Why does my Hugo 2 switch itself off, and how does standby work on the battery-powered DACs?

The practical answer

If your Hugo 2 or Mojo 2 switches off by itself, the usual cause Watts describes is auto shutdown, set at 10 minutes without a valid input Head-Fi, Jun 2018Head-Fi, Apr 2022. On Hugo 2 it is disabled in desktop mode, which begins when the charger has supplied uninterrupted power for more than 24 hours Head-Fi, Jun 2017Head-Fi, Sep 2018. A low battery is the other cause he gave: in 2020 he said Hugo 2 and the original Mojo "need at least 6.5v, otherwise it will shut down" Head-Fi, Apr 2017Head-Fi, May 2020.

Hugo 2

What triggers shutdown. In August 2017 he wrote that it will "auto shut-down after 10 minutes if there is no lock on the SPDIF inputs" or no USB connected with a valid +5V Head-Fi, Aug 2017. In June 2018: "Hugo 2 will remain on if it has a locked SPDIF or a USB device connected during the past 10 minutes" Head-Fi, Jun 2018. In September 2019 he added that "it should not do this if music is playing, and if so it needs to be serviced" Head-Fi, Sep 2019.

Why. It stops the battery going flat if the unit "comes on inadvertently, in a bag for example"; USB is judged by the 5V supply because removing a USB DAC can crash some apps Head-Fi, Dec 2017.

Silence or lock? His wording varies. In late 2017 and in 2019 he described the SPDIF trigger as digital silence Head-Fi, Oct 2017Head-Fi, Dec 2017Head-Fi, Sep 2019. In June 2018 he said it "just detects a valid SPDIF lock, so it could be not playing" Head-Fi, Jun 2018. No later statement settles it; it is not a documented change of view.

Desktop mode. "auto shutdown is disabled in desktop mode" Head-Fi, Jun 2018. In November 2020 he said desktop mode "only does a couple of things - reduce the battery voltage for longer battery life, and stop auto shutdown" Head-Fi, Nov 2020. The 24-hour timer restarts if the charger loses power, and disconnecting the charger resets desktop mode Head-Fi, Jul 2017Head-Fi, Jan 2018.

Standby and the remote. In November 2020: "You don't need to be in desktop mode for the remote to turn on or off Hugo 2 - you just need to connect the charger" Head-Fi, Nov 2020.

Turning it off on the charger. Off on the charger, it charges to 100% and then turns off the charger Head-Fi, Jun 2017Head-Fi, Jan 2018.

Other shutdowns. He gave a thermal cut-off "at 60 to protect the batteries" (2018) Head-Fi, Mar 2018, and said in 2020 that a shorted output makes it "shut-down after 15 minutes" Head-Fi, Aug 2020. In 2019 he said a unit showing blue when turned on without the charger possibly has a battery fault and should be serviced Head-Fi, Sep 2019.

Mojo 2

Auto off. In February and April 2022 he wrote that no SPDIF lock and no USB VBUS "will cause Mojo 2 to shut down after 10 minutes of inactivity" Head-Fi, Feb 2022Head-Fi, Apr 2022. In March 2023 he said the lock flag "tells me nothing about what the data actually is" Head-Fi, Mar 2023.

Desktop mode. Unlike Hugo 2, once fully charged the battery is disconnected Head-Fi, Jan 2022Head-Fi, Feb 2024. The charger circuit stays on, with the FPGA in low power mode, and the battery gets a trickle top-up every 11 days (2022 and 2024) Head-Fi, Feb 2022Head-Fi, Feb 2024. In an October 2026 podcast he said the charged battery "gets completely isolated" Distorsiuni Interioare 40:27.

Shelf life. In March 2022 he said that with Mojo 2 "it now takes 7 months to go from full charge to flat whilst leaving it on the shelf", after cutting standby current by an order of magnitude; the original Mojo needed a top-up after several weeks Head-Fi, Mar 2022.

Other units

The original Mojo "doesn't have a desktop mode, and should be turned off when the charger is connected all the time" (March 2020) Head-Fi, Mar 2020. Hugo TT2 is mains powered; its standby switch "puts power to well below 2W" Head-Fi, May 2018, and in 2020 he said he leaves his on 24/7 Head-Fi, Jul 2020.

Leave it on or turn it off

His Hugo 2 advice moved. In 2017 and 2018 he said to leave it on Head-Fi, Jun 2017Head-Fi, Jan 2018Head-Fi, Mar 2018. In March 2020, calling it "a very marginal call", he set a rule: on at 8 or more hours a day, otherwise off when not in use; failure rates are extremely low either way, and he would personally leave it on Head-Fi, Mar 2020. In July 2024: "If you are not using it for two days or more, I would turn it off, but keep it on otherwise" Head-Fi, Jul 2024.

What he has not said. The archive gives no Hugo 2 standby figure beyond his guess of about 3W in standby while trickle charging Head-Fi, Mar 2018, and no auto-shutdown timing for the original Hugo or Mojo. He did not say whether Mojo 2's auto off is disabled in desktop mode; a January 2022 reply that appears to concern Mojo 2 says it has auto off but "remains in desktop mode so long as power is applied to the charging port" Head-Fi, Jan 2022.

Quotes

“10 minutes of no signal for auto shutdown - no signal is not digital silence.”2022-04-26 Head-Fi, Apr 2022

“You don't need to be in desktop mode for the remote to turn on or off Hugo 2 - you just need to connect the charger.”2020-11-09 Head-Fi, Nov 2020

“now with Mojo 2 it now takes 7 months to go from full charge to flat whilst leaving it on the shelf.”2022-03-29 Head-Fi, Mar 2022

“auto shutdown is disabled in desktop mode.”2018-06-25 Head-Fi, Jun 2018

Dated positions

Caveats and open points

• Nearly all evidence is Head-Fi forum posts; several replies answer questions that are not shown, so the exact product or context is inferred from the thread.
• Head-Fi, Jan 2022 (2022-01-31) does not name its product in the cited sentence; it appears to concern Mojo 2.
• Head-Fi, May 2020 (2020) refers to 'Mojo', read here as the original Mojo given the date.
• No Hugo 2 post after 2019 spells out whether the SPDIF test is lock or digital silence.
• The original Hugo and Mojo have no auto-shutdown statements.

Topics: Internal batteries, charging and desktop mode, Controls, indicators and remotes