I just wrote this because it came to my mind after reading Kiteki's last post about having a proper amp.
The cheapest way is probably a Matrix M-Stage, a Schiit Asgard, or some other enty-level home amps. They start around $250, but can usually be had for significantly less in the amplification for sale part of this forum. The Ibasso Toucan is a large portable amp that is more or less comparable to these amps, but it is balanced. It is $229, but you have to reterminate the Sonys and then buy an adaptor to connect that plug with the Toucan's. The option below is the whole hog and is supposed to sound amazing.
HiFlight has the SA5000s and says they sound really good with great bass and imaging when they are run balanced through the Ibasso Toucan and Boomslang amp/DAC balanced combo. He disagrees with the commonly acknowledged "fact" that they don't have great bass, his view is that they really need a few hundred hours for the bass to develop fully. I have not heard his combo, so take this info with a grain of salt; however, HiFlight is a trusted Head-fier who helps many other Head-fiers. This whole combo certainly would not qualify as cheap, as the Toucan (amp) is $229, the Boomslang (the DAC) $219, and the interconnect between them is $39. That is completely ignoring the source (you need something with a digital out like a CD player or an Iriver H120/140 or the new QLS QA350 to utilize the DAC in the combo), the interconnect between that source and the Boomslang and the cost of reterminating the SA5000s to balanced (you could do it yourself). Oh, and if you terminate the headphones into a balanced four pin XLR plug (probably the cheapest and easiest), you need an adaptor in order to connect that to the Toucan's 6-pin Hirose plug, an other $39 at Ibasso.com.
That totals about $600, most likely a little more. I didn't write this to discourage anyone from going for this, I just write it to present an option that is good quality and actually transportable (think park, deserted library, hotel room, around the house, not airplane or bus becuae the phones are open.) I was going to try to build up to this combo, but because my order of the Sonys was cancelled twice by two different retailers, I think I am going to go a different direction now. I still think the Ibasso combo is cool, but that isn't really the point of this thread. I hope this helps anyone who was wondering about amping these phones.
The SA5000 need recabling not retermination in order to run balanced,they only have a three core cable.
