UGREEN 70303 Bluetooth 5.0 AUX Receiver with Microphone
Overview
UGREEN 70303 receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones. Its signal path is Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging. The physical build is compact black rechargeable Bluetooth 5.0 receiver with physical controls, status LED, built-in microphone, 3.5mm audio socket and Micro-USB charging port. This guide separates the product’s real function from similar-looking splitters, extensions and digital adapters.
- SKU 70303
- Portable receiver
- Black
What it does well.
Key features
connector role. Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging.
Use. Receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones.
Compatibility boundary. Bluetooth phones and tablets as sources; car AUX, powered speakers, receivers, amplifiers and wired headphones as 3.5mm output destinations.
Build and handling. Compact black rechargeable Bluetooth 5.0 receiver with physical controls, status LED, built-in microphone, 3.5mm audio socket and Micro-USB charging port.
Connector and signal-path guide
The receiver decodes Bluetooth audio from a phone or tablet and outputs analogue sound through 3.5mm. Its built-in microphone handles supported calls; the Micro-USB port recharges the battery.
Why this matters: 3.5mm plugs can look alike while carrying different numbers of contacts. TRS normally provides stereo left/right/ground; TRRS adds a microphone/control contact. Digital USB-C or Lightning audio needs conversion electronics rather than passive rewiring.
Direction check: Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging. Do not buy by connector diameter alone.
Use scenarios
Older car AUX. Receive phone audio wirelessly and feed it into a 3.5mm car stereo input.
Speakers and amplifiers. Add Bluetooth reception to powered speakers or home audio with an AUX input.
Wired headphones. Plug compatible wired headphones into the receiver for portable Bluetooth listening.
Two-phone car. Keep two source devices paired, then switch playback or supported calls between them.
Setup and usability guidance
Comfort rule: start playback at a low volume. A new adapter can expose a different device volume setting than the one used previously.
- Step 1: Charge the receiver with a suitable USB power source and the supplied cable before first use.
- Step 2: Connect the 3.5mm output to the destination. Use the supplied male-to-male adapter for a car or speaker AUX socket; plug wired headphones into the receiver socket directly.
- Step 3: Power on and enter pairing mode, then select the UGREEN receiver in the phone or tablet Bluetooth menu.
- Step 4: Start at low volume. Raise the source and destination gradually to avoid sudden loud output.
- Step 5: For a second phone, follow the product pairing sequence, then confirm which device is actively playing or calling.
- Step 6: Place the built-in microphone where speech can reach it; a low or enclosed AUX socket can reduce call clarity.
Compatible devices and systems
Compatibility class: Bluetooth phones and tablets as sources; car AUX, powered speakers, receivers, amplifiers and wired headphones as 3.5mm output destinations.
Connector first. Confirm the male/female connector, TRS/TRRS contact count and input/output direction. Brand name alone does not prove fit.
Host capability. For USB-C, Lightning or Bluetooth products, the host must support the relevant audio function. For passive cables, both endpoints must already provide analogue audio.
Headset standard. CTIA and OMTP four-pole wiring are not interchangeable in every product. Inline button behaviour can also differ by phone, headset and operating system.
Cases and recessed sockets. A protective case, recessed jack or closely spaced panel can prevent full seating even when the nominal connector matches.
What this product does
- Provides the Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging connection described for SKU 70303.
- Receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones.
- Uses the build: compact black rechargeable Bluetooth 5.0 receiver with physical controls, status LED, built-in microphone, 3.5mm audio socket and Micro-USB charging port.
- Keeps buying guidance tied to this SKU rather than borrowing capabilities from a related cable family.
What this product does not do
- receiver only—not a Bluetooth transmitter; not an FM transmitter; Micro-USB is for charging, not USB audio; does not add Bluetooth to a television output.
- It does not guarantee louder sound, remove source noise or repair worn sockets, damaged cables or incompatible wiring.
- It does not create independent audio channels, mixing, electrical isolation or professional balanced conversion unless explicitly stated—which this product is not.
- It is not a power cable, charger, video adapter or networking accessory.
- It does not prove compatibility merely because another device has a visually similar port.
What to do
Match this SKU. Use 70303 only when Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging matches the required direction.
Seat connectors fully. Push straight into clean sockets while equipment volume is low. A half-seated plug is a common cause of missing channels or microphone failure.
Test each function. Check stereo left/right, microphone, calls and controls separately; not every contact or button applies to every product.
Protect device ports. Leave slack, avoid side load and disconnect by the housing so the small audio socket is not used as a lever.
What not to do
Do not force a plug. Stop if the connector does not align or seat. Check case clearance, debris, plug diameter and male/female direction.
Do not assume TRS equals TRRS. Count the contacts and confirm stereo-only versus headset microphone/control requirements before connecting.
Do not pull the cable. Grip the connector housing. Pulling, twisting or sharply folding the cable can damage conductors and device sockets.
Do not connect live at high volume. Lower or mute amplification before changing analogue connections to avoid pops, feedback or unexpectedly loud sound.
Warnings and limitations
Hearing safety: begin at low volume and limit exposure. An adapter does not provide hearing protection.
Compatibility: receiver only—not a Bluetooth transmitter; not an FM transmitter; Micro-USB is for charging, not USB audio; does not add Bluetooth to a television output.
Environment: keep connectors dry, clean and away from extreme heat. Do not use a damaged or corroded plug.
Vehicles: pair, route and adjust controls while parked. Hands-free hardware does not remove the need to follow local driving and phone-use laws.
Selection guidance
1. Identify the job. Receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones.
2. Check direction. Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging.
3. Check contact standard. Decide whether the requirement is stereo TRS, CTIA headset TRRS, Bluetooth reception, USB Audio or Lightning audio.
4. Check limitations. receiver only—not a Bluetooth transmitter; not an FM transmitter; Micro-USB is for charging, not USB audio; does not add Bluetooth to a television output.
Troubleshooting
No audio. Confirm the source output, destination input and operating-system output selection. Reseat both ends with any obstructing case removed.
One channel only. Lower volume, cleanly reseat the plug and test with another known-good headphone/source. A partially inserted TRS/TRRS plug often drops a channel.
Microphone missing. Verify this SKU carries a microphone path, then check CTIA/OMTP wiring, input selection, app permissions and mute controls.
Buzz or crackle. Keep connections away from power noise, stop cable movement, clean dry plugs and test components one at a time to identify a worn socket or cable.
Controls behave oddly. Device and headset manufacturers can map inline buttons differently. Remove parallel splitters, confirm the standard and test basic audio before controls.
Level is too low. Check source and destination volume independently. Passive cables do not amplify; digital adapters still depend on host volume, DAC output and headphone load.
model check before ordering
Match SKU 70303, Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging, Portable receiver and the stated compatibility boundary. Similar UGREEN audio cables can differ in TRS/TRRS contacts, direction, digital conversion, microphone support and colour.
At a glance.
- Brand / SKU
- UGREEN 70303
- Product role
- receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones
- Connector path
- Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging
- Build
- compact black rechargeable Bluetooth 5.0 receiver with physical controls, status LED, built-in microphone, 3.5mm audio socket and Micro-USB charging port
- Wireless role
- Bluetooth audio receiver only
- Bluetooth version
- 5.0
- Listed wireless range
- Up to 10m in suitable open conditions
- Simultaneous source connections
- Up to 2 paired Bluetooth devices
- Listed playtime
- Up to 9 hours
- Listed standby time
- Up to 300 hours
- Listed charging time
- About 2 hours
- Charging input
- Micro-USB
- Audio output
- 3.5mm analogue
- Microphone
- Built in for supported calls
- gallery audio figures
- CVC 8.0; distortion <0.1%; SNR >90dB
- Colour
- Black
1 × Bluetooth receiver, 1 × 3.5mm male-to-male adapter, 1 × USB charging cable, 1 × user guide
No phone, computer, headphones, car stereo, speaker, charger or additional adapter is included unless explicitly named above.
Questions buyers ask.
What is UGREEN 70303 designed to do?
Receives Bluetooth audio from a phone or tablet and feeds it into a 3.5mm AUX input, speaker, amplifier or compatible wired headphones.
Which connector direction does it use?
Bluetooth wireless input to 3.5mm analogue audio output, with Micro-USB charging. Match both ends before purchase.
Does it need a driver or separate power?
It has a rechargeable battery and pairs through the source device Bluetooth settings; no special app is identified.
Will microphone and inline controls work?
Calls use the receiver’s built-in microphone, not a microphone in the connected AUX destination.
Can I use it with a phone case?
Only if the plug housing can seat fully. A deep or narrow case opening can block complete insertion; never force the connector.
Does it improve audio quality or volume?
It provides the documented connection. Real noise, level and fidelity depend on the source, destination, file, amplification, socket condition and environment; it is not a universal amplifier or sound enhancer.
Can it be used as a microphone adapter?
No microphone path is provided by this stereo-only cable.
What should I check if sound comes from one side?
Lower volume, push each plug fully into a clean socket, remove an obstructing case and test each source/headphone separately. A half-seated TRS/TRRS plug commonly loses a channel.
Is it suitable for studio, stage or balanced audio?
It is a consumer audio accessory, not presented as a balanced professional interface, isolated splitter or stage-rated installation cable.
Can I connect extra adapters or splitters?
Possibly, but each extra joint can add fit, wiring and signal-level uncertainty. Check TRS/TRRS standard and direction at every step, then test at low volume.
What is included in the package?
1 × Bluetooth receiver, 1 × 3.5mm male-to-male adapter, 1 × USB charging cable, 1 × user guide.