Thanks so much for all the support guys. Such a fantastic Axiom community we have. With regards to the hum issues... In testing this afternoon I found that by populating each module with two speakers and not one (the system is 5.1) the hum went away!! In other words using an EVEN number of speakers with the A1400-8 seems to remove the hum. I discovered this by connecting just LR first no hum... connect LR SR SL hum... add center... no hum... use center LR and one rear... no hum... add rear again for 5.1 hum.... added a rear center for 5.1 ES and again no hum. It seems to me the hum is introduced when I am using an uneven number of speakers and one of the modules is only driving one speaker. I was thinking of testing again with a 8 Ohm high watt resister connect across the terminals of a module only populated with one speaker. I also confirmed the hum using just a single channel on the amp though the hum wasn't as pronounced and seemed to increase logarithmically when uneven speaker count was connected. In other words one speaker produced least hum while 5 speakers produced the most. I will get some shop speakers over to this customers house and confirm this by populating all of the channels. I have a feeling the SNR would be LEAST with all 8 channels populated and would get worse working back in even speaker counts whilst it's the opposite with uneven speaker counts where 1 speaker would have the least and 7 the worst. It's also interesting to note this is a non issue with a pre that has balanced out. I am going to run tests using my notebook with trueRTA and REW. I'll post the graphs with results using various numbers of even and uneven speaker counts... 1,3,5,7 and 2,4,6,8 . Thanks again for the responses guys!!! sure makes one feel great and is reassuring to see the designer/OEM/ODM and other end users so willing to come forward and help. It's a fantastic example of Axiom's dedication to it's customers and a great indicator of how happy other customers are that they are willing to come on here and help others out without any volition simply because they want to share with others these fantastic products.

Justin

PS By systemic I mean anyone that's using non balanced inputs... here's dreaming this customer (a relative) gets the AVP-A1HDCI as these two pieces would be a match made in heaven IMHO ;\)