Audio Research LS17 to Headphone Amp?

I have recently purchased an Audio Research LS17 preamp and would like to connect it to my Ray Samuel's portable - battery powered - headphone amp. Since the only RCA outputs it provides are going to my Rotel amp, I'm wondering how to get a connection to the headphone amp?

Two thoughts:

1. Use the Record Out RCAs - What are the implication of doing it this way?

2. Obtain an XLR to Mini Jack combination cable - What are the implication of doing it this way?

Which is the best of these two options, or it there a better option?

I would use the Record Outs those should be a set line level and your HP amp will do the amplfication for volume.
Like Theo said. You want to receive the full volume signal and control the volume with the headphone amp, and the record out will do that. Also, you should be able to mute the sound from the speakers at the same time.
Agree the record out is the best solution for using a headphone amp.
I use an otherwise unused set of preamp outs to my headphone amp so I can control the volume with the preamp I clever or what? Call it a "variable line level signal", but do it. Do it now.
Thanks Riffer & Theo.

The Record Out works well and sounds great.

Is there any problem leaving the Record Out RCA cables disconnected from the headphone amp, yet connected to the LS17, when they are not in use?
If you must leave the cables connected, get a pair of cardas caps to put on the ends. They can create noise, etc. Basically act like little antennaes.

Keep the volume low on your preamp and see what happens when rec/out is engaged and the cables are not connected (it will undoubtedly happen accidently sometime in the future so best to know now, at a low volume level). On my preamp, I get a vicious shriek, but I do have a rec/in connected as well.
Thanks for your insights.

Not sure what you mean by "cardas caps". The RCAs from the Record Output are connected to an RCA to Stereo Mini Jack Adapter. This adaptor is the end that is "open" when the headphone amp is not connected.