SOLID STATE LOGIC VHD+ Pre Module

Product overview

The SOLID STATE LOGIC VHD+ Pre Module brings the uniquely versatile VHD preamp technology of Duality, SSL's large format studio console, to 500-series racks: ultra-clean SuperAnalogue grade recordings or rich harmonic distortion, you decide.

The VHD+ Pre is an immensely versatile recording and processing device. It delivers ultra-clean SSL SuperAnalogue grade recordings and also features a switchable VHD mode. SSL's patented Variable Harmonic Drive uses a 100 % analogue signal path to generate rich harmonic distortion: as VHD input gain rises, it introduces 2nd or 3rd harmonic distortion, or a blend of the two. At lower gain it adds gentle valve-style warmth or a touch of transistor edge; at high gain it delivers fierce, trashy transistor-style grunge.

Key features

• SSL SuperAnalogue grade preamp
• 2nd order harmonics: valve warmth to extreme distortion
• 3rd order harmonics: transistor edge to totally trashed
• Absolute control with the 2nd / 3rd order harmonic blend (DRIVE)
• Variable Harmonic Drive (VHD) in / out switch
• Switchable variable high-pass filter, 15-500 Hz, 18 dB/octave
• +48 V phantom power, 20 dB PAD, Hi-Z and polarity switches
• Front TRS line / DI input and tri-colour signal LED

Ultra-clean to heavy distortion

With VHD off the preamp is designed for a transparent sound, great for acoustic guitars, vocals and strings. With VHD on it can be driven for a wide range of overdriven sounds, from subtle to not so subtle: drums and electronic instruments often benefit from VHD colouration.

The best way to drive VHD is to raise the input gain (red pot) while using the Line Trim to reduce the overall level so the channel output does not clip: it is the input of the preamp that likes being driven. Then fine-tune the sound with the harmonic blend.

Controls

The red GAIN pot provides +20 to +75 dB of gain; the black DRIVE pot blends 2nd to 3rd order harmonics once VHD is engaged; the grey TRIM pot gives +/-20 dB to control the output when driving the VHD circuit. The high-pass filter is a switchable 18 dB/octave variable filter from 15 to 500 Hz.

• 48V: phantom power to the rear XLR, with a red tell-tale LED
• PAD: 20 dB of attenuation before the preamp
• Hi-Z: XLR impedance from 1.2 kΩ to 10 kΩ, front jack from 10 kΩ to 1 MΩ
• Ø: polarity inverted by 180°

Line in / DI

The front 1/4" TRS jack overrides the rear XLR. It is balanced, 10 kΩ, with a -10 dB pad for louder line signals, and also accepts unbalanced TS cables. With Hi-Z selected the level becomes 0 dB and the impedance 1 MΩ, for guitar pickups and other very high impedance sources. A tri-colour signal LED shows green at -24 dBu, yellow at +4 dBu and red at +21 dBu (+24 dB scale; a jumper selects a +18 dB scale).

In the box

• VHD+ Pre Module (500-series)

SOLID STATE LOGIC VHD+ Pre Module: frequently asked questions

What does VHD do?

Variable Harmonic Drive uses a 100 % analogue signal path to add 2nd or 3rd harmonic distortion, or a blend of the two, from gentle warmth to heavy grunge as the input gain rises.

Can I plug a guitar straight in?

Yes. Use the front LINE IN / DI jack and press Hi-Z for a 1 MΩ input.

Is it clean with VHD off?

Yes. With VHD off it is a transparent SuperAnalogue grade preamp.

How much gain is available?

Up to +75 dB from the GAIN control, plus +/-20 dB of output trim.

Where can I buy the SOLID STATE LOGIC VHD+ Pre Module in India?

The SOLID STATE LOGIC VHD+ Pre Module is available from Shivansh Electronics, Kolkata, West Bengal, India, with delivery across India.

Workflow 1: Clean vocal recording

Vocalists and producers.

Connections

Setup

1. Leave VHD off.
2. Set GAIN for healthy level.
3. Use HPF to clear rumble.
4. Watch the signal LED.

Tip: Yellow on the LED marks +4 dBu.

Workflow 2: Driven drums

Drum rooms and kits needing colour.

Connections

Setup

1. Engage VHD.
2. Raise GAIN to drive the input.
3. Lower TRIM to avoid clipping.
4. Blend 2nd / 3rd with DRIVE.

Tip: It is the preamp input that likes being driven.

Workflow 3: Direct guitar or bass

Players recording DI.

Connections

Setup

1. Press Hi-Z.
2. Set GAIN.
3. Add VHD for edge.
4. Record.

Tip: Hi-Z gives a 1 MΩ input.

Workflow 4: Re-amping synths

Producers colouring line-level sources.

Connections

Setup

1. Leave Hi-Z off for line level.
2. Engage VHD.
3. Set DRIVE to 3rd for edge.
4. Trim output.

Tip: The -10 dB jack pad suits louder line signals.

Workflow 5: Ribbon or dynamic mics

Quiet sources needing gain.

Connections

Setup

1. Set GAIN up to +75 dB.
2. Use HPF as needed.
3. Keep VHD off for clean.
4. Check polarity with Ø.

Tip: Only switch 48V on for mics that need it.

Workflow 6: Hybrid processing

Mixers sending tracks out to the rack.

Connections

Setup

1. Send a track out at line level.
2. Use PAD if hot.
3. Engage VHD and blend harmonics.
4. Print back.

Tip: Note settings on the official recall sheet.