Wow, I am amazed at the amount of people writing to me and asking me about the new Leben CS600X that just arrived here at Jeff's Place, and how it compares to my original CS600 - there's a lot of you Leben fans out there!

I had been planning on writing a "listening impressions" update on the new CS600X as soon as it accumulated a couple of hundred hours of run-in time, but due to popular demand, and the fact that it is sounding so good already - even with much less that a hundred hours on it - that I thought I would provide some brief preliminary listening impressions so I don't keep all you Leben fans out there in suspense.

I haven't popped the lid on the CS600X to see what brand of tubes it has in it yet, but whatever they are they sound great!

I've been listening to some very good CDs that Peter Qvortrup (Audio Note UK) gave me while I was visiting with him in Brighton, England (more on those in a future post), and video sound from my video sources, but no vinyl - I just haven't got there yet.

I really like the new input / driver combination of 12AU7A and 12BH7A vacuum tubes in the CS600X, they give the music additional warmth, color, and body - just better overall tone all around - compared to the previous NOS 6CS7 tubes Leben used in the CS600, and it gives CS600X owners even more options for mixing & matching tubes to their hearts' content.

I like the overall tone of the new CS600X even better than my CS600, and that's saying quite a lot, as I'm a huge fan of my original Leben CS600!

However, depending on your tastes, you may prefer the original CS600's tonal balance, and there's a quick & easy coupling capacitor mod that some owners are doing to their new CS600Xs to make it sound more clear and crisp like the original CS600.  

There are four coupling caps that connect the 12BH7A driver tubes to the EL34 (or other) output tubes, and the music signal goes directly through these capacitors, so their size and type has a lot of influence on the overall sound you hear from the amp.

The coupling cap mod substitutes polypropylene film capacitors (above) made by ASC Capacitors (1.0 uF ASC X335) for the stock 1.4uF film capacitors made by Harbor Electronics that are used in the original CS600 as well as the new CS600X.

The combination of the smaller and higher quality coupling capacitors are reported to give a clearer and crisper overall presentation, with the standard larger coupling capacitors giving a sweeter, warmer, and more classically "tube-like" presentation. 

From my coupling capacitor adventures with my Almarro A205A EL84 integrated amplifier, I can tell you that both varying the size and the type of the coupling capacitor makes a substantial difference in sound.

In my Almarro I preferred a larger value of coupling capacitor because it gave a bit more warmth, color, and body in the midrange, and of course whether it is polypropylene or paper-in-oil makes a big difference too, and in the case of the Almarro I'm also using paper-in-oil caps for their luxurious sound quality. 

I'm always up for a little cap-swapping adventure, but I like the way the new CS600X sounds so much that I don't think I'm going to install the smaller 1.0 uF caps, as that would tend to make things a little leaner sounding in the midrange, based on what I experienced with my Almarro. But we'll see, maybe I'll try the coupling cap mods just for fun.

What I might also try is replacing the coupling caps in my original CS600, and try putting in some nice 1.4 uF paper-in-oil caps, and see if I can't get it sounding more like the new warmer and richer sounding CS600X! 

I'll have to pop the bottom plate off the Leben and see how much room there is to work with, as that could determine what kind of coupling caps can be used, as the paper-in-oil caps tend to run pretty large.

But enough about coupling caps, and please don't be distracted by all this coupling cap talk, if you are considering a new Leben CS600X just go for it.

I think it is a really fine sounding amplifier, and for my tastes, an improvement over the original CS600. I can't imagine anyone being disappointed with the new Leben CS600X!

I'll be writing lots more about the new Leben CS600X - and in much greater detail - in the future, so please wait for it!

As always, thanks for stopping by, and may the tone be with you!