501 Mono Amplifier

Small package – big performance
Pure music in all its diversity and natural beauty. An enchanting audio experience for all. Hear it for yourself and be convinced.


The 501 mono amplifier embodies many of the same technology insights and advances of the Series 7 to deliver an outstanding performance in its own right.

The amplification circuit of the 501 is based on the technology of the 710 and 700 amplifiers. At its core is a proprietary voltage amplification stage that consists of linearized amplifiers operating up to a cutoff frequency of 80 MHz.

Current amplification is done in three stages, each using a very small and thus almost linear operating range. The high Class A operation supplemented by 47,000µF of storage capacitance results in a nearly infinite impulse response. Massive copper bars on the amplifier board and to the speaker terminals ensure that all the power of the 501 mono amplifier is available to drive the speaker.

High-precision idle current management ensures optimal Class A operation for all conditions, without requiring any readjustment in the music signal. Optimal sound is thereby guaranteed immediately from switch on. Control circuits that protect against RF or DC signals at the input, and short circuits at the output ensure safe operation in all situations. The input level is also monitored continuously.

Power supply
A total of six power supplies – optimized for each function – feed the 501 mono amplifier. Those supplying the digital and audio circuits are electrically isolated from each other by optocouplers and transformers. Two cutting-edge switched-mode power supplies deliver 1,200W of audiophile quality power. They feature high performance filtering at the input and output, and six high speed soulution voltage regulators to deliver considerably more stable power than any conventional, transformer-based technology.

The 501 mono amplifier is operated via a rotary control on the front panel. It can be switched on remotely with other soulution devices via the LINK system.

Additional information

Weight 22 kg
Dimensions 44.8 × 44.2 × 14.3 cm

220 – 240 V (50 – 60 Hz), 100 – 120 V (50 – 60 Hz)

Power Consumption

< 0.5 W standby
idle 100 W
max 1000 W


2 pairs Cu-terminal,
gold plated


+ 26 dB

Power Output

125 W @ 8 Ω
250 W @ 4 Ω
500 W @ 2 Ω

Pulse Power

> 5,000 W

Frequency Response (– 3 dB)

0 – 800 kHz


< 0.001% at 50 W @ 4 Ω
(20 Hz – 20 kHz)

IM Distortions

< 0.005 % SMPTE
< 0.0006 CCIR

Signal-to-noise Ratio

108 dB (5 W @ 1 kHz)

Channel Seperation

> 120 dB @ 1 kHz

Dampening Factor

> 10,000

Output Current Max

45 A (limited)


1 × balanced (XLR)

Input Impedance

2 kΩ balanced (XLR)