RDL STM-3 High Gain Microphone Preamp

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.

RDL STM-3 Features

• 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

• STM-3 high gain microphone preamplifier1

• Input500 Ω balanced; 5 kΩ unbalanced
• Phantom24 Vdc; IEC 61938: 2013, Filtered
• Outputs (2)+4 dBu 150 Ω balanced; -10 dBv unbalanced
• Frequency Response50 Hz to 30 kHz (± 1.5 dB)
• GainAdjustable 45 to 75 dB
• THD+N<0.05% (50dB gain)
• CMRR>50 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 Input24 Vdc @ 10 mA max.
• Power RequirementGROUND-REFERENCED, 24 Vdc @ 25 mA
• Dimensions (HxWxD)0.7" x 3" x 1.6"