The VHD+ Pre is an immensely versatile recording and processing device. It can deliver ultra clean SSL SuperAnalogue™ grade recordings but also features a switchable VHD mode. SSL’s patented Variable Harmonic Drive (VHD) system uses a 100% analogue signal path to generate rich harmonic distortion. As you increase VHD input gain, the Variable Harmonic Drive process introduces either 2nd or 3rd harmonic distortion or a blend of the two to your source material. At lower gain settings it adds gentle valve-style warmth or a touch of transistor edge. As the gain is increased the more extreme the distortion becomes until at high gain settings it delivers fierce trashy bipolar transistor style grunge.
This new 500 series version features front and rear inputs with four different impedance selections making it an extremely versatile mic pre and DI box for a wide range of microphones and instruments.
The Mic Amp provides up to +75 dB of super clean gain. The VHD switch along with the Drive control provides a variable mix of 2nd to 3rd order harmonics to add warmth and colour to the signal.
A Trim control provides +/- 20dB of output trim, which allows the Mic Pre to be ‘driven’ and then the output dialled back to prevent overload of the next module in the chain.
An 18dB/Octave High Pass Filter provides a way to filter low frequencies such as floor rumble and is switched to bypass it from the signal path.
The front panel 1/4” Tip/Ring/Sleeve (TRS) Jack Socket provides a convenient way to connect instruments when the module is fitted in a rack. This balanced input overrides the rear XLR and has a 10KΩ input impedance and features an automatic -10dB level pad to allow for typically louder balanced line level signals. The Jack input can also be used with unbalanced (TS) cables such as those from synthesizers or guitars. The input level and impedance are switched to 0dB and 1MΩ respectively (for very high impedance sources such as guitar pick-ups) with selection of the HI-Z switch.
The rear XLR and front Jack inputs have different impedances available by using the Hi-Z switch and allow for a wide variety of sources. The rear XLR input impedance changes from 1.2 KΩ to 10KΩ for Hi and Lo Z Microphones. The front panel Hi Z switch changes the front Jack input impedance from 10KΩ for line sources such as keyboards to 1MΩ for sources such as electric guitars and basses.
Signal level is indicated with a tri-colour LED and the scale of the LED can be set between two -3dB overload points at +16 and +21dBu to allow for operation with +18dBu or +24dBu operating levels.