Originally Posted by SilverEars
i would guess that HE-6 would be quite stable as long as you give it a amp with lots of wattage. It's efficiency is one of the lowest so it needs lots of power. I would suggest go for speaker amps with headphone out first as it's a cheap option(depends on what amp you get of course). I have a 2 channel Beta 22, and I am quite happy with the results.
Reason why I think HE-6 is stable is because it's impedance is purely resistive or should we say flat.
Speaker amps with headphone out ? The headphone out - single-ended or balanced - on my Taurus absolutely cremates the headphone stage on my Marantz PM6005, but I'm assuming you mean the speaker amp gives me the option of using the speaker taps to power the HE-6. Unless I read project86s review of the Taurus completely wrong, the Taurus has more than enough herbs for the HE-6. With 4.5W on tap, this isnt your Aunt May's headphone amp.
I put it up against at least half a dozen different amps I have here in the $1,000+ category and the TAURUS never once required a disclaimer. It was not outdone by the $1,500 Analog Design Labs Svetlana II single-ended triode amp with the super-permalloy output transformers. It stood its ground against the $1,000 Violectric V200 whose output stage sports eight transistors per channel. The $1,799 SPL Phonitor excelled in whiz-bang adjustability but was no match for the TAURUS in sound quality. The beastly $1,599 HiFiMAN EF-6 and the classic $3,000 Luxman P-1u could not dethrone the TAURUS—I preferred it to either of them in nearly all situations. And that's really they key phrase here—most situations. The TAURUS does a damn fine job across the board. While one amp or another may have a special synergy with a certain headphone, therefore becoming a better match than TAURUS in that one particular scenario, the TAURUS excels with just about everything. Even when it isn't the absolute top choice for a given headphone, you can be sure it's in the running, among the top two or three choices. That's not to call it a "jack of all trades, master of none" type device.... it definitely gets a fair share of first place trophies
Next I switched things up to the HiFiMAN HE-6 which is a headphone I've really struggled to enjoy. On the one hand I appreciate its resolution and clarity. On the other hand, I find it somewhat bright and at times downright unnatural. Part of the problem is the extremely low sensitivity—I'm not necessarily on board with the folks who demand huge monoblock speaker amps for the HE-6, but I will admit it needs a beefy (headphone) amp to do it justice. The TAURUS clearly seems up to the task.
This is the first time I felt the HE-6 worthy of being called a true flagship headphone. Up until now the best I had heard it perform was from the Violectric V200. In that scenario I felt like HE-6 and the less expensive HE-500 were different but roughly equal in performance. The TAURUS is the first amp I've heard allowing HE-6 to clearly surpass the more affordable sibling. They have most of the precision of the HD800 with more solidity and "punch" all around. Soundstage takes a considerable hit; this is the most expansive I've heard a planar magnetic design sound, yet it still falls short of the HD800 by a significant margin. That's just the character of the headphones and TAURUS isn't a miracle worker. Still, large orchestral works were satisfyingly grand in terms of space and scale, so I can't complain much.
The HE-500 doesn't seem to improve much when mated with the TAURUS—apparently the V200 already takes it about as far as it will go. But with the TAURUS in play, HE-6 has superior midrange articulation, better deep bass impact, and just sounds more effortless in general. Is it worth the price difference? That's subjective. For me, the answer has always been "no". Until now. I can totally see building a system around the HE-6 now that I've heard what it can really do.
I like the HE-6 a lot with both outputs. My contact at AURALiC says they prefer the BAL option, and I agree it sounds mighty good. Yet more often than not I find myself gravitating towards the STD output. I suppose this is one of those cases that comes down to individual preference. I'm glad HiFiMAN chose to include a balanced cable as well as the adapter for single ended use. It's win-win.