maybe some additional shielding was connected via chassis screws. My point is that you know what caused the symptom, but it seems like a fully assembled, grounded, shielded amp shouldn't do this regardless, although I know it can and does happen.

That said, I was playing a club that served food one time and they had a notification system for when a food order was up. The system was wireless and used the AC line for its antenna so the whole building was swarming with RF. Whenever the damn thing went off every amp on stage made a beeping sound including the P.A. I even started playing a guitar solo with the beep at one point figuring "If you can't beat 'em.............."

[oc disorder]

Makes me wonder with the ever increasing "noise" as we move into the future , how long high impedance unbalanced guitars/amps will last fighting this...!
Also I have never seen a balanced turntable pickup cartridge . Seen heaps of effort go into the mechanics of turntables tone arms etc and absolutely hideous prices on interconnects um rca to rca leads but surely a phono cartridge lends itself to a balanced circuit without much trouble ?
Used to get an enthusiastic radio amateur operating on sideband leaking through my phono input which prompted the train of thought.
I use an old portable am radio as my noise detector. Some of those new energy saving fluorescent lamps often leave a lot to be desired in the noise dept !
I bought a cheap soldering iron with temperature adjustment for those rough jobs and it uses a triac in a dimmer style circuit.
I presume noise suppression was the first casualty when the accounts dept looked over the proposed production !

[Enzo]

The amp was apart, maybe 18 inches from the phone unit. I am not worried about the amp assembled. How many times have we heard about amps ticking only to find someone's cell phone was sitting on top of it?

I listen to AM radio in my car, and usually distant stations, so I hear a ton of local electrical noise. Some of those large LED signs at Speedway that announce price per gallon make a strong burbling signal in my radio. There is one of those billboards that flips pictures every few seconds. Like Vanna White on Wheel of Fortune, the whole face of the billboard is vertical three sided strips, each side has one picture painted on it. So as they things rotate in unison, three different images result. ANyway, every time the motors cycle, I get a wwrrrAAArrrrwww sound in the radio as I drive by, each time followed by a briefy little jingle-y sound. Driving down the street, I can hear cable TV junctions whirring along. It is amazing the noise.

[km6xz]

Noise has been steadily increasing for decades. I listen to shortwave, and transmit occasionally but it is such a high base noise level now that a S9 signal or about 50 microvolts at the antenna terminal is needed for getting any intelligence from it. That is a strong signal yet the house noise, from the street, cable leak, ADSL leak, and about 500 RF emitters within 500 feet of of anyone in a city or even suburb easily overtakes it. I have a spectrum analyzer on my bench that is used for RF systems and it has a noise floor -130db down, yet connecting to a small whip antenna is enough broadband noise half up the display and when tuned to 2.4 ghz, with all the spread spectrum and even narrow band sources, it is even worse.
The FCC sets maximum exposure levels by frequency and duration and a lot of gear is pretty quiet if measured in isolation but the sum of all the jungle of RF noise is surely exceeding those legal levels. The FCC does not have much power anymore, commercial powers want the profits more than people want protection from RF exposure. It would not make any difference if the people did want some protection, profits always trump health and welfare of human citizens. Here, there is similar agency that certifies equipment and sets RF radiation standards for purity and interference potential.
I limit my radio listening and talking now to battery operated use on weekends in the summer when I can take a train to the north and be 5+ km from a power line or cable TV and hear everything so much better. A 40 ft piece of wire shot over a tree branch via a sling shot allows noise levels closer to what I had when I was a kid. That has become a pleasant escape from the city when for $1 I can ride the train to nowhere in particular and in an hour just get off anywhere with my backpack filled with radio, battery, marinated pork or salmon to barbecue, called Shashlik, a nice bottle of wine or a couple beers and hang out until the next day. When I get back I am ready to head to the clubs and get my fill of acoustic noise and crowded sweaty dance floors. There is just so much peace and solitude I can handle;>)

[defaced]

Never have I ever unplugged every light in my work room, turned off the computer, and just had an amp and scope running while I stare at it in the dark. I learned early on that an open chassis is susceptible to more noise than one in the head shell, so I almost look for EMI to be a problem when I see/hear something odd and strangely non-amp like. I've also been known to use an insulated, grounded screen to drape over the open chassis, but have since gotten away from that for lack of trusting the DIY insulation (paper).

I listen to AM radio in my car, and usually distant stations, so I hear a ton of local electrical noise. Some of those large LED signs at Speedway that announce price per gallon make a strong burbling signal in my radio. There is one of those billboards that flips pictures every few seconds. Like Vanna White on Wheel of Fortune, the whole face of the billboard is vertical three sided strips, each side has one picture painted on it. So as they things rotate in unison, three different images result. ANyway, every time the motors cycle, I get a wwrrrAAArrrrwww sound in the radio as I drive by, each time followed by a briefy little jingle-y sound. Driving down the street, I can hear cable TV junctions whirring along. It is amazing the noise.

That's kinda cool. Does this happen to all stations, or just one in particular? Is your car radio newer (digitally tuned) or an older analog unit? I'd like to see what I can hear in my neck of the woods. Any yes, I'll listen to static on low volume to do it. The car I drove for years didn't have a radio, so I just listened to the purr of the engine and exhaust leak in that beast of a 90 Mazda Protege. Listening to static has to be an improvement over that.

[Enzo]

AH yes, no radio. I drove about 250,000 miles without a radio, but these days the car just comes with one. Currently a 2002 Toyota truck, so digital tuning.

I like to DX on the radio anyway, so I am inclined to listen to far away stations. My local stations on AM are wall to wall right wing ranters, I don;t care to listen. Those are strong so noise does not interfere. But I listen to WBBM (all news) from CHicago a lot, 780AM, and WBZ Boston 1030AM. I find noise interference does tend to peak at some frequency, not all sources the same freq either. But it happens all over the band.


AM radio is easy to DX (Listen for distance), and digital tuning has nothing to do with it. Slide rule dials work fine too. I used to do my listening on a world war two era receiver, and on the clock radio by my bedside. Started that 50-60 years ago. Penna? You should get WBZ on 1030 easy enough, and probably WBBM as well, but so many others, WHAM in Rochester, KMOX in st Louis, WRVA in Richmond has a strong signal. Distance only works at night though. No ionospheric skip during the daylight. WSB Atlanta should come in, or WLW Cincinnati and WWL New Orleans.

Just go out some night and listen to the radio, tune slowly up and down until you hear something, then listen until you hear some form of ID. They give call letters and say the freq, but we also get clues like "Cleveland Area Weather calls for..." Or "MAyor Smith has asked all DesMoines residents to..." Geez I used to sit for hours listening the two or three stations on the same channel fading in and out, trying to identify what I had. Now the internet has much more info than I had to help ID stations.

yeah, the FCC used to be feared, but now they are not remotely interested unless you interfere with TV or with some essential service. If your wireless karaoke mic is coming in on the ambulance radios in town, you will hear from them. They don;t care at all about AM radio.

[big_teee]

When I was a kid I would listen half the night to the far away rock stations.
WLS Chicago.
WNOE in New Orleans
KAAY Little Rock AR
And more.
T

[Tom Phillips]

... They [FCC] don't care at all about AM radio.

That's for sure. The lack of controls and enforcement on radiation from other equipment is a big problem for just about every AM station that's more than ~50 miles away. The LED stop lights at intersections and the LED lights on trucks & buses swamp out some stations. Also things like phone charges that plug into your car's 12V outlet. Just about everything with a switch mode power supply. During local power outages a battery operated AM radio really comes to life. Same effect that Stan gets by taking the train to a remote area. I was really surprised the first time I tried it. Reminded me of the days of listening to Wolfman Jack

[Bruce / Mission Amps]

Noise has been steadily increasing for decades. I listen to shortwave, and transmit occasionally but it is such a high base noise level now that a S9 signal or about 50 microvolts at the antenna terminal is needed for getting any intelligence from it. That is a strong signal yet the house noise, from the street, cable leak, ADSL leak, and about 500 RF emitters within 500 feet of of anyone in a city or even suburb easily overtakes it. I have a spectrum analyzer on my bench that is used for RF systems and it has a noise floor -130db down, yet connecting to a small whip antenna is enough broadband noise half up the display and when tuned to 2.4 ghz, with all the spread spectrum and even narrow band sources, it is even worse.
The FCC sets maximum exposure levels by frequency and duration and a lot of gear is pretty quiet if measured in isolation but the sum of all the jungle of RF noise is surely exceeding those legal levels. The FCC does not have much power anymore, commercial powers want the profits more than people want protection from RF exposure. It would not make any difference if the people did want some protection, profits always trump health and welfare of human citizens. Here, there is similar agency that certifies equipment and sets RF radiation standards for purity and interference potential.
I limit my radio listening and talking now to battery operated use on weekends in the summer when I can take a train to the north and be 5+ km from a power line or cable TV and hear everything so much better. A 40 ft piece of wire shot over a tree branch via a sling shot allows noise levels closer to what I had when I was a kid. That has become a pleasant escape from the city when for $1 I can ride the train to nowhere in particular and in an hour just get off anywhere with my backpack filled with radio, battery, marinated pork or salmon to barbecue, called Shashlik, a nice bottle of wine or a couple beers and hang out until the next day. When I get back I am ready to head to the clubs and get my fill of acoustic noise and crowded sweaty dance floors. There is just so much peace and solitude I can handle;>)

I've been forced to use magnetic loops.... QRM/QRN kinda sucks around here too.
From my old shop, I called the FCC once because my neighbors RFI and radiated power line noise was so bad I couldn't even work on an audio amp!
The result, our Public Service electrics company busted them for outrageous noise on their power lines and they were threatened with an FCC RFI violation and then my landlord kicked me out of the commercial site with a 10 day notice three days later (I was in that location for 16 years)... a frickin' 10 day notice to vacate the premises.
The neighbor? They last 11 more months before they went out of business and bailed on their three year lease.... sheesh!

[J M Fahey]

and then my landlord kicked me out of the commercial site with a 10 day notice three days later (I was in that location for 16 years)... a frickin' 10 day notice to vacate the premises.

That's what freaks me out of USA.
How can such a "tyrannical" (can't find a better word) attitude and actions be tolerated or even legal?
It baffles me.
Same with repo men, private bailout escapee bounty hunters and similar stuff.
Maybe you don't notice it because you grew up with that, but it's the law of the jungle.

Here, and in most of the Civilized World, if you have a signed contract, which for Commercial premises is a *minimum* 3 years length, often 5 years, considering what effort and money you have to invest to make a shop take off, the Landlord can't even touch you, unless you make something very bad or stop paying rent for 3 months at least, and then he must sue you in Court and *win* and a Judge must order you leave.
And you can/must answer and fight that, also in Court, with your own Lawyer.

Kicking you out just because now he dislikes you?
With no further Legal proof?
No way José !!!!

[km6xz]

Juan, many small businesses, particularly in rural areas or those that have a long history with the building owner never bothered with leases which sets the terms and conditions of termination of the lease. So, paying month to month, you really would not have any protections. Besides, if a small business owner did not have the money to buy a place, they surely do not have the money for suing a landlord. Taking a case to court is much more costly than any normal working person can handle, unless a law firm thinks it is a slam dunk case and takes on contingency, which means they pay their own fees and and when they win they take 1/3 to 1/2 of the judgement. So they only take cases that will pay off with substantial payments. That leaves a small business person suing for wrongful termination of a rental agreement out of luck because the damages will be modest.
The first consideration in starting and operating a business in the US is the legal strategy, any mistake and all your efforts, work and assets disappear even if you have insurance. That is one of the key motivations for any business decision. It is quite different there than in most other countries where courts and lawyers are not so intertwined in all activities. There are a lot of theoretical rights, not quite to the degree as EU or Scandinavia but still a lot, but only if you can afford to defend them. Normal working people can't.

Back the topic. Noise is a potential threat to health due to its cumulative effect, whether sound noise, RF and we are entering unknown territory with the number of simultaneous sources. Regulation on emissions are based on exposure to one source but what is the threshold of harm levels when many are combined, hundreds are combined? Is it the sum or the sources or some other combining effect?