In my experience with the HD800 (again using this for convenience of example), it's much more than just a matter of one flavor or another, like wanting a warmer sound or a drier one. I've experienced a genuine improvement in performance when moving to certain amps --- what is commonly referred to as "scalability."

For instance driving the HD800 out of a Beta 22 or Objective 2 just sounds worse to me in most areas than driving it out of a Vali or SPL Phonitor. Which in turn don't sound as good as a Liquid Glass or Zana Deux SE. The most common give-away to me that someone isn't "driving the HD800 to its full potential" is when they complain about a weak bottom end response. When "properly driven" (ie. when the transducer is being controlled well) the HD800 actually has a very hard-hitting and visceral bottom end. This isn't the same to me as just pairing it with a mushier, warmer amp which is more a matter of masking sonic flaws. Rather, the actual transducer subjectively comes alive as it were. The best common-place analogy I've seen is like a flat soda compared to a fresh one.

Keep in mind though it's only the case with some transducers and not others. That's why the whole scalability descriptor was invented, as people realized some headphones have more potential for improvement than others. It goes beyond merely driving the headphones to the proper volume, and experience tells me this isn't BS. Overused by overly defensive people, sure. But not audiophile la la land magical thinking.

the HD800 bass is like a queef - always late and poorly timed.  i've had a difficult time getting the sub-bass and bass freqs to integrate well with sand amps.  it needs more mid-bass or less sub-bass.  with my ears/gears, the best i've heard the Senss was the QRV-08 = "low powered" for sand.   

I'm curious what pirates think of phrases like these that are constantly used to shut down "lesser" amps. As far as I'm concerned, an amp's #1 goal is to get your headphone to listening levels. Beyond that, picking out your favorite is a matter of budget, pairing, distortion, noise, or anything else coloring the analog signal.

Bonus question: what's the point in having gobs and gobs of overhead power? Is there a legitimate reason why HF is so hung up on "more power = better"?

First off, haven't read the contributions to the thread yet so forgive me if I gloss over anyone's points.  This is just my thought and experience on the matter.

This has been discussed ad nauseum here and elsewhere but NO, just no.  Big dynamic sings (both in volume and articulation of speed/transients), micro detail retrieval, ability to essentially grip the driver like its bitch and step out of the way of the recording material. 

The problem is the few oversimplified metrics used by some and limiting performance observed over a small static unit of time.  This is not how we listen to music either live or with headphones or whatever.  To give an automotive analogy, there are those that would have you beleive that you can take a 2000lb Suzuki Swift, strip the interior, put bigger tires and better compound on it, better brakes, and drop in a Corvette LS crate motor making 600-700hp will get you the same benchmarks from 0-60, 70-0, lateral g, 1/4 mile as a McLaren P1.  They could be right in that narrow scope, but on the track the P1 will rip the Suzuki's face off when comparing lap times (how it all comes together rather than dissected).  The problem is audio has been largely content to rely solely on benchmarks and rely on subjectivity for track times largely due to the arrogance of a few who believe science stops when we 'feel' we know it all already because it makes us comfortable to not have to worry about spending money or upgrading.  This is the opposite but same psychological bias that others who spend an extra couple grand on a shinier chassis for an amp have.  Occam's razor tends to cut both ways.

As for dynamic overhead.  I hate to link anything as authoritative from PS Audio so I'm not, but an interesting take on the question was discussed here:

http://www.pstracks.com/pauls-posts/music-math/9706/

http://www.pstracks.com/pauls-posts/riding-crest/9694/

The importance of subjective listening on verifying objective measurements (seems our counter-revolution has had an impact on even the most unlikely converts):

http://benchmarkmedia.com/blogs/news/12838141-headphone-amplifiers-specifications-are-only-part-of-the-story?utm_source=iContact&utm_campaign=5c39d4c702-Weekly_Application_Notes3_12_2014&utm_medium=email&utm_term=0_e28f43b8aa-5c39d4c702-125356205
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As for getting out the way of recorded material, IME a properly executed SET valve amp does better than 98% of all the sand/transistor based amps I& #039;ve heard.  Their topology is often more wire with gain when one looks at the relatively simple topologies employed by comparison.  The fact that certain measures of distortion are higher yet well below the threshold of the transducer's own set speaks volumes to the significance of chasing decimals and zeros by injecting feedback.  To my ears, this has often resulted in what is akin to killing a cancer patient with chemotherapy.  The cure can often times be worse than the disease.
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Also, for those (one person in particular) that think dynamic range only applies to one metric in musical theory, they would be wrong to apply that thinking to measured and observed performance.  Dynamicism is an adjective that can be applied to any metric describing the extreme range of performance of any said metric (volume, transient speed, etc.). 

For instance driving the HD800 out of a Beta 22 or Objective 2 just sounds worse to me in most areas than driving it out of a Vali or SPL Phonitor. Which in turn don't sound as good as a Liquid Glass or Zana Deux SE. The most common give-away to me that someone isn't "driving the HD800 to its full potential" is when they complain about a weak bottom end response. When "properly driven" (ie. when the transducer is being controlled well) the HD800 actually has a very hard-hitting and visceral bottom end. This isn't the same to me as just pairing it with a mushier, warmer amp which is more a matter of masking sonic flaws. Rather, the actual transducer subjectively comes alive as it were. The best common-place analogy I've seen is like a flat soda compared to a fresh one.

I don't know.. I've never heard the bass of the HD 800 as lacking in carbonation (as it were) from even a dinky O2.

My main complaint with the HD 800 is moreso its treble, which has a tendency to misbehave even on some of the most acclaimed pairings. Amp-to-amp, I have generally observed the HD 800 to have the same great strengths and same few weaknesses. This hasn't changed since my first encounter with them in 2010.

The problem is audio has been largely content to rely solely on benchmarks and rely on subjectivity for track times largely due to the arrogance of a few who believe science stops when we 'feel' we know it all already because it makes us comfortable to not have to worry about spending money or upgrading.  This is the opposite but same psychological bias that others who spend an extra couple grand on a shinier chassis for an amp have.

This is a pretty succinct quote, but I wouldn't categorize either camp as necessarily being expedient to circumstance. I would certainly consider myself biased to the former camp but if you asked me in 2009 I would have sided to the latter (participation in a well-executed DBT really changed things). I would agree that either psychological slant affects perceptions.

My take: a well-executed SET amp will offer equivalent linearity and performance to a proper solid state design, but do it with pretty lights.

I don't know.. I've never heard the bass of the HD 800 as lacking in carbonation (as it were) from even a dinky O2.

My main complaint with the HD 800 is moreso its treble, which has a tendency to misbehave even on some of the most acclaimed pairings. Amp-to-amp, I have generally observed the HD 800 to have the same great strengths and same few weaknesses. This hasn't changed since my first encounter with them in 2010.

Ah but there-in lies the fix. Bring the bass to life, overall volume can be dropped, and that piercing treble (as some call it) is no longer. It's not just an EQ fix either. The change to the bass is more than just volume. I notice this easily with the M-Stage vs higher end amps I like. The M-Stage puts out a meager 200mW @ 300ohm and while someone will surely say that is plenty to make HD800s loud I don't know if it's really enough for the entire spectrum.

What about that gigantic impedance spike at ~100Hz, what does that do to the amp-headphone relationship?

What about that gigantic impedance spike at ~100Hz, what does that do to the amp-headphone relationship?

It means around 100Hz even less power/current is needed than around 1kHz, 4x less power (2x less current) actually so makes it much easier to drive as most energy in music is concentrated in the lows.


It also means, when driven from say a 120Ohm output resistance amp you will get about 1 dB more bass and 0.5dB more upper treble due to voltage division and as the headphone is 300 Ohm.
1dB more bass is just audible.

The damping current doesn't even change that much (EMF/300 or EMF/420) just 0.3x less damping.
The damping factor with a low output R amp is around 3000 and of the 120Ohm amp is around 2.5.
Damping factor may differ a factor 1000 but there is NOT much difference in actual damping current, a factor 1.4.

Of course this doesn't explain what is heard by some and that's the beauty of this hobby.
There is 'room' for various views with plenty of headroom for beautiful theories.

Audio = electronics, mechanics, acoustics, perception... not merely one of them.
They are difficult to separate them completely as all aspects influence each other.
All of them hold some surprises in store but think (I am biased) that the electronics part of it is 'best known/quantifiable' though those with less to no electronics knowledge will surely disagree for lots of reasons.