After my short time on this site I've begun to wonder... You put strong emphasis on headphone measurements, discuss the intricacies of acoustic design like various damping schemes and such. At the same time I can't help but to notice that the requirements on amplifier design are far less stringent. Don't get me wrong- I'm not a fan of O2 (again- not to be confused with Stax O2) sound and the lengthy ramblings of its designer. However next to the remarkable opus that are the headphone measurements (and insightful comments) I'd also like to see amplifier measurements with comments on topology and how these measurements translate into psychoacoustic terms. Correct me if I'm wrong, but aren't amplifier (and DAC) measurements vastly easier in terms of needed gear and repeatability? Surely there must be someone amongst our merry bunch who has access to high grade test equipment and is trustworthy enough to receive some gear for measuring?

Otherwise it seems a tad schizophrenic for a site that has the Pirates Booty section backed up by measurements and impressions to have selected other equipment almost solely by "it sounds good/bad to me" terms.

Distortion from amplifiers is at least a magnitude, and in the case of the ODAC, several magnitudes, less than that of transducers. These tiny amounts of distortion are less that what I feel humans can ear. The exception to this would be tube amps, and even then, probably only distortion at the extremes of the audio range, like the bass.

The ODAC and other similar op-amp chip based amps with high feedback are likely to slaughter everything else in terms of measurements. In terms of distortion and noise measurements, the ODAC will kill the Mjolnir. It will kill the Dynahi. It will most certainly kill or hybrid tube amps. I've found adding more feedback when with playing with various amps to result with better numbers but worse sound. You can swap out a cheap cap and the sound changes? Transformers. opamps, components with different characteristics beyond the audible range sound different? What gives?

That being said, amp measurements will be good will determine power and noise in various loads. It would be nice to know if an amp can be crossed off the list because it may be too noisy for a certain headphone, or doesn't meet advertised specs (power, Class A, etc.)

The point of the measurements here was always to try to correlate what we hear to what is measured. If we can't do that, measurements are useless.

 You can swap out a cheap cap and the sound changes? Transformers. opamps, components with different characteristics beyond the audible range sound different? What gives?

Do they still sound different DBT'd?

Correct me if I'm wrong, but aren't amplifier (and DAC) measurements vastly easier in terms of needed gear and repeatability?

Corrected, you are completely wrong here. 


We've been looking at doing this for some time and don't have the time or resources.  Tyll, on the other hand, get's paid to do this and has been trying to get something together for the past six months and it looks like currently he will have to settle on a compromised methodology.  This is even w/ the help Lord Jerkoff who had help from Lord Benchmark and others.  Thinking like this, as many do, is akin to thinking the digital domain is just '1's and '0's.  There is absolutely nothing more complex is the audio chain than what goes on in the digital side.  This is another case of how people often perceive things backwards and over simplistically.   

Yes, many do.  Unless you like to cherry pick your DBT's to support your perspective.  There are certain opamps and CAPs that are so different, if you can't DBT, you are actually deaf or the methodology or transducer you are using is horribly flawed.

I was referring to those which are already supposed to be below the threshold of audibility between each other . Ofcourse opamps and caps can vary radically in their specs.