In a HiFi system, the quality of the preamplifier has a crucial impact on the sound reproduction. We've been working on preamps for 8 years, and our passion as audiophiles is to find the ultimate sound that satisfies us, and the result is the flagship SA001 preamp.
The volume adjustment circuit needs to be highlighted, as it is an extremely important part of any preamp that cannot be bypassed. There are a variety of volume potentiometers on the market, such as the more common ALPS 16/27 carbon film potentiometers, the mid-range film potentiometers such as AN or TKD, and the high-end precision resistor divider potentiometers such as Elma, Seiden, Amco, etc. The impact of the potentiometer on the listening is huge, because the impedance of this kind of potentiometer is very high, and the characteristics of the material are also different, when it is added to the input of the amplifier as a signal channel, it is very easy to affect the performance of the amplifier, resulting in a very obvious change in the sense of listening.
In the process of developing the preamp, we have tried various types of high-end potentiometers, such as voltage divider potentiometers made of AN silver resistors, and also tried electronic volume chips, such as NJRC's MUSE72320 series. The final volume adjustment part, using a fully discrete circuit design, low-impedance current transmission mode, completely avoids the mechanical potentiometer and electronic volume chip that we tried before, and finally contributes to the sound we want, full and powerful, wide sound field, clear and textured. And the implementation process of such a circuit is "difficult and painful".
In addition to the "ideal" potentiometers mentioned above, we pay special attention to power supply design. Interference and signal crosstalk caused by poor power supply design can lead to a decrease in sound purity and poor focus. The SA001 pre-stage uses three power transformers. The power supply of the left and right channels and the control part is separated from the transformer, so that the crosstalk caused by magnetic coupling can be avoided, and this practice is proved to be effective, and at the same time, we isolate the digital control part and the left and right channels through the signal isolator, which can be said to completely eliminate the crosstalk of each part of the signal.
In terms of chassis structure, the left and right channel circuits of the SA001 preamplifier use a separate design, which is located on the top layer of the chassis and separated by thick metal plates in the middle. The power supply part is designed at the bottom of the chassis, and the amplification circuit on the top layer is isolated by the metal plate of the chassis, and when the top plate of the chassis is covered, it is equivalent to placing the left and right channels in their respective sealed cavities.
We also pay special attention to the selection of power supply decoupling capacitors. We searched for dozens of capacitors for a long time to listen to the screen, and finally confirmed the right match, different capacitor combinations will also significantly change the listening experience. This process requires a lot of patience and a lot of fun, otherwise it's almost impossible. For example, we chose Duelund capacitors for power filtering.
Thanks to the above-mentioned pursuit of extreme design, this preamp has an extremely rich sound in all frequency bands, realistic, natural, high and low frequency extension without compression, balanced energy distribution, outstanding texture, and excellent focus. And this kind of listening sensation has completely surpassed the vacuum tube preamplifier I used to do at any cost.
The main features of SA001 are as follows.
1. Separate all circuits of left and right channels to achieve complete isolation.
2. All Class-A amplification circuit design.
3. Full discrete components low resistance path current mode volume control circuitry.
4. 256 volume levels, with 0.25dB step resolution for common volume areas.
5. Frequency Response -1dB 1.3Hz~900Khz.
6. THD + N lowest about 0.00049% (A-weighted).
7. 5 input ports, RCA*3, XLR*2 .
8. Support RCA input to XLR output, or XLR input to RCA output.
9. Overall dimensions WxDxH 430x380x122mm.
10. Weight 12.2kg.
The volume adjustment circuit needs to be highlighted, as it is an extremely important part of any preamp that cannot be bypassed. There are a variety of volume potentiometers on the market, such as the more common ALPS 16/27 carbon film potentiometers, the mid-range film potentiometers such as AN or TKD, and the high-end precision resistor divider potentiometers such as Elma, Seiden, Amco, etc. The impact of the potentiometer on the listening is huge, because the impedance of this kind of potentiometer is very high, and the characteristics of the material are also different, when it is added to the input of the amplifier as a signal channel, it is very easy to affect the performance of the amplifier, resulting in a very obvious change in the sense of listening.
In the process of developing the preamp, we have tried various types of high-end potentiometers, such as voltage divider potentiometers made of AN silver resistors, and also tried electronic volume chips, such as NJRC's MUSE72320 series. The final volume adjustment part, using a fully discrete circuit design, low-impedance current transmission mode, completely avoids the mechanical potentiometer and electronic volume chip that we tried before, and finally contributes to the sound we want, full and powerful, wide sound field, clear and textured. And the implementation process of such a circuit is "difficult and painful".
In addition to the "ideal" potentiometers mentioned above, we pay special attention to power supply design. Interference and signal crosstalk caused by poor power supply design can lead to a decrease in sound purity and poor focus. The SA001 pre-stage uses three power transformers. The power supply of the left and right channels and the control part is separated from the transformer, so that the crosstalk caused by magnetic coupling can be avoided, and this practice is proved to be effective, and at the same time, we isolate the digital control part and the left and right channels through the signal isolator, which can be said to completely eliminate the crosstalk of each part of the signal.
In terms of chassis structure, the left and right channel circuits of the SA001 preamplifier use a separate design, which is located on the top layer of the chassis and separated by thick metal plates in the middle. The power supply part is designed at the bottom of the chassis, and the amplification circuit on the top layer is isolated by the metal plate of the chassis, and when the top plate of the chassis is covered, it is equivalent to placing the left and right channels in their respective sealed cavities.
We also pay special attention to the selection of power supply decoupling capacitors. We searched for dozens of capacitors for a long time to listen to the screen, and finally confirmed the right match, different capacitor combinations will also significantly change the listening experience. This process requires a lot of patience and a lot of fun, otherwise it's almost impossible. For example, we chose Duelund capacitors for power filtering.
Thanks to the above-mentioned pursuit of extreme design, this preamp has an extremely rich sound in all frequency bands, realistic, natural, high and low frequency extension without compression, balanced energy distribution, outstanding texture, and excellent focus. And this kind of listening sensation has completely surpassed the vacuum tube preamplifier I used to do at any cost.
The main features of SA001 are as follows.
1. Separate all circuits of left and right channels to achieve complete isolation.
2. All Class-A amplification circuit design.
3. Full discrete components low resistance path current mode volume control circuitry.
4. 256 volume levels, with 0.25dB step resolution for common volume areas.
5. Frequency Response -1dB 1.3Hz~900Khz.
6. THD + N lowest about 0.00049% (A-weighted).
7. 5 input ports, RCA*3, XLR*2 .
8. Support RCA input to XLR output, or XLR input to RCA output.
9. Overall dimensions WxDxH 430x380x122mm.
10. Weight 12.2kg.
