Longdog Audio P6100M Biamp 2x2 (4 units)
13 lost · Anchored, Artisan, Characterful, PRaT, Reference, Romantic
Against the Anchored brief, the Longdog Audio P6100M Biamp 2x2 (4 units) keeps the slot decisively.
Leben CS600X (EL34 / 6L6)
Integrated amplifier
Relative price
well above typical
Among the 59 integrated amplifiers in the catalogue, this one is well above typical.
A band places a component against its peers and carries no price. It is deliberately the only price indicator on this page: a second one, measured against a different set, would narrow the two together far enough to give the figure away.
What it is
Leben CS600X — Taku Hyodo's flagship integrated valve amp; introduced 2005 as CS600, refreshed as CS600X (2019). 28W EL34 push-pull (32W with 6L6); EXTENSIVE tube-rolling support — accepts EL34/KT66/KT77/KT88/6550/6L6GA/GB/WGB/350B via voltage + cathode resistor switches. ECC802S + 12BH7-A + 6DN3 NOS Sylvania driver complement. Hand-made point-to-point in Japan.
Stereophile Class A Recommended Component. Positive Feedback (2024 CS600X review): "Leben charms with beautiful timbre—this is just a given with Japanese amplifiers—but Leben also offers great dynamics, great bass and spacing, that is elements that are not commonly associated with the EL34 tubes. RED Fingerprint" (PF's highest recommendation).
UNIQUE FEATURE: "Preamp In" input that PRESERVES volume control when used as power amp (most preamp-input bypasses don't do this). Allows CS600X to function as integrated AND as power-amp-with-attenuator depending on configuration. Useful when paired with sources having volume control (Ayon CD-35 HF Edition, Auralic streamers, etc).
Devore Fidelity's John Devore reportedly uses CS600X at trade shows more than any other amp to demo his Orangutan speakers — speaker-amp pairing endorsed at the highest level.
CRITICAL ELECTRICAL FIT: 28W output mandates ≥88dB sensitivity speakers. Excellent partner for Devore O-baby/Nines/Orangutan, Audio Note AN-E/AN-J, Living Voice, Wilson WATT/Puppy 5.1 (per forum reports), Rogers LS3/5a 15Ω. Forum users pair successfully with Wilson Watt Puppy 5.1 (87dB borderline but listenable in modest rooms).
For matching headphone use: comparable to dedicated valve headphone amps; loves planar magnetic headphones via dedicated transformer output tap.
Spec_completeness=partial — Leben publishes minimal CS600X numerical specs (vs CS300XS which has full HiFi Engine spec sheet). Most fields inferred from Leben CS300XS lineage and reviewer reports.
Competition record
Assessed against 15 rivals across the sixty systems: it takes the slot in none of its 48 head-to-heads.
Where it gives ground
The dimension the engine names as the weakest link, counted across every head-to-head it lost.
- low-level clarity ×8
- tonal body ×4
Who it comes up against
Sugden ANV 50
4 lost · BBC Sound, Twin Arms
Against the Twin Arms brief, the Sugden ANV 50 keeps the slot decisively.
On its own merits the Leben CS600X (EL34 / 6L6) is the weaker integrated amplifier for that brief.
Leema Hydra II
4 lost · Cavity-Native, Characterful, Romantic
Against the Cavity-Native brief, the Leema Hydra II keeps the slot decisively.
Audiolab 9000P
4 lost · Characterful, PRaT, Romantic, Silent Path
No completion of this shape fits that slot's budget.
NVA S300 Stereo (Artisan)
4 lost · Artisan, Cavity-Native, Intimate, Reference
No completion of this shape fits that slot's budget.
Icon Audio Stereo 30 SE (KT150)
3 lost · Vocals-First
Against the Vocals-First brief, the Icon Audio Stereo 30 SE (KT150) keeps the slot clearly.
With the Tom Evans Groove+ SRX MkII, the pairing gives up most on tonal body.
On its own merits the Leben CS600X (EL34 / 6L6) is the weaker integrated amplifier for that brief.
fullness and weight that epitomises the valve amp soundStereoNET, Hughes, 2023
Audio Note P1 SE
3 lost · Intimate, Silent Path
Against the Silent Path brief, the Audio Note P1 SE keeps the slot decisively.
EAR Yoshino V12
3 lost · BBC Sound, Vocals-First
Against the BBC Sound brief, the EAR Yoshino V12 keeps the slot decisively.
With the Rega Aura Reference MC, the pairing gives up most on low-level clarity.
With the Falcon LS3/5a Gold Badge, the pairing gives up most on low-level clarity.
On its own merits the Leben CS600X (EL34 / 6L6) is the weaker integrated amplifier for that brief.
fullness and weight that epitomises the valve amp soundStereoNET, Hughes, 2023
Exposure XM9 Biamp 2x2 (4 units)
3 lost · Artisan, PRaT, Reference
Against the Artisan brief, the Exposure XM9 Biamp 2x2 (4 units) keeps the slot decisively.
EAR Yoshino 890
2 lost · Intimate
Against the Intimate brief, the EAR Yoshino 890 keeps the slot decisively.
Chord ULTIMA 6
1 lost · Cavity-Native
Against the Cavity-Native brief, the Chord ULTIMA 6 keeps the slot decisively.
Longdog Audio P6100M (pair)
1 lost · Anchored
No completion of this shape fits that slot's budget.
Exposure 3510
1 lost · Twin Arms
Against the Twin Arms brief, the Exposure 3510 keeps the slot decisively.
On its own merits the Leben CS600X (EL34 / 6L6) is the weaker integrated amplifier for that brief.
It sits well above the share of the budget this brief aims at the integrated amplifier position.
Sugden A21 Signature
1 lost · BBC Sound
Against the BBC Sound brief, the Sugden A21 Signature keeps the slot decisively.
With the Naim NVC TT MM/MC, the pairing gives up most on low-level clarity.
With the Harbeth P3ESR XD2, the pairing gives up most on low-level clarity.
On its own merits the Leben CS600X (EL34 / 6L6) is the weaker integrated amplifier for that brief.
Quad Artera Stereo
1 lost · Silent Path
Against the Silent Path brief, the Quad Artera Stereo keeps the slot decisively.
What the reviewers said
EL34/6L6 selectable, flagship Leben integrated Leben CS600X + Stereophile· Harmonic texture
fullness and weight that epitomises the valve amp sound StereoNET, Hughes, 2023· Tonal body
vocals full and very present, yet backing voices clear StereoNET, Hughes, 2023· Presence & articulation
mellifluous velvety smoothness and rich, mellow sonority StereoNET, Hughes, 2023· Harmonic texture
not quite the vice-like control of good solid-state StereoNET, Hughes, 2023· Bass control
detailed, balanced and cohesive without being euphonic StereoNET, Hughes, 2023· Tonal consistency
very quiet, virtually no buzz, residual hum or hiss StereoNET, Hughes, 2023· Electrical noise floor
How it scores
Clarity
- Electrical noise floor 76 from listening evidence
Voice
- Tonal body 76 from listening evidence
- Presence & articulation 76 from listening evidence
- Harmonic texture 77 from listening evidence
Bass
- Bass control 70 from listening evidence
- Physical impact 59 from specification
- Bass extension 59 from specification
LowerVolume
- Low-level noise floor 78 from specification
- Micro-dynamic resolution 72 from specification
- Tonal consistency 76 from listening evidence
Specifications
| power 8ohm w | 28.0 |
|---|---|
| power 4ohm w | 28.0 |
| power class | AB |
| damping factor | 10.0 |
| line inputs | 4 |
| line input sensitivity mv | 600.0 |
| line input impedance kohm | 100.0 |
| has phono | False |
| phono mm | False |
| phono mc | False |
| pre out | False |
| pre power separable | true_break |
| internal bass management | none |
| headphone out | True |
| frequency response hz | 15/100000 |
| snr db | 85.0 |
| thd pct | 0.7 |
| weight kg | 20.0 |
| integrated dac | False |
| digital inputs | 0 |
| notes |