Ok...I've had a Supreme for a while now and have been curious about what the purpose of the gain switch is? Is this to power higher impedence headphones? What setting is considered the best for most headphones?

I had a pair of Sennheiser ministar ms100 headphones for 15 years+ until they were accidentally destroyed. These weren't a high-end headphone but they more than did the job and I had really liked them. The PX100 reminds me a lot of these headphones. About the same size and similar look except...

Hi, I'm looking into buying a new set of headphones. What in your opinion would give me the best bang for the $$$? A Total Airhead amp and Etymotic ER6 combo or a Etymotic ER4p by itself (can't afford an amp if I buy the ER4p)? The TAH/ER6 combo is about the same price as the ER4p by...