"Speaker amp designers typically tune their products for speakers, and pay only moderate attention to headphones. Obviously for economic reasons (smaller market), but also for technical reasons (much more variety of headphone behavior in terms of impedance compared to speakers) and due to a lack of understanding of the headphone aficionado market.The CS600 is just an example of this trade off. It is definitely not marketed/sold as a headphone amp - although it performs very nicely with a very minor adjustment."
An interesting post on a site devoted to said "headphone aficionados".
The fact is that there are many more audiophiles that listen to loudspeakers than those that listen to headphones. I did not purchase the CS-600 to listen to cans, very rarely plug a headphone into the output jack of the Leben, and have commented before that the CS-600 is a wonderful amp when paired with synergistic speakers, but this site is specific to headphone users and prospective buyers of Leben gear should know as many pertinent facts as they can before plunking down their hard-earned dollars. There are hundreds of comments on this site regarding the use of a Leben integrated and headphones, the vast majority being of a positive nature. There are also several posts commenting on the "low level hum" that is experienced by many. Some of those making such comments rule out the usage of a Leben as a headphone amplifier because to them, listening to headphones with the amp humming away in the background is unacceptable.
My question would be, if this so called fix is a "minor adjustment", why is it not performed at the factory before the unit is unleashed on an unsuspecting public? It is not a QC issue. The problem is well known, has existed for some time, and it remains unresolved.
Most if not all tube amps have a slight hum if you turn up the volume with no input
Who listens to nothing? If a perfectly black background is all that is important then get a SS amp
And under that condition with no input most SS amps will exhibit a slight hum or hiss too.
As a Engineer I would like to know what this simple fix is?