Can I use Hugo, Mojo or Mojo 2 while it is charging, and is it OK to leave it plugged in all the time?
Short answer
Hugo and Hugo 2 can stay plugged in: in 2014 he said Hugo on charger has no significant effect on sound Head-Fi, May 2014, and Hugo 2 enters desktop mode after 24 hours, though by 2024 he advised turning it off if idle two days or more Head-Fi, Mar 2017Head-Fi, Jul 2024. Mojo 2 is designed for it, with the battery disconnected Head-Fi, Feb 2024Head-Fi, Nov 2024. For the original Mojo he said in 2020 to turn it off if the charger stays connected Head-Fi, Mar 2020.
The practical answer
Watts has said Hugo, Hugo 2 and Mojo 2 can be left on a charger, with caveats for each, and advised differently for the original Mojo Head-Fi, May 2014Head-Fi, Jul 2024Head-Fi, Feb 2024Head-Fi, Mar 2020.
Hugo (original), 2014 to 2016
In April 2014 he wrote "I leave mine permanently plugged in" and said the charger "will either switch off, or run in constant current trickle charge mode" Head-Fi, Apr 2014. In May 2014: "You can leave it plugged in, it has no significant affect on SQ, I did a number of listening tests." Head-Fi, May 2014. He described the trickle charge as matching the current Hugo draws, so there is no net current from the battery when it is left on Head-Fi, Jun 2014. For chargers he said in 2014 "Do not use other PSU's apart from the supplied charger" Head-Fi, Jul 2014.
Hugo 2, 2017 to 2024
In 2017: "When you plug in a charger for longer than 24 hours it will enter desktop mode", which balances charger current against Hugo 2's draw and lowers battery voltage for life Head-Fi, Mar 2017. In 2017 he said that normally "you would leave it on all the time in desktop mode, as it only consumes 2W" Head-Fi, Jun 2017, and in 2018: "Keep it on, desktop mode keeps the voltage on the battery at a safe level for longevity POV" Head-Fi, Mar 2018. In June 2018 he estimated "about 10 years of being on permanently" before capacity halved Head-Fi, Jun 2018. For a full charge before portable use, turn it off Head-Fi, Jun 2017.
From 2019 his advice became conditional Head-Fi, Jul 2019, and in March 2020 he said "my advice changed": "if you use it 8 or more hours a day every day, keep it on", otherwise turn it off when not using it, adding "If it was me, I would keep it on all the time as I am too lazy to turn things off" and that the failure rate is extremely low either way Head-Fi, Mar 2020. In that post he also calculated, ignoring other effects on battery life, 70% capacity at 13 years if Hugo 2 is turned off daily and 65% if kept on, allowing for higher temperature Head-Fi, Mar 2020. In October 2022: probably best to turn it off when not in use, particularly for 12 hours or more Head-Fi, Oct 2022. 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.
On charging while playing, his 2017 and 2018 warnings concern a low battery: heat is highest charging at red while running, and charging from flat while playing is "not a good idea", though "in practice probably won't matter" Head-Fi, Jul 2017Head-Fi, Jun 2018. In November 2021 he went further: "I would not charge and play at the same time", but listen, then charge overnight with it off Head-Fi, Nov 2021.
On sound, he said in 2017 and 2018 that he could not measure or hear a difference with the charger connected Head-Fi, Apr 2017Head-Fi, Aug 2018. In October 2021 he said adding the charger can make Hugo 2 sound brighter, and suggested a battery power bank for desktop use Head-Fi, Oct 2021.
Mojo 2, 2022 to 2026
In February 2024 he wrote: "Mojo 2 in desktop mode, the battery is completely disconnected. Every 11 days a trickle charge is applied to keep the battery at 100%." Head-Fi, Feb 2024. It does not need 24 hours to get there Head-Fi, Mar 2024. In April 2022 he said you can charge it and listen and "it won't get hot" Audio Force 4:58.
On sound, in January 2022 he said desktop mode brings no improvement and no loss, but "you're always going to get the best sound quality by having it purely battery" Darko.Audio 16:39. In June 2022 he said it usually won't matter: disconnect the charger and see whether you hear a difference; if you do, use a power bank charged overnight Head-Fi, Jun 2022. In an interview at a Quartet launch event in Romania, published October 2026 (recording date not stated), he said the difference is "very, very low", depends on your system, and that "nobody has commented on sound quality losses by using it with the charger" Distorsiuni Interioare 42:28.
Mojo (original)
In June 2017 he wrote that "Mojo does not need it; it charges at the lower voltage for longer battery life" and does not add charge cycles when the charger is left on Head-Fi, Jun 2017. In March 2020 he described Mojo as having no desktop mode, and said it "should be turned off when the charger is connected all the time" Head-Fi, Mar 2020. In January 2022, of Mojo used on a desk, he said the battery "is constantly being tricklecharged and it's constantly wearing out" Darko.Audio 15:38Darko.Audio 15:59. On heat, he said in a podcast published June 2020 (recording date not stated) that charging and playing at once is when it gets warm, at roughly 3 to 4 W while charging (check the recording for the figures) Part-Time Audiophile 31:24, and in 2022 that it "would get too hot" Audio Force 2:44. In the same Romanian interview (published October 2026, recording date not stated) he said "you could definitely hear problems with Mojo one when you connected up the charger" Distorsiuni Interioare 43:23.
What he has not said
This archive has no battery-life figure for original Hugo, Mojo or Mojo 2 left on a charger, and the earlier Mojo advice he mentions in 2020 was not found here Head-Fi, Mar 2020.
Quotes
“You can leave it plugged in, it has no significant affect on SQ, I did a number of listening tests.”2014-05-16 Head-Fi, May 2014
“Keep it on, desktop mode keeps the voltage on the battery at a safe level for longevity POV”2018-03-26 Head-Fi, Mar 2018
“If you are not using it for two days or more, I would turn it off, but keep it on otherwise.”2024-07-15 Head-Fi, Jul 2024
“Mojo 2 in desktop mode, the battery is completely disconnected. Every 11 days a trickle charge is applied to keep the battery at 100%.”2024-02-19 Head-Fi, Feb 2024
Dated positions
| When | Products | Position |
|---|---|---|
| 2014-04 to 2016-01 | Hugo (original) | Leaves Hugo plugged in permanently; trickle charge matches Hugo's draw and he heard no significant effect on sound quality. Head-Fi, Apr 2014Head-Fi, May 2014Head-Fi, Jun 2014Head-Fi, Jan 2016 |
| 2017-03 to 2018-06 | Hugo 2 | After 24 hours on a charger Hugo 2 enters desktop mode and he advises leaving it on; in 2018 he estimated about 10 years of permanent use before capacity halves. Head-Fi, Mar 2017Head-Fi, Jun 2017Head-Fi, Mar 2018Head-Fi, Jun 2018 |
| 2019-07 to 2024-07 | Hugo 2 | Advice becomes conditional on use: keep on if used 8 or more hours a day, otherwise turn off when idle, with later versions at 12 hours and two days; he says the failure rate is very low either way and that he would personally keep it on. In March 2020 he calculated 70% battery capacity at 13 years if turned off daily against 65% if kept on. Head-Fi, Jul 2019Head-Fi, Mar 2020Head-Fi, Oct 2022Head-Fi, Jul 2024 |
| 2017-07 to 2021-11 | Hugo 2 | Warns against charging and playing from a low battery because of temperature, while noting the thermal trips make it unlikely to matter; in 2021 says he would not charge and play at the same time. Head-Fi, Jul 2017Head-Fi, Jun 2018Head-Fi, Nov 2021 |
| 2017-02 to 2021-10 | Hugo 2 | Could not measure or hear a difference with the charger connected in 2017 and 2018, but said in 2021 it can make Hugo 2 sound brighter and suggested a power bank. Head-Fi, Feb 2017Head-Fi, Apr 2017Head-Fi, Aug 2018Head-Fi, Oct 2021 |
| 2022-01 to 2026-10 | Mojo 2 | Mojo 2 desktop mode disconnects the battery with a trickle top-up every 11 days and it can charge while listening without getting hot; battery operation remains the best sound, but he says the difference is very low. Head-Fi, Feb 2024Audio Force 4:58Darko.Audio 16:39Head-Fi, Jun 2022Distorsiuni Interioare 42:28 |
| 2017-06 to 2026-10 | Mojo (original) | Said in 2017 Mojo does not need desktop mode and adds no charge cycles on a charger; in 2020 that it should be turned off when the charger is connected all the time; in 2022 that a desk-bound Mojo battery is constantly trickle charged and wearing out; in 2026 that problems were audible with the charger connected. Head-Fi, Jun 2017Head-Fi, Mar 2020Darko.Audio 15:59Distorsiuni Interioare 43:23 |
Caveats and open points
- The Mojo advice behind his March 2020 remark about turning Mojo off was not found in this archive.
- His continuous-charging battery estimates are for Hugo 2 only: about 10 years to half capacity (2018, Head-Fi, Jun 2018), and in March 2020 70% capacity at 13 years if turned off daily against 65% if kept on, ignoring other effects on battery life (Head-Fi, Mar 2020); none is given for original Hugo, Mojo or Mojo 2.
- His Hugo 2 advice varies between posts (keep on, turn off when idle); he said in 2020 his advice changed, and later posts give differing idle thresholds rather than a clear reversal.
- His original Mojo statements differ: 2017 says no added charge cycles on a charger, 2022 (transcript) says the desk-bound battery was constantly trickle charged and wearing out.