SGP1, Reference-grade Class AB Stereo Audio Power Amplifier
2. THD+N: < 0.0003%(-110 dB); SNR: < -130 dB
3. Patented Driver Module
4. Ultra-low Noise and Extremely Fast Rise Time of the Power Module
5. 600,000 mm² of Heat Dissipation Surface Area
6. 4 Pairs of Tube Parallel Push-Pull Output
SGP1
Overview
The SGP1 is a Class AB reference stereo audio power amplifier designed for high-resolution audio (HRA) recording and playback systems. Developed by SONCOZ over 3 years, its extraordinary SNR and THD+N performance pushes the capabilities of fully discrete Class AB amplifiers to a whole new level. Each channel features a 4-parallel NPN/PNP power transistor push-pull output, delivering up to 120W into an 8Ω load-enabling the SGP1 to drive challenging speaker loads with ease.
The SGP1 is a Class AB reference stereo audio power amplifier designed for high-resolution audio (HRA) recording and playback systems. Developed by SONCOZ over 3 years, its extraordinary SNR and THD+N performance pushes the capabilities of fully discrete Class AB amplifiers to a whole new level. Each channel features a 4-parallel NPN/PNP power transistor push-pull output, delivering up to 120W into an 8Ω load-enabling the SGP1 to drive challenging speaker loads with ease.
The SGP1 is not only a core product of SONCOZ but also lays the foundation for the brand's future product direction. Specifically designed for speaker systems to deliver acoustic expression, it achieves rich sound quality gradation from deep bass to clear high tones.
Family Style Design
We believe that every aspect of our products such as the look and satisfying feel of the controls contributes to the overall SONCOZ product experience. Because of this, SONCOZ products exude the hallmarks of Scandinavian design-simple, elegant, with approachable and easy-to-understand functionality, such as our SGD1, SGA1, etc. In other words, SONCOZ products follow a minimalist design: nothing more, nothing less. Everything is balanced, proportional and harmonious.
We believe that every aspect of our products such as the look and satisfying feel of the controls contributes to the overall SONCOZ product experience. Because of this, SONCOZ products exude the hallmarks of Scandinavian design-simple, elegant, with approachable and easy-to-understand functionality, such as our SGD1, SGA1, etc. In other words, SONCOZ products follow a minimalist design: nothing more, nothing less. Everything is balanced, proportional and harmonious.
Reference-Grade Performance
High-resolution audio is intrinsically tied to low noise and low distortion. System noise is the lower resolution limit of an analog system, because it determines whether the smallest signal is masked by the noise floor.
Therefore, it is highly desirable to pursue an inherent low noise level and wide dynamic range. The full rated power output with A-weighted SNR is approximately 130 dB, which makes the SGP1 15 to 30 dB quieter than most top-quality power amplifiers. A 130 dB SNR is approximately equivalent to the noise performance of an excellent 22-bit digital system.
Therefore, it is highly desirable to pursue an inherent low noise level and wide dynamic range. The full rated power output with A-weighted SNR is approximately 130 dB, which makes the SGP1 15 to 30 dB quieter than most top-quality power amplifiers. A 130 dB SNR is approximately equivalent to the noise performance of an excellent 22-bit digital system.
Power Output Stage
The role of the power amplifier is to faithfully amplify the sound signal and precisely vibrate the speaker. Thus, excellent drivability and stable linearity of the output circuit are essential. SGP1 is ready for instantaneous high energy and speaker impedance changes. For the circuit configuration with such mighty power, SGP1, based on our long experience in amplifier development, finally features a patented module and 4 pairs of transistor parallel push-pull output amplifier circuits. This transistor design extends high-frequency response and features tighter tolerance gain matching between complementary NPN/PNP pairs.
The role of the power amplifier is to faithfully amplify the sound signal and precisely vibrate the speaker. Thus, excellent drivability and stable linearity of the output circuit are essential. SGP1 is ready for instantaneous high energy and speaker impedance changes. For the circuit configuration with such mighty power, SGP1, based on our long experience in amplifier development, finally features a patented module and 4 pairs of transistor parallel push-pull output amplifier circuits. This transistor design extends high-frequency response and features tighter tolerance gain matching between complementary NPN/PNP pairs.
These circuits reduce distortion at high frequencies or low volumes, resulting in quieter background noise for the SGP1. Meanwhile, they convey sound emotions with fine detail and intensity, and precisely reproduce even the most minimal sound details.
Patented Driver Module
The SONCOZ-patented driver module virtually eliminates distortion at all input signal levels and loading conditions. When combined with the push-pull output stages, which switch between different loads, the SGP1 shows no crossover distortion. Without crossover distortion, low-frequency details are rendered with precision, while the SGP1 remains virtually distortion-free even when driving heavy loads.
The SONCOZ-patented driver module virtually eliminates distortion at all input signal levels and loading conditions. When combined with the push-pull output stages, which switch between different loads, the SGP1 shows no crossover distortion. Without crossover distortion, low-frequency details are rendered with precision, while the SGP1 remains virtually distortion-free even when driving heavy loads.
High Performance Power System
Realistic sound quality requires abundant power, which serves as the cornerstone of amplifier design for SGP1 audio systems. In fact, we have developed new high-performance power modules to meet the substantial power requirements of the amplifier modules. This enables the SGP1 to deliver immediate and continuous powerful output. After AC input and before rectifier filtering, the SGP1's power module is equipped with four large 2700uF/200V capacitors to suppress grid interference and noise, providing a strong guarantee for the SGP1 to obtain a pure power supply.
Realistic sound quality requires abundant power, which serves as the cornerstone of amplifier design for SGP1 audio systems. In fact, we have developed new high-performance power modules to meet the substantial power requirements of the amplifier modules. This enables the SGP1 to deliver immediate and continuous powerful output. After AC input and before rectifier filtering, the SGP1's power module is equipped with four large 2700uF/200V capacitors to suppress grid interference and noise, providing a strong guarantee for the SGP1 to obtain a pure power supply.
The ultra-low noise and extremely fast rise time of the power module, coupled with the absolute linear amplification of the power amplifier module, enable the SGP1 to produce naturally fast, clean, and agile sound across the audible frequency response range. More importantly, to reduce power supply and output transmission loss under high power, the main current wires between the power supply unit and the output stage are directly hardwired using multi-strand 6N OCC single-crystal copper wire.
The ultra-low noise and extremely fast rise time of the power module, coupled with the absolute linear amplification of the power amplifier module, enable the SGP1 to produce naturally fast, clean, and agile sound across the audible frequency response range. More importantly, to reduce power supply and output transmission loss under high power, the main current wires between the power supply unit and the output stage are directly hardwired using multi-strand 6N OCC single-crystal copper wire.
No Warm-Up Required
Unlike most Class AB power amplifiers, the SGP1 reaches its full rated performance in less than one minute. For this reason, there is no need to keep the SGP1 powered on when not in use. The SONCOZ-patented driver module in the SGP1 keeps it very stable over a wide range of operating temperatures.
Unlike most Class AB power amplifiers, the SGP1 reaches its full rated performance in less than one minute. For this reason, there is no need to keep the SGP1 powered on when not in use. The SONCOZ-patented driver module in the SGP1 keeps it very stable over a wide range of operating temperatures.
High Efficient Cooling System
Each heatsink starts with a 5.2 kg aluminum block, and after approximately 3 hours of machining, 60% of the material is removed to yield a refined 2 kg aluminum heatsink. This design provides over 300,000 square millimeters of heat dissipation surface area per amplifier. More importantly, the thickness of the heatsink fins varies slightly to help reduce resonance and ringing in the heatsink, while multiple high-power heat pipes evenly distribute heat for optimal thermal and electrical performance. This high-efficiency heatsink design greatly improves the cooling capacity of the power amplifier module, ensuring the SGP1 operates safely and reliably at full rated power.
Each heatsink starts with a 5.2 kg aluminum block, and after approximately 3 hours of machining, 60% of the material is removed to yield a refined 2 kg aluminum heatsink. This design provides over 300,000 square millimeters of heat dissipation surface area per amplifier. More importantly, the thickness of the heatsink fins varies slightly to help reduce resonance and ringing in the heatsink, while multiple high-power heat pipes evenly distribute heat for optimal thermal and electrical performance. This high-efficiency heatsink design greatly improves the cooling capacity of the power amplifier module, ensuring the SGP1 operates safely and reliably at full rated power.
Front Panel
1. Left and right channel outputs power pointer | 2. Left channel output status indicator |
3. Power status indicator | 4. Right channel output status indicator |
5. Power switch(latching switch) | |
Design Details
Check the voltage level switch and switch it to your local voltage. The AC input connector accepts standard IEC input cables. Use a grounded cable appropriate for your location. The fuses are located in the bottom compartment of the AC input connector.
Indicators
Connect The Audio Inputs
The SGP1 features left and right balanced XLR audio inputs. If you don’t have a balanced audio source, special adapter cables are required. The adapter cables convert the three-wire balanced connection into an unbalanced RCA output. Please note that unbalanced RCA sources will limit the overall performance of the playback system due to the noise limitations of unbalanced output drive stages. High-level balanced interconnects are required in low-noise systems. We strongly recommend using balanced interconnects to maximize the SGP1's performance.
The SGP1 provides very high-quality custom twist-lock speaker connections. These connectors have very low resistance and the ability to reliably carry high current.（Use OUT L/R+ and OUT L/R- for left/right channel output）
Test
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Dimensions | 350mm(W) * 260mm(D) * 125mm(H) | Containing Protrusion |
Net Weight | 8.8 Kg | Without packaging and Accessories |
Rated Out Power | 240 W * 2 @ 4 Ω, 120 W * 2 @ 8 Ω | Max Undistorted Output |
SNR | 130 dB, A-Wt., 20 ~ 20kHz | Full Rated Power Output |
THD+N | < -110 dB(< 0.0003%), A-Wt., 20 ~ 20kHz | Full Rated Power Output |
Output Current | 8.5A Peak Output Current per Channel | Load Impedance≥2Ω |
Output Voltage | 95 Vpp Peak-to-Peak Output per Channel | Full Rated Power Output |
Output Configuration | Bipolar 4-Parallel Push-Pull per Channel | Patented Driver Module |
Frequency Response | ± 0.12 dB @ 8 Ω; ± 0.13 dB @ 4 Ω | @20 ~ 20kHz |
Crosstalk | -110 ~ -90 dB | @1k ~ 20kHz |
Input Sensitivity | 2.5 Vrms or 28 dB | Fixed Gain Output |
Input Impedance | 20kΩ | Fixed Gain Output |
Environmental | 0℃ to 50℃ Ambient Temperature; Up to 80% Humidity; Non-condensing | |
From SONCOZ Lab @AC 220 V/50 Hz | ||
Q1: Will stacking the SGP1 with other equipment affect heat dissipation?
A1: The top cover and bottom plate have ventilation holes covered with dust-proof nets. The bottom is also raised to allow for ventilation. The main heat dissipation is handled by the two large side heat sinks. Therefore, stacking it will not cause issues as long as proper ventilation is maintained.
Q2: What is the output power of the SGP1? Can it drive a 8Ω@150W speaker?
A2: The SGP1 specifies its undistorted output power: 4Ω@240W or 8Ω@120W per channel.
This is measured under the condition of 1 kHz, THD+N <0.0003% (-110dB). There is some power headroom, so it can drive a 150W speaker. It is recommended to contact customer service to arrange a trial listen.
Q3: What is the power consumption of the SGP1?
A3: 240W×2 (Output Power) / 0.6 (Efficiency) = 800W.
Adding standby power consumption of about 50W, the total rated power consumption is approximately 850W.
Q4: What is the standby power consumption of the SGP1?
A4: Approximately 40W~70W. Standby power consumption varies slightly depending on different international voltage levels.
Q5: What is the power supply (transformer) consumption of the SGP1?
A5: The SGP1 uses a custom LLC high-frequency switching power supply with a custom transformer (not a toroidal transformer). Peak power is 1200W, rated continuous output power is over 850W.
Q6: Why doesn't the SGP1 use a linear power supply? Won't a switching power supply degrade the sound quality?
A6: Limited by the chassis size, a switching power supply was used. The power supply module took over two years to debug and iteratively optimize until its performance fully met our product design requirements. The switching power supply frequency is above 130kHz and does not degrade the amplifier's sound quality.
Q7: What is the damping factor of the SGP1? Is it high or low?
A7: Damping Factor = Speaker Impedance / Amplifier Output Impedance (10mΩ).
Taking an 8Ω speaker as an example: 8Ω / 10μΩ = 800. This damping factor is considered very high.
Q8: Does the SGP1 have gain? Is it adjustable?
A8: The SGP1 has a fixed gain of 24dB, determined by its internal discrete op-amp, and is not adjustable.
Q9: What is the slew rate of the SGP1?
A9: The slew rate is determined by the internal discrete op-amp and is 28V/μs. This means the output voltage can rise by 28V per microsecond, comparable to precision op-amps.
Q10: What is the sensitivity of the SGP1?
A10: Sensitivity is 2.5Vrms (or 24 dB). This means when the input signal amplitude reaches 2.5Vrms, the SGP1 can output full power.
Q11: What is the signal-to-noise ratio (SNR) of the SGP1?
A11: 130dB.
Q12: What is the frequency response range of the SGP1?
A12: 20Hz - 20kHz (±0.1dB).
Q13: What is the input impedance of the SGP1?
A13: 20kΩ.
Q14: Does the SGP1 have a preamp function?
A14: No, the SGP1 is a pure power amplifier (rear amplifier) and needs to be paired with a preamplifier. Input sensitivity is 2.5Vrms for balanced input.
Q15: What is the Class A output power of the SGP1?
A15: Approximately 5W, with slight practical deviations.
Q16: Why doesn't the SGP1 have a cooling fan?
A16: Fans generate noise, and poorly handled back EMF from the motor can increase system interference.
Q17: What are the key parameters of the SGP1 amplifier?
A17: Rated power: 4Ω 240W*2, 8Ω 120W*2; Signal-to-Noise Ratio (SNR): 130dB; THD+N: <0.0003%.
Q18: Can I use a mobile phone or a Bluetooth receiver as the preamp?
A18: Yes, but be careful to set the volume to minimum during the first connection.
Q19: What amplifier module is used?
A19: A self-developed amplifier module architecture.
