Got a really great amplifier and want to mate a great pair of headphones to it? Make your own resistor box to eliminate that little bit of underlying hum and save your money for something else.
Just curious why you want to attenuate the headphones? There is a benefit and a negative here.
Benefit is a higher load and therefore an easier load on the amp. This should theoretically help the amp with damping although headphones have much higher impedance compared to speakers so it shouldn’t be an issue with any halfway decent amp. An amp seeing a higher impedance will theoretically produce less distortion as well (although this difference shouldn’t be audible with any decently designed amplifier).
Negatives are a lower power output from the amp in addition to lower headroom. The lower headroom would also push the amp further out of it’s linear range resulting in more distortion.
Sorry i was not clear, we are talking about full powered speaker amplifiers NOT headphone amps. Attenuating the amp helps reduce the high noise floor so that it is palatable enough for you to use headphones on it.
So, I was a reading an older really long thread over at head-fi about running your headphones off of speaker amps. I have one of those little adaptor boxes for my own HE6se and it works great for that particular pair. Not so great on some others. Long story short, my understanding is that by building the box appropriate to a particular set of headphones based on their specs you can reduce the noise floor and make using the speaker amp a much more enjoyable prospect. I want to try this eventually for another pair and see how it works myself. I looked into a few of the more custom made adaptor boxes and they can be several hundred dollars. This seems to me like a more affordable option to at least try and play with.
Ignorant little old me here but… is this to create a network to make sure the Thevenin impedance matches the headphones for optimum power transfer? Additionally, why not do the double diode trick instead?