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Sugden Masterclass SPA-4

Power amplifier

Relative price

above typical

Among the 25 power 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

NO BRIDGE MODE. Sugden's monoblock partner is the dedicated MPA-4.

KEY DIFFERENCE FROM MPA-4: SPA-4 accepts both RCA AND XLR inputs (MPA-4 is XLR-only). This makes SPA-4 the natural Sugden power amp partner for RCA-output preamps like Exposure 3510 Pre, or for systems where the user prefers RCA connection (Rega philosophy).

Competition record

Assessed against 17 rivals across the sixty systems: 1 head-to-head won, 39 lost.

Where it gives ground

The dimension the engine names as the weakest link, counted across every head-to-head it lost.

  • bass control ×13
  • quietness at rest ×13
  • vocal presence ×6
  • timing and drive ×4
  • midrange truth ×3

Who it comes up against

Longdog Audio P6100M Biamp 2x2 (4 units)

9 lost · Anchored, Characterful, PRaT, Romantic

Against the Anchored brief, the Longdog Audio P6100M Biamp 2x2 (4 units) keeps the slot decisively.

With the Emmae Reginae (custom), the pairing gives up most on bass control.

With the Audiolab 9000Q, the pairing gives up most on quietness at rest.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

free of solid-state irritantHomeTheaterReview 2009 (Masterclass mono)

Audiolab 9000P

4 lost · Anchored, Characterful, PRaT, Romantic

Against the Characterful brief, the Audiolab 9000P keeps the slot decisively.

With the Audiolab 9000Q, the pairing gives up most on vocal presence.

With the Neat Petite Classic, the pairing gives up most on bass control.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

deep, tight, controlled bass without overbearingHiFiMART user review + Audio Tailor review

NVA S80 Stereo

4 lost · Characterful, Intimate, PRaT, Romantic

Against the Characterful brief, the NVA S80 Stereo keeps the slot clearly.

With the NVA P50 MKII, the pairing gives up most on vocal presence.

On its own merits the Sugden Masterclass SPA-4 is the stronger power amplifier — but it loses here on fit: the pairing with the NVA P50 MKII gives up vocal presence under the Characterful weighting.

It sits well above the share of the budget this brief aims at the power amplifier position.

free of solid-state irritantHomeTheaterReview 2009 (Masterclass mono)

Sugden ANV 50

3 lost· 1 won · BBC Sound, Twin Arms

Against the Twin Arms brief, the Sugden ANV 50 keeps the slot by a whisker.

EAR Yoshino V12

3 lost · BBC Sound, Vocals-First

No completion of this shape fits that slot's budget.

EAR Yoshino 890

2 lost · Intimate

Against the Intimate brief, the EAR Yoshino 890 keeps the slot decisively.

With the EAR Yoshino 868L (Line), the pairing gives up most on midrange truth.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

Sugden Class A stereo power ampSugden Masterclass SPA-4 stereo power

Leema Hydra II

2 lost · Characterful, Romantic

Against the Characterful brief, the Leema Hydra II keeps the slot decisively.

With the Emmae Reginae (custom), the pairing gives up most on bass control.

With the Leema Neutron, the pairing gives up most on vocal presence.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

Hydra II reference Leema stereo power ampLeema Hydra II positioning

Longdog Audio P6100M (pair)

1 lost · Anchored

Against the Anchored brief, the Longdog Audio P6100M (pair) keeps the slot decisively.

With the Neat Petite Classic, the pairing gives up most on bass control.

With the NVA P50SA MKII, the pairing gives up most on quietness at rest.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

free of solid-state irritantHomeTheaterReview 2009 (Masterclass mono)

NVA S300 Stereo (Artisan)

1 lost · Intimate

Against the Intimate brief, the NVA S300 Stereo (Artisan) keeps the slot decisively.

With the NVA P50SA MKII, the pairing gives up most on quietness at rest.

On its own merits the Sugden Masterclass SPA-4 is the stronger power amplifier — but it loses here on fit: the pairing with the NVA P50SA MKII gives up quietness at rest under the Intimate weighting.

It sits well above the share of the budget this brief aims at the power amplifier position.

free of solid-state irritantHomeTheaterReview 2009 (Masterclass mono)

Exposure 3510

1 lost · Twin Arms

No completion of this shape fits that slot's budget.

Rega io

1 lost · Twin Arms

No completion of this shape fits that slot's budget.

Leak Stereo 230

1 lost · Vocals-First

No completion of this shape fits that slot's budget.

Creek 4040A

1 lost · BBC Sound

No completion of this shape fits that slot's budget.

Audio Note P1 SE

1 lost · Intimate

Against the Intimate brief, the Audio Note P1 SE keeps the slot decisively.

With the Audio Note M2 Phono, the pairing gives up most on midrange truth.

With the Emmae Reginae (custom), the pairing gains most on timing and drive.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

Sugden Class A stereo power ampSugden Masterclass SPA-4 stereo power

Exposure XM9 Biamp 2x2 (4 units)

1 lost · PRaT

Against the PRaT brief, the Exposure XM9 Biamp 2x2 (4 units) keeps the slot decisively.

With the Emmae Reginae (custom), the pairing gives up most on timing and drive.

With the NVA P50SA MKII, the pairing gives up most on quietness at rest.

On its own merits the Sugden Masterclass SPA-4 is the weaker power amplifier for that brief.

free of solid-state irritantHomeTheaterReview 2009 (Masterclass mono)
only matched in terms of dynamicsStereo Magazine 2021

What the reviewers said

Sugden Class A stereo power amp Sugden Masterclass SPA-4 stereo power· Harmonic texture
free of solid-state irritant HomeTheaterReview 2009 (Masterclass mono)· Electrical noise floor
grain-free top end... sweet richness HomeTheaterReview 2009 (Masterclass mono)· Tonal body
no chunky bass thwack HomeTheaterReview 2009 (Masterclass mono)· Physical impact

How it scores

Clarity

  • Electrical noise floor 74 from listening evidence

Voice

  • Tonal body 74 from listening evidence
  • Harmonic texture 72 from listening evidence

Bass

  • Bass control 66 from specification
  • Physical impact 66 from listening evidence
  • Bass extension 63 from specification

LowerVolume

  • Low-level noise floor 76 from specification
  • Micro-dynamic resolution 76 from specification
  • Tonal consistency 76 from specification

Specifications

is monoblockFalse
is balanced internalTrue
power classA
power 8ohm w80.0
power 4ohm w110.0
damping factor80.0
accepts rcaTrue
accepts xlrTrue
accepts dinFalse
input impedance rca kohm47.0
input sensitivity rca mv110.0
speaker terminal typebinding post
gain db32.0
sold as pairFalse
notes