I have bought JAMO sub 250 subwoofer and Pioneer VSX919AH-K amp. Please advise how can I connect them. The amp has one RCA out for sub but the sub has two line in sockets (left and right). Do I need to use one of those RCA cables with one socket on one side and two on other? Please assist.

You simply connect a RCA type line cable from the subs line input to the dedicated socket on the back of the Onkyo.
When you run speaker set up it will set the subwoofer up.

The Jamo speakers need an AV Receiver to drive them properly. The TV doesn't have the correct outputs nor does it have the power required.

The Jamo kit consists of a powered subwoofer ans 5 small surround speakers. Each surround speaker needs to be powered by the speaker output from an an AV Receiver. The subwoofer should also be connected to the receiver, but the connection is a phono/RCA lead from the receiver's "Sub Out" socket.

Your TV connects to the AV receiver via the Optical out.

Is everything hooked up correctly sounds off I know also could be your amp is going on you cold be a multitude of problems or one of the simple ones i stated

the easiest solution is to get yourself a cord that switches from headphone plug to RCA and connect it that way. I sure hope that this helps you in hooking your ipad up to the Jamo 200 Sub. Thanks, Cody

Refer to the applicable Jamo manual.

http://www.jamo.com/na-en/support/owners-manuals/

http://www.jamo.com/images/download/313.aspx

The actual owners manual is right here...

http://www.jamo.com/images/download/766.aspx

On page 16 I see a Sub Pre-Out right under the Center Pre-Out

connect the left line out to your sub
be sure that the volume ingrease or degrease at the same time.

What do you mean that it sometimes doesn't work? It doesn't power on automatically?
Check settings of your receiver - if it has subwoofer output enables and if low frequencies from all channels are directed also to the SUB. By default only the LFE channel (.1) of 5.1 signal input is fed to the subwoofer. So Sub will work in this case only when you listen to 5.1 signal (DVD movie for example), but for radio or stereo music, only front speakers are used. By configuring this bass redirect, you can use subwoofer for all signal types.

Use the PRE-OUT SW (subwoofer) output and connect it to the left RCA socket of your subwoofer.

You need a subwoofer cable then you attatch the cable from the back of the amp into the sub and power on the subwoofer and amp and hey presto your away.