Twin-Servo™ - Specifications

The Jensen Twin-Servo 500 is a faithful recreation of Deane Jensen's famous 990 microphone preamp in a 500 series format. This unparalleled circuit design includes two cascaded 990 op-amps to share the load and provide 60dB of clean gain, as well as two servos that eliminate signal degrading capacitors from the audio path that allow for less than -120dBu of noise. Oversized Jensen input and output transformers produce an exceptionally wide frequency response and plenty of headroom. Twin-Servo is well-suited for recording highly dynamic sources, with 91dB of dynamic handling. Even more important than the specifications is the sound of the Twin-Servo; exceptionally natural and transparent, with detailed highs and an extended low end that will have you hearing your mics like never before.

Circuit type:  Two stage variable gain all discrete using original Deane Jensen circuit with IC DC servo. Jensen transformer coupled input and output.
Frequency response: 14Hz to 85kHz / 8Hz to 100kHz (±1dB / ±3dB)
Total harmonic distortion:  0.004%
Dynamic range:  91dB
Input impedance - XLR:   1.3kΩ
Input impedance - instrument:   220kΩ, unbalanced
Output impedance:   75Ω
Maximum output:  +22dBu
Mic preamp gain:  +60dB
Common mode rejection (CMRR): -72dB
Equivalent input noise (EIN):  -120dBu @ maximum gain
Total Harmonic Distortion (THD+N): 0.004%
Intermodulation distortion:  0.004%
Microphone input:  Transformer coupled, Jensen JT-15KE
Meter: 10 segment peak indicator with hold
Polarity reverse: 180°
Pad: -15dB
Ground lift (rear panel): Lifts ground on XLR inputs
XLR configuration: AES spec: pin-1 ground, pin-2 (+), pin-3 (-)
Power: 110mA
Phantom power: 48VDC - 10mA (as supplied by 500 frame)
High pass filter: 6dB/octave @ 150Hz
Construction: 500 Series module
Size: 5.25" x 1.5" x 7" (134mm x 38mm x 178mm)
Weight:  1.75lb (0.79 kg)
Shipping size: 6.75" x 1.875" x 9" ( 171mm x 48mm x 229mm)
Shipping weight: 2.20lb (0.997 kg)
Conditions: For use in dry locations only between 5°C and 40°C
Warranty:  Radial 3-year, transferable
Specifications are subject to change without notice.