Pioneer A-27 Headphone Optimization

[audiosceptic]

I bought a Pioneer A-27 Integrated Amp a few months ago and sent it to Hamad at Amplifier Surgeries to have it rebuilt. I and others here have had Hamad do wonderful work on Pioneer M-22 amps.

Since I will be using this amp sometimes with headphones (but mainly driving my Sound Lab speakers) I asked Hamad to check the headphone circuit to make sure it is optimized as much as possible. He indicated he would and asked what headphones I was using so he could "check to see if the resistor network can be matched for my headphones".

The hard part is I don't know which headphone to have this amp optimized for. The dynamic headphones I use are the LCD-2, HE6 and HD800. I like them all but they have quite different impedance and sensitivity ratings. I'm leaning to have it optimized for the HD800 but was wondering what others thoughts were on this.

Here is a picture of my amp: