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Leben RS28CX preamp
by Paolo Dimarcoberardino
Speaking of a “Leben” product is like walking middle way in a sort of innovative ground which is not a compromise, but rather meditated choices and reasonableness.
The motive is that the Japanese through and through brand doesn’t reach the peaks of esotericism and price like the products of Audio Note Kondo or Audio Tekne, just to mention two well-known brands of the Land of the Rising Sun. While these ones have made of their creed and personal way of being on the market a sort of “audiophile Puritanism”, Leben seeks another direction. In fact it’s not about exclusive circuit choices or a particular passive component, on which Mr Kondo has found its planning creed, but it’s about a purpose of musical research. A research not much standardized in a modern audiophile world where everything seems to play in a way that is uniform or alike.
Leben’s creator, Mr. Hyodo San, started his career designing tube devices with Luxman. Besides, he brought about an added value for an audio builder: the fact of being a guitarist and a musician too.
In the sober but nice website, you can find few but significant news concerning the production based on three preamplifiers, one only phono, two integrated and, at the moment, one power amp.
Mr. Hyodo didn’t give in at the very profitable temptation of dividing the production (I could say… as others did, a bit cunningly… yes, I say it) into qualitative “steps” more and more expensive of the same device. Maybe changing a handful of quite cheap internal components in order to justify a final price twice increased. He has simply focussed himself on a small number of machines where the differences rest on the preamp functionality or on the output power of the amplifications, rather than on the musical performances which always respond to the designer’s best intentions.
In brief, no easily improvable or intentionally not improved product comes out from his artisanal lab. There are no MK versions or additional changes of an object. Every product enters the market mature or fully responding to its aims.
The solely concession to “change” are the kind of tubes placed into each device. Being a lover of them, he rightly thinks that the best performances come from the exemplars produced till the end of the ‘80s. So he prefers to use NOS valves, when available, instead of new types, with the unavoidable variability of the electric parameters during the years.
The musical box
The outcome of the test on the Leben RS28CX preamplifier requires a close analysis to exhaust all its cues and characteristics. Let’s start saying that it’s not brand new: the very first C version has been issued since 1998, although it was a different product and project, moreover with different tubes, while the CX model dates back to 2006.
So why coming back to the subject?
As far as I’m concerned, at least for two reasons.
The first is the high quality of this gear that deserves a further deepening and a sort of consecration. Of course, always pointing out any strength and weakness since every object which reproduces music, also the dearest and exclusive one, has got some faults. At least as regards the “reproduction” issue. The second reason is the praise that has to be recognised to the productive policy of the brand which makes of the longevity of its products a commercial creed: an added value for the purchaser.
Those who love the novelty at all costs resign themselves to it and let themselves “fall” in the net of who appears, surely not phony, but unquestionably commercially astute.
Maybe someone would consider what I’m saying as excessive or politically incorrect, but, you know, sometimes it can be useful. Indeed!
Moreover this preamp, with the passing of time, plays always better. You can find out new emotions while listening to the records you think to know deep inside: in short, it needs time, your time.
How it is made up
The appearance of a machine is something easy to see and evaluate with our own eyes. This is why I do not like talking about it, but I'll make an exception with this Leben.
There's a similarity with some old products due to the gold coloured refinement, which recalls the great age of Luxman, or to the well refined and polished wooden sides.
It’s a charming object consonant to your listening room, whether it’s a typical bare room of some sad audiophiles or a common living room.
In this model, the power supply circuit is set into an identical small unit, not very heavy, to be placed with the main chassis, a couple of centimetres aside.
There’s nothing so gigantic here to strike the imagination of the most unwary customer; no brainwaves or subterfuges just to look like something else: only grace and sense of measure.
Good level for the components and good make for the connectors. As the circuit is nearly air wired, this represents an advantage - for the constancy of the performances in the course of time- if compared with the common Polychlorinated biphenyls printed circuits.
Welding and junctions are well made and if you look inside you can notice that everything has been made, besides in an artisanal way, in an easy way too. I do love praising slowness.
The passive components are very good without strange esoteric capacitors realized in the nights of full moon: electrolytic Nichicon and Elna with metallic polypropylene (when low values are required) Riken resistors and an Alps Blu potentiometer.
In the feeding block there’s an adequate traditional transformer with a NOS RCA 5Y3WGTA tube and a solid state stabilisation, together with an inductive filtering system.
The gain circuit counts a Shunt Regulated Push Pull (SRPP) scheme used for years by several manufacturers (i.e. one out of four or five circuits needed to build a preamp), which is generally defined by an output low impedance and a high gain. The gain here can go up to 25,2 db with a maximum output equal to 80 V: a very high value, sufficient to drive any power amp.
Luckily Mr. Hyodo, on the rear of the pre, has put a small potentiometer to make variable the output on the RCA clamps. This because, if used, the fixed output can be excessive with normal sensitivity power amps, like my Pass.
It can be useful though, to calibrate this potentiometer and using, for customary listening levels, the normal volume switch set around 12:00 hours even if, the fixed output, without another potentiometer, can guarantee a higher clearness level.
The line stage’s tubes are two 6CG7 General Electric; tube that at that time was used not only in the audio segment but also for the deflection of the TV sets. It’s a strong tube, in brief a version with Noval socket of the famous 6SN7. It has been employed by many manufacturers, for example Audio Research and Conrad Johnson, as driving stadium for tube power amps.
The phono stage follows what Mr. Hyodo considers a masterpiece: the scheme of the Harman Kardon Citation IV. A CR type equalizer with passive Riaa, free from any negative feedback, here only between the two stadiums made active by the two General Electric 12AT7.
CR type equalization requires a gain level of only 20db and that needs a gain step-up transformer paired with MC cartridges with an output not very low, let’s say not below 0,3 MV.
In this case the generosity of the line stage is helpful and by using the fixed output the low gain of the phono is partially balanced.
I’ve personally recourse with great satisfaction to my Lyra Lidian Beta whit its quite strong output. Nonetheless it has been sufficient to pair it with two step-ups with a transformation ratio 1:10 to obtain a congruous gain.
To minimize noise problems are needed a careful estimate of the mass points and an exemplar building. However, the choice of the circuits and the intentional lack of a counter reaction do not follow the direction of low surface noises. In addition Mr. Hyodo has inserted the tubes in a metal container to prevent microphonic effects.
The pre is rather versatile with a balance control (very useful indeed) and a double input bar (less useful…). There’s also a warm-up system which gives current to the tubes progressively, as prefigured by Mr Hyodo in all his devices to preserve the tubes’ health. A pilot on the front shows the full efficiency.
The pre needs at least thirty minute warming up to express its best, but after few nanoseconds tells to the lucky owner what it’s capable of.
Listening
Smart audiophiles, who develop their system with humility and judiciousness, improving their sensitivity without turning to the plethora of “autosanctified pundits”, know very well the importance of the preamplifier.
Some lightweight technocrats will tell you that’s not true; when all is said and done the preamp is only a gain damper, hence an unnecessary component.
I’ve never listened to a system whose source was directly connected to the power amp playing more than decently, included the almost entire range with a passive pre.
I mean, the pre is necessary and it has to be of a superior quality level than the other components of the system.
You can buy the most expensive loudspeakers, the most transparent and dynamic source, but if your preamp it’s just mediocre, the sound will be mediocre too.
Today it’s quite difficult to find, at the same price of this Leben preamp, a gear that performs very badly. Better, I’d say that most products of this category show a pleasantly “Hi-Fi” sound, well-balanced even if, quite often, a bit standardized.
Maybe it’s something related to our times, where the majority desires only objects that are appeasing and homogenous, let’s say standardized and not very demanding: neither an effort in searching the best conditions of use, nor a different listening or something that can catch us “unprepared”. The aim of Taku Hyodo san is the reaching of a natural sound with a firm personal character connotations. A sound maybe not so catchy (and then tiring) but a sound that generate in the user’s psyche a “certainty of sound”.
I can actually say that the RS28CX offers recognizable musical performances with an evident naturalness and without any listening weariness.
Its voice is peculiar indeed, but nevertheless close to reality.
I inserted the preamp in my system using two different power amps: the solid state Pass XA 30.5 and the valve state BAT VK 55 SE (this last one with adapters RCA/XLR), with my faithful Martin Logan SL3, which are extremely revealing of what is at the beginning of the system, and the digital source Naim CD5X fed with its FlatCap 2X.
The pre analog stage has been tested using the Lyra Lydian beta interfaced with a Jensen step-up with a transformation ratio of 1:10. It allows you to obtain a congruous gain without mortifying the dynamic qualities of the Japanese pickup which reads a load impedance of 470 Ohms: in my opinion the best with this cartridge.
The Leben line stage shows great neutrality, with the low range typically valvelike, that is just soft and not very fast, never overfull or pasty, definitely in line with the entire range.
The timbre is wide open in the medium-low range, with the high frequencies very “flat” and fine-grained as deserved by a high rank machine; this preamp is a fine chisel, a gear that can entirely represent what the source send to it and, substantially, an excellent and transparent “tuner” of the entire system.
Everything with the Leben seems to find its place with balance and great naturalness.
Voices are never artificial or with a timbric deviation and all the sonic characteristics bring back reciprocally in a ground made of sound truth, both with a sax or a string quartet.
Lots of dynamic but without strains or unnatural accelerations: all flows with no effort and very close to the live performances, exactly how our ears expect to listen to.
With small ensembles, jazz or classic, there’s the capability of catching punctually the single instruments very well defined and sculptured, the excellent air of the scene and the concrete timbre which gives back the sounds with intimacy.
A hearing pleasure with no listening exertion at all.
The great class comes out with more demanding programmes where many competitors turn their elevated detail into stridency and their marked dynamic into continuous and not very homogeneous strains.
The Leben keeps its naturalness instead without loosing control and musical coherence: briefly no breathlessness.
If you get some problems in pumping up the volume, which becomes less pleasant with the increasing of the level, you should listen what happens with the RS28CX, that simply doesn’t modify anything with the varying of the potentiometer but reproduces it louder.
Like with all the Leben devices, also here the harmonic content is of a high level and the instruments are never affected or not lively. You feel like listening to the finest reproduction of something real, palpable and solidly tangible.
Sometimes it’s just a touch, an echo or an intonation or maybe a sense of realism hardly describable, but with this preamp you can listen first of all the humanity and the truth of the recording.
And the rest, made of frequencies, dynamic and detail comes afterwards.
The phono stage gives a softer timbre than the line stage, more personal and warm in the midrange and a bit more valvelike, in a classical meaning, in the low frequencies.
The Lyra has a good control on the low range and is very synergic. So it would be advisable to pair any pick ups with similar characteristics, avoiding those “very mellow” and slightly dynamic which, however, is better to stay away from them, ever…
The midrange becomes warmer, agreeably euphonic, even if in a correct and measured way.
It’s like a bit of romanticism in your setting up. That afflatus we’re always seeking when we are trying to assemble very good analog systems and that the Leben expresses with velvet decision.
Beautiful indeed the top range, extremely polished, measured but well extended, in short musical.
I realize that with a record by B.B. King recently bought in London on a stall, which is definitely poorly recorded but with the Leben seems more listenable as it fixes the critical and sharp midhigh frequencies and the little homogeneous high frequencies.
This Leben seems to be the care for every audiophile disorder.
With the classical music the correct timbre, never aseptic, makes every score enjoyable, with very good transparency skills.
In the Beethoven Symphony No 9 (Karajan, 1962, Deutsche Grammophon) you can clearly perceive the expressive power of the first movement, as well as the poetry of the third or the exaltation of the fourth.
The strings, in this recording a little sour, are given back with rare mastery as the sound came from the rubbing of the bow on the string, from the contact of the materials.
Same clear impression with the Four Seasons of the Solisti Veneti (RCA), were the soloist has a sureness of touch but the instrument is never unnatural or without harmonics.
In short, with every kind of music the Leben is able to amalgamate your feelings with the chosen music, both with the distort notes of Hendrix and the genial intuitions of Mozart.
Also the treatment of the voices is exemplary, maybe the best thing the Leben can do, thanks to its harmonic truth which turns every word into reality.
I freeze head-on the beauty of Suzanne by Leonard Cohen or the pitiless desperation of Strange Fruit by Lady Day.
The sibilants are totally without grain and as happened with the strings, also here it’s clearly perceivable the “physical” origin of the sound, that is the vibration of the vocal cords, the air emission of the diaphragm.
Same sharp certainty with the winds, where the sensation of the air insufflate in the instrument is clear, with the intonations and small mistakes that every musician can do, also the best ones.
Definitely extraordinary.
Conclusions
From the employable point of view, the Leben is a very universal preamp, both for the high gain which gets and for the possibility of adapting the output through the back switch when driving a very sensitive power amp.
Both Pass and BAT felt very comfortable with it, expressing their best.
With a more airy preamp the Pass would have given an outcome too unbalanced in the midrange, whilst a warmer mid range joint to a more vigorous bass range would have given, with the BAT, a timbre not very homogenous.
But the Leben has driven these different power amps with correctness and extreme musicality.
I think there are on the market preamps more transparent or dynamic than the Leben, others more engaging and airy, others more solid in doing bass.
All these qualities are present in the RS28CX but are wisely and exclusively interpenetrate in a music machine that achieves the goal of bringing you to the core of music, forgetting all the rest.
It can fully solve your doubts and perplexities and realign your head with the wish of emotion.
It can divert the system from every straining or excess, taking away insane thoughts about cables and diabolic accessories and let you think only of Music.
Need something else?
SCHEME SUMMARY
top score ***** stars
Timbric ****1/2 | Correct with a mid range just warm and a mid high range very broad and determined. Very enjoyable.
Dynamic **** | Indeed realistic and without splits, fluid and controlled.
Detail **** | High with no unnatural efforts in the perception of the secondary details
Clearness**** line ***1/2 phono | High level, mostly the line stage, less the phono stage.
Image **** | Realistic and never afflicted by a wide angle perception. More developed in length than in width.
Velocity ***1/2 | Quick impulses, mostly in the mid high range, less in the bass. Descent fronts never sudden or flat, also for the consistent harmonic content.
Manufacture ****1/2 | Great level with air wiring embellished by the separate unit. Standard equipment with NOS tubes. Excellent and personal look.
Price/quality ratio ***** | Extraordinary if compared to the musical performances and the included phono stage.
Official technical specifications:
Tube Complement: 2 x 6CG7 (G.E.); 2 x 12AT7 (G.E.); 1 x 5Y3WGT
RIAA Curve; <0,3 dB
Gain phono: 20,2 dB
Input: 400 mV (2KHz)
Gain line: 25,2 dB
Output: 80V
Output Impedance: 580Ohms
Weight: kg 13,5 (main body+ power supply)
Official Italian dealer: to the Audio Point Italia website
Official current price in Italy: 6,840.00 EUR
RIGHT OF REPLY | MANUFACTURERS FEEDBACK
Dear Mr. Castelli, Mr. Rocchi,
Thank you very much for your nice review on Leben RS-28CX.
Your evaluation is just hitting a thought of Mr. Hyodo.
Mr. Hyodo was willing to sell RS-28CX as an independent apparatus(not as a set with a power amp), RS-28CX was designed to match with several power amps regardless to its sensitivity.
Another point of this preamp is the phono stage.
As you clearly indicated, in order to bring a full capability of CR-type/Non-NFB phono equalizer, Mr. Hyodo decided to have a separate power supply.
Therefore, we do not have any extra comments to your perfect review.
Thank you very much.
Yoshi Hontani, Managing Director
17/11/2011
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发表于 2012-3-30 11:34:12
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