I have owned the Leben CS600 and Harbeth M30 combo for over 3 years, had a lot of fun tube rolling (I also own the Leben RS30EQ Phono) and have tried most of the variants of 6l6s, el34s, KT tubes, of different brands, NOS or new. I think I have now come to the end of my quest with KT120 which had just burn in for 200 hours - this is as good as a major component upgrade. Now I realize the leben was actually under powered to drive the m30s fully (I listen to classical music mostly in a small 12sqm listening room, I listen quite loud). Recently I start to enjoy listening to rock music in this system, not before. I would seriously recommend anyone with my same combo to give these tubes a try.
Leben CS600 Owners - Help
I have recently become a happy owner of CS600. I will write another post about my overall impression of its sound, but there is one minor issue. There is a very subtle hum coming out of the transformer. It does not interfere with music listening, but I can still hear it from the listening position when the music stops and the room is quiet without AC or other ambient noise. Using the Decibel app on iPhone, I tried to measure the sound level. It is not detectable from the listening position. When I place the iPhone just an inch above the top grill of the amp, the sound level goes up from 55 dB (ambient level) to about 68-9 dB. Should I call it 15 dB increase or just a noise at 69dB?
I am just wondering if this is an expected level of transformer hum for a normal CS600. Can any owner of CS600 try it for yourself and confirm? Much appreciated.
I am just wondering if this is an expected level of transformer hum for a normal CS600. Can any owner of CS600 try it for yourself and confirm? Much appreciated.