Correct I knew that don’t know why I said both are used
They’re gone. If one of you bought them please come back and let us know what you think after putting some on various devices. I use several layers to build up and soak up more as the range the 3M AB5030 works most effective is in the GHz range not Mhz.
Here’s what Ted said regarding placement in the DS some years ago now:
The difference using some of the shielding material should be noticeable - people have used “audiophile” RFI absorbers and noticed the results. In general the biggest digital offenders are the biggest chips
I don’t want to take the time to wade thru all of the options and make specific recommendations, but here are the best places to try and the frequency ranges of interest:
The PIC/control processor/display processor on the back of the display board is the worst offender in the box. (80MHz plus all sort of impulses reading flash and ram, etc.)
I don’t know which of the following causes the least or most RFI/EMI:
The USB processor is next to the USB connector, a little smaller and says XMOS. (About 400MHz + harmonics)
The FPGA says “Spartan 6”. (some 22.6MHz, a little less 56MHz and a lot of 170MHz - the number vary a little from release to release.)
The two small inductors near the USB chip might be a place to try if you can make sure that nothing can get shorted - they are part of the XMOS chip’s power supply so they have a lot of changing current.
In the DS Sr if your digital board still has rectangular epoxy PCB material just over where the audio transformers are, adding some magnetic shielding to the BACK of the digital board might be useful. Make sure to not short anything. There are no traces in those rectangle on any lower of the board.
There’s probably no reason to shield any of the other bigger chips (mostly regulators and higher current diodes.) But it shouldn’t hurt.
On the analog board there are only two places I’d try anything, both just under the ribbon cable: the oscillator module (22.6MHz) and the big 28 pin digital switch (which says “MC100E…FNG” - 11.3MHz.) Some people have reported good things when shielding them and others the opposite.
You might also find that wrapping some of the absorbing material around your power cord and/or you interconnects (especially digital interconnects) may make a noticeable difference, perhaps good, perhaps bad depending on the rest of your system.
Glad to hear that we all have the memory slips once and a while. I just did not want to see someone spend big bucks for a fuse that would do nothing for them.
I really appreciate your posting of photos of fully treated components. Other opinions are welcome, but there’s no need for all of us having to re-invent the wheel.
Looks like you’re not using the bridge…