The SSL X-Rack Mic Amp Module is a workhorse preamp with crystalline sound and versatile input amplifiers for mic, instrument, and line level sources
Perhaps the most remarkable thing about X-Rack modules is the fact that SSL has managed to enable them to behave with the consistency of digital software while retaining the character and musicality of analog devices. In fact, if you send a sine wave through two X-Rack modules and invert the phase of one, you’ll see that cancellation is nearly 100%. A very tricky thing to do with analog circuitry. The point is that with an X-Rack full of Mic Amp Modules, you can count on capturing your source material consistently in a multi-mic scheme, and hear precisely what you recorded. The Mic Amp Module also features versatile input options, including mic amp, front-panel instrument DI, and line input. Front-panel controls include high- and low-pass filters, phase reverse, selectable low- and high-impedance, plus phantom power. It also has a front-panel ground-lift switch to deal with hum from amplified instruments going in via the DI. Selectable L/R record outputs complete the picture. And with a linear frequency range out to 150kHz, plus +75dB gain and super low-noise performance, the X-Rack Mic Amp is both ribbon-mic friendly and suitable to capture the subtle nuance of anything from a jazz ensemble to orchestral instruments and voice.
SSL X-Rack Mic Amp—Just the Facts:
- Electronically balanced ultra-high bandwidth input with -5dB to +75dB gain control and Pad switch
- Continuously Variable input impedance control (1.2kOhm to 10kOhm) can accommodate signals from instruments or be adjusted to suit a wide range of microphones
- Phase Reverse and Phantom Power
- Dedicated Additional XLR Line Input
- Front panel instrument input with ground lift switch
- Independently switched 12dB/Octave HF (Low-Pass) Filter
- Independently switched 18dB/Octave LF (High-Pass) Filter
- Independent routing to L/R Record bus
SSL X-Rack Mic Amp Module—Under the Hood
The X-Rack Mic module contains three separate input amplifiers; a microphone amplifier, instrument input, and a line input. By default, the microphone input on the rear of the module active. Pressing the INST switch selects the mono instrument input jack on the front of the module, which is a very high-impedance, unbalanced input for guitar bass, keyboards, etc. To deal with hum from ground loops generated by amplified instruments, a ground lift switch sits next to the DI jack, which places a 1.2k ohm impedance in series with the sleeve of this connector and audio ground in the module. The gain of both mic and DI inputs is continuously variable between +12dB and +75dB.
Don’t be mislead by the apparent lack of a line-level input. The Mic Amp Module can accept line-level signals by varying the impedance of the Microphone input, which can be varied between 1.2 ohms and 10k ohm by selecting the ‘IMP IN’ switch and adjusting the ‘Z’ control. This allows the connection of line-level signals to the Microphone input if required, and provides an alternative input impedance for low-sensitivity dynamic microphones.
For hot signal sources, the Pad switch reduces the signal level of both the Microphone or Instrument inputs by 20dB. Phantom power can be switched on using the +48V switch.
To control unwanted room buildup in the lower frequencies, or give extra-bright condenser mics the smoother top end of a ribbon mic, the Mic Amp has a high- and low-pass filter section. Both filters can be switched into the circuit independently.
- HF (Low Pass): Frequency range 50kHz – 3kHz (–3dB point) Slope: 12dB/Octave
- LF (High Pass): Frequency range 30Hz – 600Hz (–3dB point) Slope: 18dB/Octave
Mic Amp output section
This small section contains a tricolor signal present indicator and two routing switches (Rec L and Rec R) which route the module signal onto a common internal record bus. The signal-present indicator measures signal immediately prior to the output amplifier. It will light green for output signals above the lower threshold of –60dBu, amber for signals between +4dBu and +24dBu, and lights red for signals above +24dBu.
If you’ve been wanting the sound of SSL’s large-format console but work in a small control room, the X-Rack enables you to build a mini SSL SuperAnalogue desk, starting with the Mic Amp as your input section. For more information, call or chat online with your PAD Studio Specialist today.
Mic Input (Signal applied to Microphone Input and measured at Output. Pad switched out and Input Gain control set to +12dB minimum)
- Gain: Continuously variable from +12dB to +75dB (Independently switchable 20dB Pad available)
- Input Impedance: Continuously variable from ≈1.2k ohm to ≈10k ohm
- Output Headroom: > +26dBu at onset of clipping
- THD + Noise (-18dBu applied, +28dB gain): < 0.003% at 1kHz; < 0.006% at 10kHz
- Frequency Response: +0.05dB/-0.1dB from 20Hz to 20kHz; –3dB at 150kHz
- Equivalent Input Noise: < –127dB at maximum gain; input terminated with 150 ohm: < –90dB at 0dB gain (+20dB with Pad ‘IN’)
- Common Mode Rejection: > 75dB from 50Hz to 1kHz; > 70dB at 10kHz (-10dBu applied, +30dB gain)
Instrument Input (Unbalanced signal applied to Instrument Input and measured at Output. Pad switched out and Input Gain control set to +12dB minimum)
- Gain: Continuously variable from +12dB to +75dB (independently switchable 18dB pad available)
- Input Impedance: 1M ohm
- Output headroom: > +26dBu at onset of clipping
- THD + Noise: < 0.03% at 1kHz; < 0.05% at 10kHz (-18dBu applied, +28dB gain)
- Frequency Response: +0.05dB/-0.1dB from 20Hz to 20kHz –3dB at 150kHz
- Equivalent input noise: < –82dB at +12dB (minimum) gain
- EIN (input terminated with 150 ohm): < –88dB at +28dB gain mid’ position
Line Input (Signal applied to Line Input and measured at Output. Input Gain control set to 0dB indent)
- Gain: Continuously variable from –20dB to +20dB
- Input impedance: > 10k ohm
- THD + Noise: < 0.005% from 20Hz to 20kHz (+24dBu applied, 0dB gain)
- Frequency response: ±0.1dB from 20Hz to 20kHz –3dB at 150kHz
- Equivalent Input Noise (Input terminated with 150 ohm): < –90dB