Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: I plugged the e17 into this dock and tried to use an rca to 3.5mm into my computer jack and the e17 doesn't work on aux in the switch? Thank you!
Document: The shipping was perfect and I really like the amplifier. I'm using it, hooked to my computer, as a dock & amp for the E17.My only problem was the power supply. When I received my shipment, I plugged everything in to be sure it was working. About four hours later, when I was able to sit down to use it,  the power supply was dead. The power supply is also not a common volt/amp configuration (15V/1.5A).
I've tested e17 docked with e09k amp and plugged dac usb meridian explorer with minijack (lineout) to aux in e09k.Meridian is far better than fiio e17 dac docked on e09k amp.I sold my e17 and my combo is explorer dac with e09k. No regrets. Better bass infrabass treble more present and soundstage more airy than with e17.
This is my first headphone amp. Build quality is astounding, works well with my E17 (which I have permanently married to this thing. )However, if you want to use optical-out on your PC, PS3, or whatever device you're running, you need to run it through the top TOSLINK jack on your E17, not the E9K dock. Just something I thought I'd mention.
Safely shipped to my FPO address, free shipping can't beat that. Use the dock to charge my Fiio E17 DAC Headphone Amp. Hooked up to my computer. Okay sound for such a small footprint.
I bought the E9 a few years ago & loved it. For some reason, it just stopped working with my HD650 cans. I tried using it with others (on both mini & full-sized plugs) and it never worked. This gave me the impression that the amp died.I decided to update to the E09K. Unfortunately, it works as a pre-amp/amp through the RCA jacks, but also doesn't work with any of my headphones.
It was nice while it worked (though when docking the E17 moves a lot). After 7 month though BOTH units died. Even by itself the E09K doesn't work now. Tried contacting the company and couldn't get any response. Don't buy it.
So far no complaints - works well, nice and solid. The sound that comes out of it is clean and puts out what you put into it. Looking to buy a decent sound card on my computer now to make this work even better since I am still using the stock built in one on the mobo of my computer.
Another quality product from FiiO. It's a stylish, well-constructed headphone amp, brushed metal with a power/volume knob that harkens back to receivers from the 1970s.I have this paired with my E17, and the combo drives my Sennheiser HD-598s beautifully. I also have my modest 2.1 computer speakers plugged into it, so that I don't have to swap cables back & forth.
Like many people, this is my first true headphone amplifier. I recently purchased a pair of Beyerdynamic DT 880 (250 ohm) headphones and I needed an amp to drive them. This works perfectly, and the sound coming from this amp compared to the regular headphone jack on my computer is like night and day. This amp provides more than enough power to drive both my DT 880s and my Audio Technica ATH-M50, which also benefited (sonically) from it.
Of course Amazon had no problem refunding/replacing. The second one works perfect. Great purchase, highly recommended! Below is setup:HT Omega eClaro 7.1 Sound CardMediabridge 3.5mm to RCA CableFiiO E9K Headphone AmpSennheiser HD 598 Headphones
Answer: When the e17 is docked in the e09k the only input that is selectable is "dock-in". To select any other input it can't be in the dock. I ended up using an optical cable for input into the e17 and my headphones plugged into the front of e09k. The instructions that came with the e09k were a little difficult to follow. Hopefully my answer helped.