Comfort, pristine and detailed sound quality

Low impedance, Low efficiency. Slightly recessed high treble.

I have been a happy owner of a pair of CD999s since 1991 so whilst in a major Sony store recently I took the opportunity to check out the current range. The flagship F1s made an immediate impression and they are without doubt the most accurate, most dynamic and transparent headphones that I have heard from Sony and way better than my CD999s. Like a few others who have submitted postings, I also felt on first listening that the bass was a tad shy but being so detailed I was prepared to live with that. Being very insensitive and a tough load for a cd player or preamp headphone amplifier I decided to build a dedicated 1 Watt class A low impedance amplifier to see what improvements I could yield. A week later and having spent another $500 in parts adn going completely overboard, my Class A headphone amp/buffer was completed and the results were unbelievable. The bass is now all there and it's as deep, detailed and as dynamic as I've ever heard from a pair of headphones. The mids and treble are so sweet and also clean and with such detail and dynamic agility that it makes it very difficult to go back to listening to speakers. I think I have conclusively proved that these headphones whilst useable from a wide range of sources do really need a dedicated amplifier to get the very best out of them. Even many acclaimed commercial headphone amps will be struggling to deliver enough currents to maintain class A operation at even normal listening levels. The reason for being bass shy when plugged into the headphone socket of a preamp or cd player etc is no doubt due to impedance dipping at LF. Also, be aware that some generic headphone amps use DC blocking capacitors which when driving 12 ohms will roll off the low bass.

In summary, these headphones should be regarded more as small loudspeakers. The open air design with the assosiated low efficiency and impedance does not really lend itself to use with portables, CD/MD players etc..and although these do a comendable job with such devices there are several other headphones in the Sony range that do this far better and for less money. For critical monitoring and / or extended listening however, these are as good as it gets but it's not that cheap when you consider how much more you need to spend on a dedicated amplifier to make it all happen. I can now see why open air designs are still persisted with despite the associated drive problems. If properly partnered with a worthy headphone amplifier then the F1s can provide a level of performance that a sealed can design can only dream about.

Similar Products Used:

MDR CD999, Audio Technica ATH-8s