StereoLM.RU - Stereo Level Meters
Universal signal level indicator (stereo) on the dBu/dBVU/power scales with a self-choice of four display modes - peak level, TrueRMS, peak-factor and dynamic of the audio signal StereoLM-PA ver 1.0

Universal signal level indicator (stereo) on the dBu/dBVU/power scales with a self-choice of four display modes - peak level, TrueRMS, peak-factor and dynamic of the audio signal StereoLM-PA ver 1.0

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To connect the power supply a standard USB-micro connector is provided, as well as two through contact pads for self-soldering wires. For power supply you can use an unstabilized DC source with voltage changes within the specified limits.

To connect external audio signals two standard 3.5mm Jack connectors are provided (same pinout each), as well as through contact pads for self-soldering of wires, for example, when the indicator is directly connected to the outputs of the Power Amp, including bridge type (with outputs that do not have a common point). When the plug is connected to the 3.5mm Jack connectors, one of the differential input lines of the left channel is automatically connected to a similar differential input line of the right channel – this connection is electrically connected to the common signal source line inside the connector. The remaining differential input lines of both channels are connected to the signal lines of the left and right channels of the signal source. When removing the plug from the 3.5mm Jack connector the connection circuit of the two differential lines between the channels automatically opens again. Since the audio inputs are made according to the scheme of instrumental amplifiers it is not necessary to check the polarity between the signal source and the indicator inputs.

The operating modes are selected cyclically one by one with each short pressing of the built-in button on the PCB. The selected mode is stored in the non-volatile memory of the device and is restored at the next supply voltage.
Price List
Batch (pcs)
Price for 1 pc
≥ 1013.49$
≥ 2013.32$
≥ 3013.28$
≥ 4013.25$
≥ 5013.24$
≥ 10013.17$
1 pc  ✔  in stock
Key Features
  • Independent selection of the display mode using the built-in button: Peak level, TrueRMS level, Peak-factor, Dynamics with AGC.
  • Two hardware voltage modifications: StereoLM-PA-DBU (dBu scale), StereoLM-PA-DBVU (dBVU scale).
  • Four hardware modifications for output power from 0.002 to 125 W (0 dB = 1 W): StereoLM-PA-R02 (dB scale, RL = 2 ohms), StereoLM-PA-R04 (dB scale, RL = 4 ohms), StereoLM-PA-R08 (dB scale, RL = 8 ohms), StereoLM-PA-R16 (dB scale, RL = 16 ohms)
  • Input differential instrumental amplifiers provide the possibility of direct connection to signal sources both with a common point (AUX) and to high-voltage bridge output stages (Power Amp) without a common point.
  • The display range is from -27 to +21 dB.
  • Measuring the level of both positive half-waves of audio signals and negative ones, unlike 99% of similar budget indicators, which control only positive half-waves, cutting off and ignoring negative ones.
  • 23 points in each scale with optimally selected colors for the comfort visualization.
  • Wide supply voltage range from 5 to 15 V.
  • A marker (point) for fixing peak values with freeze and slow falling.
  • Detection of the constant voltage and signal limitations in each channel.
  • Large input capacitance to expand the range of analyzed frequencies of signals in the woofer region.
  • Standard connectors for quick connection to external circuits, as well as contact pads with holes for connecting (soldering) your own wires.
  • Compact size and four mounting holes for easy integration into sound equipment.
  • The applied circuit solutions and techniques in the design of the PCB exclude the possibility of introducing distortions into the primary signal circuits, such as background noise due to the operation of the microprocessor, LED scales, etc., which are characteristic of indicators from other manufacturers.
Block Diagram
StereoLM-PA - Block Diagram
Indication modes
Peak level, TrueRMS level, Peak-factor, Dynamic with AGC
Supply voltagefrom 4.8 to 15 V
Incorrect power supply polarity protectionNo
Current consumption<40.0 mA
Without current consumed by the LEDs.
Number of audio channels2 (stereo)
Lots of LEDs supported54
Two scales of 23 level LEDs + 2 distortion indicators in each. Additionally, there are 4 indicators of the selected mode.
Signal distortion detectorYes
Detection of constant voltage (VDC) and signal limitation (CLIP) in each channel.
Signal sweep during measurementBipolar
Positive and negative half-waves separately.
StereoLM-PA - User Guide 2023-05-09 [0.95 MB]
Terms of use and warranty conditions
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