INSTRUCTIONS FOR USE

Dear music lover,

Thank you for purchasing a Pro-Ject Audio Systems streaming amplifier. In order to achieve maximum performance and reliability, you should study these instructions for use carefully.

! Warning of a hazard for the user, the unit or possible misuse.

Important notice.

Safety instructions

! AC outlet voltages vary from country to country. Before connecting to the mains, make sure that the voltage in your area meets the voltage requirements printed on the power supply.

The power supply is used to connect/disconnect the unit from the mains. Make sure that the power supply is easily accessible at all times. Never handle the device, the power supply while your hands are wet or damp. Avoid letting liquids enter the device or the power supply. Never place any item containing liquid, such as a flower vase on or near the device. Never spill any liquid on the device or the power supply. Never place any naked flame sources, such as lighted candles on or near the device. The product shall not be used in damp or wet locations, next to a bathtub, sink, swimming pool or any other similar conditions.

Connectors

Diagram showing the rear panel connectors:

• L (Input 1 - Phono)
• R (Input 1 - Phono)
• L (Input 2)
• R (Input 2)
• L (Input 3)
• R (Input 3)
• Variable Output L
• Variable Output R
• WiFi BT Antenna
• UK CA CE EAC logos
• In 4 (S/PDIF Optical)
• In 5 (S/PDIF Optical)
• In 6 (S/PDIF Coaxial)
• In 7 (HDMI)
• TV Input (ARC)
• BT
• Disconnect
• Power (20V = )

Audio Tuning Vertriebs GesmbH, Pro-Ject Audio Systems, Margaretenstrasse 98, A-1050 Wien. Contains FCC ID: 2ANOG-ASR001

1. Make all connections except the connection to the headphone whilst the unit is disconnected from the mains.
2. Never connect or disconnect power supply to or from the unit whilst the power supply is connected to the mains! Never use any other power supply than the one supplied with the unit, with the exception of dedicated Power Boxes which can replace original power supplies.
3. Take care to connect the left and right channels of In 1, In 2, In 3 correctly. The right channel is usually marked red, the left channel black or white.
4. Speaker connections for the left speaker are located on the right hand side of the rear view. Speaker connectors marked red represent + according indicators on speaker terminal.

Analog output (Variable Output)

A power amplifier, active loudspeakers or an active subwoofer can be connected to the output sockets marked Variable Output.

Connection to the speakers

The output terminals accept speaker cables terminated with 4mm Ø Banana plugs, spades connectors or naked wire.

Phono input

Connect the tonearm signal lead to the In 1 (Phono) of the amplifier. The earthing wire may be connected to the screw terminal if you encounter hum problems when using the turntable. The phono input is suitable for MM and High-Output MC cartridges.

Line inputs

Line level sources (CD player, radio or TV) can be connected to the inputs marked In 2 or In 3.

Digital inputs

Sources with a digital output such as TV satellite/cable receiver or a game console can be connected to the digital inputs. Optical to In 4 and In 5, Coaxial to In 6, HDMI to In 7.

Mains power connection

Connect the low voltage plug from the power supply to the Power socket before connecting the power supply to the mains.

Front panel controls

Diagram of the front panel with controls labeled:

• Power button (left side)
• Input selector buttons (with LEDs indicating active input)
• Volume knob (large)
• Stream button (lower right corner)
• Stream LED (to the left of the Stream button)

To switch on from standby or to standby

The push button on the left side of the front panel turns the unit on or back into standby. The blue LED above the stand-by push button shows that the unit is switched on. Mute is active when LED is blinking.

Input selector

Pressing the buttons [select previous input] and [select next input] selects the desired input. The LEDs show which input is currently active.

Stream button

The Stream button in the lower right corner on the front panel can be used to pause/resume streaming. The Stream LED to the left of it shows the current streaming status:

Factory & WiFi Reset

Press and hold the Stream button for 10s, afterwards you will see the Stream LED flash red. Factory reset clears all streaming - source, volume, and network - settings and returns the streaming module back to the original factory settings.

Volume

Adjust the volume to the desired level, using the large knob on the front panel.

On the Stream input (In 8), the Uni Box S3 offers you two volume control stages: the physical fully analogue volume control with the knob on the front panel, and the digital volume control in the Pro-Ject Home App. It is recommended to set the digital in-App volume control to maximum and use the analogue volume control of the Uni Box S3 as your main volume control. Use the digital volume control only for fine tuning the level as necessary and for convenience reasons. This way you are getting the full digital resolution and use the lossless analogue volume control to maximise audio quality and your hifi stereo music listening.

Connecting a headphone

Connect the headphones to the ½“ (6,3mm Ø) jack socket on the front of the unit.

Streaming, WiFi & BT connection

Make sure the antenna is attached to its connector WiFi BT Antenna on the back panel prior to using.

! Only use the supplied antenna!

Select In 8 on the Uni Box S3 and use the Pro-Ject Home App to choose your streaming service of choice. The Uni Box S3 physical inputs can only be changed on its front panel or with the remote. The Pro-Ject Home App is only used to control the streaming service that is being played.

WiFi Setup

• Download the Pro-Ject Home App (available for Android and iOS).
• Power on the Uni Box S3 (make sure to connect the antenna before powering on the Uni Box S3).
• Open the Pro-Ject Home App.
• The app will automatically find the Uni Box S3 and walk you through the setup process. If not, tap Add Device in the top right corner in the Devices tab.
• Make sure to give the app Bluetooth access on your phone for this to work.

Screenshots illustrating the WiFi setup process and device connection.

Spotify Connect

Use your phone, tablet or computer as a remote control for Spotify. Go to spotify.com/connect to learn how.

The Spotify Software is subject to third party licenses found here: https://www.spotify.com/connect/third-party-licenses

Bluetooth Connection

Pairing phones:

• In the Pro-Ject Home App, go to Browse and select Bluetooth.
• Make sure Bluetooth is turned on on your phone. Open your phone's Bluetooth settings and look for a new Bluetooth device called "Uni Box S3". Tap on "Uni Box S3" to pair your phone.

Pairing a Pro-Ject Bluetooth turntable:

• In the Pro-Ject Home App, go to Browse and select Bluetooth.
• Put a vinyl record on your turntable and start playing the record (Bluetooth on your turntable still turned off).
• Turn on Bluetooth on your turntable.
• Wait a few moments, the connection is established automatically.

Bluetooth Troubleshooting:

• Make sure the two devices to be connected are in as close a proximity as possible.
• Your phone is typically very close to the Uni Box S3 when you try to connect it via Bluetooth.
• Probably, your turntable is not. But the same rules apply. Establishing Bluetooth connections works best when the devices are as close as possible to each other. If possible, within 1-2 meters.
• Make sure nothing else is connected via Bluetooth to the Uni Box S3 when trying to connect new devices. Turn off Bluetooth on ALL other devices except the one you want to connect.

Screenshot showing the Bluetooth browsing interface within the Pro-Ject Home App.

Multiroom Input Streaming

The Uni Box S3 can stream In 1 - In 7 to other compatible Pro-Ject and WiiM streamers.

1. Group all devices the Uni Box S3 should stream to.
2. Tap on the group to select it. Tap Browse and select Aux In.
3. Select the physical input on your Uni Box S3 that you want to stream. Only the currently selected and active input is being streamed. Mute the Uni Box S3 via remote or turn down its analogue volume potentiometer, if you don't want to listen to the Uni Box S3 locally. Even when muted or volume turned down, the full input signal will be streamed to your network.
4. Enjoy your turntable, CD player and all other locally connected audio sources across your entire home!

Screenshots illustrating the multiroom input streaming setup.

Remote control

Diagram of the remote control with buttons labeled:

• ON/OFF: turns the unit on/off
• VOL-: turns the volume down
• VOL+: turns the volume up
• CH-: select the input down
• CH+: select the input up
• MUTE: activates and deactivates mute

Replacing batteries

Proceed as follows:

• Unlock and slide open the battery case cover.
• Replace the battery. Make sure the battery is the right way round!
• Close the battery case cover.

Battery type: 2x AAA 1,5V

Do not dispose of the batteries as ordinary domestic refuse. Please dispose of your exhausted batteries at the appropriate collection sites - usually located at supermarkets and drugstores.

Technical specifications Pro-Ject Uni Box S3

• Power output: 2x 23W/40W at 8 ohms/4 ohms (1%THD)
• Frequency response (20Hz-20kHz): < -0,4dB: 20Hz, -0,9dB: 20kHz (@4ohm)
• Channel separation: >67dB at 10kHz
• Signal to noise ratio PA output: 94dB (97 dB - 'A' weighted) at 4ohm
• Signal to noise ratio Variable output: 94dB (96 dB - 'A' weighted)
• THD: < 0,05% at 10W / 4 ohms
• Gain: 33,5dB (measured via line level input)
• Headphone amplifier output: 2x 70mW at 32ohm (1%THD)
• Variable line level output: 1 pair RCA
• Line level inputs: 2 pair RCA (sensitivity: 270 mV)
• Line input impedance: 50kohms
• Phono input: 1 pair RCA
• Phono input sensitivity: suitable for MM, MI or high output MC cartridges
• Phono input impedance: 47kohms
• Phono input gain: 46dB
• Digital to Analogue converter: Cirrus Logic CS4344 24bit/192kHz Multi-bit Delta Sigma type
• S/PDIF coaxial input: up to 24bit and 192kHz
• S/PDIF optical input: 2 inputs - up to 24bit and 192kHz
• TV input: 1 x ARC
• Input streaming: selected Uni Box S3 input
• Wireless connectivity: Wi-Fi 5, 802.11 b/g/n/ac 2.4 G and 5G dual bands, BT 5.1
• Streaming control app: Pro-Ject Home
• Streaming services: Tidal, Tidal Connect, Spotify Connect, Amazon Music, Qobuz, Deezer, Soundcloud, Webradio (Tuneln, vTuner, iHeartRadio, BBC Radio) *supported streaming services can change without prior notice
• BT music receiver codec: SBC, AAC, A2DP profile
• Speakers connectors: Ø4mm banana plugs, spades connectors or naked wire
• Headphone output: 6,3mm jack (16 – 600ohms)
• Outboard power supply: 20V/3A DC, suitable for your country's mains supply
• Power consumption in standby: <0.5W
• Replacement battery remote control: 2x AAA 1,5V
• Dimensions W x H x D (D with sockets): 206 x 55 x 153 (176) mm
• Weight: 1100 g without power supply

Should you encounter a problem which you are not able to alleviate or identify, please contact your dealer for further advice. Only if the problem cannot be resolved there, the unit should be sent to the responsible distributor in your country.

Disclaimer for 3rd Party Content

Access to content provided by third parties requires a high speed internet connection and may also require account registration and a paid subscription. Third party content may be changed, suspended, interrupted, or discontinued at any time without notice and Pro-Ject Audio Systems disclaims any liability in connection with such occurrences. Pro-Ject Audio Systems does not represent or warrant that content services will continue to be provided or available for a particular time period, and any such warranty, express or implied, is disclaimed.

Warranty

The manufacturer accepts no responsibility for damage caused by not adhering to these instructions for use. Modification or changes to any part of the product by unauthorized persons release the manufacturer from any liability over and above the lawful rights of the customer.

Copyright, trademarks

Pro-Ject Audio Systems is a registered Trademark of H. Lichtenegger.

This guide was produced by: Pro-Ject Audio Systems. Copyright © 2025. All rights reserved.

BT® is a trademark owned by the BT SIG Inc.

UK PSTI Statement of Conformity

The information was correct at the time of going to press. The manufacturer reserves the right to make changes to the technical specification without prior notice as deemed necessary to uphold the ongoing process of technical development.

Audio Tuning Vertriebs GmbH hereby declares that this Stream Box S2 complies with the applicable security requirements set out in Schedule 1 of The Product Security and Telecommunications Infrastructure (Security Requirements for Relevant Connectable Products) Regulations 2023 at the time of this Statement, required by the UK government in the Product Security & Telecommunications Infrastructure Act 2022.

Audio Tuning Vertriebs GmbH will provide software security updates for this product as described on this webpage: https://www.project-audio.com/en/product-security-software-updates/

If you detect a vulnerability with this product, please contact us following the guidance covered on this webpage: https://www.project-audio.com/en/data-protection-declaration/

This statement was last updated on 01.05.2025.

Waste from Electrical and Electronic Equipment (WEEE)

This directive mandates the collection and recycling of electronics and component materials in order to reduce the amount going to landfills. Outside North America, when the user decides to discard this product, it must be sent to a separate collection facility for recycling. Please contact your point of purchase for more details.

Federal Communication Commission (FCC) Interference Statement FCC Part 15

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

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. FCC Radiation Exposure Statement: This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment.

To maintain compliance with FCC´s RF exposure guidelines, this equipment should be installed and operated with minimum distance 20cm between the radiator and your body. Use on the supplied antenna.

Contains FCC ID: 2ANOG-ASR001

Declaration of Conformity

We, Canor spol. s r.o. (manufacturer), Družstevná 13925/39, 08006 Prešov, Slovakia, and Pro-Ject Audio Systems, a division of Audio Tuning GmbH (distributor), Margaretenstrasse 98, 1050 Vienna, Austria, declare under our responsibility that the product is in conformity with the provisions of Directives: 2014/35/EU, 2014/30/EU, 2014/53/EU (including amendments).

The following harmonised standards were applied:

• Health: EN62479:2010
• Safety: EN60950-1:2006+A11:2009+A1:2010+A12:2011+A2:2013, EN62368-1:2014/A11:2017, EN61558-1:2005/A1:2009, EN61558-2-16:2009/A1:2013
• EMC: EN301489-1 V2.2.0: 2017-03, EN301489-17 V3.2.0:2017-03, EN55032:2015, EN55035:2017, EN61000-3-2:2014, EN61000-3-3:2013
• Radio Spectrum: EN300328 V2.1.1 (2016-11)

Pro-Ject Audio Systems, a division of Audio Tuning GmbH, 1050 Vienna, Austria, Margaretenstrasse 98. info@project-audio.com