Quick answer: Plug a Bluetooth receiver (a small box that outputs line-level audio on RCA sockets) into a line-level input on the amp: AUX, Tape Play, Tuner or CD. Never use the Phono input, which is built for the tiny signal from a record cartridge and will sound loud, distorted and boomy. A budget receiver such as the 1Mii B06+ does the job; an audiophile-oriented one such as the Audioengine B1 adds a better DAC and an optical output. If you hear hum, power the receiver from a different USB adapter, or add a ground-loop isolator.
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The receiver specs below come from the manufacturers’ published information. We have not run listening tests, so we compare on specifications and features only.
Which input should you use on a vintage amp?
Old amplifiers have two kinds of input, and the difference is huge. Pioneer’s SX-780 receiver is a typical example: its manual lists the phono input at 2.5 mV sensitivity and the AUX and tape inputs at 150 mV. A Bluetooth receiver puts out line level; the Audioengine B1, for example, is rated at 2.0 V RMS full-scale output. That is about 13 times the AUX sensitivity and 800 times the phono sensitivity.
| Input on the amp | Use it for Bluetooth? | Why |
|---|---|---|
| AUX | Yes, first choice | Line level, no equalisation |
| Tape Play, Tape Monitor or Tape 2 | Yes | Line level. Press the Tape Monitor button to hear it on many receivers |
| Tuner (if the amp has a separate tuner input) | Yes | Line level |
| CD or Video | Yes | Line level |
| Phono | No | Built for about 2.5 mV with RIAA bass boost: heavy distortion and boom |
| Tape Rec or Tape Out | No | These are outputs |
Because the receiver’s output is well above what the AUX input needs for full power, you will use less of the volume knob than with a turntable. Start with the amp’s volume low, and set the phone’s volume to about three-quarters so you are not boosting noise.
What to look for in a Bluetooth receiver
- Outputs: RCA analogue for any vintage amp. An optical (Toslink) output is only useful if you also have an external DAC.
- Codecs: Bluetooth always supports SBC. aptX, aptX HD and aptX Adaptive are used by many Android phones; Apple devices use AAC. Choose a receiver that supports the codec your phone sends.
- Power: most receivers run from a 5 V USB adapter. A separate adapter, rather than a USB socket on another device, helps avoid hum.
- Range and placement: Bluetooth range drops through walls and furniture. Mount the receiver where it has a clear view of the room, not behind a metal amplifier case.
- Auto-reconnect: useful if several people pair with it.
Two receivers compared on published specs
| Spec | Audioengine B1 | 1Mii B06+ |
|---|---|---|
| Bluetooth version | 5.3 | 5.3 |
| Codecs | aptX Adaptive, aptX HD, aptX, AAC, SBC | aptX Adaptive, aptX HD, SBC (as listed) |
| Outputs | RCA and optical (S/PDIF) | RCA and 3.5 mm |
| DAC | ESS ES9018K2M | Not stated as a separate DAC |
| Rated range | Up to 100 ft (30 m) typical | Up to 98 ft (30 m) outdoors, less indoors (listing) |
| Power | 5 V, 200 mA | See listing |
| Published noise and distortion | SNR 104 dB, THD+N under 0.03% | Not published in the listing |
Sources: Audioengine B1 technical specifications; 1Mii B06+ Amazon listing. Audioengine says the B1 remembers up to six devices but connects to one at a time, and quotes latency of about 80 ms, which is fine for music but may be noticeable with video.
Which to choose: the 1Mii B06+ covers the basics for a kitchen or workshop system. The Audioengine B1 is the better fit for a good vintage system or an iPhone (it supports AAC), and for anyone who wants to feed an external DAC by optical.
- 1Mii B06+ Bluetooth receiver: check current price.
- Audioengine B1 Bluetooth receiver: check current price, and check the listing says Bluetooth 5.3.
How to connect it, step by step
- Switch the amp off and turn the volume down.
- Connect the receiver’s RCA outputs to the amp’s AUX (or Tape Play) inputs: red to right (R), white to left (L).
- Power the receiver from its own USB adapter at the wall.
- Switch on the amp, select AUX (or press Tape Monitor), then pair your phone with the receiver.
- Play something quiet, then raise the amp’s volume slowly.
Fixing hum, hiss and dropouts
| Problem | Likely cause | Fix |
|---|---|---|
| Hum or buzz that changes when you touch the cable | Ground loop between the receiver’s power and the amp | Use a different USB adapter, plug both into the same wall socket, or add a ground-loop isolator on the RCA lead |
| Whine that changes with the music or Bluetooth activity | Noise from a shared or poor power supply | Power the receiver from a separate, better adapter. Retronics describes using an isolated DC-DC converter when sharing a supply |
| Distorted or very loud even at low volume | Connected to Phono | Move to AUX or Tape |
| Crackles when you turn the volume knob | Dirty volume pot or input selector on the amp | Clean with contact cleaner. See our scratchy volume knob guide |
| Dropouts | Distance or obstacles | Move the receiver into the open, away from the amp’s metal case and Wi-Fi routers |
Other ways to add Bluetooth
- Tape deck or cassette adapter: a Bluetooth cassette adapter in a deck works, but the sound goes through the tape heads. A receiver on the AUX input is cleaner.
- Internal Bluetooth board: possible on some vintage radios, but it means opening a mains-powered set. Leave that to someone qualified.
- A streamer: a Wi-Fi streamer with RCA outputs adds multiroom and better quality, at a higher price.
Related guides
- Best vintage hi-fi amplifiers for beginners
- Vintage amplifiers explained
- Best vintage stereo receivers
- How to fix a scratchy volume knob
- Best affordable vintage amplifiers under $200
Sources: Audioengine B1 technical specifications; Pioneer SX-780 operating instructions, specifications page; Retronics: powering Bluetooth audio adapters; 1Mii B06+ product listing.
FAQ
How do I add Bluetooth to an old stereo?
Connect a Bluetooth receiver to a line-level input such as AUX, Tape Play or Tuner with an RCA cable, power it from a USB adapter, select that input and pair your phone.
Can I plug a Bluetooth receiver into the phono input?
No. The phono input expects a few millivolts from a cartridge and adds bass boost, so a line-level Bluetooth receiver will sound distorted and boomy. Use AUX or Tape.
Why does my Bluetooth receiver hum through my amp?
Usually a ground loop or a noisy USB power supply. Try a different adapter, plug both into the same wall socket, or fit a ground-loop isolator on the audio lead.
Which Bluetooth codec is best for an iPhone?
Apple devices use AAC, so choose a receiver that lists AAC support, such as the Audioengine B1.
Does Bluetooth sound worse than a cable?
Bluetooth compresses the audio, and how much depends on the codec. For casual listening most people find it fine; for the best quality use a wired source or a Wi-Fi streamer.