Should I use balanced or single-ended headphone drive, and why are Chord headphone outputs single-ended?
Short answer
Use the single-ended headphone output. Watts says a headphone sees only the voltage across it, so balanced drive brings no benefit unless the headphone needs more voltage or power, and it costs some transparency Head-Fi, May 2018Head-Fi, Jan 2021HiFi Buys 1:09:22. On Hugo TT 2 he reserves the XLRs for very low sensitivity headphones Head-Fi, Mar 2025. Dave's XLRs will not drive headphones Head-Fi, Dec 2015Head-Fi, Feb 2016. For the 2026 Mojo 2 with a 4.4mm socket, he named the gain as dropping adaptors and did not say how it is wired Audio Force 32:33.
The practical answer
Use the single-ended (SE) headphone output. In May 2018, in the Hugo TT 2 thread, Watts wrote "there is no benefit from the headphone POV of balanced drive" Head-Fi, May 2018. In January 2021, again on TT2, he said a headphone sees "only the difference in voltage from positive to negative", so "if you do not need the extra voltage or power, you will hear a loss in transparency" Head-Fi, Jan 2021. In an interview published in October 2026 he said "headphones don't care whether it's single-ended or balanced" and that with his very linear amplification balanced "won't give you any benefits, it's just going to give you losses" (check the recording) HiFi Buys 1:09:22.
Why Chord headphone outputs are single-ended
In 2015 he wrote that "going SE on a discrete DAC is possible, and is how all my DAC's are done" Head-Fi, Jul 2015, and that balanced headphone drive "would degrade transparency, so I do not and will not do it for headphones" Head-Fi, Dec 2015. In 2021 he said balanced operation for a DAC "always involves extra amplifier(s) in the signal path" Head-Fi, Jan 2021. In 2022, on Mojo 2: "adding balanced outputs would degrade transparency with my DAC architecture" Head-Fi, Jan 2022.
By product
Hugo TT 2. He gives 7W into 8 ohms from the headphone and RCA outputs and 18W from the XLRs Head-Fi, Nov 2018Head-Fi, May 2018. In May 2018 he said to consider the XLR only if the headphone needs the voltage or power: "it's difficult to imagine needing any more power at all" Head-Fi, May 2018. In 2019: "Only consider using the balanced if you are at +6H or above!" Head-Fi, Mar 2019. He advised staying SE for the Abyss in 2018, 2020 and 2021, the Susvara in 2022, and the DCA Stealth in 2023 ("You will not need the balanced, unless you want permanent hearing damage!") Head-Fi, Aug 2018Head-Fi, Jul 2020Head-Fi, Jan 2021Head-Fi, Mar 2022Head-Fi, Mar 2023. A post dated only to between March 2025 and March 2026 says "TT2 balanced is intended for very low sensitivity headphones with say 32 ohms impedance, when the extra voltage drive is needed, or for driving balanced inputs on amps" Head-Fi, Mar 2025.
On sound, he said in 2022 that the XLR outputs measure the same noise and distortion as SE, but the added parts "subtly degrades depth and detail resolution" Head-Fi, Aug 2022. To owners hearing balanced as better, he wrote in 2021 that "the most likely explanation is people are not turning down the volume by 6dB", also naming cabling, connectors and placebo Head-Fi, Jan 2021.
Cautions: in January 2021 he wrote "18v RMS is a lot of voltage to feed into a headphone!" and "XLRs into 16 ohm loads or greater is fine" Head-Fi, Jan 2021. In May 2018 he said XLR adaptors or re-terminated cables would work, "But I can't see anybody needing more than 7W/8 ohms or 9V RMS for headphones from the SE drive anyway!" Head-Fi, May 2018. In June 2018, agreeing with other posters, he said "in the long term adaptors are not a good idea - they do degrade the SQ quite noticeably" Head-Fi, Jun 2018.
Dave. Its XLR outputs are not for headphones. In 2015: "Categorically do not do this. The balanced drive has insufficient current drive and is intended to drive power amps only" Head-Fi, Dec 2015. In 2016 he said production units have protection resistors on the XLRs, "so it absolutely won't drive headphones!" Head-Fi, Feb 2016. In 2021: "with Dave the negative output is not high current, so it will not drive headphones" Head-Fi, Mar 2021.
Mojo, Mojo 2, Hugo 2. In 2018 he said there were no plans for a balanced portable design, since "The requirements of power-hungry headphones can be easily addressed on the single-ended connection" article, Apr 2018. In May 2022, in the Hugo 2 thread, he said balanced, against single-ended "configured for the same power OP", would always degrade transparency with his DACs, "so it's again something I would not consider" Head-Fi, May 2022. In 2023 he called a 4.4mm connector very expensive for Mojo 2, while saying "we constantly re-appraise what is going on" Head-Fi, Jun 2023, and at CanJam SoCal said "You don't need a balance" The Source AV 38:55.
In an interview published in March 2026 (recording date not stated) he discussed an updated Mojo 2 with a 4.4mm Pentaconn socket. He said "with the older Mojo II, you had to use adapters", that dropping them improves sound quality, and that "all of the audio parts is identical to the original Mojo" Audio Force 32:24Audio Force 32:33Audio Force 34:28. He did not say there whether the socket is wired balanced.
Line outputs into amplifiers
This is separate: for power amps and active speakers he wrote in 2019 "If you can, give both a try and see which sounds best" Head-Fi, Apr 2019.
Gaps. The archive has no listening comparison by him of balanced against SE on a named headphone, and nothing on how the 2026 Mojo 2 socket is wired. His 2023 remark that Pentaconn sockets will go on the Ultima DAC does not say whether they are balanced The Source AV 39:10.
Quotes
“When driving headphones (or passive loudspeakers) there is no benefit from the headphone POV of balanced drive.”2018-05-19 Head-Fi, May 2018
“So if you do not need the extra voltage or power, you will hear a loss in transparency.”2021-01-20 Head-Fi, Jan 2021
“Categorically do not do this. The balanced drive has insufficient current drive and is intended to drive power amps only.”2015-12-01 Head-Fi, Dec 2015
“Hence going balanced would only give you degraded transparency and no benefits.”2020-08-16 Head-Fi, Aug 2020
Dated positions
| When | Products | Position |
|---|---|---|
| 2014-08 to 2015-12 | Hugo (original), DAVE | Single-ended is best for his discrete DACs because balanced adds analog parts to the signal path; he does not and will not do balanced drive for headphones. Head-Fi, Aug 2014Head-Fi, Jul 2015Head-Fi, Dec 2015 |
| 2015-08 to 2016-03 | DAVE | Dave's XLR outputs are for power amps and are not intended to drive headphones; production units later got protection resistors on the XLR. Head-Fi, Aug 2015Head-Fi, Dec 2015Head-Fi, Feb 2016Head-Fi, Mar 2016 |
| 2018-04 | Mojo (original), Hugo 2 | No plans for a balanced portable design, as power-hungry headphones can be driven from the single-ended connection. article, Apr 2018 |
| 2018-05 to 2019-03 | Hugo TT2 | Consider the TT2 XLR for headphones only if the headphone needs the voltage or power; balanced has no benefit for the headphone itself. Head-Fi, May 2018Head-Fi, May 2018Head-Fi, Mar 2019 |
| 2018-08 to 2023-03 | Hugo TT2 | For the Abyss, Susvara and DCA Stealth he advises staying with the single-ended outputs. Head-Fi, Aug 2018Head-Fi, Jul 2020Head-Fi, Jan 2021Head-Fi, Mar 2022Head-Fi, Mar 2023 |
| 2020-08 to 2022-08 | Hugo TT2 | Balanced would degrade transparency with no benefit when single-ended already has more than enough drive; XLR measurements match SE, but added parts degrade depth and detail; unmatched volume, cabling and placebo may explain reported differences. Head-Fi, Aug 2020Head-Fi, Jan 2021Head-Fi, Jan 2021Head-Fi, Aug 2022 |
| 2021-03 | DAVE, Hugo TT2 | TT2 and Dave differ: TT2's XLR outputs are wired to high current stages, Dave's negative output is not high current and will not drive headphones. Head-Fi, Mar 2021 |
| 2022-01 to 2023-10 | Mojo 2, Hugo 2 | Adding balanced outputs would degrade transparency with his DACs (in the Hugo 2 thread, compared with single-ended configured for the same power) and is not something he would consider; in 2023 he called a 4.4mm connector very expensive for Mojo 2 while saying the question is re-appraised. Head-Fi, Jan 2022Head-Fi, May 2022Head-Fi, Jun 2023The Source AV 38:55The Source AV 38:59 |
| 2025-03 to 2026-03 | Hugo TT2 | TT2 balanced is intended for very low sensitivity headphones needing extra voltage, or for balanced amp inputs (exact post date unavailable). Head-Fi, Mar 2025 |
| 2026-03 | Mojo 2 | The updated Mojo 2 has a 4.4mm Pentaconn socket, which removes the need for adaptors; the audio parts are otherwise unchanged. He did not say whether the socket is wired balanced. Audio Force 32:24Audio Force 32:33Audio Force 34:28 |
| 2026-10 | General | Headphones do not care whether they are driven single-ended or balanced; with his very linear output stages balanced gives only losses. HiFi Buys 1:09:22HiFi Buys 1:10:07 |
Caveats and open points
- Many Head-Fi dates are estimated from post IDs; the TT2 post Head-Fi, Mar 2025 can only be dated to between March 2025 and March 2026.
- The 2018 to 2023 TT2 advice on the Abyss, Susvara and Stealth rests on his sensitivity and SPL figures in each post; readers should check those posts for the numbers.
- The June 2018 adaptor remark agrees with other posters; the May 2018 replies say adaptors or re-terminated cables will work on TT2's XLRs.
- This archive does not say how the 2026 Mojo 2 4.4mm socket is wired, and has no listening comparison on a named headphone.
Topics: Balanced vs single-ended, Analog output stage design, Driving headphones and IEMs