Is Amp synergy/pairing real?

Synergy could be the result of colorations from output impedance and specific distortion characteristics, but most of the time when people mention synergy, I immediately think placebo.

I think it's differences in impedance matching as well as tube coloration.  Impedance factor greatly impacts the headphone's sound output, and different people have different preferences in what they consider their neutral.

Quote:

Originally Posted by DivergeUnify 

So these colorations should be persistent, no matter what headphone you stick through it, right?   Its not just a matter of finding a beautiful woman you have chemistry with like so many on this forum make it sound?

Not necessarily. Amps will change from headphone to headphone depending on impedance. Low impedances are harder for the amps to provide with clean power, so they'll distort more. And if the amp has high output impedance, that's more likely to color low impedances than high impedances, and can increase distortion further due to lower electrical damping factor (potentially allowing the driver to ring, keep playing a note after it's supposed to stop). So low impedance loads are going to make the differences between amps more obvious, if there are differences. With high impedances it's less of a problem, and any competent amp should remain neutral.

Take for example two amps, both with ~0 ohm output impedance. One has 0.5% THD with 32 ohm loads and 0.05% with 300 ohm loads. The other has 0.05% THD with 32 ohms and 0.005% THD with 300 ohms. That's a potentially audible amount of THD on the first amp with low impedances, but the second isn't likely to be heard. They'll both sound the same with 300 ohms, more or less.

It's looking that way to me. 

Yes. Filters generally are deliberate coloration. 

My personal preference is to look for a clean, uncolored amp, if I'm looking at solid state. That means a very low noise build, with appropriate output impedance, and enough power for my intended use. That's pretty much it. A wire with gain. It can be worth it to spend more than $250 to get a clean build, and enough power. But I do not think it is strictly necessary - the matrix m-stage, for instance, is pretty good on those counts. 

I do have a soft spot for tube amps as well, but I make no claims to neutrality for the majority of those. I like them because they are colored.

DACs don't connect to the headphones, just the amp. So the load they should expect is predictable and fairly standard. The only synergy there is, again, distortion and intentional coloration.

If you are running your headphones through your dac, it also has a amplifier in it. A pure dac would just have a line level output for an amp to use. 

In simplest terms use of the word "synergy" implies a result that is greater than the sum of its parts. There is no proposed mechanism for why this should occur and it is generally false. In practice, "synergy" is an overused hyperbole here on head-fi which should in most cases be replaced by "these components work together without causing any issues". Some people are (understandably) pleased about a satisfactory pairing of headphone to amp and recommend it to others. The more popular pairings gain clout and (ironically) it is the appearance of that clout which is closer to the meaning of synergy.