I thought I'd just share this with you. I was working on my new power amp this weekend, and using an overhead light fitted with a CFL lamp - rated I believe for the equivalent output of a 100W incandescent. The attached picture you see is the output from the amp - about 60KHz at 70mVpk-pk. The amp has a filter on the front but is exposed and about 1m from the lamp. Turn the lamp off, and the amp output is quiet as a mouse.
There's a lot of garbagae around now with these new lamps. I recommend you keep them away from your workbench, and you find something else for your listening room as well.
There's a lot of garbagae around now with these new lamps. I recommend you keep them away from your workbench, and you find something else for your listening room as well.
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i had to replace the flourescent lights illuminaing the back of my record (LP) shelf with a string of LED christmas tree lights. Too much noise in the hifi.
I'm fairly annoyed anyway at the single source nature of CFL's. In the stores I am offered the opportunity to buy 50 different brands, all made in the same country, probably the same factory. My electric utility gives CFLs away, paid for by my base service fee - we are supposed to use CFL's as a patriotic gesture to avoid wasteful domestic coal production.
I found a few CFL's 5 years ago assmebled in City of Industry, CA. The one I operate in the room with the hifi does not present a sound problem. It is obviously an inferior product, deserving bankruptcy.
I'm fairly annoyed anyway at the single source nature of CFL's. In the stores I am offered the opportunity to buy 50 different brands, all made in the same country, probably the same factory. My electric utility gives CFLs away, paid for by my base service fee - we are supposed to use CFL's as a patriotic gesture to avoid wasteful domestic coal production.
I found a few CFL's 5 years ago assmebled in City of Industry, CA. The one I operate in the room with the hifi does not present a sound problem. It is obviously an inferior product, deserving bankruptcy.
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Yes, I once had a DVD player from Philips which generated interference (made in China of course). Got my money back and bought a Sony. Much better - I guess the Japs are more suspicious of Chinese factories so insist on things being done properly.
The legislation exists, certainly in EU, but it is rarely enforced. The political will is currently to encourage/force adoption of CFLs etc, so inconvenient truths like poor EMC performance are ignored. In the UK it would be a job for local Trading Standards officers, but they are more interested in serious safety issues and fake designer labels.
The legislation exists, certainly in EU, but it is rarely enforced. The political will is currently to encourage/force adoption of CFLs etc, so inconvenient truths like poor EMC performance are ignored. In the UK it would be a job for local Trading Standards officers, but they are more interested in serious safety issues and fake designer labels.
The new fluorescent lamp we got for the kitchen recently has been quite unconspicuous in terms of RF emissions so far, even down on 160m. (Maybe not that surprising, as it's sold by what appears to be a joint-venture involving Osram.) The one it replaced (about 9..10 years old) had been much worse, at shorted tube length.
ESLs haven't been much trouble either, as long as I keep antennas like 0.5 m to 1 m away (scaling with power, an 11 W Osram emits less than a 23 W Philips). And that's stuff that's SUPPOSED to pick up RF.
The worst interference sources here are a plasma TV (Panasonic eventually wised up and by about 2009 apparently modified their panels so they'd be RF-tight, but this model precedes that by a few years), and as it is much closer to my antennas, the SMPS inside my ethernet switch (about 10 years old; no CE anywhere in sight, I don't think that really was legal at the time).
Plasmas are a real pest on MW and lower SW. Their direct radiation (when using unshielded panels) is readily detected from meters away.
I'm not sure how RF from florescents/ESLs would get into amplifiers. While they do involve some high-impedance nodes, normally they have a metal case which is connected to circuit ground somewhere. RF filtering on the input may not be effective at a few 10 kHz yet, but a low source impedance or even a short on the input should keep that down, too.
BTW, when using LEDs for biasing, note that they also work in reverse. Something to keep in mind.
ESLs haven't been much trouble either, as long as I keep antennas like 0.5 m to 1 m away (scaling with power, an 11 W Osram emits less than a 23 W Philips). And that's stuff that's SUPPOSED to pick up RF.
The worst interference sources here are a plasma TV (Panasonic eventually wised up and by about 2009 apparently modified their panels so they'd be RF-tight, but this model precedes that by a few years), and as it is much closer to my antennas, the SMPS inside my ethernet switch (about 10 years old; no CE anywhere in sight, I don't think that really was legal at the time).
Plasmas are a real pest on MW and lower SW. Their direct radiation (when using unshielded panels) is readily detected from meters away.
I'm not sure how RF from florescents/ESLs would get into amplifiers. While they do involve some high-impedance nodes, normally they have a metal case which is connected to circuit ground somewhere. RF filtering on the input may not be effective at a few 10 kHz yet, but a low source impedance or even a short on the input should keep that down, too.
BTW, when using LEDs for biasing, note that they also work in reverse. Something to keep in mind.
EMI on switch mode driven anything (SMPS, lighting etc) is something I've been aware of for about 25 years. Try designing the T/C amplifier on the same bench as the guy who's working on a 50W flyback converter . . . .
Ditto the flourescent lamps driven by SMPS PSU's that started to appear in the late 80's. We had some fitted under the instrument shelf on our two tier workbenches. I recall bitching and moaning in the lab and going around and turning them off so I could do low level uV measurements. A lot of fun.
Ditto the flourescent lamps driven by SMPS PSU's that started to appear in the late 80's. We had some fitted under the instrument shelf on our two tier workbenches. I recall bitching and moaning in the lab and going around and turning them off so I could do low level uV measurements. A lot of fun.
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