Leben RS-100 preamp


I have always loved passionate objects.

Objects made and thought with passion, objects that exude and excite passion.

The rest is industry, marketing strategy.

Hi-Fi does not escape. The aim of every manufacturer is selling his products, but in different ways.

The passion shines through the details, the choices and, most of all, through the sound.

When someone capable makes an object with passion, it will perform in an exciting way.

This preamble wants to make you consider what separates the things you like from the tiring things, the things that enrapture you from the things that leave you indifferent.

Just the passion itself.

Only a designer fond of music will make an involving object with great performances. After all Music is emotion, isn’t it?


And the Leben preamp?

The passion is there, just in front of you.


The Leben RS-100 has a definite propensity to passion despite some sound peculiarities and not irreproachable measurements as some technocrats could object.

Passion in the make, in the perfume of the materials, in the controls and, obviously, in the sound.

Hence, I test with pleasure the RS-100 after having tested its older brother RS-28 CX, the two only preamplifiers made by Leben. The Japanese company is not eager to make new products that are an end in themselves. They respect their customers – avoiding a disputable restyling of their electronics after a couple of months – and the production logic that comes from a proper “thought and meditated” development.

It follows that it is not necessary to substitute or pretend to renovate, after one or two years, an electronic that has had a long and attentive gestation, as some manufacturers sometimes do.

Anyway, since the progress makes everything easier, we have two advantages here: you can have a useful basis of comparison to understand how Hyodo San – creator and mentor of the Japanese brand - has structured its quite limited catalogue, and you can refer to many info contained in my previous article since we are online.


The two preamplifiers have many things in common but also important differences that, in my opinion, state their alternative character and use.

First of all, the RS-28 CX is more sophisticated. It has a phono input, a separate power supply and costs around two thousand euro more than the RS-100, which is a line preamp only.

There are two motives for having a separate power supply in the RS-28 CX.

The first one is that the phono stage, for reasons of noise reduction and performances, must count on a power supply separated from the line circuit and definitely performing. These goals are better reachable with two chassis. The second reason is that the 28 “must” play better than the 100 because is more expensive.

Actually, the two preamps behave differently and the major model has slight higher performances as it is understandable.


The line stage of the two preamps is essentially very similar since they are both a SRPP, Shunt Regulated Push Pull, with two 6CG7 double triodes, made by General Electric: in this case American tubes of the early ‘80s.

The Japanese designer believes that this scheme – firstly employed by Philips in the early ‘50s and still in use today – represents the best compromise among the different skills required by a preamp, mainly in terms of low output impedance, linearity and driving capabilities at undistorted levels.

The SRPP is a circuit with many advantages also in terms of simplicity. Therefore, it is strictly pertinent to the oriental credo that pursuits the realization of circuits with the lesser number of components and without making massive use of the counter-reaction. The counter-reaction, in fact, if on one hand helps to linearize the electrical performances, on the other hand – as many audio enthusiasts state - brings some musical features not always up to the top. I belong to these “many” people.


The internal making reflects this credo. Simplicity and linearity are visible also to a quick look: the quality of the components is good and you have the impression that the designer has concentrated the budget only on the fundamental points.

For the descriptions of the look and the functioning, please refer to the article on the RS-28 CX. The basic difference between the two amps is that the power supply of the RS-100 is obviously crammed in one chassis, with the 6X5GT rectifier tube and the filter inductance. Under the utilization point of view, also this model has the helpful rear potentiometer - although not properly “purist” – which allows the perfect matching with whatever sensitiveness of the power amp. I suggest, if the power amp has no problems of exuberance of the output signal, to connect the preamp to the fixed output, certainly more performing than the variable output whose potentiometer is not transparent at the signal in terms of purity.


Very useful is the direct input that lets the signal bypassing the input selector and maybe some other path of the circuit.

As happened with the 28-CX, also the RS-100 is quite silent and reliable in the operation. It interfaces itself at best with my PassLabs XA 30.5 via variable output. The fixed output instead, limits the volume control. In fact, I reach the maximum sound impact already at “nine hours”.


Please remember to use the potentiometer just past the middle of its run, compatibly with the noise floor of the electronic device, in order to minimize the decay introduced by any classic potentiometer, which is sensitive also in the components of good quality like the blue series Alps of this Leben.


One last thing about the designer: he is not a legendary Japanese guru like the guru of other over-known brands. Mr.Taku Hyodo does not make any objects in full moon nights with heaven-sent components for millionaire enthusiasts. On the contrary, his story is the story of an engineer moulded in Luxman of two or three decades ago. When he started working on his own, he followed the idea of making electronic equipments affordable to many people.


The noise and the grace

I have tested several musical objects of this Japanese manufacturer, home-made in his factory based in Amagasaki and all with a recognizable quid in their auditory DNA.

Therefore, I could recognize one of these gears not “with eyes closed” but with “well open ears”.

The mid range of the RS-100 is absolute delight, sound grace, velvet caress.

It has not a dynamic vehemence, the velocity of the execution has a measured manner to let you taste the musical texture with lots of details. Details that are set with natural decision not into the foreground but into a coherent and quite relaxed sound context.

We cannot define it as an “old style” tube sound, tender and scarcely incisive. Besides there is also some contrast and a right amount of detail.

It does not run. It does not get anxious of making you prick up your ears with muscular performances.

You get creeps with the music, with what the device can give you of the music.

The best adjective to describe this preamp is “naturalness”.


Every sound can reach our hearing in natural or unnatural way. A sound can be unnatural but also undistorted, clear or pleasant anyway.

An electric keyboard can be very enjoyable, although not natural because it does not exist in nature. The man invented it.

Maybe you do not agree but sometimes we miss the real meaning of the terms we use.

And, in nature, the sounds have a precise timbric and harmonic disposition. The Leben reproduces it with disarming affinity, as it would make us appropriate again of the term naturalness, and of its meaning.


You can understand it through the most natural instrument an equipment can reproduce: the human voice.

The tone and the humanity of every singing voice are preserved almost completely, by making the singing very realistic.

Just play a record by Muddy Waters or Maria Callas or whatever singer, better if not very recent as in the past only two mics were used, while today the voices are distorted by the sound technicians… And you will have all the humanity you need to get involved.


Another great merit of the RS-100 is the output of the acoustic instruments, harmonically rich, with a pale halo that grinds the contours without limiting the detail, never bright or cut in many pixels but fluid, liquid.

Listen with this electronic to the Brandenburg Concertos and, if Bach does not sent you to sleep, you will understand what the baroque is. Just a hint of transparency is missing. That hint that consents a perfect intelligibility of the instruments, which are conceived in these operas as many single solo virtuosos with intricate and complex melodic lines.

The whole is more amalgam than recognizability of the singles, as it should be with this repertory, but the instrumental timbre given back by the Leben is pure delight.


The image is very plausible, wide and deep although slightly imprecise in the physical collocation of the sounds and of the instruments. It seems that in the playback a light but perceptible precision rise time is missing.

The orchestral pieces suffer, in the most intense moments, of a minor confusion as usually happens with the electronics of this price. Here the Leben plays its cards on the agreeableness of the timbres, mainly the strings, whilst a percussive instrument like the piano let filter its venial meditative character, rather than the dynamic size of the sounding board.

With the modern songs some verve is missing, mostly in the range extremes that are a bit limited in extension. The bass is solid, not very dynamic and sculpted, typically tube-like, with a first octave just hinted, while the high frequencies, also these ones a bit descending, are concrete and pleasantly liquid, never annoying although not so extended.


The good thing is the mid range, where the substance of the music lays.

Also here the Leben finds its elective terrain more in jazz than in rock music, more within the acoustic instruments than within the electrified ones: naturalness, do you remember, don’t you?

Also, more complicate and “indigestible” programs like Coltrane’s A love supreme, are performed with a rare pleasance, without enrapturing the listener with muscular performances. What strikes is the lack of listening fatigue thanks also to low or little bothering distortions.

You are wake of listening to a playback, but you can clearly perceive the sound particles that gave life to it, the real paradigm at the basis of every support, both solid and streaming.



I consider this preamplifier as a valuable object.

The faults are so well amalgamated with the sound output that are seen as its character and not as faults.

Like a woman with an amazing body and an aquiline nose: you like her anyway.

For our women readers is like a man with a fascinating face and a hint of belly: you like him anyway.

Three final considerations:

The RS-100 is made also in the RS-100U version with the ECC82 tubes and obviously with the required modifications to make operate at best this triode instead of the 6CG7. The designer loves the tubes and knows that every tube has its sound.

Some times ago, I listened to an exemplar and I can tell you that there are some differences.

Maybe we can make in future a direct comparison.

Between the two preamps, I believe that the RS-28 CX is better and universal, while the tested model interfaces better with the Leben power amps. If you decide to switch to the vinyl, you can buy the RS-30 EQ, definitely better than the phono input of the RS-28 CX.

Finally, the considerations on the quality/price ratio of this preamp are particularly simple and immediate: it sounds for its entire price and more.

Better object or better musicality at this price is hard to find.

At the end, passion does not cost so much.



top score ✳✳✳✳✳ ReMusic Sparks

Tone colour: ✳✳✳✳ | Personal and very rich, without irritating excesses. Mid range harmonically contoured by measured and pleasant higher frequencies and by a mid bass only sometimes hyperbolic.

Dynamics: ✳✳✳ | Measured dynamic contrasts without evident compressions. Better the microdynamics than the macro.

Detail: ✳✳✳✳ |Concrete and realistic, never excessive nor deficient.

Clearness: ✳✳✳1/2 | Of good level. Everything contoured by a dense and richly described air.

Image: ✳✳✳✳ | Realistic and pleasantly wide. The sound subjects at the edges are less precise than those in the middle of the scene.

Rise time: ✳✳✳ | Just a bit slowed down, in both attacks and releases. Consequently, the output is sometimes involving although not fully realistic.

Manufacture: ✳✳✳✳ | Optimum level, simple and tidy. Standard equipment with NOS tubes. Personal and very agreeable look.

Price/quality ratio: ✳✳✳✳✳ | Very high, chiefly for the character skills that ratify the uniqueness aside from the price.


Official technical specifications:

Tube complement: two 6CG7 General Electric (or 12AU7A for RS-100U) and one 6X5GT Sylvania

Gain: 23dB

Max. output: 52V variable, 0-52V fixed

Output Impedance: 600ohms

Residual noise: 0,08mV

Power consumption: 23W

Weight: 7,5kg

Dimensions: 390x142x230mm (WxHxD) side-panels and legs included

Attachment: AC power cable

Official Italian dealer: to Audio Point Italia website

Official current price in Italy: 3,980.00 EUR

Associated equipment: to Paolo “Miracle” Di Marcoberardino's system

by Paolo
Di Marcoberardino
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