Yes, an Onkyo TX-8500 Bluetooth connection needs no soldering. Best path: a Bluetooth receiver with RCA output into an open high-level input (150 mV / 50 kOhm; the set documents three tape inputs including one Dolby loop). If those are taken, the third tape remains. Rated 110 W/ch into 8 ohms, it opens the Onkyo shelf in this archive.
Figures on this page were checked September 2026. Every table row carries its source; the MKII wattage spread is disclosed rather than settled.
Spec snapshot
| Item | Value | Notes | Source |
|---|---|---|---|
| Production run | 1976–1978 | Approx. 3,500 DM in German lists; mkI and mkII builds documented | HW |
| Power output | 110 W/ch @ 8 Ω | Continuous at 0.1% THD; 150 W into 4 ohms; FR 15-30,000 Hz | HW, HE |
| Phono inputs | 2 × 2.5 mV / 50 kΩ | MM stages per the specification sheet | HW |
| Line inputs | 3 × Tape · Dolby | Three tape inputs at 150 mV / 50 kOhm plus a Dolby in/out loop at the same level | HW |
| Speakers | 3 pairs | Headphone jack on the receiver | HW |
| Weight | 25 kg | The mkII transcription block lists 28 kg and 160 W/ch at 0.05% | HW, HE |
Source codes: HW hifi-wiki.com · HE HiFi Engine transcription (Wayback snapshot) · CR classicreceivers.com (MKII wattage context). Data as of September 2026. The MKII's wattage quotes differ across sources and are disclosed in the FAQ rather than settled.
Where to connect
AUX or tape input
RecommendedThe documented high-level positions, three tape inputs and a Dolby loop, all sit at 150 mV / 50 kOhm. Any line-level Bluetooth receiver with RCA output occupies one of them without adapters. The set documents no AUX-labeled position, so the tape positions are the line-level homes.
Tape monitor loops
Good alternativeWith three tape positions, the TX-8500 offers the most loop capacity documented in this archive's Onkyo and Kenwood shelves. Feed a loop's play jacks, select the tape position to listen, and switch the monitor back off for the other sources.
Phono inputs
Not for line-levelThe two MM phono stages expect a cartridge's 2.5 mV. Line-level Bluetooth output would overload them, and the turntables would lose their inputs.
Set up in three steps
- Pick a high-level input
Three tape positions plus the Dolby loop give room; AUX-style selection follows the receiver's own labeling.
- Connect and power
Bluetooth receiver RCA out to the chosen input, USB power attached, pair once with your phone.
- Level check
Volume low, select the input, then raise. Fixed/line output on the adapter if it offers the option.
Quirks and notes
- Onkyo's shelf opens at 110 watts (verified): the specification sheets and retrospective coverage agree on 110 W/ch into 8 ohms for the base receiver, with the mkII transcription block reaching 160 W and 28 kg, and this page keeps the base record with the variant noted.
- Three tape positions, one a Dolby loop (verified): the TX-8500 documents more tape capacity than most sets here, and the Dolby in/out at 150 mV doubles as a processing insert, a layout the KR-9400's Dolby NR loop parallels.
- The MKII wattage spread, disclosed (verified): the transcription's mkII block reaches 160 W/ch at 0.05% while the MKII retrospective page quotes 110 W into 8 ohms and 150 W into 4 ohms. Both carry their attribution here; neither is smoothed into the other.
What you need
- Bluetooth receiver with RCA output, LDAC or aptX HD preferred
- 0.5–1 m RCA cable
- USB power for the receiver
FAQ
Plug a Bluetooth receiver with RCA output into an open high-level input and select it; the set documents three tape positions at 150 mV / 50 kOhm plus a Dolby loop, all at line level.
Per the specification sheets: two MM phono inputs at 2.5 mV / 50 kOhm; three tape inputs at 150 mV / 50 kOhm; a Dolby input and output at 150 mV / 50 kOhm; three speaker pairs; and a frequency response of 15 Hz to 30,000 Hz. The sheets document no AUX-labeled input.
Continuous output is rated 110 W per channel into 8 ohms (150 W into 4 ohms) at 0.1% distortion per the specification sheets, and retrospective coverage of the MKII variant quotes the same 110 W into 8 ohms as underrated, alongside a 150 W into 4 ohms figure.
The references document two builds: the transcription lists an mkI at 110 W/ch (25 kg) and an mkII at 160 W/ch (28 kg) with a wider-bandwidth front end, while the MKII retrospective page quotes 110 W into 8 ohms and 150 W into 4 ohms. The wattage quotes for the MKII differ across sources, and this page carries the base-model record with the MKII spread noted.
blafili B3 Bluetooth Music Receiver
RCA + XLR + optical out, LDAC and aptX HD, OLED status display. Matches the TX-8500 line-level inputs without adapters.
- Full connection and amplifier specifications (2× Phono MM 2.5 mV / 50 kOhm; 3× Tape In 150 mV / 50 kOhm; Dolby In/Out 150 mV / 50 kOhm; 3 speaker pairs; 110 W/ch at 8 ohms, 150 W at 4 ohms; THD 0.1%; FR 15-30,000 Hz; weight 25 kg; years 1976-1978; approx. 3,500 DM): hifi-wiki.com/index.php/Onkyo_TX-8500, accessed 2026-09-25. The set documents no AUX-labeled input.
- Variant blocks (mkI: 110 W/ch at 0.1%, 25 kg, 570 × 160 × 455 mm; mkII: 160 W/ch at 0.05%, 28 kg, FR 3 Hz-30 kHz): HiFi Engine, Onkyo TX-8500 manual page (hifiengine.com, bot-gated to direct fetches; verified via Wayback snapshot 20190922160658), accessed 2026-09-25
- Modern retrospective coverage of the TX-8500 MKII ("the line receiver at the time", "an under rated 150 watts per channel into 4 ohms and 110 watts per channel into 8 ohms"): classicreceivers.com/onkyo-tx-8500, accessed 2026-09-25