DK Design VS.1 Reference mkII - Optimization

I have not tried ERS paper, but one manufacturer that supplies a lexan cover instead of an aluminum one is DartZeel. Their amplifier, as you can see in a lot of literature, is supplied with a clear cover specifically for that reason.

Maybe shoot an email to DartZeel to explain this effect in more detail?

Also, while I believe that almost all components sound better with the aluminum cover off, this effect is especially prevalent in the DK amplifer where the difference is quite dramatic.

By removing the cover you will have changed the mechanical mass of the entire chassis.Vibration and it effects on the circuitry will also have been changed. Vibration influences can greatly alter the spectral balance. The amp has been retuned within its own environment. Tom

Tom, Your explanation is as good as any I've seen for the reason this amp sounds best with the top off. Tubes are microphonic to some degree and the less vibrations (from any source) the better. Removing the top would certainly eliminate one potential source of vibrations. I've done this with some CDP's/Dac's and pre-amps.

I just don't understand these electro-magnetic 'waves'comments.

Apparently the amp generates a lot of EMI which must then be disappated in some fashion and taking the top off facilitates that disappation. But if the amp is creating the EMI in the first place, and its harmful to the signal, it seems to me as if the damage is already done.

If the EMI is externally produced it seems that having a non-ferrous case, including top, would be beneficial in keeping it out of the amp. I also don't understand the 'wave' concept, I can understand EM fields of changing intensity, but 'waves' which bounce back and forth off some surfaces but not others? Are you aware of any science which supports this?

Tvad, Audioaril, Tom, anyone - please help me to understand this.