This article contains complete operating instructions for Universal Audio Volt 4P Max hardware controls and connections.

• Introduction
• Volt Quick Start
• Using Your Volt
• Volt 4P Max Hardware Descriptions
• Reset Volt to Factory Default
• Volt 4P Max Specifications
• Notices

Introduction

Volt 4P Max is a flagship desktop USB audio interface with four Tone Shaping Preamps, a Smart Display with bright visual feedback, speaker switching, and Max dynamics processing. Taken together, it gives drummers, bands, and producers the connectivity to record large sessions with the full sound of a pro studio.

Built by the same Universal Audio team as legendary Apollo interfaces, Volt Max gives you studio mic preamp tones and classic compression on every channel at the push of a button. And when it's time to commit, you get the perfectly tailored suite of award-winning UAD plug-ins and the LUNA Digital Audio Workstation.

Key Benefits

• Four Tone Shaping Preamps. Get the rich, full character of a record, not a demo.
• Max Processing. Record with classic compressor presets tuned for vocals, guitar, and bass.
• Full 32-Bit Audio. Hear your performance in incredible detail with legendary UA quality.
• Expanded I/O. Record a full band with instruments and drums, connect external hardware over MIDI, and add inputs over ADAT.
• Smart Display. Select channels and set levels fast, with bright visual feedback.
• Auto-Gain & Clip Protection. Never worry about signal peaks ruining your take again.
• Easy to Use. Quickly connect and record using your favorite music apps.
• Premium UAD Software. Get the same EQs, compressors, synths, and guitar amps used by the pros, plus the award-winning LUNA DAW.

Features

• 12-in / 6-out desktop USB audio interface with professional 32-bit / 192 kHz audio conversion
• Four Tone Shaping Preamps with 60 dB gain and three harmonic character modes — Warmth, Focus, and Shine — for the rich sounds of classic analog mic preamps at the source
• Four mic / line inputs for tracking up to four sources at once
• Max Processing — onboard realtime compression with six musical presets for vocals, guitars, and bass, modeled on classics like the LA-2A and 1176
• Over 18 character combinations by pairing Tone and Max, all completely noise-free
• Two front-panel Hi-Z instrument inputs and additional line outputs
• Speaker switching between two sets of monitors (Main and Alt)
• Built-in talkback microphone for effortless studio communication
• ADAT or S/PDIF optical input for up to eight channels of digital expansion, plus MIDI In and Out
• Onboard USB hub for connecting peripherals and powering external MIDI controllers
• Full-color Smart Display for bright, at-a-glance visual feedback, including gain-reduction metering
• Auto-Gain and Clip Protection for perfect recording levels, every time
• Two studio-quality headphone outputs (with one shared cue mix) for monitoring and collaboration
• Full integration with the UAD Console app and LUNA, including session recall and low-latency cue mixes
• Built-in loopback for podcasting, streaming and content creation
• Independent 48V phantom power per channel for condenser microphones
• USB bus-powered and class-compliant for easy setup with Mac, Windows, iPad, and iPhone*
• Stylish, rugged construction built to withstand years of use

* Windows systems use the ASIO driver, available in the UA Connect app. Requirements for bus-power vary by model and device. Lightning devices require the Apple Lightning to USB Camera Adapter.

Volt Quick Start

To get started, install UA Connect, Universal Audio's app for managing Volt registration, updates, bundled software, and plug-in installation. When you connect Volt for the first time, UA Connect features an onboarding tutorial to help you set up your new hardware.

To get started manually, use the instructions and references in this section.

About Volt Documentation

• For hardware setup and operating instructions, use this manual.
• For software configuration and operating instructions, see the UAD Console for Volt Manual.
• To register your Volt in UA Connect and redeem included software, see How to set up your Volt Interface.

System Requirements

For Volt system requirements, go here.

Getting Started

To begin your setup, follow the steps below.

Hardware Installation

1. Place your Volt on a flat surface.
2. Connect your Volt's HOST port to a USB 2.0 or higher port on your computer. Your Volt includes a USB-C to USB-C cable.

Software Installation

1. Download and install the UA Connect app from uaudio.com/volt/start.
2. Launch UA Connect and follow the instructions within the app to register and set up your Volt hardware.
3. If a firmware update is available, install it.
4. Download and install the UAD Console app from UA Connect.

Note: For optimum performance on Windows systems, install the Volt driver via UA Connect. Mac and iOS/iPad do not require a driver.

Using Your Volt

Follow the overviews in this section to learn how to use your Volt's features. Additional details are provided in the hardware description sections.

Connect your Volt

Connect your monitor speakers, headphones, and inputs to your Volt. See About Volt Connections for details.

Controls overview

Your Volt has two types of controls on the top panel: ten push buttons, and a large knob with a press function.

Each button has a dedicated function and its label color indicates the active state. The knob adjusts (among other functions) output volume and mute when Monitors or Headphones are active, or gain and channel linking when a preamp input is selected. The display shows input and output information, depending on the current selection.

Tip: Controls can also be adjusted in UAD Console, the companion app for Volt Gen 2, Volt Max, and Volt 876 hardware.

Selecting and adjusting output volumes

You can adjust Volt's monitor and headphone output volumes independently. To adjust output volumes, first select an output with the Monitor/Headphone button, then adjust its volume with the knob.

• To toggle between the monitor and headphone outputs, press the Monitor/Headphone button, then rotate the knob to adjust the selected output volume.
• The button label color and display shows the current selection. When Monitors are selected, the button label and speaker icon are green. When Headphones are selected, the button label and headphones icon are amber.
• To toggle muting of the output, press the knob. The outer volume ring is red when muted.
• When Headphone/Monitor mode is active, all other button labels are dimmed except for INPUT, DIM/TALK, and ALT.

Selecting inputs and adjusting preamp gain

Volt has multiple input channels with independent controls. To adjust a channel's preamp gain, first select the channel with the INPUT button, then adjust its gain with the knob. When an input is selected, the buttons control that input channel.

• To adjust gain, press the INPUT button repeatedly until the display shows the channel number of the preamp, then rotate the knob.
• The thin green inner ring is the channel's input signal level meter. If input signals peak in the red zone, either reduce the preamp gain, or reduce the output level of the device connected to the input.
• To set the preamp's gain automatically, press the AUTO button.

Selecting Meter View

Meter View displays the signal levels of all inputs and outputs at the same time. You can still adjust channel controls and output volumes in Meter View by using the INPUT button to cycle through inputs, and the Monitor/Headphone button to toggle between outputs.

The currently selected input or output channels are lit above the meters, and the channel's gain or volume is indicated by the outer level ring.

• To enter Meter View, press and hold the knob to show the menu, then press the knob when Meter View is highlighted.
• To exit Meter View, press and hold the knob to show the menu, then press the knob when Input View is highlighted.

Selecting Tones

All Volt analog inputs feature Tone Shaping with three character modes — Warmth, Focus, and Shine — for the sound of classic analog mic preamps. Each mode includes an EQ curve and harmonic saturation derived from analog hardware. Harmonic saturation increases as you add gain to the inputs.

To cycle through available Tones, press the INPUT button to select any channel, then press the TONE button repeatedly.

Tip: You can also select Tones in UAD Console.

• The color of the display outer ring and the TONE button label changes to reflect the current setting. When the ring and button label color is white, Tone Shaping is off.
• Tone ring and button colors follow the input channel selection.

Three Tones are available:

• OFF (white): No tone shaping.
• Warmth (amber): Vintage, saturated tube glow with soft transients and smoothness, reminiscent of the UA 610 tube preamplifier.
• Focus (green): Punchy transients with focus and clarity, well-liked on drums, guitars, and bass, reminiscent of classic solid-state American consoles.
• Shine (blue): Musical and full, with a silky top end, reminiscent of venerable British Class-A consoles.

Applying Max Compression

You can control dynamics and add punch, clarity, and balance without manually adjusting volume, by using Max compression. Max is available on all analog inputs. Six presets are tuned for particular uses, but they all can enhance any source.

The Smart Display shows real-time gain reduction metering on the channel when compression is active.

• To cycle through the available Max presets, press the INPUT button to select a channel, then press the MAX button repeatedly.
• The color of the MAX button label and the arc at the bottom of the display changes to reflect the current Max preset.
• You can also select Max presets in UAD Console.

The following Max presets are available:

• Off: Compression off.
• Great Vocal: 1176 compression with a slow attack, fast release, and medium ratio for a great all-purpose vocal sound.
• Rap Vocal: LA-2A compression with limiter setting for aggressive focus.
• Album Vocal: 1176 compression with slow attack, very fast release, and low ratio for overall vocal smoothing.
• Electric Guitar: 1176 compression with medium attack, very fast release, and low ratio, for punchy but smooth electric guitars.
• Jangly Acoustic: LA-2A compression for smooth, warm acoustic guitars.
• Tight Bass: VCA compression tuned for fat, round bass tones.

Using Assistive Auto-Gain

Assistive Auto-Gain automatically sets the optimal preamp gain amount for your input signal, saving time and ensuring you are recording at a good level without manual adjustments.

To automatically set gain for a single preamp channel or linked channels:

1. Press INPUT to select the desired channel.
2. Press AUTO. The display shows Waiting.
3. Play or sing at your loudest level for 10 seconds. The display shows Listening and a progress bar.

When Auto-Gain completes (after 10 seconds), your level is set and the display returns to the previous view.

Auto-Gain tips

• To use Auto-Gain on all preamps at once, press and hold AUTO.
• If there's not enough input signal level, the display shows Too Quiet. In this case, sing or play louder, or increase the output level of the device connected to the input.
• You can also start Auto-Gain and adjust related settings in UAD Console.
• Auto-Gain automatically adjusts preamp levels for recording. To avoid damage to your hearing, confirm your monitor levels are set safely before proceeding.

Using Direct Monitoring

Direct monitoring passes input signals directly to the monitor and headphone outputs, instead of being monitored through the audio software (DAW). Direct monitoring lets you hear your live inputs in real time, without audible latency. Without direct monitoring, inputs are subject to DAW buffering latency.

Toggle direct monitoring

• To toggle direct monitoring on/off for the selected channel, press DIRECT.
• To toggle direct monitoring on/off for all channels, press and hold DIRECT.

The DIRECT button label is green when Direct is on for the channel, and white when off. The display also shows the state briefly when toggling the feature.

Why use direct monitoring?

With direct monitoring (also known as hardware monitoring), you hear the input signals with Tone Shaping and Max compression directly from the Volt hardware with no latency, bypassing your audio software altogether.

When you monitor input signals through your audio software (software monitoring) with Direct off, those signals pass through the software before you hear them from the Volt monitor and headphone outputs. These signals use the software's I/O buffer, which causes latency, an amount of delay that increases as the buffer size is increased.

Use direct monitoring when you are recording sources that you don’t want to monitor through your software, for example, when recording vocals or instruments without plug-in processing from your DAW, but including Volt Tone Shaping and Max compression.

Direct monitoring notes

• Direct includes the input's Tone Shaping and Max compression (if enabled on the channel).
• When Direct is on, disable the software monitoring feature in your audio software to prevent signal doubling, which can make your input sound thin or "phasey."
• When Direct is off, you may notice your inputs have latency (a slight delay) before they are heard, as a result of buffering and signal processing in your DAW.
• If you want to hear your input signals processed through plug-ins loaded in your DAW, keep Direct off.
• The input signal is always sent to the DAW for recording, regardless of Direct on/off state.

Direct with UAD Console

• In UAD Console, the input is unmuted when Direct is on, and muted when Direct is off.
• When one or more channels are soloed in UAD Console, direct monitored signals on other channels are not heard.
• When Direct is on, input levels, panning, and Cue sends can be controlled in UAD Console. See the UAD Console for Volt Manual for more information.

Linking input channels

You can link input channels for stereo operation. When inputs are linked, channel settings are applied to both inputs and the channel pair is panned left/right in the monitor bus. Press again to unlink.

To link and unlink adjacent channels

• Press the LINK button.
• To unlink channels, press the LINK button again.

Link notes

• Only adjacent channel pairs can be linked.
• You cannot link channels of different input types (for example, 1/4” and XLR). If you attempt to link incompatible channels, the INPUT label flashes red and the display shows Input Mismatch.
• If you unplug one channel of a linked pair, the link persists until you unlink the channels on the unit or in UAD Console, or you connect a different type of input.

Using Talkback

The DIM/TALK button activates the built-in talkback microphone and reduces (dims) the level of your monitor output signals by 20 dB. DIM/TALK is typically used to communicate with performers via Cues.

• Press and release the DIM/TALK button quickly to latch or disengage talkback.
• To momentarily activate talkback and dim, and deactivate upon release, press and hold the button for longer than 0.5 seconds.
• The DIM/TALK button is lit green when the feature is active.

Using alternate monitor speakers

You can monitor the stereo mix on a secondary pair of speakers with the ALT feature.

• Connect the left channel alternate speaker to Line Out 3 and the right channel alternate speaker to Line Out 4.
• Press the ALT button to toggle the function. The feature is active when the ALT button label is lit green.

Important: To prevent ALT from accidentally overriding existing Line Out 3-4 assignments, you must first enable the ALT function before the feature can be used. If the ALT button is unlit, the function is not yet enabled.

Enable/disable the ALT function

• Enable ALT when button unlit: Press and hold ALT until its button label flashes (approximately 2 seconds)
• Disable ALT when button lit: Press and hold ALT until its button flashes (approximately 2 seconds)

Tip: You can also enable/disable the function in UAD Console settings.

When ALT mode is active

• The ALT button label is lit green
• The primary monitor outputs are muted
• The main stereo mix is routed to line outputs 3-4
• Signals that were previously routed to line outputs 3-4 are no longer heard

Note: Line 3-4 output assignments that were overridden by toggling ALT mode must be reassigned to the outputs.

Using MIDI

Connect your MIDI devices using MIDI Type A 1/8" (3.5 mm) connectors.

MIDI connection diagram

MIDI Type A uses specific wiring (which differs from MIDI Type B). The diagram shows the MIDI Type A connections you need for Volt.

Using your MIDI devices

On macOS, MIDI devices are automatically recognized by the operating system, and Volt devices are identified by their name. On Windows systems, you must install the Volt driver via UA Connect.

Using the Optical Input

Connect the digital audio output port from other gear to this TOSLINK optical input.

The TOSLINK port uses the ADAT Lightpipe Optical Interface or S/PDIF protocol. Up to eight channels of ADAT audio, or two channels of S/PDIF audio, can be input over a standard TOSLINK optical cable.

Unlike analog inputs, there are no channel controls for digital inputs. Signal levels for the digital inputs are set by adjusting the output levels of the digital gear connected to Volt. You can view digital input signal levels in UAD Console.

Note: Volt supports ADAT or S/PDIF format digital audio. You can select the digital audio format in UAD Console Settings.

At higher sample rates, industry-standard S/MUX is used to maintain high-resolution ADAT transfers. The following sample rates are supported:

ADAT input channels

• 44.1/48 kHz: Eight channels
• 88.2/96 kHz: Four channels
• 176.4/192 kHz: Two channels

S/PDIF input channels

• Two channels at all supported sample rates

Preventing audio clipping with Clip Protection

Clip Protection prevents unexpectedly loud signals at the preamp inputs from causing clipping overload distortion in your recordings. Clip Protection is on by default, but it can be disabled from the menu on your Volt, or in UAD Console settings.

Toggle Clip Protection on/off

1. Press and hold the knob until the menu is displayed.
2. Rotate the knob so the Clip Protection menu item is highlighted, then press the knob to toggle the state.
3. When enabled, a green dot appears next to the menu item and ON is lit green.

How Clip Protection works

Clip Protection on your Volt Max applies a hardware limiter before the signal reaches the analog-to-digital converters to prevent signals from clipping the preamp inputs.

About Volt connections

Use the following cables for best results:

• 1/4" (6.35 mm) TS (tip-sleeve) cable to connect a guitar or bass to a front panel instrument input
• XLR cable to connect a microphone to a rear panel combo jack input
• 1/4" TRS (tip-ring-sleeve) cable to connect a keyboard or other line-level audio source to a rear panel combo jack input
• 1/4" TRS cables to connect your stereo monitor speakers or other audio gear to the rear panel monitor and line outputs
• 1/4" and 1/8" TRS headphone plugs to connect one or two stereo headphones to the front panel headphone jacks

About balanced connections

Volt monitor/line outputs and the rear 1/4" combo input jacks are balanced when connected to balanced equipment. Use TRS (balanced) audio cables for the best results. Balanced equipment uses three-conductor wiring to reduce interference and electrical noise, and to provide better audio quality over longer cable runs. TS (unbalanced) connections are suitable for shorter output cables, where electrical interference noise may not be an issue.

Volt 4P Max Hardware Descriptions

All hardware controls, connections, and indicators are explained in this section.

Volt 4P Max Front Panel

(1) Instrument inputs 1-2

Connect your guitars, basses, and other high-impedance instruments here. The instrument jacks override the XLR/TRS 1-2 combo jacks on the rear panel when connected.

Tip: Use standard 1/4" TS instrument cables to connect your instruments.

(2) Headphone output jacks

Connect stereo headphones to these outputs. Two headphone jacks are provided, for 1/4" (6.35 mm) and 1/8" (3.5 mm) TRS headphone plugs. Both headphone jacks output the same signal.

You can route a CUE mix to the headphone outputs. See the UAD Console for Volt Manual for details.

Volt 4P Max Top Panel

(3) Talkback microphone

The built-in talkback mic is located here. Use talkback to communicate with performers, while dimming (reducing) all other audio. Talkback can be activated with the DIM / TALK button. See Using Talkback for details.

Caution: The talkback microphone is sensitive. To avoid equipment damage, do not insert any object into the mic hole, apply pressurized air into the mic hole, or use a vacuum over the mic hole.

(4) Smart display

The round display shows information for the selected input channel or output.

Refer to Using Your Volt for more information.

(5) TONE button

Applies analog-style Tone Shaping with saturation and harmonics to the selected input channel.

• To cycle through available Tones, press the INPUT button to select any channel, then press the TONE button repeatedly.
• The color of the Smart Display outer ring and the TONE button label changes to reflect the current setting. When the ring and button label color is white, Tone Shaping is off.
• Tone ring and button colors follow the input channel selection.
• Tones can also be selected in UAD Console.

See Selecting Tones for more information.

(6) MAX Button

Cycles through available Max compressor presets for the selected input channel. Press repeatedly to cycle through all six compressor settings and OFF.

• The color of the MAX button label and the arc at the bottom of the display matches the current Max preset.
• Max compression can also be selected in UAD Console.

See Applying Max Compression for more information.

(7) 48V button

Enables +48V phantom power to a condenser microphone connected to the selected rear-panel XLR input. The label flashes red when phantom power is being applied, and is lit red when active and white when inactive.

Phantom power is disengaged (the label is unlit) when a 1/4" plug is connected to the selected channel.

Note: Disable phantom power before connecting or disconnecting microphones. Phantom power can damage some ribbon microphones.

(8) LINK button

Press to link input channel pairs for stereo operation. When channels are linked, channel settings are applied to both inputs and the channel pair is panned left/right in the monitor bus. Press again to unlink.

(9) INPUT button

Selects the active input channel displayed on screen and adjusted by other controls. Press repeatedly to cycle between inputs. Press and hold to link or unlink channels for stereo operation.

See Selecting inputs and adjusting preamp gain for more information.

(10) AUTO button

Starts Assistive Auto-Gain level detection for the selected channel. Press and hold to set Auto-Gain on all inputs simultaneously. See Using Assistive Auto-Gain for more information.

Tip: To set the correct level for guitar and bass modeling plug-ins, set gain for instruments connected to the Hi-Z instrument inputs to minimum (0). For optimum results, do not use Auto-Gain to set levels for instruments connected to the Hi-Z instrument inputs.

(11) DIRECT button

Press the DIRECT button to toggle direct monitoring on the selected channel. Direct monitoring passes the audio from monitored inputs, including Tone and Max processing, directly to the outputs. Direct monitoring also unmutes input channels in UAD Console.

See Using Direct Monitoring for more information.

(12) DIM/TALK button

Simultaneously engages the built-in talkback microphone and reduces the monitor output volume by 20 dB. You can press and release to latch the function, or press and hold for momentary operation.

Tip: In momentary mode (press and hold), talkback stays active only while the button is held, which is useful for quick communication without accidentally leaving talkback on.

(13) ALT button

The ALT button routes the main stereo mix to line outputs 3-4, for alternate monitoring on a secondary pair of speakers. To toggle ALT mode, press the ALT button.

Important: To prevent ALT from accidentally overriding existing Line Out 3-4 assignments, you must first enable the ALT function before the feature can be used. If the ALT button is unlit, the function is not yet enabled.

See Using alternate monitor speakers for more information.

(14) Monitor/Headphone button

Press to select the outputs for the knob and display. Pressing this switch repeatedly toggles between the monitor output and headphone output. The button label lights green when Monitor is selected, and amber when Headphones are selected.

See Selecting and adjusting output volumes for more information.

(15) Encoder knob

The knob is a dual-function rotary and pushbutton control that adjusts various settings, depending on the currently selected function.

Rotate the knob to adjust:

• Input gain when a preamp channel is selected
• Monitor volume when the Monitor output is selected
• Headphone volume when the Headphone output is selected

The knob is inactive when a line input is selected.

Tip: Rotate the knob slowly for fine adjustments, and quickly for faster adjustments.

Press the knob to:

• Mute the monitor output when Monitor is selected
• Mute the headphone output when Headphone is selected

Press and hold the knob to:

• Show the Input/Meter View and Clip Protection menu
• When the menu is displayed, rotate the knob to choose a function
• Press the knob to toggle the function or exit the menu

Volt 4P Max Rear Panel

(16) XLR/TRS combo inputs 1-4

Four XLR/1/4” combo jacks accept XLR or 1/4” TS/TRS plugs. The XLR and 1/4” combo jack inputs use the Volt preamp, Tone Shaping, and Max compression. 48V phantom power is applied only to the XLR jack.

• Connect a microphone with an XLR cable
• Connect a keyboard or other audio gear with a 1/4” TRS or TS cable
• Adjust preamp gain for the combo inputs by selecting the channel with the INPUT button, then rotating the knob

Note: Phantom power is disabled on a channel when a cable is plugged into the front instrument jack for that channel.

(17) Monitor L/R outputs

Connect your stereo speaker system to the monitor outputs. Connect the left speaker to MON OUT 1/L and the right speaker to MON OUT 2/R with TS or TRS 1/4" cables.

Note: Monitor outputs are not powered. You need active (powered) monitors or a separate amplifier and passive speakers.

To adjust the monitor output volume, first select the output with the Monitor/Headphone button, then rotate the knob.

(18) Line 3-4 outputs

Connect these assignable outputs to the line-level inputs of other audio gear with TS or TRS 1/4” cables. The line outputs are typically used for alternate monitor speakers, headphone amps for cue outputs, or other audio gear.

(19) MIDI I/O

You can connect a MIDI device to Volt with standard 1/8” (3.5 mm) TRS MIDI Type A cables. Connect the MIDI OUT of your device to the MIDI IN on Volt, and the MIDI IN of the device to the MIDI OUT on Volt.

See Using MIDI for more information.

(20) HUB port

Connect other USB devices to this USB 2.0 expansion port. For example, you can connect a MIDI controller or iLok USB here. You can also connect a Volt 876 for ADAT expansion to this port. This port is not for connection to the host computer or USB power.

The USB Hub port supplies 5VDC, up to 0.5A. You might need to connect the included power supply if the output power is insufficient.

(21) HOST port

Connect the HOST port to a USB 2.0 (or higher) port on your computer with the included USB-C cable, or another data cable. The computer port can be USB-C or USB-A, and any USB 2.0 or higher data cable can be used.

For iOS and iPad devices, connect Volt with a USB-C cable (devices with USB-C ports) or with the Apple Lightning to USB Camera Adapter (for devices with Lightning ports).

Power from the computer connected to this port supplies bus power to Volt.

(22) 5VDC port

If Volt does not receive enough bus power to operate from the USB HOST port, connect this port to a suitable 5VDC USB power supply.

Note: Volt must be connected to the computer with the Volt HOST port to be recognized.

(23) Optical input

Connect the digital audio output port from other gear to this TOSLINK optical input.

The TOSLINK port uses the ADAT Lightpipe Optical Interface or S/PDIF protocol. Up to eight channels of ADAT audio, or two channels of S/PDIF audio, can be input over a standard TOSLINK optical cable.

See Using the Optical Input for more information.

(24) Power switch

Apply power to your Volt with this rocker switch.

Reset Volt to Factory Default

Use the following procedure to reset your Volt to default values.

1. Power off the Volt unit.
2. Press and hold both TONE and 48V buttons and power the unit on.
3. Wait for the backlit text above all buttons to flash four times, then release the buttons.

Volt 4P Max Specifications

Note: All specifications are subject to change without notice.

SYSTEM

I/O Complement

• Microphone/Line Preamp Inputs: Four combo XLR/TRS
• Instrument Inputs: Two ¼" TS
• Line Outputs: Four (including monitor outputs)
• Monitor Outputs (selectable MON or ALT): Line outputs 1-2 or 3-4
• Headphone Outputs: One 1/4" stereo One 1/8" stereo
• USB (Type-C connectors):
  • One USB 2.0 host port (bus-power capable)
  • One USB 5VDC power port
  • One USB hub port
• MIDI: In, out (two 3.5 mm Type A)

A/D – D/A Conversion

• Supported Sample Rates (kHz): 44.1, 48, 88.2, 96, 176.4, 192
• Bit Depth Per Sample: 32
• Simultaneous A/D Conversion: Four channels
• Simultaneous D/A Conversion: 6 channels (4 main, 1 stereo headphone)

ANALOG I/O

Mic, Line, Instrument Inputs (AC Coupled)

• Available Gain: 60 dB
• Tone Shaping (selectable per channel): Warmth, Focus, Shine
• Max Processing (selectable per channel): Great Vocal, Rap Vocal, Album Vocal, Electric Guitar, Jangly Acoustic, Tight Bass

Microphone Inputs

• Frequency Response: 20 Hz to 20 kHz, ±0.08 dB
• Dynamic Range (A–weighted): 119 dB
• Total Harmonic Distortion + Noise (1 kHz @ -1 dBFS): -110 dB (0.0003 %)
• Maximum Input Level: 14 dBu
• Input Impedance: 2 Kilohms
• Phantom Power: +48V (switchable per channel)
• Connector Type: XLR Female, pin 2 positive

Instrument Inputs

• Frequency Response: 20 Hz to 20 kHz, ±0.02 dB
• Dynamic Range (A–weighted): 116 dB
• Total Harmonic Distortion + Noise (1 kHz @ -1 dBFS): -108 dB (0.0004 %)
• Maximum Input Level: 13 dBu
• Input Impedance: 1 Megohms
• Connector Type: ¼" TS unbalanced

Line Inputs

• Frequency Response: 20 Hz to 20 kHz, ±0.05 dB
• Dynamic Range (A–weighted): 119 dB
• Total Harmonic Distortion + Noise (1 kHz @ -1 dBFS): -108 dB (0.0004 %)
• Maximum Input Level: 22 dBu
• Input Impedance: 10 Kilohms
• Connector Type: ¼" TRS balanced or TS unbalanced

Monitor & Line Outputs (DC Coupled)

• Frequency Response: 20 Hz to 20 kHz, ±0.05 dB
• Dynamic Range (A–weighted): 126 dB
• Total Harmonic Distortion + Noise (1 kHz @ -1 dBFS): -112 dB (0.0003 %)
• Maximum Output Level: 20.2 dBu
• Output Impedance: 200 Ohms
• Connector Type: ¼" TRS balanced

Stereo Headphone Outputs (DC Coupled)

• Frequency Response: 20 Hz to 20 kHz, ±0.08 dB
• Dynamic Range (300 Ohms, A–weighted): 116 dB
• THD + Noise (1 kHz @ -1 dBFS, 300 Ohms): -103 dB (0.0007 %)
• Maximum Output Power into 32 Ohms: 45 mW per channel
• Maximum Output Power into 300 Ohms: 24 mW per channel
• Connector Type: ¼" TRS Stereo

DIGITAL Input

S/PDIF

• Connector Type: Optical TOSLINK JIS F05 (shared with ADAT)
• Format: IEC 958
• Supported Sample Rates (kHz): 44.1, 48, 88.2, 96, 176.4, 192

ADAT

• Connector Type: Optical TOSLINK JIS F05 (shared with S/PDIF)
• Format: ADAT Digital Lightpipe with S/MUX
• Supported Sample Rates (kHz): 44.1, 48, 88.2, 96, 176.4, 192
• Channel Assignments @ 44.1 kHz, 48 kHz: Channels 1 – 8
• Channel Assignments @ 88.2 kHz, 96 kHz: Channels 1 – 4
• Channel Assignments @ 176.4 kHz, 192 kHz: Channels 1 – 2

Synchronization Sources

• Internal, ADAT, S/PDIF

ELECTRICAL

• DC Input Connector Type: USB-C
• DC Requirements: 5VDC
• Power Consumption (@5VDC): 6.0 W typical, 9.1 W maximum

ENVIRONMENTAL

• Ambient Temperature Range: 32° to 104° F (0° to 40° C)

MECHANICAL

Dimensions

• Chassis (including knobs): Width x Depth x Height 8.5 x 4.5 x 2.1 in (21,6 x 11,5 x 5,4 cm)
• Shipping Box: Width x Depth x Height 10.4 x 5.7 x 4.7 in (26,4 x 14,6 x 12,0 cm)

Weight

• Shipping Weight (with box & accessories): 3.3 lbs (1.5 kg)
• Weight (bare unit): 1.5 lbs (0.7 kg)

Package Contents

• Volt 4P Max USB audio interface
• One-meter USB cable (Type-C to Type-C)
• External power supply with AC adapter kit
• Important safety instructions
• End-user license agreement

Notices

Important Safety Instructions

1. Read these safety instructions and the instruction manual of the product.
2. Keep these safety instructions and the instruction manual of the product. Always include all instructions when providing the product to other parties.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Only clean the product when it is not connected to the power supply system. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
9. Only operate the product from the type of power source indicated on the power supply unit.
10. Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the point where it enters into and/or exits from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Unplug this apparatus during lightning storms or when unused for long periods of time.
13. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as when the power supply cord or plug is damaged, liquid has been spilled into or objects have fallen into the apparatus, or when the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
14. Warning: To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture. Objects filled with liquids, such as vases, should not be placed on this apparatus.
15. To completely disconnect this apparatus from the AC mains, disconnect the power supply cord plug from the AC receptacle.
16. The mains plug of the power supply cord shall remain readily accessible.
17. Do not attempt to open the product housing. The warranty is voided for products opened by the customer.
18. Let the product reach ambient temperature before switching it on.
19. Caution: High signal levels can damage your hearing and your loudspeakers. Reduce the volume on the connected audio devices before switching on the product; this will also help prevent acoustic feedback.
20. Intended use. The product is designed for indoor use. The product can be used for commercial purposes. It is considered improper use when the product is used for any application not named in the corresponding instruction manual. Universal Audio does not accept liability for damage arising from improper use or misuse of this product and its attachments/accessories. Before putting the product into operation, please observe the respective country-specific regulations.

Manufacturer’s Declarations

Warranty

The product is covered by a limited warranty. For the current terms of such warranty, please visit uaudio.com/eula.

Maintenance

• CAUTION: To reduce the risk of electric shock, do not open the unit.
• This product does not contain a fuse or any other user-replaceable parts. The unit is internally calibrated at the factory. No internal user adjustments are available.

Repair Service

If you are having trouble with your hardware, first check all system setups, connections, and operating instructions. If that doesn’t help, contact our technical support team.

To learn about repair service, or to contact UA Customer Care, visit help.uaudio.com.

Notes on Disposal

In compliance with the following requirements:

WEE-DIRECTIVE (2012/19/EU)

The symbol of the crossed-out wheeled bin on the product, the battery/rechargeable battery (if applicable), and/or the packaging indicates that these products must not be disposed of with normal household waste, but must be disposed of separately at the end of their operational lifetime. For packaging disposal, please observe the legal regulations on waste segregation applicable in your country.

Further information on the recycling of these products can be obtained from your municipal administration or from the municipal collection points. The separate collection of waste electrical and electronic equipment, batteries/rechargeable batteries (if applicable) and packaging, is used to promote the reuse and recycling and to prevent negative effects caused by e.g., potentially hazardous substances contained in these products. Herewith, you can make an important contribution to the protection of the environment and public health.

Declaration Of Conformity

FCC: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation.

CANADA: Complies with Canadian ICES-003 Class B/ Conforme au reglement Canadien NMB-003 Classe B.

CE: This device has been tested and found to comply with the limits of the EC Electromagnetic Compatibility Directive 2014/30/EU.

End User License Agreement

Your rights to the Software are governed by the accompanying End User License Agreement, a copy of which can be found at www.uaudio.com/eula.

Copyrights & Trademarks

© 2026 Universal Audio, Inc. All rights reserved worldwide. The "Universal Audio" name, UA "diamond" logo, and "UA Volt" are trademarks or registered trademarks of Universal Audio, Inc. All other products and trademarks pictured herein are the property of their respective owners.

ASIO is a trademark and software of Steinberg Media Technologies GmbH.

Disclaimer

The information contained in this manual is subject to change without notice. Universal Audio, Inc. makes no warranties of any kind with regard to this manual, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Universal Audio, Inc. shall not be liable for errors contained herein or direct, indirect, special, incidental, or consequential damages in connection with the furnishing, performance, or use of this material.

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