Soulution 501

Solid state with soul?


The 501 monoamplifiers are based in many areas on the proven technical concepts of the Series 7. However, the "small" monoamplifiers do not have to hide behind their big brothers.


The amplification circuit of the 501 monoamplifier, is based on the technology of the amplifiers 710 and 700. Core is a novel voltage amplification stage without feedback to the input (no differential amplifier!). It consists of linearized amplifier stages which operate up to a cutoff frequency of 80 MHz. The current amplification is done in three stages, each stage uses a very small and thus almost linear operating range. The high Class A operation supplemented by 47,000 microfarads of storage capacitors are resulting in a nearly infinite impulse response. Massive copper bars on the amplifier board and to the speaker terminals ensure that the power of the 501 monoamplifier is actually available at the speaker. The high-precision idle current management ensures optimal Class A operation for all operating conditions, without the necessity of any readjustment in the music signal. Optimal sound is thereby guaranted immediately after switching on. Extensive control circuits that protect against high frequency or DC signals at the input or output short circuit ensure safe operation in all situations. The input level is also monitored continuously.


A total of six power supplies - optimized for each function - feed the 501 monoamplifier. The power supplies to supply the digital and audio circuits are electrically isolated from each other through opto couplers and transformers . Two modern switched-mode power supplies with a total power 1'200VA complemented by high performance filtering at the input and output provide supply voltages in audiophile quality. Locally, these voltages are additionally stabilized with 6 high speed soulution voltage regulators. They are considerably more stable than achievable with any conventional, transformer-based power supply technology.


The 501 Monoamplifier is operated via its rotary control on the front panel. It can be switched on by one another soulution devices with the LINK function.


Analogue inputs:

- 1 x balanced input (XLR)

Analogue outputs:

- 1 x balanced output (XLR)

- 1 pair speaker binding posts


Matej Isak

Mono and Stereo ultra high end audio magazine
All rights reserved, December 2011