Devices that still work when the internet doesn't.

Audio & Video / AV receiver

Denon AVR-S770H

D2 Cloud-Optional — Full function with the router off.

The unplug test

Unplug the router and this receiver keeps doing its job: HDMI switching, video pass-through up to 8K, Dolby Atmos/DTS:X decoding, and amplification to seven channels all run locally with no network required, exactly as shipped. What stops working is HEOS multi-room audio, AirPlay 2, Spotify Connect and the online-streaming side of the HEOS app — anything that needs Denon's or a music service's server. The Setup Assistant that configures speakers and HDMI never asks for a network connection or an account; those only come up afterward, when you go looking for streaming.

Why this tier: Denon's own Quick Start Guide diagrams a 'Required for setup' list (TV, HDMI cable, speakers, speaker cables) that is separate from an 'Optional' list containing the LAN cable and Wi-Fi router, and the Setup Assistant reaches a 'Setup Assistant Complete!' screen before the HEOS and Denon AVR Remote apps are even mentioned as a later download step. HEOS is a real, nameable Denon cloud service — signing into a HEOS account is required only to use network music streaming and multi-room features, per Denon's own HEOS-account support article — but the receiver's core function, amplifying and switching HDMI/analog sources, requires no account and no network connection at all.

Specifications

Account requiredapp only
Works offlinepartially
Lost when offlineHEOS multi-room audio and the HEOS app's online music streaming (Spotify, TIDAL, Pandora, etc.), AirPlay 2 and Bluetooth-app remote control features that route through the HEOS account, Voice control via Alexa/Google Assistant/Siri, which requires the receiver on the network and linked to those separate cloud accounts, Automatic firmware update checks (the setup wizard offers 'Update Later' and can be declined)
Forced firmware updatesyes but blockable
Radioswifi, ble
FCC IDnot checked
Local controlunknown
Phones homeunknown
Self-hostable partial — partly replaceable on your own hardware
The receiver's core switching/amplification needs no replacement since it works fully offline. HEOS multi-room specifically has no open local equivalent; readers who want networked multi-room audio without a vendor account typically look at Home Assistant media-player integrations driving the receiver over its documented IP control protocol instead of HEOS, but that was not independently verified for this model this run.
Parts availableunknown
Availabilityin stock
Price bandunknown
Vendor risk 0 / 3

Where to buy

Open questions

Sources

Class A is primary (manual, FCC filing, teardown). Class B is corroborated community reporting. Class C is never sufficient alone.

History

Last verified 2026-09-05 — 1 days ago.