I always get a little bit excited when there's a knock on the door and its the friendly FedEx delivery person dropping off a new piece of hifi kit to write about for you here at Jeff's Place and Positive Feedback. 

This time FedEx dropped off a hefty little parcel from our friends Yoshi Hontani and Elia Hontani at MuSon Pro in Japan (the Leben exporters in Japan), containing a Leben Hi-Fi Stereo Company CS-300F integrated amplifier.

Like all Leben products the CS-300F integrated amplifier is finely crafted and aesthetically pleasing to behold.

The power output of the Leben CS-300XS and CS-300F are identical - 15 watts, as are their price of $3995 USD.

Visibly, the CS-300XS and CS-300F are almost identical, except that Hyodo-san fitted the CS-300F with a subtly purple "royalty" top cover to distinguish between the two models.

It's a little hard to see in the photos, as the purple coloration of the top-plate is subtle, and I didn't even notice it until Yoshi-san pointed it out to me. 

The Leben CS-300F integrated amplifier is a little different in concept from the CS-300XS amplifier that it shares a chassis with. So what's the difference?

Instead of the CS-300XS's more typical EL84 pentode power tubes and 12AX7A drivers, the CS-300F utilizes NOS GE JAN 6197 pentode power tubes and 17EW8 drivers.

The NOS GE JAN 6197 power tubes and 17EW8 drivers - as far as I can determine - have never been used in a hifi amplifier before.

Size-wise the 6197 is a diminutive vacuum tube even in comparison to the already svelte EL84. The 6197 looks like like a slightly taller driver tube rather than a power tube.

According to The National Valve Museum "The 6197 is a special quality power pentode that was designed for operation for long periods either full on or at cut-off. The applications were within digital computers of the 1950s. Also on the data-sheet is a specification for operation as a Class A amplifier."

The RCA Receiving Tube Manual says the 17EW8 is high-mu twin triode for use in "... rf-amplifier and oscillator-mixing circuits in FM and AM radio receivers."

While the 6197 power tubes and 17EW8 drivers are not current production vacuum tubes, they do appear to be plentiful in my brief survey of websites selling vacuum tubes.

Prices of 6197 tubes are very reasonable, being about $3 USD to $7 USD per tube depending on the seller. The 17EW8 driver tubes sell for between $5 USD and $10 USD depending on the seller. That's a good buy for high-quality NOS vacuum tubes, and if you are Leben CS-300F owner it might be wise to purchase a few sets of tubes with the future in mind.

As Yoshi-san related it to me, Hyodo-san wanted to do something new design-wise, he was impressed with the performance of the NOS GE JAN 6197 power tubes and 17EW8 drivers, so he bought up a large stock of them for use in the Leben CS-300F.

Yoshi-san told me that, "The sound characteristic is different between two models. The CS-300XS is more classically tube-like and CS-300F is more clear and transparent."

Last night I powered up the CS-300F and did a little listening with the CS-300F driving my Tannoy Westminster Royal SE loudspeakers, using the Audio Note (UK) CD 2.1x/II Level Two Red Book CD player as a source. 

The CS-300F had zero run-in time on it, but sounded very impressive on the well-recorded jazz guitar CDs I listened to after powering it up. There was a relaxed clarity to the sound that was very intriguing. Clear, resolving, linear, transparent, etc., but still nicely musical. Not bright, forward, or harsh at all, was my initial impression. 

However, later in the evening when I played some vintage AML Russian classical 78 transfers to CD, the CS-300F emphasized the 78's recording quality issues more than I am used to hearing from my Westminsters with the other amplification electronics I have on hand.

That may be due to having no run-in time on the CS-300F at the moment, which is not a particularly unusual situation with an amplifier fresh out of the box. 

I suspect that the CS-300F is a specialty design, with voicing tailored specifically for a particular kind of listener in mind. Perhaps for a listener living in a space like a smaller apartment, where listening levels must be moderate to not offend the neighbors.

That listener would want an amplifier that enables you to hear everything in a recorded musical performance that you would normally hear at louder volumes, but at lower volumes, which are more suitable to a smaller space where lower listening levels are desired. 

I also suspect that the CS-300F might be a particularly good match to my "Stokowski" Altec loudspeakers, which have a more romantic voicing than my Tannoy Westminster Royale SE loudspeakers.

My Facebook friend, Neil Young, tells me that his CS-300F is a particularly good match to his classic LS3/5A loudspeakers.

The Leben CS-300F is quite a ways out in my review queue, so it will likely be towards the end of 2021 before I'll be able to write the feature article about it for Positive Feedback.

In the mean time, I'll be rotating the Leben CS-300F through my other audio and audio-visual systems to get some run-in time on it, and I will be reporting back periodically on listening impressions until the CS-300F's turn comes up in my review queue.

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