rcprince is the man for AL DAC upgrades, he has a review of the differences between the AL DAC before and after the newest mod. I have the 34 that has the 24/96 chip upgrade plus other parts. I am using Amperex 7316s and Amperex Bugle Boy 6DJ8s in the DAC. It gives a little warmer and smoother sound in my system which I prefer. The newest model has better separation of vocals/instruments, was clearer, more detailed and better bass definition. It also costs more then a used 34. Good to know that there you can always upgrade later.
Look up Russ's review and Happy Listening.
