Leben CS 300F Integrated Amplifier
- Alan Sircom
- Aug 2021
Some time ago, the Japanese company Leben had a brief flurry of activity in the UK’s online community. The company’s CS 300X integrated amplifier was suddenly the darling of the forums. As many have learned to their cost, this usually means a tiny number of products bought second-hand and resold time and again around that community until every box-swapper has tried it. They moved on, but Leben is back… and the company’s latest CS 300F integrated amplifier marks that return.
Depending on your viewpoint, Leben makes evergreen audio products that have a timeless classic appeal, or it makes retro products that call upon the designs of a bygone age. It doesn’t really matter either way, but no-one’s going to buy the Leben if they are a fan of 1980s-style matt-black minimalism or garish excess; the look and feel of the CS 300F – as with all Leben models – is very much from the Golden Age of stereo. With its Canadian white ash side cheeks – used for ‘baseball bats and oars for low boats’, apparently – brushed gold knobs and dials and matching front and rear panels (with green accent for the product details), the CS 300F looks about as 1960s as Mini Coopers and Mini Skirts.
The CS 300F may look classically conventional, but this all-valve design uses some distinctly non-standard toobs. Where most designs (including Leben’s own CS 300X(S) model) might use something like two pairs of EL84s as power output tubes to achieve its modest-yet-meaty 15W per channel, the CS 300F uses two pairs of JAN 6197/6CL6 valves made by General Electric. This power pentode valve from 1954 was a dual-use design; although it was made to be used as a Class A amplifier valve, its primary use was in early digital computers, as it was designed to be robust enough to survive being switched between full operation and cut-off. In fact, the prefix ‘JAN’ comes from ‘Joint Army/Navy’, so the JAN 6197 was intended for Cold War military computational use. Because it is considered a computer valve, its use in an audio capacity was all but overlooked, but the joy of this valve in audio is its linearity and reliability. Leben invested in large numbers of NOS (new, old stock) JAN 6197 valves because there are no modern aftermarket models available. The two double triode driver valves are from a more conventional provenance; they are Hitachi 17EW8. This high-gain radio tube was also known as the HCC85 and was also produced by RCA and Mullard. As with the JAN 6197, it’s not in current production and Leben has stockpiled NOS Hitachi valves for users. The amplifier is fully self-biasing.
The amp has five line inputs (technically four line inputs and one dedicated CD input) and it has a tape loop. Both the front and rear panels (and the four-page, not quite comprehensive enough) manual have this as ‘tape’ not ‘Home Theatre’, perhaps anticipating the revival of compact cassette, but more likely tapping into the Open Reel movement. The front panel controls are from a time before minimalism stripped amps of any tone shaping, and the Leben has a two-step bass boost that fills in +3dB or +5dB below 100Hz, and is switchable from the front panel. There is also a 6.35mm headphone socket, with a large black rocker switch to move between loudspeaker and headphone use. Retro ends with the terminals themselves, as the speaker terminals are solid WBT models and the amp is switchable between four, six and eight ohm speaker loads.
However we like to look at it, 15W is not a powerhouse by modern standards. In some parts of the audio world, 1.5kW is an acceptable power output to be considered a ‘powerhouse’ and an integrated amp of 150W or more might get that title. Modern loudspeakers are often designed with the expectation that they will be fed by a more powerful amplifier than the Leben CS 300F, but strangely it doesn’t seem to matter too much in the listening. Sure, if you have desperately insensitive loudspeaker designs or are wanting to play at ‘bombastic’ levels in a huge room, the CS 300F might not be the best choice, but I found no problems partnering them with speakers like the Audiovector R1 Arreté, for example, and even the Wilson Duette Series 2 proved an excellent combination.
It’s clear we collectively missed a trick with this Cold War computer tube because it gives the CS 300F a speed and finesse that is all too rare in audio. What’s more, usually when that sort of speed happens in electronics, it’s often accompanied by a bright, brash and forward sound that can all too easily tip ‘speed’ over and make it ‘over-exuberant’ and ‘lean’ in presentation. Here, however, the speed is accompanied by a more ‘creamy’ sound, meaning the Leben combines many of the good parts of the sonic characteristics normally associated with solid-state and valve electronics in one. While this is one of those “I wish I’d worded it better” sentences, recently I’ve become obsessed with Ma Rainey’s Black Bottom [Branford Marsalis, Sony]. It’s a fabulously recorded soundtrack from a Netflix movie of the Jazz Age, sometimes orchestral and distinctly modern jazz, other times sounding like you’d like to think some old Okeh 78 would sound if well recorded in the modern era. A track like ‘Levee and Dussie’, which is just syncopated piano shows what the Leben CS 300F does so well; it brings out the sense of the music ‘breathing’ yet highlights the quality of both the piano recording (and its acoustic space) and the musicianship behind those keys. It has that late-night pianist improvising while everyone is cleaning up around them vibe, which can so easily be lost in the syncopation itself.
Meanwhile, the very next track – ‘Levee Confronts God’ – is almost like something from late-era Coltrane, and the linearity of the amplifier stops the track from becoming too self-absorbed and introverted. The interplay between sax and percussion is gossamer-delicate, and the deft touch of the Leben CS 300F lets this music through with elegance and passion. A warmer sounding amplifier would over-emphasise the sax, while a more bright or forward sound would exaggerate the percussion leading edges. The Leben sits in the goldilocks spot, of making this sound just creamy enough to draw you in, but not so creamy you feel like the music has enveloped you. It’s an attractive, enticing sound that lends itself to a wide range of music, not just recreated Jazz Age movie scores.
Staying with new recordings, Hosokawa/Mozart (Live) [Kodama, Mito Chamber Orchestra, Ozawa, ECM] is an odd musical mix, but a rewarding one. While the Mozart Piano Concerto No 23 is played beautifully, the first track – ‘Lotus Under The Moonlight’ by Toshio Hosokawa is a homage to the same Concerto, but viewed through the lens of traditional Japanese arts. It’s been likened to a musical haiku.
There is a layering and texture to the sound that is easy to lose while trying to focus on the musical themes and especially when trying to hear that quote from the Mozart piano concerto within the distinctly Japanese landscape. This is a piece that makes great demands on an amplifier, especially a small valve amplifier, but the CS 300F more than rises to the challenge, giving each note an accuracy and space to breathe that it needs.
Relatively low output notwithstanding, the CS 300F passes most tests with flying colours. That creaminess can mean a little too much ‘shape’ in the upper bass; not tubby sounding, but just a little broader in the beam, especially when compared to the thin sound of many systems. Also, if you do push the CS 300F to its limits, those limits start to show with a little muddiness in the deepest bass, as if the last two keys on the piano were not playing. But these are more observations than criticisms, and you need to be playing the CS 300F well past its limits to hear these emerge.
Leben has made a beguiling amp in the CS 300F, but perhaps not in the way you might expect from its external appearance. The amplifier is extremely clean and accurate sounding, but not in the cold and stark way often associated with clean-sounding electronics. Yes, it’s a valve amplifier, but one that brings out many of the good things of both valve and solid-state audio. If you have efficient speakers, this is the Little Leben That Could!
- Inputs: 5x line input, 1x tape input/output (all RCA), earth tag for optional phono stage
- Tubes used: 2x 17EW8, 4x JAN 6197
- Power output: 2x 15W
- Frequency Response: 15Hz–100kHz (-2dB)
- THD: 0.7% (at 10W)
- Input sensitivity: 600mV
- Output Impedance: 4/6/8Ω (Selectable), 300Ω (headphones)
- Headphone output: 1000mV
- Dimensions (W×H×D): 38 × 14 × 27cm
- Weight: 11kg
- Price: £2,850
Leben Hi-Fi Stereo Company
Midland Audio xChange
Tel: +44 (0)1562 731100
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