I was so happy to read John Marks' take on the Leben CS600 he heard at the FSI show. The fact that both JA & JM liked it so much makes me feel lucky that I got this gem as my 1st audio purchase. I don't think it'll be leaving my system, ever.
I believe at the FSI, they were running some EL34 tubes on the Leben... I wonder what tubes they were using? I was using Winged C EL34s for a while, and the limitations of the Leben that Marks notes in his report re: bass extension & dynamics - became very apparent. Also, I heard tube glare & kind of grainy breakage at loud volumes. I was considering using NOS tubes, like the Mullards, but purchased a quad of just-released Genalex "Gold Lion" KT-77 reissues. The improvement is significant. Better balance & poise in the music, and they don't fray at the extremities of loud passages like the Winged C EL-34s. The depth of soundfield is, well, deeper. Texturally more complex, too. The tonal lustre of music w/ the Gold Lion reissues is very golden in hue, very lovely, like the EL34s, especially in the midrange, but the KT77s bring a great balance and control in the sonic presentation. Winged C EL34s were too forward & extroverted in that regard, and a lot of the times, the bass would become flabby and fly away. I feel like these KT77s are a happy compromise between the EL34s and the 6L6s.. and these reissues are sweet modern tubes, a fantastic match for the Leben CS600, and after listening with these, I no longer have the particular desire to seek NOS tubes. Just my 2 cents about anyone considering the Leben CS600 after reading JM's column this month...
P.S. - I'd love to see a Tubes section in this forum! 
I know it will be DUP's favorite section...
I was so happy to read John Marks' take on the Leben CS600 he heard at the FSI show. The fact that both JA & JM liked it so much makes me feel lucky that I got this gem as my 1st audio purchase. I don't think it'll be leaving my system, ever.
I believe at the FSI, they were running some EL34 tubes on the Leben... I wonder what tubes they were using? I was using Winged C EL34s for a while, and the limitations of the Leben that Marks notes in his report re: bass extension & dynamics - became very apparent. Also, I heard tube glare & kind of grainy breakage at loud volumes. I was considering using NOS tubes, like the Mullards, but purchased a quad of just-released Genalex "Gold Lion" KT-77 reissues. The improvement is significant. Better balance & poise in the music, and they don't fray at the extremities of loud passages like the Winged C EL-34s. The depth of soundfield is, well, deeper. Texturally more complex, too. The tonal lustre of music w/ the Gold Lion reissues is very golden in hue, very lovely, like the EL34s, especially in the midrange, but the KT77s bring a great balance and control in the sonic presentation. Winged C EL34s were too forward & extroverted in that regard, and a lot of the times, the bass would become flabby and fly away. I feel like these KT77s are a happy compromise between the EL34s and the 6L6s.. and these reissues are sweet modern tubes, a fantastic match for the Leben CS600, and after listening with these, I no longer have the particular desire to seek NOS tubes. Just my 2 cents about anyone considering the Leben CS600 after reading JM's column this month...
P.S. - I'd love to see a Tubes section in this forum!
I know it will be DUP's favorite section...