The new Leben CS600X vacuum tube integrated amplifier that is in for review has been getting run-in time in my vintage Altec A5 Voice of the Theatre loudspeakers based audio-visual system in the place normally occupied by my gracefully aging original Leben CS600.

I was impressed with what I was hearing from the new Leben CS600X with its new input / driver tube complement from the get-go, and it has been subtly improving since the "first light" of its vacuum tubes.

The Leben CS600X, like the CS600 before it, can use a variety of output tubes (a quad of 6L6GC and its variants, or a quad of the EL34), but my favorite by far in my CS600 has been the Sophia Electric EL34-ST, which are just magic in the CS600.

Eventually I'll get around to trying the Sophia Electric EL34-ST tubes in the new Leben CS600X, but for now I'll be doing evaluations with the stock vacuum tube complement.

The new CS600X has switched to using a pair of 12AU7A and a pair of 12BH7A as inputs / drivers instead of a quad of 6CS7 tubes like the CS600, as the 6CS7 tubes are no longer manufactured and NOS stocks are being depleted, which is the reason for the switch to new vacuum tube complement.

I've been curious as to what brand of tubes come in the new Leben CS600X integrated amplifier, so I thought it was time to pop off the bonnet and take a look inside. 

There's six Phillips screws that hold the top cover in place, and unlike the Allen screws in my original CS600, they are very tastefully gold-plated - they look nice!

I removed the six screws and removed the top cover to take a look inside.

Inside the new CS600X looks just like the CS600 that I know & love and have been enjoying for over a decade now, with the exception of the vacuum tube complement.

The power tubes are the Electro-Harmonix EL34EH, which I'm not very familiar with, but which I hear good reports from the wild about. I can't fault their performance in the Leben CS600X, it sounds superb!

It will be interesting to compare them to my Sophia Electric EL34-ST tubes at some future point.

The slow turn-on tube is a classy looking Raytheon 6CJ3.

The 12BH7 used in the new CS600X is the JJ 12BH7-A.

The 12AU7 tube used in the new Leben CS600X is the JJ ECC802-S / 12AU7.

Just In: This tube complement sounds really nice, but here's something to look forward to. Just as I was finishing the sentence above, I got a message from Sue at Sophia Electric and they are going to send a quad of their Sophia Electric EL34-ST and a pair of their Sophia Electric 12AU7 tubes to try in the new Leben CS600X (they don't make a 12BH7), so that is really exciting - thank you so much, Sue! 

I'm looking forward to giving the Sophia Electric 12AU7 a listen in the new Leben CS600X, and of course you already know the Sophia Electric EL34-ST is my all-time favorite tube in my original Leben CS600, so it'll be fun to give it a listen in the new Leben CS600X as well.

So there you have it, a peek into the inside of the new Leben CS600X, with same Leben quality as the original Leben CS600, along with its new tube complement of the Electro-Harmonix EL34EH power tubes, the Raytheon 6CJ3 slow turn-on tube to extend the life of the other tubes, and the JJ 12BH7-A & JJ ECC802-S / 12AU7 as inputs / drivers.

I'll look forward to telling you more about the new Leben CS600X in future blog posts here at Jeff's Place (and its upcoming feature review article in Positive Feedback).

I'll also looking forward to telling you more about the Sophia Electric 12AU7 and EL34-ST vacuum tubes that are on the way now!

Stay tuned, I'll have much more to say about the Leben CS600X and the Sophia Electric vacuum tubes as I work towards the feature review at Positive Feedback.

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