My housing situation is currently in transition as my wife, daughter and I have moved in temporarily with my in-laws. For the next few weeks, I only have enough room for my B60 and an HRT iStreamer I recently acquired. I have Etymotic ER4S and ER6i IEMs. The ER6is are a lot more sensitive and designed for portables like my iPod, whereas the ER4s is designed to be used with amplification.
The B60's headphone section is dead quiet. I don't hear any hum or hiss through the ER4S at all. I can turn the volume all the way up with no source material playing, and absolutely nothing comes through. With the ER6i, I get a very feint hiss at about 99.9% volume.
Not only that, but it just sounds phenominal. Tone, texture, etc. I hate to call anything perfect, but I can't find a single fault whatsoever. My Rega DAC fed by my Apple TV Gen 1 sounds better than the iStreamer, but it should as the Rega costs 5 times what the iStreamer costs.
The ER4S are ruthlessly revealing IEMs. They've been called the most accurate headphones their are. If this is true, I'd pick up every flaw in the B60. I can't find any.
I know the BHA-1 is due out soon. If you're into headphones, I can't imagine anything sounding better. I take it the BHA-1's main advantage is it'll drive more difficult cans?