I bought the ASUS ZenPad, great little Tablet. Hell of a time getting full specs out of the manufacturers. What type of DAC was the main question. But would be nice to know Headphone output/Impedance. Did the unit have OTG and USB Audio. Contacted ASUS, they fumbled for an answer and then came back with no. I recall reading an article saying it did. I think the CSR was basing his information on the Euro Version that came out with earlier Andorid 4.4. The one I bought came with 5. I then came across an article indicating that there are free programs you can download to determine if the unit is OTG. I did and it is. Long and short. It did not have enough output to drive the Car System. Returned it.
Timing is everything. Microsoft was having a sale. The Surface 3 128 GIG was on for 599.10" with the ability to charge and output at the same time. Brought along my Vamp Versa and a set of Grado's RS1. In and out in less than 15 mins. Confirmed it had OTG before hitting the store via the online chat. Microsoft offer a 30 day return policy and a 45 day option on the extended warranty. The Warranty is a replacement variety including accident damage for $99, good for 2 years. During the first 30 days. you are covered automatically without charge. Smart.
The Audio output works for me. By itself, there is more than enough jam to power the Car System, and the sound rivals the Vamp Versa with a little EQ tweaking. So when the iPod/Vamp Versa power down on the long trips, this will do the trick nicely. One thing, it is not, or so it seems, hot swappable. There is a power up and down scenario when using the Vamp Versa.