Headphone amp as pre amp


Hej

I'm considering to buy a tube pre amp and a tube power amp. Then I realized that my headphone amp, Feliks Audio Elise, has line out and should work as a pre amp. But what are the draw backs compared buying a pre amp?
http://feliksaudio.pl/en/products.php

Any suggestions of tube power amp, with EL84 or EL34 tubes. It has to be a Push-Pull as my speakers ar at 89dB sensibility. And if you have suggestions of a pre amp too I would be grateful.
Budget is aprox $4500 for both.

simna
It can work well but is one line input sufficient?  

I am currently using a rogue audio RH-5 headphone amp / linestage preamp even though I have no interest in headphones.  It sounds amazing and has (4) inputs.  
The Felixaudio headphone amp sure looks like a fine product. Have no experience with it. Only drawback I can see is that it only has a single input. On the web site you provided I did not find what the output impedance was, which would help in matching it to a amplifier. I would give it a try and purchase an amplifier. 
I send Feliks Audio a mail and this is their answer: "Yes it can work as a very good pre-amp, without any draw backs. It’s going to add the tube signature of Elise to any signal that you pass through it."

And yes, the drawback is just one line in.

The Music Reference RM-10 looks nice, but will 35w not be a little to hard on the EL84 tubes?

About ST-70 Bob Latino; Anyone know why keeping the input at the front? Nostalgia? It's just stupid. 


About ST-70 Bob Latino; Anyone know why keeping the input at the front? Nostalgia? It’s just stupid.
To keep the AC Power input and the signal input separate to avoid noise on the signal line. My Quicksilver monoblocks are the same, as are many others.