In case anyone is interested in the comparison between the P-1 and P-700u:
http://www.amazon.co.jp/LUXMAN-%E3%83%A9%E3%83%83%E3%82%AF%E3%82%B9%E3%83%9E%E3%83%B3-P-700u-%E3%83%98%E3%83%83%E3%83%89%E3%83%95%E3%82%A9%E3%83%B3%E3%82%A2%E3%83%B3%E3%83%97/dp/B00AGOKUFA/ref=sr_1_1?ie=UTF8&qid=1433566464&sr=8-1&keywords=Luxman+P-700u
I asked my Japanese friends for a direct translation:
I’ll be comparing the P-1 that I used to use regularly for 10 years and the new state-of-the-art P-700u.
Design: P-700u’s blaster-white outer shell appears more high-quality than the gold-plated P-1. However, perhaps because it is so multifunctional, all the knobs and jacks look a bit cluttered.
Sound quality: For the following comparisons, Accuphase DP-78 and the amps were connected via an XLR balanced cable (?), and headphones were connected unbalanced to maintain fair comparison.
- SACD (EMI, 1976 analog recording) En Saga (Sibelius) played by Karajan/Berlin Philharmonic: On P-1, gentle ripples of the string instruments at the beginning sounds as if they separated to two batches in left and right, wheres on P-700u the sound of the strings extend softly and more sounds are audible, making it sound really like rippling waves at the beach with a 360deg. surround sound. I was surprised by detailed and the fine sound.
- SACD (2007-8, digital recording) Symphony No. 5 (Mahler) played by Jansons/Amsterdam Royal concertgebouw: On P-1, the full orchestra of No. 5 sounds like a sharp batch that jumps into the years, but on P-700u it sounds like a vast wall of sound that closes in. For a moment I thought the sound pressure went down, but sound comes with an ambience, making the instruments sound much more realistic, and sound quality and quantity vastly increased to the point where I had the weird experience of not feeling like it was loud/noisy even with increased volume, which is to say, it sounded like it would at an orchestra hall.
Therefore, P-700u’s sound tendency is that it is very balanced and doesn’t add its own weird/unnecessary character, but reproduces all sounds evenly and maintains sound quality full of ambience, whereas I felt that sound tendency of P-1 lacks quality and quantity of sound, and has its own character, with sound stage that lacks a core, which it tries to make up for with higher sound pressure, resulting in a batch-like, forced sound.
Ease of use: Electronic volume controller of P-700 has low torque and feels very empty compared to heavy feel of P-1. If possible, considering the price, I want the hardness and high quality of Accuphase products that seems to be engineered to a margin of error smaller than a strand of hair.
Functionality: P-700u is more than satisfactory as a headphone amp.
Overall: At this point, including the manufacturer’s unwillingness to compromise, P-700u is an amazing headphone amp--one of the best out there.