Audio Fix / setup help

NAD C 389 / NAD C 399: check normal standby after an idle interval

Check normal standby after an idle interval. Exact C 389 or C 399 entered standby after about 20 minutes with no user interaction and no active source signal. There is no protection warning, abnormal heat, update or power failure.

Manufacturer-documented Reviewed 2026-11-10 · Revision 1

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When this guide applies

Exact C 389 or C 399 entered standby after about 20 minutes with no user interaction and no active source signal. There is no protection warning, abnormal heat, update or power failure.

Connection scope: Device controls / power only. Symptom: Power-on or automatic standby isn’t working.

This is a documented check, not a diagnosis of your equipment. The model name does not confirm the selected input, mode, software or connected partner.

If your exact model or a required setting is unknown, use the “I don’t know” branch below. Do not apply a similarly named model’s instructions.

Checks and possible outcomes

Start at scope. Follow the link that matches what you actually observe. Alternative branches are not a single sequence of actions.

scope

Confirm the exact setup

Exact C 389 or C 399 entered standby after about 20 minutes with no user interaction and no active source signal. There is no protection warning, abnormal heat, update or power failure.

Look for: Continue only when all stated prerequisites are known.

  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10
  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10

a1

Compare the observed conditions

Check the timing and whether the selected source had actually stopped. Auto Standby does not explain an unexplained shutdown during confirmed active playback.

Look for: The idle interval and lack of active signal are known.

  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10
  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10

a2

Wake normally and read the setting

Use the ordinary front Standby or SR 10 ON control, with playback level kept safe. Read Settings > Auto Standby rather than resetting the amplifier.

Look for: The unit wakes and Auto Standby is On.

  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10
  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10

a3

Keep the power-saving preference explicit

On permits the documented idle transition. Leave it enabled if desired and resume the known source quietly. If the actual conditions differ or it will not wake, retain that observation for support.

Look for: Normal wake and the idle-standby explanation are confirmed.

  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10
  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10

result

Check the actual result

Does the amplifier wake normally, with Auto Standby On explaining the confirmed idle interval?

Look for: A changed setting is not proof of a physical repair.

  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10
  • Manufacturer-documented NAD C 389 / NAD C 399 — original manufacturer instructions ↗C 389 p.15 / C 399 p.16, Auto Standby; front/remote controls — Auto Standby On permits standby after 20 minutes without user interaction or an active source input. Normal wake uses the front Standby control or the remote ON command.Only NAD C 389 / NAD C 399 and the stated connection role. Unknown hardware options, partner compatibility or menu state must stop. · Source checked 2026-11-10

Possible result

Checks completed — report the actual outcome

The stated observation was confirmed. Completion is not automatically Solved, an Audio Review physical test or a hardware diagnosis.

steps completed

Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

    Possible result

    Keep the observation for support

    Record the model, connection role and last visible result. Do not reset equipment, open its case, defeat protective limits or install an update to compensate for an unknown state.

    next support

    Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

      Possible result

      Confirm the unknown detail first

      An unknown detail is not a diagnosis. Check the exact manufacturer instructions before continuing.

      insufficient data

      Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

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