Musetec MH SA001: Flagship preamplifier with separate channel circuits

Musetec MH SA001 is the new flagship preamplifier with separate channel circuits. So separate that the body is divided into 2 parts by a partition. Operates in Class A. Uses current mode volume control circuitry designed using fully discrete components.

256 volume levels, frequently used volume areas with 0.25 dB resolution.

In a hifi system, the characteristics of the preamplifier have a decisive influence on sound reproduction. We researched preamps for 8 years to find a sound that would satisfy our audiophile passion, and the end product was this transistor flagship preamp, called the MH-SA001.

This preamplifier, with a completely self-designed circuit, uses 12 groups of amplifier modules operating in class A for each channel, and to achieve the best operating condition, various parameters of the circuit are set according to the corresponding functions in it. For example, there are matched JFET input modules for buffering the input signal, constant current driver modules for the volume circuitry, and high-current output modules for signal output.

Particular attention should be paid to the volume control circuit, which is an extremely important detail that should never be bypassed in a preamplifier. There are various audio volume potentiometers on the market, such as the more common and inexpensive ALPS 16/27 type carbon film potentiometer, mid-range potentiometer such as AN or TKD film potentiometer, high-end potentiometers such as some precision voltage divider type resistor potentiometers , and further – high-end potentiometers, for example, attenuator switches from Elma, Seiden, Amco and other brands. In general, potentiometers have a huge impact on sonic performance, and the reason for this lies mainly in their high impedances, reaching tens of kilo-ohms. The audio signal first passes through a high-resistance potentiometer and then enters the amplifier circuit. Too high an input impedance will affect the operating state of the amplifier and subsequently the sound.

To form the resistive attenuation network, we tried to use different types of potentiometers, such as Seiden four-terminals and 88 AN non-inductive resistors, and on the most commonly used gears we used silver AN resistors. This has to be our most “elite” effort, and can also be considered the “ultimate” of traditional mechanical potentiometers. We also tried using electronic volumetric chips, such as the MUSE7232x series from NJRC. Potentiometers with a multiplicative relay network of resistors were also used. All of the above solutions, each of which has its own advantages and disadvantages. The volume potentiometer solution we ended up using was inspired by our many years of experience developing DACs. We used a custom modular circuit to convert the input audio voltage signal into a current signal, and then attenuate the current signal through a constant low-impedance network. Thanks to this approach, we got the “ideal” potentiometer that we had been looking for for so long, and achieved the desired sound. The process of implementing the scheme was “difficult and painful.”

In addition to the “ideal” potentiometer, we paid special attention to the power supply. Poorly designed power supply leads to signal interference and interference, resulting in loss of purity and clarity of sound. Therefore we use 3 power transformers for the left and right channels and also for the control circuit. At the same time, we use isolators to decouple the digital control circuit and the left and right channels, resulting in the effect of complete independence of the left and right channels and control circuit, without a common ground. This completely eliminates crosstalk between channels, and also eliminates crosstalk between the digital control circuit and the analog circuitry. Although we use a single chassis for this preamp, the internal structure is completely independent from the three parts.

We also paid special attention to the selection of power supply decoupling capacitors. We tried dozens of capacitors over extensive listening and finally confirmed that different combinations of capacitors would also make a significant difference in sound. This process requires a lot of patience from you and the ability to enjoy the room, otherwise it is almost impossible to complete the task.

Thanks to the aforementioned commitment to extreme design, this preamp has an extremely full and tight sound across the entire listening range, realistic, natural, high and low frequency extension without compression, balanced energy distribution, outstanding texture and excellent sense of line. The balanced sound is better than my tube preamp, which was made at any cost, perhaps because the tube preamp uses a high impedance potentiometer, it doesn’t sound very natural. For me, the sonic performance of my tube preamp cannot meet my listening requirements for different types of music. And the new SA001 certainly surpasses my tube preamp in many sonic characteristics and meets my requirements.

Price : $5499