I've recently been using my specialty SS amp at the speaker taps and comparing it with the Pioneer SX-650. It outputs 25 watts per channel compared to the SX-650 at 35 watts per channel. The 25 watts sounds more musical and integrated than the 35 watts which in comparison at times sounds edgy and as if it's outputting more power than needed. Just wondering what the outside power limit for the HE-500 may be? I know the good doctor gave 1 watt as the minimal requirement for the HE-500 but I have not come across a number for the top limit. Based on experience I personally do not think 1 watt is anywhere near enough, so the true minimal number must be higher. As to the upper limit it's open for debate - I'm still experimenting, but beginning to feel it may be somewhere between 20 and 35 watts. What do ya think?
Surprisingly, my other ortho (a Yamaha HP-2 from the late 1970s) clearly specifies minimal and upper power requirements as 3 watts to 10 watts. That's for an ortho with probably half the driver size of a Hifiman. Not sure whether ortho power requirements have become more efficient (probably), but with it's size I think the HE-500 true power requirement for best performance would be higher than 3 to 10 watts, probably 5 to 30 watts.
Phew ... I finally made myself a new HE-500 cable using the extra connectors, yippee what fun soldering that inner pin. I finally came up with an adequate solution for not filling the whole cup with one big gob of solder .. yikes! I threaded a double-folded piece of electrical tape under the stem and then soldered the active wire on top of the stem. That way the solder stayed away from the ground wire connector. Just from doing this my confidence is really up and I feel I could now make as many Hifiman cables as I want, . My new cable is giving the Hifiman silver cable a run for its money - very nice detail.