I have no idea why no one else has done it? It was originally a comment in Stereophile from the correspondent in Belgium(?) years back. mentioning stuffing antistatic foam to reduce digital grunge. it really only seems to affect the highest frequencies, the HF digital glare/grunge. (the idea is to absorb the RFI EMI generated by the chips inside the case so that stuff does not affect the signal) Maybe no one can hear it? I tried it on my DAC. At least ten years ago. Then I bought another DAC and did that one too. The Black antistatic foam, not the blue! Used it for a long time like that.I wrote about it several times over the years. But, no one ever followed up on it as far as I know. If I had an audio business, I would have designed a soft plastic tray to fit into various DAC cases with the foam prefilled. So it could slip into the case easily, a wire trailing out to screw to the chassis to ground it. No one seems to be interested, Worked for me ****************************************************************
The other tweak is higher AC frequency. a LOT harder to implement since you need a regenerator which can up the AC frequency. Only one which could do it was the PS Audio "P" series back from ten fifteen plus years ago. Some had a optional board allowing the change in AC frequency. Rare now, and hard to find. One alternative would be 400Hz airplane AC. (All commercial airliners use 400Hz AC frequency on board the plane for AC power. There ARE ground based 400Hz AC converters one can buy (check eBay).. Paul McGowan of PS Audio experimented with alternate AC and found 400Hz to be the ideal highest Hz to use on audio equipment anyway. Personally if I had a lot of money I would own a couple of 400Hz ground based airplane 400Hz AC devices to play around with. As is, all I can do is max 120Hz from my PS Audio P-600 regenerator. I use AC 110 Hz for all my digital gear.The higher AC frequency is another idea I first got from a Stereophile article years ago, and reinforced by Paul McGowan’s experiments. You can find a uTube video of him talking about higher AC frequency. Here is a link: https://www.youtube.com/watch?v=Np--y3Kfy28 ...Enjoy!
The other tweak is higher AC frequency. a LOT harder to implement since you need a regenerator which can up the AC frequency. Only one which could do it was the PS Audio "P" series back from ten fifteen plus years ago. Some had a optional board allowing the change in AC frequency. Rare now, and hard to find. One alternative would be 400Hz airplane AC. (All commercial airliners use 400Hz AC frequency on board the plane for AC power. There ARE ground based 400Hz AC converters one can buy (check eBay).. Paul McGowan of PS Audio experimented with alternate AC and found 400Hz to be the ideal highest Hz to use on audio equipment anyway. Personally if I had a lot of money I would own a couple of 400Hz ground based airplane 400Hz AC devices to play around with. As is, all I can do is max 120Hz from my PS Audio P-600 regenerator. I use AC 110 Hz for all my digital gear.The higher AC frequency is another idea I first got from a Stereophile article years ago, and reinforced by Paul McGowan’s experiments. You can find a uTube video of him talking about higher AC frequency. Here is a link: https://www.youtube.com/watch?v=Np--y3Kfy28 ...Enjoy!

