I am not able to compare headphone to headphone without amp & source - they are just silent theirselves

In any case, we need some device to plug headphone in. Probably there is some wide known and only reference source for headphones comparisons? Sorry, I never heard about it. On the other hand, I know that amp to headphone matching is must for top notch rigs. I also know that HD650 and W5000 have different requirements to the amps. Thus I can only compare them in a whole rigs, otherwise I will compare their tolerance to the unmatched amps.
I agree that it would be nice to have some base for comparison. But I do not think there is any ultimate source which drives any can with excellence. The only valid approach I see is to set equal $$ amount spent to the whole rig. Then we will have some kind of valid discussion, like:
- Man, if you are limited to $2000, then W5000 plus X amp is the winning combo.
- But if you have one more grand to spare then go with HD650 recabled with Y and amped by Z.