Posted in | Acoustic Sensor

High Intensity Acoustic Sensors: 765M30 & 765M35 Models

The High Intensity Acoustic Sensors (Microphones) Models 765M30 and 765M35 are developed for the monitoring of gas-borne sound in industrial applications. These sensors are compatible with type 316 stainless steel diaphragms and are designed for usage in corrosive settings.

When paired with the all-welded structure, the electrically isolated, coaxial stainless steel hermetic connection creates a perfect hermetic seal.

Electrically, Models 765M30 and 765M35 use piezoceramic sensing elements in a balanced and floating design to enable improved rejection of electrical noise in a variety of industrial settings. The inherent acceleration sensitivity of the acoustic element is eliminated by an inbuilt accelerometer. When utilized with a real differential input amplifier, the best results are obtained.

For customized versions of this sensor, contact the manufacturer.

  • High temperature to +500 Deg F
  • Vibration compensated
  • Electrically isolated
  • High sensitivity (2100 pC/psi)



Table 1. Source: Columbia Research Laboratories, Inc.

Transfer / Electrical 765M30 765M35
Charge Sensitivity 2100 +/-300 pC/psi
Frequency Response 2 Hz To 8,000 Hz
Dynamic Range 0.28 x 10-4 to 10 psi (191 dB SPL Max.)
Vibration Sensitivity 1.0 pC/g Typical, 2.0 pC/g Max.
Avg Temp Coeff of Sensitivity 0.08% / Deg F
Transducer Capacitance 14,500 pF +/-15%
Insulation Resistance 100 Megohms Min., 50 VDC Test
Isolation Resistance 100 Megohms Min., 50 VDC Test
Dielectric Strength 550 Vrms, 60 Hz, Element to Housing



Table 2. Source: Columbia Research Laboratories, Inc.

Environmental 765M30 765M35
Vibration Limit 100 g Max. (Sine)
Shock Limit 1,000 g Max., 0.25 mSec
Temperature Range -10 To +500 Deg F (-23 To +260 Deg C)
Humidity3 0 To 100% R.H.
Static Pressure 3,000 psi Max. (Diaphragm)
Electromagnetic Sensitivity 0.005 g (Equiv / 100 Gauss)



Table 3. Source: Columbia Research Laboratories, Inc.

Physical 765M30 765M35
Configuration Balanced Floating Compression
Size 1.375 In. Hex x 2.25 In. H (35.0 mm Hex x 57.2 mm H)
Weight 7.0 Oz (200 Gm)
Body & Diaphragm
Type 316 Stainless Steel
Electrical Interface Isolated 10-32 Coaxial Connector Isolated 10-32 Coaxial Connector
Supplied with 1/2-14 NPSM 
Straight Pipe Thread for Armored Shielding
Mounting 1.125 – 12 UNF-2A Straight Thread


NOTE: The unit is hermetically sealed when the connector is mated or protected.

High Intensity Acoustic Sensors: 765M30 & 765M35 Models

Image Credit: Columbia Research Laboratories, Inc.

Accessories Supplied

  • Standard Calibration Data
  • Low Noise Cable Assembly (3M) (300 pF)
  • Hardwood Storage Case

Other Equipment by this Supplier