Radio Design Labs STM-3 High Gain Microphone Preamplifier

High Gain Microphone Preamplifier - 45 to 75 dB Gain

The STM-3 is a quality low-noise microphone preamplifier designed for use in surveillance, commercial sound, broadcast, and recording where higher than normal gain is required. The STM-3 is very flexible, with gain adjustment from 45 to 75 dB, two balanced or unbalanced outputs, and available phantom supply input. Its low-distortion and low-noise performance make it the best choice, even when larger preamps could be used. The STM 3 supply input is single ended and operates from 24 Vdc. Operation from 12 Vdc is possible with a 6 dB reduction in headroom. Each output drives high or low impedance loads.

• Low-Noise, High-Gain, Mic Preamp
• Adjustable Output Levels
• High or Low Impedance Mic Inputs
• Mic Input to Line Outputs
• Two Balanced or Unbalanced Outputs
• Phantom Capability
• RF-Filtered Inputs

• Input: 500 Ω balanced; 5 kΩ unbalanced
• Phantom: 24Vdc; IEC 1938: 1996-12, Filtered
• Output (2): +4 dBu 150 Ω balanced; -10 dBV unbalanced
• Frequency Response: 50 Hz to 25 kHz (+/- 1 dB)
• Gain: Adjustable 45 to 75 dB
• THD+N: < 0.05% (50 dB gain)
• CMRR: > 60 dB (50 Hz to 20 kHz)
• Residual Noise: < -70 dB (below +4 dBu, 150 Ω source)
• Headroom: > 20 dB (24 Vdc supply); 14 dB (12 Vdc supply)
• Phantom Power Input: 24 Vdc @ 10 mA maximum
• Power Requirement: GROUND-REFERENCED, 24 Vdc @ 25 mA
• Ambient Operating Environment: 0 C to 55 C