Hi Ted, maybe it is interesting to the forum to share an overview picture of the insides of the MKII showing the digital board, analog board and the power transformer (and perhaps some other components outside the 2 board like filtering caps)?
I definitely used space to separate things that need to not interfere with each other. Keeping power supplies away from the outputs, paying attention to the location of components on the digital board vs the analog board, spacing higher frequency traces away from critical traces, using ground fill to help isolate each critical trace… Also, things like being able to power down circuits that aren’t in use (e.g. network upgrade path, USB, I2S…) will help to lower hash in the box.
We definitely want to keep streaming hardware out of the DAC box… Anything that can connect to Ethernet requires a fast processor which equates to noise, and certainly Ethernet packet arrival is asynchronous to anything else in the box which also leads to non-white noise. And, yes, extra spacing is good.
Yes, toroidal transformers radiate axially. When mounted on the back wall they radiate directly into the audio transformers, not good. The magnetic field falls off quickly radially, so not so much of a problem when mounted on the bottom of the chassis. Even so, in the DS we found that we needed to rotate the power transformer carefully to lower the amount of interference in the (far) audio transformer.
A magnetic field isn’t affected nearly as much by aluminum as steel. That’s one reason to be careful when sticking audio components, if the power transformer in one ends up in a bad place on the unit above or below you can get hum, etc. in your system.
Thanks Ted! So what would be recommended to put between the toroidal and the audio transformers to improve things?
Regarding stacking components, that’s what I always thought to be honest. I not only wondered about audiophiles doing this all around, but also Paul often mentioned there’s no problem doing it. Many even seem to put power plants on top of racks or inbetween.
From experiments with active HF protection I know how much impact even a normally radiating component, placed alone, has when placed alone between speakers.
All of the different shielding we tried between the AC transformer and the audio transformers when working on the DS made things worse: muffled, rolled off… This happened whether we shielded close to the AC transformer (which does make the most sense) or we shielded the audio output transformers. The people who build the audio transformers probably have already shielded them well and it’s not simple to do better than they can.
The blueish circumferential wrap feels like paper or foil and is very thin. I’m not sure it’s an active part of the design of the transformer. There is no shielding specified in the request for quote or the returned spec.