The Allnic Audio A-2500 is a high-end single-ended triode monoblock power amplifier designed around either a 211 or 845 power tube, selected when ordering. Each monoblock delivers 20 W of pure Class A continuous power and incorporates Allnic Audio’s Permalloy transformer technology and point-to-point hard-wired circuitry.

The A-2500 combines a powerful tube driving circuit with direct-heated vacuum tube rectification and Allnic’s Full Engagement output transformers. Its analogue power-tube current meter provides direct monitoring of tube current and allows the bias to be adjusted as required.

Features

Single-ended triode monoblock design
20 W of pure Class A continuous power per monoblock
Choice of 211 or 845 power tube
Permalloy transformer cores
Point-to-point hard-wired circuitry
Powerful, low-noise tube driving circuitry
Fixed bias for the 211 and 845 power tubes
Direct-heated 5R4 vacuum tube rectification
Full Engagement output transformers with four independent secondary windings
Large 105 mm nickel/FeSi-core output transformers
Analogue power-tube current monitoring
Mirror-imaged monoblock construction
Available 4 Ω and 8 Ω speaker impedance selection
Designed and constructed using RoHS-compliant materials

Dimension	440 mm W x 370 mm D x 260 mm H per monoblock
Output Power	20 W per monoblock
Power Tube	211 or 845, selected when ordering
Total Harmonic Distortion	0.3% at 5 W / 1 kHz
Frequency Response	20 Hz to 20 kHz, ±0.5 dB
S/N Ratio	-80 dB (CCIR, 1 kHz)
Damping Factor	4 at 8 Ω load at 1 kHz
Voltage Gain	+28 dB (211 version); +26 dB (845 version)
Input Impedance	100 kΩ (single-ended, unbalanced)
Input Sensitivity	0.7 V for maximum rated power
Speaker Impedance	4 Ω or 8 Ω; 8 Ω and 16 Ω available by special order
Input	1 x XLR, 1 x RCA per monoblock
Speaker Terminals	1 pair per monoblock
Tubes	211 or 845 x 1; 6CM7 x 1 for 211 version or 6DR7 x 1 for 845 version; 5R4 x 1 per monoblock
Mains Fuse	5 A, 250 V, 20 mm slow-blow for 110–120 V; 3 A, 250 V, 20 mm slow-blow for 210–230 V
Power Tube Protection Fuse	0.5 A, 250 V, 20 mm slow-blow
Weight	20 kg net per monoblock; 25 kg shipping weight per monoblock