Grace Design m103 single channel preamp/DI/EQ/compressor

Sale price$ 2,245.00 Regular price$ 2,495.00
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SKU: m103

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Grace Design m103 single channel preamp/DI/EQ/compressor


Grace Design m103 single channel preamp/DI/EQ/compressor

The m103 starts with the tried and true m101 microphone preamplifier circuity. For many engineers, the m101 is an introduction to what quality mic preamplification is all about, and the perfect starting point for a channel strip - musical, transparent and pure. Headroom, detail, clarity - its all there. Complete with our exclusive ribbon mic mode, a 75Hz HPF and 48V phantom.

The 3 band EQ section is built around single stage parallel tuning architecture, which minimizes circuitry and delivers natural tonal shaping from 20Hz to 20kHz. Controls include a fully parametric mid, with sweepable high and low bands which can be operated in shelving or peak modes. Because of its accuracy of this design, smaller increments of cut or boost can be heard, providing a greater level of control over tone shaping.

The compressor circuit is based on an optical attenuator - the purest, high fidelity gain control mechanism available. It provides gentle limiting to fairly heavy compression, while remaining neutral and transparent. The perfect way to zip it all up and send it downstream - clean, intact and alive.

10 segment gain reduction and output meters make monitoring compression and output levels simple. The front panel accessed HI-Z input makes this an amazingly high quality instrument preamp. Comprehensive I/O options allow the mic pre and EQ/COMP sections to be accessed independently of each other, and the order of the EQ/COMP is switchable.

A dual function link/ sidechain input on rearpanel is provided for inserting external sidechain signals (for de-essing, ducking) or connecting two m103's together for stereo compression applications. Predictably, the m103 is built to last, and proudly backed by our 5 year transferable warranty. So there it is, we've done it. The m103 - a channel strip by name, a powerful tool by design.



  • Fast and musical transimpedance microphone preamplifier architecture
  • Updated audio path with 0.5% precision metal film resistors
  • New 12 position gold plated rotary gain switch
  • High performance output line driver amplifier and HPF amplifier
  • Ribbon mic mode (also great for dynamic mics) -Relay bypass of phantom power decoupling capacitors, increased input impedance, and 48V lockout
  • 3-band presicion EQ, fully parametric mid band, peak and shelf mode for hi and low bands
  • newly designed optical compressor
  • Mic amp direct output
  • EQ/COMP section line input
  • Bombproof laser-etched black anodized frontpanel
  • Sealed gold contact relay for Hi-Z input switching
  • Built in power supply
  • Led indicators for +48V, Ribbon mode, and HPF
  • powerful 10 segment meters for gain reduction and output level
  • Five year transferable warranty on parts and labor
  • Made in the USA

  • Specfications

    GAIN RANGE (5dB steps)

    • Mic input 10-65dB
    • Hi-Z input -10-45dB

    THD+N 1kHz, 22Hz-22kHz BW

    • @ 20dB Gain +20dBu out <0.00085%
    • @ 40dB Gain +20dBu out <0.0010%
    • @ 60dB Gain +20dBu out <0.0050%


    • @ 40dB Gain +20dBu out 
    • SMPTE/DIN 4:1 7kHz/50Hz <0.0020

    NOISE - REFERRED TO INPUT @60dB Gain 22Hz-22kHz BW

    • 50Ω source <-130dB
    • 150Ω source <-128dB
    • 600Ω source <-124dB

    CMRR @60dB Gain, 3.5Vcm

    • 100Hz >60dB
    • 1kHz >75dB
    • 10kHz >65dB


    • Mic input @ 40dBm Gain -3dB 3.7Hz-140kHz
    • Hi-Z input @ 20dB Gain -3dB 1.2Hz-112kHz


    • Mic input 8.1kΩ
    • Mic input, Ribbon mode 20kΩ
    • Hi-Z input (unbalanced) 2.5MΩ
    • Hi-Z input (balanced) 5MΩ
    • Balanced Output 300Ω
    • Unbalanced Output 150Ω

    PEAK LED METERGreen threshold -10dBu

    • Red threshold +16dBu


    • 100k Ohm load, 0.1% THD +28dBu

    EQ/COMP Section

    • Output Trim -10 - +10dB
    • EQ: 3 Bands of 0-12dB Cut or Boost
    • Low Frequency Range 20Hz - 750Hz
    • Mid Frequency Range 500Hz - 4kHz
    • Mid Frequency Q 0.5 - 5
    • High Frequency Range 3kHz - 20kHz
    • Low and High Frequency Peak/Shelf switches 
    • Compressor - Inserts Pre or Post EQ
    • Threshold Range -15 - +15 dBu
    • Attack Range 3 - 200 ms
    • Release Range 0.03 - 3 s
    • Ratio Range 1:1 - 12:1
    • Gain Reduction 0 - 10dB

    THD+N 1kHz, 22Hz-22kHz BW

    • @ 0dB Gain +20dBu out <0.002%


    • @ 0dB Gain +20dBu out 
    • SMPTE/DIN 4:1 7kHz/50Hz <0.002%

    OUTPUT NOISE 22Hz-22kHz BW

    • @0dB Gain <-78dB

    CMRR @0dB Gain, 3.5Vcm

    • 100Hz >75dB
    • 1kHz >75dB
    • 10kHz >75dB


    • @0dB Gain -3dB 0.016Hz-150kHz


    • Line In 24kΩ
    • Main Out balanced 350Ω
    • Main Out unbalanced 150Ω
    • Link In - sidechain mode 100kΩ


    • EQ Peak threshold 6 dB below interstage clipping
    • Output Level VU Meter 0dB VU = +4dBu output
    • Gain Reduction Meter 0-10dB Gain Reduction


    • 100k Ohm load, 0.1% THD +28dBu


    • 4.5 lbs
    • H1.7” x W19” x D9.0”
    • 2.05 kg H4.3cm x W48.3cm x D22.9cm


    • 85-264VAC / 120-370VDC 14 Watts Max


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