My impressions of HE-6 vs HD800 vs Stax SR-007

I've been happy with my Stax SR-007 (Omega 2 mk1) and KGSS amp for over 3 years now. I used to have a few dynamic headphones and amps, but I sold all of my dynamic headphones and most of my amps when I started using the SR-007. There was just no point in keeping the dynamic stuff because the SR-007 was much better.

I recently decided to check out a couple of new headphones - the HE-6 and the HD800 to see if stats really have some competition now.

I've had only limited time to listen to these new headphones, but here are my impressions:

1. The HE-6 is powered well by the headphones amp in the Benchmark DAC1 HDR which I use as my source. A comfortable listening level is achieved with the pot at the 12 o'clock position. This is with the internal jumpers set to 0dB of attenuation for the headphones amp. The DAC1 amp can provide 250mA of current, which seems sufficient. My Gilmore Lite, on the other hand, doesn't do very well with the HE-6. It can reach high volume, but it doesn't sound as good as the DAC1 with the HE-6 (the Gilmore Lite is lower power).
2. The HD800 works well with both the DAC1 headphones amp and the Gilmore Lite. I think I have a slight preference for the Gilmore Lite with these headphones, but the difference is very slight.
3. The HE-6 has a lusher but somewhat less detailed sound than the SR-007 and HD800.
4. The HE-6 has more bass "kick" than the other two.
5. Acoustic instruments sound best on the SR-007, then HD800, then HE-6. This hierarchy is quite noticeable when listening to piano, violin, trumpet, etc.
6. Close-miked female vocals sound slightly less intimate on the HE-6 than on the other two. They sound intimate on the HD800, but there's some tendency to approach sibilance sometimes. The SR-007 is again best on this.
7. The HD800 has a larger soundstage than the other two. The SR-007 is second, and the HE-6 is third.

Overall, the SR-007 is definitely ahead of the other two on my music. It really doesn't take long to figure this out - it's apparent pretty much right away when listening to orchestral classical music, for example. The HD800 is excellent and definitely better than any dynamic headphones that I heard 3 years ago, but it's just not quite as good as the SR-007, and the increased soundstage of the HD800 doesn't really make much of a difference since it still sounds like the soundstage of headphones.

From a purely technical point of view, I think the HE-6 are third in this comparison. However, if I could only keep two of these three, I would keep the SR-007 and the HE-6. The reason is that the HE-6 sounds quite different from the SR-007. The HE-6 adds some lushness and weight to the sound, so it's a nice complement to the SR-007 which is more neutral. Basically, there's something that's very pleasant about the sound of the HE-6 even if it doesn't get things quite right (such as the sound of acoustic instruments which is not 100% right, but not at all bad).

These are my impressions so far. I'll try the HE-6 and HD800 on a couple of higher-end balanced amps in the future (they're both balanced headphones). I don't really expect much difference when changing amps because I feel that my HE-6 and HD800 are already amped quite well by the DAC1 and the Gilmore Lite, respectively.

Bottom line: the Stax SR-007 keeps its position at the top, but there are now non-electrostatics that come closer than ever before. Fortunately, there's a new high-end electrostatic coming: the Stax C32.

Quote:

Originally Posted by moodyrn 

Your impressions of the he-6 sounds like most people impressions when they first tried them without proper amplification. You are not coming anywhere close to powering the he-6 to their potential. There are very few and I mean very few headphone amps that can power them. Most people power them on speaker amps. You need at least 6 full watts at 50 ohms to power them adequately. The sound does change significantly when you amp them properly. There are headphone amps that can get them to a loud volume, but we all know that loud volume and properly driven are two different things. These things need k1000 type power. I've never seen a headphone this hard to drive which is a huge minus for most people. But very rewarding once you drive them properly. In the he-6 thread people are urged not to even bother with them if you don't have the proper juice to drive them.

I don't see how this is compatible with the sensitivity of the HE-6 and fundamental electric laws.

The HE-6 produces 83.5dB at 1mW and it's 50Ohm, so if you feed it 0.224V you will get 83.5dB of SPL.

The DAC1 is capable of providing a current of 0.250A, which is 12.5V and 3.125W at 50Ohm. 12.5V gives you 35dB of gain compared to 0.224V, so with the DAC1 the HE-6 can play at 118.5dB with the full power that you get from Ohm's Law (3.125W).  

118.5dB is way higher than the volume that you need even for peaks. I would conclude based on the above that the DAC1 has enough power to drive the HE-6 to their full capabilities.

The 6W @ 50Ohm that you mentioned would produce 17.3V which would result in a gain of 37.8dB instead of the 35dB that you get with the DAC1, so if the amp was feeding that to the HE-6, they would play at 121.3dB instead of 118.5dB - completely irrelevant...

The reality is that even the 3.125W that the DAC1 can provide won't be used fully because the voltage (i.e. volume) would be too high based on the sensitivity of the HE-6 and the basic electric laws.

If someone can show that I'm missing something here, then I'd be very interested in hearing that.

Quote:

Originally Posted by hawkhead 

Theory is all very well but my ears do the listening

 

my Woo WA6SE could make them loud enough but connecting them to a 75wpc speaker amp made an enormous difference - it was like a different headphone

 

My current amp provided further improvements though not to the same extent

The WA6SE has a maximum power output of 1W (same as Gilmore Lite), while the DAC1 headphones amp is over 3W. However, even 1W should be sufficient based on the math. Assuming the impedance of the headphones is fixed (is that a correct assumption?), increasing the power (wattage) just increases the voltage and volume beyond reasonable levels.

This is why I'm also a little baffled by the fact that the GLite doesn't drive the HE-6 well, while the DAC1 does it much better. My theory is that even though the GLite and WA6SE are rated at 1W, they don't perform well at that power level.

Again, if there's something I'm missing here, I'd love to know what it is. I think this is an interesting topic that goes to the heart of the question of why some amps sound better with "hard to drive" headphones even though the specs and physics don't seem to explain it. Either the specs are wrong or I don't know enough physics (or both)...

Quote:

Originally Posted by hawkhead 

It does not seem to be just about watts - these planar's seem to love current

It's the same thing... Divide power (watts) by resistance (ohms), take the square root of the result, and you get the current (amperes). Providing current and power go hand-in-hand. If an amplifier can't drive the amperes, it won't drive the watts either and vice versa.

I see only 4 potential explanations:

1. The HE-6 sensitivity isn't really 83.5dB at 50Ohm and 1mW.
2. The HE-6 impedance isn't flat, and it goes under 50Ohm.
3. Amps with a rating of 1W that we tried don't actually perform well at power levels anywhere near that.
4. I'm missing some chunk of physics here.

Quote:

Originally Posted by Blackmore 

Maybe if you have tried them from out of speaker outputs, just for fun, you may got an differ impressions.

 

 

Again, if there's something I'm missing here, I'd love to know what it is. I think this is an interesting topic that goes to the heart of the question of why some amps sound better with "hard to drive" headphones even though the specs and physics don't seem to explain it. Either the specs are wrong or I don't know enough physics (or both)...

Maybe, but there has to be an electrical explanation - it can't be magic (see the options I listed above). As I mentioned, I can't even explain why the DAC1 which is 3W performs better with the HE-6 than the GLite which is 1W since 1W should be sufficient based on the math.

I guess the problem might be that when the spec sheets of amps say something like "max power output: 1W", it doesn't mean much without specifying the load resistance. For example, a headphones amp which can provide 1W into 200Ohm may not be able to provide anywhere near 1W into 50Ohm.

On the other hand, a speaker amp which can provide 50W into 8Ohm obviously has no problem with 50Ohm...

Basically, I think that if your amp can drive half a watt into 50Ohm, you're fine with the HE-6. This gives 5V which results in a peak volume of 110.5dB on the HE-6 based on its sensitivity.

I'm even ignoring the gain from the source here - in reality the volume will actually be even higher.

My understanding is that the DAC1 headphones amp can provide well over 1W into 50Ohm based on its specs, so I don't see what I would gain from going to a speakers amp.

Based on my listening, the GLite must not be able to provide enough power into 50Ohm. I don't know at what load it can do 1W - the specs don't say.

One of my pet peeves with manufacturers of audio equipment is that they rarely provide specs which are detailed-enough to be useful (so you don't really know what you're buying and can't really compare products effectively). Benchmark is one of very few exceptions. Also, some DIY projects such as the Beta 22 have good information.