I've just purchased Yamaha's CLP-470 Digital Piano (~$5000), and I'm looking for a recommendation for equipment to use with it. I mainly plan to use it to play classical piano music with headphones (I currently have Sony MDR-7505 which are actually great for their value but I thought about upgrading). This digital piano has RCA outputs and a standard "large" headphone output (I think it's 1/8 inch, in my country we call it "Large PL").
In addition I sometimes find some time to listen to classical music, which is generally the only genre of music I listen to.
This digital piano has a midi output (so theoretically I could connect it to a computer (or any other device which accepts midi input) to produce the piano signal from a an external sound card), but I'm not sure it is relevant for my question since I'm mostly interested in just playing classical piano music, i.e., I plan to use it as an alternative to an acoustic piano, and I'm not sure that using midi will utilize all the great effects of this piano that are used to simulate the playing experience of an acoustic piano (I'm not sure this data actually is transferred through the midi interface).
ThereforeI, I would like to enjoy the maximum quality of this digital piano sound through headphones. Since I I'm actually not sure about the quality of this digital piano's analog outputs, I don't think it will be wise to invest more than $1000 on equipment (such as headphones, amp, etc.) because I'm not sure that this digital piano as a source will justify such an high-end expensive equipment (Even though it's quite an expensive digital piano, I'm not that sure about the quality of it's various output signals).
So, I currently plan to buy a used pair of Sennheiser HD650 (at ~250$), and I was wondering about the following questions:
1. Are these headphones a good place to start with for my purposes? I also read some people recommending Sennheiser HD700, Sennheiser HD800, Audeze, and Beyerdynamic, all of these being more expensive and I don't' know if they worth the extra cost for my purposes, and in light of the fact that I'm not sure about the source quality.
2. Should inverst in an amp. (I've read that the HD650 quite demands one)? If so, which one? I saw some recommendations on both FiiO E09K (~110$) and Schiit Valhalla (350$).
3. Should I invest on replacement cables for these headphones, such as Cardas?
4. Which cables should I buy to connect the RCA output of the digital piano to the amp's input?
Saying I would like to invest up to a total of 800-1000$ on all these devices (headphones + optional amp + optional cables), what would you choose as the preferred combination for my purposes?
for example, should I take:
used HD650 + Valhalla?
used HD650 + Fiio E09K + Cardas replacement cables?
HD700 + Fiio E09K?
Unfortunately, I currently have no way to test these in my country in my own ears since these products are not available here (I will do a second check on internet stores but so far I haven't seen any store selling this stuff).
I will be grateful for your help.