I'd expect a line DC problem, or ground loop, to start immediately. Hum coming later sounds more like failing capacitors to me. You could try a DC blocker to see if it helps.
Yes. From what you describe, that’s sound like DC induced hum.
Almost certainly not. A DC blocker helps with DC, and DC doesn't magically appear or disappear when playing music or after having your system on for a certain amount of time. It may come and go on the line but would do so independently of what you do with your music (do you play with crappy dimmers and high powered lighting, is the wife drying her hair with the hairdryer on the low setting, do you have a dodgy fridge compressor, etc, etc).Hmm, I'm having a bit of a humming issue with a Yammy AS-1200. The amp dead silent when playing music and idling at first start, but if it idles for more than about 10-15 mins, it starts humming audibly from a few feet away. The sound doesn't go away unless I power cycle the receiver, or goes away on its own after playing music for a few minutes. I wonder if this is something that would benefit from a DC blocker?
An Isolation transformer will block out DC offset. And it does it very very effectively. Then you may ask, "well the isolation transformer will hum itself from the DC offset." A well designed toroidal will not hum from DC offset.
I have few Emotiva CMX-2, but it's only 2 outlets. Why the f would Emotiva not design one that is 6 outlets?
Anyway, that is why I have a Torus isolation transformer, it has 8 outlet and it works superbly. However, the problem with isolation transformer is that (well there are 2 problems) it consumes a lot of power when idle. The one that I have, I measured it at 175w when idle. The other problem is that an isolation transformer of that size has a huge transformer and the magnetic field is VERY strong. I don't feel comfortable being around something with this strong of magnetic field, anyone saw X-Men when Magneto mutated everyone in NY? However, the EMF, is easily addressed by shielding the toroidal with mu metal, it is super effective, which is what I did.
I have since retired my Torus, until if and when I get solar panels.
Until then, I am on the market for a 6 outlet DC blocker or a DC blocker that is capable of 15A so that I can plug a strip to it.
Toroidal transformers tend to constrain the magnetic field to the donut-shaped core, much better than the E-I stacked laminated ones do to their cores. Your exposure to a magnetic field is tiny once you are a few inches away from either type of transformer, especially the toroid, and even near it, it's no big deal. Of course, I am talking about transformers in consumer equipment, not power stations.An Isolation transformer will block out DC offset. And it does it very very effectively. Then you may ask, "well the isolation transformer will hum itself from the DC offset." A well designed toroidal will not hum from DC offset.
I have few Emotiva CMX-2, but it's only 2 outlets. Why the f would Emotiva not design one that is 6 outlets?
Anyway, that is why I have a Torus isolation transformer, it has 8 outlet and it works superbly. However, the problem with isolation transformer is that (well there are 2 problems) it consumes a lot of power when idle. The one that I have, I measured it at 175w when idle. The other problem is that an isolation transformer of that size has a huge transformer and the magnetic field is VERY strong. I don't feel comfortable being around something with this strong of magnetic field, anyone saw X-Men when Magneto mutated everyone in NY? However, the EMF, is easily addressed by shielding the toroidal with mu metal, it is super effective, which is what I did.
I have since retired my Torus, until if and when I get solar panels.
Until then, I am on the market for a 6 outlet DC blocker or a DC blocker that is capable of 15A so that I can plug a strip to it.
The theory is correct. However, I have a fairly decent EMF meter at home, don't ask me why and how. Anyway, based on my measurements, few inches is way too optimistic. And the numbers I see on the meter, does not make me comfortable, if I remember correctly, at about 8 inches away, it was like 30 guass. High enough for me to use mu metal for shielding.Toroidal transformers tend to constrain the magnetic field to the donut-shaped core, much better than the E-I stacked laminated ones do to their cores. Your exposure to a magnetic field is tiny once you are a few inches away from either type of transformer, especially the toroid, and even near it, it's no big deal. Of course, I am talking about transformers in consumer equipment, not power stations.
EMF meters indicate the presence of radio frequency interference (RFI), not isolated magnetic fields. There is a magnetic component to RFI, but it is exceedingly small. You need a magnetometer to do measure what you are looking at. Perchance, that is the type of meter you may be using. If that's true, then that seems like a rather high magnetic field.The theory is correct. However, I have a fairly decent EMF meter at home, don't ask me why and how. Anyway, based on my measurements, few inches is way too optimistic. And the numbers I see on the meter, does not make me comfortable, if I remember correctly, at about 8 inches away, it was like 30 guass. High enough for me to use mu metal for shielding.
You know what, I don't remember if the unit of measure is guass or milliguass is being displayed. I just remembered that "the goal is to keep it under 1."EMF meters indicate the presence of radio frequency interference (RFI), not isolated magnetic fields. There is a magnetic component to RFI, but it is exceedingly small. You need a magnetometer to do measure what you are looking at. Perchance, that is the type of meter you may be using. If that's true, then that seems like a rather high magnetic field.
If you have an EMF meter, the units will be in volts per meter. A magnetometer will have units in gauss. As for 1 gauss, the earth's magnetic field is almost 1 gauss.You know what, I don't remember if the unit of measure is guass or milliguass is being displayed. I just remembered that "the goal is to keep it under 1."
I'll take a look at the meter tonight.
And I'm confused why the EMF meter wouldn't be applicable.
Every phone has a 3 axis oneVoltage field strength meters for power line emissions and RFI are fairly common; magnetic field strength meters much less so IME
Where, used for what? Not disputing it, curious. I don't think putting my phone near a magnet has confused it, but not something I do often (I have done it, though, and do not recall any adverse effects).Every phone has a 3 axis one
Magnetometers are used for things like dead reckoning, compass or other sensor fusion stuff. There are also apps to find hidden electrical wires.Where, used for what?
Yah, I was curious and found several articles online, which led me back to a couple I had saved myself.Magnetometers are used for things like dead reckoning, compass or other sensor fusion stuff. There are also apps to find hidden electrical wires.
Mine is measures in gauss. I think its unit is milliguass, I have to double check. The display doesn't specify the unit of measure and only provides the number. So I probably just mistaken/misspoke it to be gauss.If you have an EMF meter, the units will be in volts per meter. A magnetometer will have units in gauss. As for 1 gauss, the earth's magnetic field is almost 1 gauss.
Wouldn't that 3-axis sensor in a phone be an accelerometer, rather than some sort of RFI sensing device? I'm not aware of 3-axis magnetometers or RFI meters, although I could be wrong on that.Every phone has a 3 axis one
Usually both are present, as well as a gyro, giving 9 axis measurements of magnetism, acceleration and angular velocity.Wouldn't that 3-axis sensor in a phone be an accelerometer, rather than some sort of RFI sensing device? I'm not aware of 3-axis magnetometers or RFI meters, although I could be wrong on that.
I looked that up. Amazing!Usually both are present, as well as a gyro, giving 9 axis measurements of magnetism, acceleration and angular velocity.
Single chip solutions exist, like this one:
ICM-20948 | TDK InvenSense
The ICM-20948 is the world’s lowest power 9-axis MotionTracking device that is ideally suited for Smartphones, Tablets, Wearable Sensors, and IoT applications. 1/3 the power of existing 9-axis devices 3-axis gyroscope, 3-axis accelerometer, 3-axis compass, and a Digital Motion Processor™ (DMPTM)...invensense.tdk.com
This is the one I got. It literally saids milliguass right on it.If you have an EMF meter, the units will be in volts per meter. A magnetometer will have units in gauss. As for 1 gauss, the earth's magnetic field is almost 1 gauss.