Longdog Audio P6100M Biamp 2x2 (4 units)
7 lost · Anchored, Characterful, Romantic
Against the Anchored brief, the Longdog Audio P6100M Biamp 2x2 (4 units) keeps the slot decisively.
Sugden IA-4
Integrated amplifier
Relative price
above typical
Among the 59 integrated amplifiers in the catalogue, this one is 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
Sugden IA-4 — Masterclass flagship integrated. 33W/8Ω pure Class A. CORRECTION: previously catalogued as 50W/no-phono — both wrong. Actual: 33W/8Ω with onboard MM phono stage.
Preamp derived from Masterclass LA-4 line stage. Class A power output upgraded from A21 family with larger PSU and improved capacitors.
Available in Titanium silver, Graphite black, or 13 anodised custom shades including Bronze, Red, Stealth Black, three blues and three greens.
Competition record
Assessed against 11 rivals across the sixty systems: it takes the slot in none of its 24 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 ×2
- timing and drive ×2
- bass control ×1
Who it comes up against
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 by a whisker.
On its own merits the Sugden IA-4 is the weaker integrated amplifier for that brief.
EAR Yoshino V12
3 lost · BBC Sound, Vocals-First
Against the BBC Sound brief, the EAR Yoshino V12 keeps the slot clearly.
With the Rega Aura Reference MC, the pairing gives up most on low-level clarity.
On its own merits the Sugden IA-4 is the weaker integrated amplifier for that brief.
With the Falcon LS3/5a Gold Badge, the pairing gives up most on timing and drive.
black backgroundStereo Times (Hoffman) 2025
EAR Yoshino 890
2 lost · Intimate
Against the Intimate brief, the EAR Yoshino 890 keeps the slot decisively.
Audiolab 9000P
2 lost · Characterful, Romantic
No completion of this shape fits that slot's budget.
Leema Hydra II
2 lost · Characterful, Romantic
Against the Characterful brief, the Leema Hydra II keeps the slot decisively.
Longdog Audio P6100M (pair)
1 lost · Anchored
Against the Anchored brief, the Longdog Audio P6100M (pair) keeps the slot decisively.
NVA S300 Stereo (Artisan)
1 lost · Intimate
No completion of this shape fits that slot's budget.
Sugden A21 Signature
1 lost · BBC Sound
Against the BBC Sound brief, the Sugden A21 Signature keeps the slot by a whisker.
On its own merits the Sugden IA-4 is the weaker integrated amplifier for that brief.
With the Harbeth P3ESR XD2, the pairing gains most on timing and drive.
It sits well above the share of the budget this brief aims at the integrated amplifier position.
Audio Note P1 SE
1 lost · Intimate
Against the Intimate brief, the Audio Note P1 SE keeps the slot decisively.
Sugden ANV 50
1 lost · BBC Sound
Against the BBC Sound brief, the Sugden ANV 50 keeps the slot clearly.
With the Falcon LS3/5a Gold Badge, the pairing gives up most on bass control.
On its own merits the Sugden IA-4 is the weaker integrated amplifier for that brief.
controlled, clear bassStereo Times (Hoffman) 2025
What the reviewers said
IA-4 Masterclass series flagship integrated Sugden IA-4 Masterclass integrated· Harmonic texture
broad and deep soundstage... holographic Stereo Times (Hoffman) 2025· Spatial resolution
warm, lush midrange, natural timbres Stereo Times (Hoffman) 2025· Tonal body
black background Stereo Times (Hoffman) 2025· Low-level noise floor
controlled, clear bass Stereo Times (Hoffman) 2025· Bass control
How it scores
Clarity
- Electrical noise floor 78 from specification
- Spatial resolution 82 from listening evidence
Voice
- Tonal body 76 from listening evidence
- Harmonic texture 72 from listening evidence
Bass
- Bass control 76 from listening evidence
- Physical impact 60 from specification
- Bass extension 60 from specification
LowerVolume
- Low-level noise floor 76 from listening evidence
- Micro-dynamic resolution 76 from specification
- Tonal consistency 76 from specification
Specifications
| power 8ohm w | 33.0 |
|---|---|
| power class | A |
| damping factor | 30.0 |
| line inputs | 5 |
| line input sensitivity mv | 125.0 |
| line input impedance kohm | 50.0 |
| has phono | True |
| phono mm | True |
| phono mc | False |
| phono mm gain db | 36 |
| phono mm load | 47kΩ MM |
| pre out | True |
| pre power separable | pre_out_parallel |
| internal bass management | none |
| headphone out | False |
| frequency response hz | 14/200000 |
| snr db | 84.0 |
| dimensions mm | 430/165/440 |
| weight kg | 20.0 |
| notes |