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HOME  >>  PRODUCTS  >>  Assembeld Sigma22 ultra-low uV noise FET discrete DC stabilized servo Power supply
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Assembeld Sigma22 ultra-low uV noise FET discrete DC stabilized servo Power supply
Item ID:CL20-08-14
List Price:US$34.00
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Note: this is assembeld board.  Please tell us what the output votlage is you  need. we will adjust it well before shipping.


This power supply is based on the well-known Sigma22 V2.0 high-performance DC voltage regulator circuit at home and abroad. Its noise level is as low as uV, the background is dark, the space is quiet, and the overall sound quality is improved.
By replacing the trimming potentiometer, it can be used as 5V-36V dual power output, which is very suitable for the use of pre-amplifier, decoder DAC, headphone amplifier and power amplifier voltage level regulator.
The rational, stable, true, and natural balance of Sigma22 tends to monitor style, and the effect with lower-priced capacitors is also good. When using high-level HIFI capacitors, there will be a small amount of capacitor personality tone under the monitoring base. , Very wonderful.

Official information:


Size: 100mm*75mm*1.6mm (the center of the fixed hole is 4mm from the edge of the board)

PCB process: FR4 military grade, 1OZ copper, electroplating immersion gold.

Technical features:

1. Ultra-low noise (μV level), high PSRR

It uses a fully discrete single-stage error amplifier with a gain of 102.5dB, and uses capacitance multipliers to enhance PSRR (power supply rejection ratio). The whole can be divided into three stages, the first stage is differential amplification and current mirror/constant current source; the second stage is the voltage amplification stage (VAS), and the third stage uses the field tube as the source follower. It is commendable that the output noise is only about uV level under load! This is three levels less than the common mV, which is nearly a thousand times worse. No ic is used, so that the entire design can control each control loop node so that the performance parameters of the voltage regulator reach the best state of Zui

2. No current limit

To put it simply, the field tube MOSFET with high current output has no output current limit, as long as the heat dissipation is sufficient. The bottleneck of the output limitation is the wattage of the cow, the rectifier diode, and the fuse (but note that the original version did not use a fuse on the board...). The feature of no current limit allows the S22 to support many instantaneous large current needs. Especially power amplifiers. As long as you want current, S22 is ready. Remarks: The version currently on sale in our shop is a low-current version, which is affected by rectifier diodes, heat sinks, PCBs, etc. It is recommended that the output voltage does not exceed 30V and the load current does not exceed 1A. The standard heat sinks of the kits and finished boards sold in this shop can withstand close to 0.2 watts of power consumption. It can be estimated according to PT=VI (voltage difference * load current). When the heat is too large, it is recommended to use the chassis bottom plate Perform heat dissipation.

3. Ultra-high bandwidth

The fully discrete design of the S22 allows the bandwidth to be expanded by Zui. Since the output impedance of S22 is even lower than Zui's expensive low-ESR electrolytic capacitors, the fast charge and discharge speed of S22 is greater than that of traditional large pond capacitors. Surprisingly, the output impedance of S22 is only μΩ (generally the capacitance is about mΩ, a difference of 1000 times). In fact, the test line during the measurement occupies more of the impedance, so the value is still overestimated. For capacitive loads, even as high as 10000μF, S22 can be calm and comfortable, which makes S22 more application possibilities. The inflection point frequency of the low-pass filter is as low as 1.6 Hz to prevent diode switching noise from entering the error amplifier behind. In addition, this part has a soft-start function.

4. Flexible output, low internal resistance

The output voltage of S22 is adjustable, mainly determined by the ratio of the Zener diode and the two resistors.

Common output voltages are typically ±5V, ±9V, ±10V, ±12V, ±15V, ±18V, ±24V, ±27V, ±30V or ±36V. (even higher)

The output impedance of sigma22 is much lower than that of Zui's good low-ESR large-capacity electrolytic capacitors on the market. Thanks to the high bandwidth design of sigma22, sigma22 can easily cope with the ever-changing amplifier current demand, ensuring that the back-end amplifier can play the potential of Zui . (The output impedance is as low as μΩ, 1Ω=1000mΩ=1000000μΩ)

5. Automatic tracking of positive and negative voltage

There is tracking between the positive and negative output systems, that is, the negative output will follow the positive voltage at any time, which makes the voltage symmetrical, also greatly increases the common mode noise rejection ratio (CMRR), and avoids the popping sound of the switch. The positive and negative voltage error is less than 3%. If you need more precise consistency of the positive and negative voltage, you can fine-tune the resistance of the resistor R11=10K.

Selection of Zener diodes and potentiometers corresponding to different output voltages: (updated data)

When plus or minus 5~8V, Zener tube=3.3V, potentiometer=10K
When plus or minus 8~15V, Zener tube=3.3V, potentiometer=5K
When the voltage is positive or negative 15-30V, the regulator tube = 3.3V, potentiometer = 2K

You can contactt customer service if you need other voltages.

Input voltage requirements:

Generally, the voltage difference after the input voltage is rectified should be 6~10V higher than the output voltage.

[Calculation formula: input AC*1.414-output DC= 6-10V]

The relationship between the output DC voltage and the secondary AC voltage of the transformer is as follows:
Output: when ±5VDC, the transformer selects 2*9VAC
Output: when ±9VDC, the transformer selects 2*12VAC
Output: when ±12VDC, the transformer selects 2*15VAC
Output: when ±15VDC, the transformer selects 2*18VAC
Output: when ±18VDC, the transformer selects 2*20VAC
Output: when ±24VDC, the transformer selects 2*25VAC
Output: when ±30VDC, the transformer selects 2*30VAC
Output: when ±36VDC, the transformer selects 2*35VAC

About heat dissipation:

The standard heat sinks of the kits and finished boards sold in this shop can withstand close to 0.2 watts of power consumption. It can be estimated according to PT=VI (voltage difference * load current). When the heat is too large, it is recommended to use the chassis bottom plate Perform heat dissipation.

installation tips:

This power supply kit, as long as you carefully follow the markings on the PCB board, carefully solder the parts, and do not solder wrongly, you can ensure that the power is successfully once. According to the experience of other customers, the following points need special attention:

Constant current diode 2ma (202) and 5.6ma (562) are easy to confuse, please note that the transparent diode of the strip package is 562, and the other two transparent diodes are 202. The silver diode is a ZD Zener diode.
The models of the two power tubes are different by one letter, which is easy to confuse and needs attention. In addition, the power tube must be installed on the radiator in accordance with insulating rubber particles and insulating gaskets! Otherwise it will cause output short circuit and burn out the circuit board!

the following assembeld board photo just for reference!!

Reference circuit diagram: Sigma22 Ver2.0 (for reference only, the actual product has fine-tuning changes)
Assembled board
Items No:16032439
Assembled board
Items No:CL20-08-25
Assembled board
Items No:CL20-08-24
Assembled board
Items No:CL20-08-23
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