[flame]

Sorry i have few noob questions to ask, i tried to do a search, just couldn't find any info on it.

What is the difference between Headphone amp and home audio amp? Let's say if i want to power up a Sennheiser 650, with a good home audio amp, it will do the job? Or i still need a headphone amp? Is headphone amp completely different from home audio amp?

Also i have a Yamaha receiver at home instead of amp and pre-amp. Is it true it will not sound as good as amp and pre-amp setup? Again do i need a headphone amp for a receiver?

Lastly i have seen the HeadRoom web site, they have portable Airhead, it listed the frequency response is 20-20k. If i have a headphone that has frequency response from 8-35k, and with the Airhead amp, it will limit the full potential of the headphones?

Thanks in advance!

 

[Uncle Erik]

A headphone amp is, generally, different from a home amp. First, most speakers have a 4 or 8 ohm impedance, while headphones range from 32 to 600. Home amps will have an output impedance in line with speakers and headphone amps will be in line with those for headphones.

To clear up any confusion, impedance tells you how well power will transfer between the amp and the headphones. The close the numbers match, the more power goes from one to the other. From there, you can use the amount of power that gets through and the headphone's sensitivity to figure how loud they will get.

But not to get sidetracked, a home amp usually offers far more power than is necessary. Most headphones will do fine with 500mW, maybe a little more. That's half a watt, so if you hook up 100W to to them, you can cook a voice coil.

Home amps usually operate in class AB, as well. That's alright, but you'll really want to get into class A if you're listening to headphones. Speakers are one thing, but putting the driver 1 cm from your ear will show up any problems with the amp, the recording, your source, etc. Most home amps/receivers don't operate in class A since that's expensive (four figure territory) and throws off a lot of excess heat in the process. Since you're only looking for half a watt or so for a headphone amp, heat isn't going to be as bad and the parts aren't as expensive.

Your Yamaha receiver has a preamp, it's an integrated amp. There's a preamp section in there as well as a power amp section. Audiophiles usually use separate preamps and power amps, but separateness doesn't confer quality. A good circuit, parts and construction give quality. There are good integrated amps on the market.

Some receivers are good with headphones, some aren't. Since there are so many models, you're best off plugging in a pair of headphones and seeing if you like it. If you do, great. If not, get a headphone amp. Most receivers use a voltage dropping resistor off the power amp section to power the headphone jack. It'll be in class AB and not always the best sound quality.

As for the frequency range, 20Hz-20kHz is the generally accepted limit of human hearing. The Airhead probably does a little more on either side, but they only tested it to 20Hz-20kHz. Also, if you're listening to MP3, other compressed formats, or CDs, your range will be limited to 20Hz-20kHz, as those formats don't have frequencies outside that range. If you want more bandwidth, you'll need a turntable, SACD or reel-to-reel.

 

[flame]

Awesome!
Thanks for clearing things up for me Uncle Erik!