popeman, there is nothing to suggest additional shielding would be needed with information or measurements you have offered so far. Perhaps you are being cautious - it is often easy to leap-frog ahead in what may be needed, only to miss the important first steps of defining/measuring if you have a problem for starters.
TBH, I'm not sure what additional information I should provide.
My initial question was whether some copper tape around the coil former would provide any shielding in a multi-tap RM inductor like the one in the picture.
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Your query relates to identifying what level of additional shielding could be provided. That relates back to the egress frequency you are concerned about (ie. 1Hz, or 1MHz or ....), and the type of EMI (ie. electrostatic or electromagnetic), and the affected equipment/circuitry that one assumes is nearby (ie. how close, and what the direction is from the RM core - including RM core apertures where any egress may be more directional). That type assessment is nearly always best assessed by having a base set of measurements, and then making a change to the inductor and re-measuring.
My concern is that you don't know what your problem is, or how to make a base set of measurements that might cover your concern. The other side of the coin is that any modification you make to the inductor may also modify operating/spec values that you were relying on for normal function, given that additional shielding could be modifying the inductance value, its impedance with frequency, the frequency dependant losses, and capacitive coupling to the inductor.
My concern is that you don't know what your problem is, or how to make a base set of measurements that might cover your concern. The other side of the coin is that any modification you make to the inductor may also modify operating/spec values that you were relying on for normal function, given that additional shielding could be modifying the inductance value, its impedance with frequency, the frequency dependant losses, and capacitive coupling to the inductor.
100% agreed. Plus the fact that copper shields around pot cores are very rare birds tells us you most probably are barking the wrong tree.
OK thank you gents.
The question was more for educational purposes. I don't have any inductor at hand yet so I can't really take any measurements under real circumstances.
This is an interesting one. I realise that some copper tape around the bobbin can introduce some anomalies but are you saying that even a mu-metal can can affect the performance of an inductor?
The question was more for educational purposes. I don't have any inductor at hand yet so I can't really take any measurements under real circumstances.
This is an interesting one. I realise that some copper tape around the bobbin can introduce some anomalies but are you saying that even a mu-metal can can affect the performance of an inductor?
Hi all,
I like to report some defective UMCs.
Two of my students tried to measure the frequency response of a power amp, maybe without a resistor divider at the output of the amp.
The result are 3 broken UMC. They all show the same behavior. USB communication seems to be ok. I can change the sample rate with the AudioTester SW and read it back with the UMC Control Panel.
But there is so signal coming out and no spectrum also a signal is at the CS4272 inputs.
I compared the signals at the CS4272 of a working and a defective unit.
Power, Clocks and Data from the USB controller are present. The mute signals are low and VCOM is only 0.7V instead of 2.23 V
Seems that the CS is dead.
Any experience?
Alfred
I like to report some defective UMCs.
Two of my students tried to measure the frequency response of a power amp, maybe without a resistor divider at the output of the amp.
The result are 3 broken UMC. They all show the same behavior. USB communication seems to be ok. I can change the sample rate with the AudioTester SW and read it back with the UMC Control Panel.
But there is so signal coming out and no spectrum also a signal is at the CS4272 inputs.
I compared the signals at the CS4272 of a working and a defective unit.
Power, Clocks and Data from the USB controller are present. The mute signals are low and VCOM is only 0.7V instead of 2.23 V
Seems that the CS is dead.
Any experience?
Alfred
They have a great reputation in the MIDAS consoles. I wonder if people were expecting the same preamps in this interface, but we got a lesser preamp still designed by the same team. So they get to keep the name, but it's not performing as well. Or else, it might mean it's great for console use, with colouring, but for our use, not so much. This section is noisy in the interface.
by "in line" you mean digital switch before the ADC?
from my experience, I guess so...
Hope you all, enjoy the summer like i do (well in this part of the world ofcause) 
Saturday we will throw a party, wife getting older
I bought a little Chinese multi-streamer, to be used for folk's streaming also through they're bluetooth....
The Aiyima accept's both USB (24/192), AUX, Bluetooth, COAX & TORX.
Also it's capable of adjusting Bass & Treble (working fine actually)
I'am not very comfortable taking some FFT of it, because
1. I now some class-D don't like wrong load (i used non grounded 8ohm power resistor's on both channels when i did the FFT)
2. I don't have a lowpass filter to attach between the Aiyima and the Behringer.
3. It's hard to track down howto excatly test thoose machines.
There is a slight hiss when holding ear on speakers, the hiss is not affected by volume... Really it's very fine... very very low hiss, but i think's this it was making the noisefloor climbing up to near -100dB ?
The thing is playing nicely, and i had it on for +24hour's now to really test it out.
FFT is ~1vac / Loaded on 8ohm powerresistor's / 1kHz, ~1vac Sine output (Victor's)
As i wrote before, i'am not comfortable doing the FFT on it, as i don't know enough of the Class-D machines
Jesper.
Saturday we will throw a party, wife getting older
I bought a little Chinese multi-streamer, to be used for folk's streaming also through they're bluetooth....
The Aiyima accept's both USB (24/192), AUX, Bluetooth, COAX & TORX.
Also it's capable of adjusting Bass & Treble (working fine actually)
I'am not very comfortable taking some FFT of it, because
1. I now some class-D don't like wrong load (i used non grounded 8ohm power resistor's on both channels when i did the FFT)
2. I don't have a lowpass filter to attach between the Aiyima and the Behringer.
3. It's hard to track down howto excatly test thoose machines.
There is a slight hiss when holding ear on speakers, the hiss is not affected by volume... Really it's very fine... very very low hiss, but i think's this it was making the noisefloor climbing up to near -100dB ?
The thing is playing nicely, and i had it on for +24hour's now to really test it out.
FFT is ~1vac / Loaded on 8ohm powerresistor's / 1kHz, ~1vac Sine output (Victor's)
As i wrote before, i'am not comfortable doing the FFT on it, as i don't know enough of the Class-D machines
Jesper.