Phono preamp and TV both connect > Bluetooth Transmitter and Receiver > A5+ powered speakers.

So you can play the turntable and TV audio to Bluetooth headphones.

Or has pass through to play the turntable and TV audio to the speakers.

Plus has Bluetooth input for playing audio from your smartphone, tablet or computer to the speakers.

Well, there are a few ways you can do this. You can purchase something from Bose second-hand (it should be cheaper than Amazon for $265) or something that uses the Wave III's AUX or BoseLink input.

• From Bose (Bluetooth Only):
  • Wave Bluetooth music adapter
    • Good: Uses the BoseLink port to power this accessory and to allow the Wave system to control it. Connecting Bluetooth might turn on the wave system (I have not verified this, but it would make sense).
    • Negative: Doesn't work with all Wave systems, but will for the Wave III
  • Wave III dock with BoseLink + Bluetooth Dock
    • Good: Uses the BoseLink port to power this accessory and to allow the Wave system to control it. Connecting Bluetooth might turn on the wave system (I have not verified this, but it would make sense).
    • Negative: Doesn't work with all Wave systems, but will for the Wave III. Requires two items, a 30 pin dock & an item docked into it to work.
  • Bose Bluetooth Audio adapter
    • Good: Uses the AUX input on the wave.
    • Negative: Requires a separate power source to work. Connecting Bluetooth will not turn on the wave system.
• From Bose (Bluetooth & Wifi):
  • SoundTouch Wireless Link adapter
    • Good: Uses the AUX input on the wave. Has both Internet radio, Airplay 2, Bluetooth, Spotify Connect, NAS support, FLAC support, iTunes support, etc
    • Negative: Requires a separate power source to work. Connecting Bluetooth will not turn on the wave system. SoundTouch has been discontinued.
• Non-Bose (Bluetooth Only):
  • Bluetooth Receiver (multiple versions out there)
    • Good: Uses the AUX input on the wave.
    • Negative: Requires a separate power source to work. Connecting Bluetooth will not turn on the wave system.
• Non-Bose (Wifi):
  • Sonos Port
    • Good: Uses the AUX input on the wave. Has both Internet radio, Airplay 2, Spotify Connect, FLAC support, etc
    • Negative: Requires a separate power source to work. No Bluetooth. Connecting WiFi will not turn on the wave system. Expensive.

Or a Bluetooth Transmitter Receiver should work.

Has 3.5mm input for an RCA to 3.5mm audio cable from the phono preamp.

Has digital optical input for the TV.

Then it can transmit the TV or turntable audio to Bluetooth headphones.

Or has pass through to play TV or turntable audio to the A5+ powered speakers.

Plus Bluetooth receiving of streaming audio to the A5+ powered speakers.