Wadia 922 vs 921

Does anyone know and can describe both the technical changes and the soundwise changes of these products?
My understanding is that there are some new circuit boards and each DAC now has 2 transformers instead of 1. I was told that in addition to sonic benefits, this reduced heat and increase reliability, FWIW.

The upgrade increases the speed and depth of the bass. It is not insignificant, but it is also quite a pricey upgrade. I would put it on the same order of magnitude as adding good power cords.
My understanding is that the changes are all in the power supply, including new capacitors. There are no changes to the conversion stages. I was considering the upgrade but was advised by Wadia that it might be worth it to wait until they completed the USB input circuitry and do it all together. I have since sold the 921 set but it remains a formidable digital source in my estimation.