PURE DRIVE OCTO User Guide

Overview

Introduction

The PURE DRIVE OCTO is an 8-channel, 2U rackmount device featuring SSL's highly regarded PureDrive™ mic preamps, cutting-edge conversion, and flexible digital connectivity. It draws inspiration from the SSL ORIGIN console.

3 Flavours, 1 Mic Pre

Each of the 8 preamps offers three modes: Clean, Classic Drive, and Asymmetric Drive.

• Clean: A linear, ultra-low noise preamp for clarity and detail.
• Classic Drive: Introduces harmonic distortion, emphasizing odd harmonics, similar to the ORIGIN console's sound.
• Asymmetric Drive: Offers even harmonic content dominance for increased thickness and softened transients.

Analogue Obsession

Building on SSL's commitment to analogue circuit design, the PURE DRIVE OCTO uses high-performance mic preamps evolved from VHD™ (Variable Harmonic Drive) technology. It features balanced analogue outputs/insert sends, high-headroom insert returns/ADC inputs (+24 dBu A/D line-up level), and digitally controlled analogue circuits with stepped controls for precision and ease of recall. It avoids electro-mechanical components in the critical audio path for increased longevity.

Extensive Connectivity

The PURE DRIVE OCTO offers extensive connectivity for various studio setups. It includes line-level inputs for processing DAW stems, an integrated USB audio interface (32-bit/192 kHz conversion), ADAT and AES outputs for connecting to other audio interfaces, and auto-ranging word clock input/output for digital clocking.

Features

• 8 high-performance PureDrive™ mic preamps.
• +48V phantom power, polarity invert, and 75 Hz 3rd order hi-pass filter per channel.
• Stepped Gain control up to +65 dB.
• 31-step Trim control with 1 dB increments.
• Mic/Line Input Switching via XLR or TRS Jack/D-Sub.
• 3 Drive modes per preamp: Clean, Classic Drive, Asymmetric Drive.
• 4 front panel Hi-Z/DI Instrument inputs with automatic detection.
• 4 mic preamp input impedance options: 12 kΩ, 1.2 kΩ, 600 Ω, 400 Ω.
• Balanced analogue outputs/insert sends.
• +24 dBu professional line level insert returns/ADC inputs.
• Analogue to digital connectivity via ADAT, AES, and USB.
• ADAT and AES can be re-purposed to source audio from DAW outputs via USB.
• USB audio interface: 8-in/24-out @ 44.1/48 kHz (8 analogue in / 8 AES + 16 ADAT out).
• Digitally controlled analogue electronics for precision and recall.
• Up to 192 kHz and 32-bit conversion.
• Selectable Auto-Sleep mode.
• Auto-ranging Wordclock In and Out.

Installation

Unpacking

The package contains the PURE DRIVE OCTO unit, an IEC power cord, and a Safety Sheet. It is recommended to save the original packaging for potential service needs.

Rack Mounting, Heat and Ventilation

The PURE DRIVE OCTO is a 2U, 19" rackmount device. Ensure adequate ventilation space above and below the unit to dissipate heat. Do not block the chassis cut-outs. Allow the unit to cool before handling.

Safety Notices

Refer to the included Safety Sheet for important safety information, also available in the Appendices.

Hardware Overview

Front Panel

The front panel features 8 identical channels, each with controls for GAIN, TRIM, ZΩ (Impedance/Insert), and DRIVE [TYPE]. It also includes indicators for POLARITY, +48V PHANTOM POWER, and HIGH-PASS FILTER (HPF). Additional controls include STANDBY, INSERT MODE, and DIGITAL CLOCK SETUP. Metering and status indicators display signal level, sample rate, and clocking status.

Rear Panel

The rear panel includes:

• USB: 'C' Type connector for the USB audio interface.
• ADAT OUT: Optical ADAT outputs for digital audio transmission.
• LINE INPUTS: Dedicated line inputs on a D-Sub (DB25) connector.
• INSERT RETURNS: Balanced analogue insert returns/ADC inputs on a D-Sub (DB25) connector.
• AUTO-RANGING PSU & Rocker Switch: For power connection and on/off control.
• WORDCLOCK: BNC connectors for Wordclock In and Out, with a 75Ω termination button.
• AES/EBU OUT: XLR connectors for AES/EBU digital audio outputs.
• ANALOGUE OUTPUTS/INSERT SENDS: Balanced analogue outputs/insert sends on a D-Sub (DB25) connector.
• ANALOGUE INPUTS: XLR for mic level and TRS for line level.

Connections Overview

The document illustrates various connection scenarios:

• 1 - MICROPHONES CONNECTED TO MIC/LINE INPUTS: Connect microphones via XLR or line sources via TRS jacks, selecting from four impedance options.
• 2 & 3 - AUDIO INTERFACE & EXTERNAL PROCESSING CONNECTED TO OUTPUTS/INSERT SENDS: Route analogue outputs to an audio interface or external processors.
• 4 - SSL 12 ADAT IN CONNECTED TO ADAT OUT: Connect digitally to an audio interface with ADAT input.
• 5 - MAC/WINDOWS COMPUTER CONNECTED TO USB: Use the built-in USB audio interface to record directly into a DAW.
• 6 - MASTER CLOCKING DEVICE CONNECTED TO WORDCLOCK IN: Integrate into a digital clocking system via BNC connectors.
• 7 - AES/EBU DEVICE CONNECTED AES/EBU OUT: Connect to external devices accepting AES/EBU inputs.
• 8 - EXTERNAL PROCESSING CONNECTED TO INSERTS RETURNS: Route signals from external analogue processors.
• 9 - LINE-LEVEL DEVICES CONNECTED TO LINE INPUTS: Connect outputs from dedicated line-level devices.

Tutorial

Power On

Power the unit using the rear panel rocker switch. The start-up sequence includes blinking +48V LEDs.

Front Panel Controls

Each of the 8 channels shares identical controls:

• GAIN: 11-step stepped control (+5 to +65 dB for mic, 0 to +30 dB for line, +11 to +41 dB for Hi-Z).
• TRIM: 31-step stepped control (+/- 15 dB in 1 dB increments), used post-GAIN for fine-tuning levels. A tip suggests using GAIN for overdrive and TRIM to reduce levels to prevent clipping.
• HPF (High-Pass Filter) LED: A 75 Hz, 3rd order HPF can be engaged/disengaged by pressing the TRIM control.
• POLARITY ( LED): Pressing the GAIN control flips polarity, useful for resolving phase cancellations in multi-mic setups.
• +48V PHANTOM POWER: Long press on GAIN engages +48V phantom power (red LED). Required for condenser mics; avoid with dynamic/passive ribbon mics. A 4-second mute occurs during engagement/disengagement to prevent clicks/pops.
• LINE INPUT: Long press on TRIM switches to line mode (rear TRS or D-Sub). +48V and ZΩ are disabled; impedance is fixed at 22kΩ.
• ZΩ (IMPEDANCE): Cycles through input impedance options (Green: 12kΩ, Dim White: 1.2kΩ, Amber: 600Ω, Red: 400Ω). Affects tone, especially for ribbon/dynamic mics. Higher impedance offers a more natural response; lower impedance accentuates timbre. A slight level drop may occur when lowering impedance.
• INSERT (Secondary function of ZΩ): Pressing the INSERT button (below STANDBY) allows ZΩ buttons to enable/disable insert returns. Useful for external processing or bypassing the preamp for direct analogue-to-digital conversion.

DRIVE [TYPE]

Selects preamp modes:

• Clean: Linear, ultra-low noise.
• Classic Drive: Adds odd harmonic distortion.
• Asymmetric Drive: Adds even harmonic distortion for thickness.

The DRIVE button flashes red to indicate clipping; lower GAIN or TRIM to correct.

Classic Drive vs Asymmetric Drive

A graph illustrates harmonic differences, showing prominent even harmonics in Asymmetric Drive and odd harmonics in Classic Drive.

Hi-Z/DI - Instrument Inputs

The first four channels have 1MΩ Hi-Z/DI inputs for guitars/keyboards. Plugging in automatically selects this input, disabling +48V, LINE, and ZΩ buttons, but DRIVE modes remain active.

Power, Digital Clock Setup & Metering

• STANDBY MODE (SLEEP): Press and hold STANDBY to put the unit into a low-power sleep state. Press again to wake. Can be configured for automatic standby after inactivity.
• RATE: Cycles through sample rates (44.1, 48, 88.2, 96, 176.4, 192 kHz). Indicated by LEDs.
• CLOCK: Cycles through clock sources (INT - internal, W/C - wordclock). Indicated by LEDs. USB connection makes RATE and CLK buttons inactive.
• USB: Solid green light indicates connection to a host computer.
• Metering: 6-segment LED meters display signal level in dBu. Peak hold and release ballistics are adjustable in Settings.
• INSERT MODE: Hijacks ZΩ buttons to enable/disable insert returns. The INSERT MODE button pulses white when active.

Rear Panel Connections

Details the rear panel connectivity:

• Mic/Line Analogue Inputs: Combo-XLRs for mic/line inputs. LINE switch (long press on TRIM) or D-Sub for line inputs.
• Analogue Outputs / Insert Sends: D-Sub (DB25) for balanced analogue outputs and insert sends.
• Line Inputs: D-Sub (DB25) for dedicated line-level inputs, offering convenience over Combo-XLRs. TRS and DB25 are parallel; use one or the other.
• Insert Returns: D-Sub (DB25) for insert returns.
• ADAT OUT: Optical ADAT outputs for digital transmission (8 channels @ 44.1/48 kHz, 8 channels @ 88.2/96 kHz S/MUX, 4 channels @ 176.4/192 kHz S/MUX). Can be fed from DAW via USB for 16 channels.
• AES/EBU OUT: XLR connectors for AES/EBU digital audio (1/2, 3/4, 5/6, 7/8 pairs). Requires specific AES/EBU cabling.
• WORDCLOCK: BNC connectors for In/Out. 75Ω TERM button for terminating the input if it's the last device in the chain.
• IEC Mains Inlet: Standard IEC power connection.
• USB: 'C' Type connector for USB audio interface connection.

USB Audio Interface

The built-in USB audio interface allows direct recording of PURE DRIVE's outputs into a DAW. For Windows, the SSL USB ASIO/WDM Audio Driver needs installation. Mac OS is class-compliant.

Aggregate Soundcard (Mac only)

As the PURE DRIVE OCTO lacks a monitoring section, Mac users can utilize the Aggregate Device feature to combine it with another audio interface for monitoring.

USB Audio Interface/DAW Inputs

The unit provides 8 analogue inputs (Mic/Line/Inst) to the DAW via USB, available up to 192 kHz.

Re-purposing the Digital Outputs as DAW Outputs

By default, AES and ADAT outputs carry analogue inputs converted to digital. Optionally, these outputs can be re-purposed to carry DAW outputs via USB. This is configured in the Settings menu.

The number of DAW outputs depends on the sample rate. The document details output mapping for 44.1/48 kHz, 88.2/96 kHz, and 176.4/192 kHz.

Firmware Updates

Firmware updates are available via the SSL USB Audio Firmware Updater application. A direct USB connection is recommended for updates.

Settings

Various settings can be configured by holding the CLK button during power-on.

Settings Layout - Overview Map

A diagram shows which front panel controls affect specific settings like Relay Feedback, Autopower On, Auto Standby, Button Brightness, Meters Brightness, Peak Hold, Meter Release, and AES/ADAT routing.

Button Brightness

8 levels of brightness. Use Channel 1 ZΩ (decrease) and DRIVE (increase) buttons in Settings mode.

Meters Brightness

8 levels of brightness. Use Channel 2 ZΩ (decrease) and DRIVE (increase) buttons in Settings mode.

Relay Feedback

Enable/disable audible button clicks. Toggled by pressing the Channel 2 GAIN control in Settings mode. Default is enabled.

Autopower On Enable

Determines if the unit automatically boots on power application. Toggled by pressing Channel 4 GAIN in Settings mode. Default is enabled.

Auto Standby (Sleep) Mode Enable

Allows the unit to enter standby automatically after inactivity. Toggled by pressing Channel 8 GAIN in Settings mode. Default is disabled.

Auto Standby (Sleep) Timeout

Adjusts the inactivity time before Auto Standby engages. Use Channel 8 ZΩ (decrease) and DRIVE (increase) in Settings mode. Default is 20 minutes. Timeout is displayed in binary on the meter LEDs.

Re-purposing the Digital Outputs as DAW Outputs

Configure AES outputs using Channel 3 ZΩ (Red = internal ADC, Green = USB DAW) and ADAT outputs using Channel 3 DRIVE (Dim White = internal ADC, Red = USB DAW).

Safe Mode for Ø, +48V, HPF and LINE Push Functions

Increases the press duration required to toggle these functions, reducing accidental activation. Toggled using Channel 4 ZΩ in Settings mode (Dim white = normal, Red = Safe Mode).

Peak Hold

Adjusts the peak hold meter segment. Use Channel 6 ZΩ in Settings mode (Dim white: OFF, Green: 1s, Orange: 3s default, Red: 10s).

Meter Release

Adjusts meter release time (ballistics). Use Channel 6 DRIVE in Settings mode (Green: Slow, Orange: Standard default, Red: Fast).

Factory Reset

To reset the unit to factory defaults, press and hold Channel 1 ZΩ and Channel 8 DRIVE buttons during power-up until DRIVE buttons flash red. Settings affected include switch states, brightness, relay feedback, autopower, auto standby, and timeout.

Troubleshooting

UID Display

Enter UID Display Mode by holding the RATE button during power-up to view firmware and hardware revisions. Digits are shown in binary on the meter LEDs.

Soak and Potentiometer Test Mode

Enter Soak mode by holding Channel 1 ZΩ and DRIVE during power-up to test lights and indicators. Channel 1 GAIN controls the speed. Potentiometer operation can also be tested.

Specifications

Detailed specifications are provided for Power, Physical dimensions, and Connectors.

Power

• Power Supply: Auto-Ranging 100-240 VAC
• Operating Power: < 27 Watts
• Standby Mode: < 4.8 Watts

Physical

• Width: 482.6 mm / 19 inches
• Height: 88.1 mm / 3.5 inches (2 RU)
• Depth: 302.8 mm / 11.9 inches (chassis only) / 338.4 mm / 13.3 inches (with connections)
• Weight: 5.9 kg / 13 lbs
• Boxed Dimensions: 550mm x 470mm x 210mm

Connectors

• Inputs: Combo XLR x4
• Outputs/Insert Sends: Male XLR x4
• Insert Returns & Line Inputs: 25-way D-type Female (D-Sub) x1
• AES/EBU Outputs: Male XLR x2
• ADAT Output and ADAT Link In: Optical TOSLINK Port x2
• Wordclock Input and Output: BNC connector x 2
• USB: 'C' Type USB Port x1

Detailed specifications for Mic In to Insert Send, Line In to Insert Send, Hi-Z to Insert Send, Insert Return to ADC, and Trim & High-Pass Filter are provided in tables.

Block Diagram

The block diagram illustrates the signal flow, showing analogue inputs (MIC, LINE, INSERT RETURNS), the ADC, the AUDIO PROCESSOR, digital outputs (AES/EBU, ADAT), and USB connectivity for both input and output routing.

Safety Notices

General safety guidelines cover handling, environment, maintenance, and power safety. Key points include earthing the unit, using compliant power cords, and avoiding modifications. It also details WEEE disposal instructions and FCC/Industry Canada compliance.