Saxum Mono Block

The Synaestec Saxum amplifier have made a statement in the high-end audio industry. Its outstanding noise performance, vanishing low distortion and ultra-wide bandwidth are unsurpassed.

Nevertheless, we have been asked frequently whether the Saxum can be bridged into mono for the even higher output power. The answer is yes and no. It is possible to connect the Saxum into bridge-tied load, but just like any other bridged amplifiers, the noise will be increase and the extra demand of current will easily make the amplifier overheat. Therefore, it is not recommended.

Finally, we have successfully developed numerous techniques to overcome all the limitations. The Saxum mono block has achieved an astonishing 134dB dynamic range, much wider than the capability of human hearing sense. The Saxum mono block is the bigger and better, the absolute state of the art amplifier.

A complete redesign

For the dual monaural Saxum amplifier, it is the best practice to isolate the stereo channels as much as possible in order to achieve the lowest crosstalk. On the contrary, in the case of the mono block Saxum, it would be the best to integrate the in-phase and the reversed-phase sections as much as possible for the best common mode noise rejection. This is the reason why the mono block version is actually a complete redesign, both in the structure and circuit layout.


Customized dual mode compound amplifier

The dual mode amplifier circuit is the core technology of the Saxum. It combines the benefit of ultra-low noise, vanishing low distortion of the trans-conductance frontend, and the wide bandwidth, high slew rate of the trans-impedance backend. This revolutionary technology is now further optimized in order to adapt to the much higher power bridged-tied load amplifier application.

Remote sensing error correction

Bridge tie load amplifiers used to be noisier because the in-phase and reverse-phase circuit failed to operate in unity. This is particularly true for high power amplifiers where their size is big and the two channels are physically separated apart. We have eliminated this drawback by the use of remote sensing error correction.

In the Saxum mono block, the amplifier circuit is divided into two sections, the in-phase section and the reverse-phase section. In each section, not only the hot and the cold audio signal, but also the internal reference voltage is ingeniously routed out of their corresponding circuit board through a self-shielding twin-axial cable. The signals from each section will then go to the star connection point located on the centralized input circuit board. Doing this, the error correction function of the in-phase and reverse-phase amplifier sections are being forced to reference to the exact same point, cancelling any dissimilarity. The result is extremely promising. The noise floor of the mono block Saxum is 11% lower than that of the original dual monaural version.

Closed loop ultra-high current regulated power supply

The dual monaural power supplies used in the Saxum are replaced by one big, ultra-high current power regulator. This is the second-generation design equipped with closed loop control, which is able to provide much more stable performance especially when driving low impedance loudspeakers. Together with the use of twice the amount of regulator transistors, gold plated solid copper power bus bars and magnetically shielded toroidal transformers, it is the perfect power supply for this gigantic mono block which can output 900-watt into 4-ohm continuously.

Zero delay thermal protection

Heat is the major enemy for every solid-state power amplifiers, even more for high power class AB amplifiers. The mono block Saxum is installed with thermal detector not on the main heatsink, but directly on top of every output transistors. There are 44 of them inside each of the mono block. This will ensure zero time lag reaction and instant protection against any potential failure. The mono block Saxum is well prepared for driving power hungry monster size loudspeakers.

Non-invasive current limit

In order to eliminate ballast resistors or any series current sensing element that would inevitably increase the output impedance of the amplifier, non-invasive current sensors are installed in the Saxum mono block. This advanced non-invasive current limit circuit will turn off the amplifier only when the current limit threshold is exceeded. This current limit action is very precise, highly repeatable and without any side effect. It is totally invisible even when the amplifier is drawing tremendously high output current.

Resonance free low profile heat sink

Due to the generous amount of class-A bias current applied to the output stage of the Saxum mono block, its static power dissipation is as high as 180W for each channel. That means a big heat sink is required to dissipate this high idle power. Unlike traditional long fin heat sink, the heat sink of the Saxum mono block is a low profile design that is immune to mechanical resonance. 5mm thick solid copper bars act as heat pipe that effectively distribute the heat evenly around all four side panels of the aluminium housing. No noisy ventilation fan or ringing metal fin is used.

Self-leveling Tri-axial mechanical suspension

Weighting more than 120Kgs, the Saxum mono block requires dedicated mechanical supporting structure. Four enormous suspension feet loaded with special damping springs, are strategically orientated to provide balanced compliance in both the horizontal and vertical directions. The Saxum mono block is 360 degree isolated from the vibration coming from any angle, maintaining a perfectly steady platform for the sensitive electronic circuit within.



Power output:

450 W RMS, 8Ohm
900 W RMS, 4Ohm
1500W RMS, 2Ohm

Frequency response:

10 Hz to 20 kHz (+0/-0. 2 dB)

Voltage gain:

26.7 dB (+/-0.5 dB)



Signal to Noise ratio:

>134 dB (A weighting)

Damping factor:


Input impedance:

20K Ohm asymmetrical
40K Ohm symmetrical

Power consumption:

250 Watt typical

2800 Watt maximum


520 mm x 544 mm x 618 mm (W x D x H)


130 kg