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.
Ultrafide ENSO INT-125
Integrated amplifier
Relative price
typical
Among the 59 integrated amplifiers in the catalogue, this one is 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
Ultrafide ENSO INT-125 — first integrated from UK pro-audio brand Ultrafide (hi-fi arm of MC² Audio + XTA Electronics, hand-built Devon). UltraSigma output topology. 125W/8Ω + 250W/4Ω Class AB. Tone controls designed by Alex Cooper (pro-audio EQ industry legend). MM phono with adjustable gain + capacitance.
KEY UNIQUE FEATURE: send/return pre-out + power-in loop. The amp can function as standard integrated, OR split into separates internally for external equaliser/processor insertion, OR drive an external power amp via internal preamp, OR use as standalone power amp driven by external preamp. Pro-audio modular thinking.
CRITICAL ELECTRICAL FIT: 125W/8Ω + 250W/4Ω + UltraSigma topology drives most demanding speaker loads including reactive low-impedance speakers. Pro-audio current-delivery emphasis means "effortless rather than strained" performance under load.
Competition record
Assessed against 19 rivals across the sixty systems: 2 head-to-heads won, 58 lost.
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
NVA S80 Stereo
8 lost · Artisan, Cavity-Native, Characterful, Intimate, PRaT, Reference, Romantic, Silent Path
No completion of this shape fits that slot's budget.
Audiolab 9000P
5 lost · Anchored, Characterful, PRaT, Romantic, Silent Path
Against the Characterful brief, the Audiolab 9000P keeps the slot decisively.
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 Ultrafide ENSO INT-125 is the stronger integrated amplifier — but it loses here on fit: the way it sits with the rest of this system under the Twin Arms weighting.
Leema Hydra II
4 lost · Cavity-Native, Characterful, Romantic
Against the Cavity-Native brief, the Leema Hydra II keeps the slot decisively.
NVA S300 Stereo (Artisan)
4 lost · Artisan, Cavity-Native, Intimate, Reference
Against the Intimate brief, the NVA S300 Stereo (Artisan) keeps the slot decisively.
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 Ultrafide ENSO INT-125 is the stronger integrated amplifier — but it loses here on fit: the pairing with the Tom Evans Groove+ SRX MkII gives up tonal body under the Vocals-First weighting.
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 Ultrafide ENSO INT-125 is the stronger integrated amplifier — but it loses here on fit: the pairing with the Rega Aura Reference MC gives up low-level clarity under the BBC Sound weighting.
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
Against the Anchored brief, the Longdog Audio P6100M (pair) keeps the slot decisively.
Exposure 3510
1 lost · Twin Arms
Against the Twin Arms brief, the Exposure 3510 keeps the slot by a whisker.
On its own merits the Ultrafide ENSO INT-125 is the weaker integrated amplifier for that brief.
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 Ultrafide ENSO INT-125 is the stronger integrated amplifier — but it loses here on fit: the pairing with the Naim NVC TT MM/MC gives up low-level clarity under the BBC Sound weighting.
Leak Stereo 230
1 lost · Vocals-First
Against the Vocals-First brief, the Leak Stereo 230 keeps the slot by a whisker.
On its own merits the Ultrafide ENSO INT-125 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.
Quad Artera Stereo
1 lost · Silent Path
Against the Silent Path brief, the Quad Artera Stereo keeps the slot decisively.
Rega io
0 lost· 1 won · Twin Arms
Against the Twin Arms brief, the Ultrafide ENSO INT-125 takes the slot decisively.
On its own merits the Ultrafide ENSO INT-125 is the stronger integrated amplifier for that brief.
It sits well above the share of the budget this brief aims at the integrated amplifier position.
Creek 4040A
0 lost· 1 won · BBC Sound
Against the BBC Sound brief, the Ultrafide ENSO INT-125 takes the slot clearly.
With the Falcon Q7 Complete@Home, the pairing gains most on timing and drive.
On its own merits the Ultrafide ENSO INT-125 is the stronger integrated amplifier for that brief.
It sits well above the share of the budget this brief aims at the integrated amplifier position.
effortless rather than strainedStereoIndex Feb 2026
What the reviewers said
strong current delivery and controlled low-frequency performance StereoIndex Feb 2026· Physical impact
effortless rather than strained StereoIndex Feb 2026· Dynamic coherence
How it scores
Clarity
- Electrical noise floor 85 from specification
Bass
- Bass control 67 from specification
- Physical impact 77 from listening evidence
- Bass extension 68 from specification
LowerVolume
- Low-level noise floor 85 from specification
- Micro-dynamic resolution 72 from specification
- Tonal consistency 72 from specification
Specifications
| power 8ohm w | 125.0 |
|---|---|
| power 4ohm w | 250.0 |
| power class | AB |
| damping factor | 150.0 |
| line inputs | 4 |
| line input sensitivity mv | 380.0 |
| line input impedance kohm | 47.0 |
| has phono | True |
| phono mm | True |
| phono mc | False |
| pre out | True |
| pre out level v | 2.0 |
| pre power separable | true_break |
| internal bass management | none |
| headphone out | True |
| frequency response hz | 20/50000 |
| snr db | 100.0 |
| thd pct | 0.01 |
| dimensions mm | 420/100/380 |
| weight kg | 12.0 |
| integrated dac | True |
| digital inputs | 2 |
| notes |