Should I add an external headphone amp to a Chord DAC?
Short answer
For Hugo, Hugo 2, Hugo TT 2 and Dave, Watts has said repeatedly not to add an external headphone amp, because an extra stage costs transparency Head-Fi, Apr 2014Head-Fi, Jan 2018Soundnews 12:37. His exception is a headphone needing more drive than the DAC gives, such as the Susvara on Dave Head-Fi, Aug 2014Head-Fi, Jun 2023. He calls preferring an amp's thicker sound personal taste Head-Fi, Dec 2016. Qutest was built to feed easy loads such as pre-amp inputs Head-Fi, Sep 2019; he said Qutest plus an amp suits those who like an amp's coloration or whose headphones need added warmth, but for headphones he told owners to get Hugo 2, which he says easily outperforms Qutest plus an amp Head-Fi, Jan 2018Head-Fi, Jan 2018Head-Fi, Feb 2018.
The practical answer. For Hugo, Hugo 2, Hugo TT 2 and Dave, Rob Watts's advice from 2014 to 2025 is not to add an external headphone amp. His stated reason is that every extra stage, cable and connector degrades transparency Head-Fi, Aug 2022Soundnews 12:37. He allows one exception, a headphone that needs more power than the DAC can give, and he accepts that some listeners prefer what an amp adds, calling that taste Head-Fi, Aug 2014Head-Fi, Dec 2016. Qutest is different: he says it was designed to feed easy loads such as pre-amp inputs Head-Fi, Sep 2019Head-Fi, Sep 2021. For headphones, though, he pointed Qutest owners to Hugo 2 unless they want an amp's coloration or added warmth Head-Fi, Jan 2018Head-Fi, Jan 2018.
Hugo (2014 to 2016). In April 2014 he wrote: "Adding an extra headphone amp will only make things worse as extra components degrades transparency." Head-Fi, Apr 2014 In August 2014 he said: "Now if you need more power, then add another amp, no argument from me here" and that adding an amp when you do not need power degrades transparency Head-Fi, Aug 2014. In December 2016 he said the HD800S would reach 116 dB SPL from Hugo, and advised: "Unless the 'phones are crazily insensitive, I would not use an external amp - you will only lose transparency." Head-Fi, Dec 2016
Hugo 2 and Mojo 2 (2017 to 2024). In January 2018 he said of Hugo 2: "so long as volume is not white, it will not distort or clip - ever" Head-Fi, Jan 2018. Later that month he said pretty much all the posts he had seen where amps are used were not about power delivery from Hugo 2 or Dave Head-Fi, Jan 2018. In April 2018, on an easy-to-drive headphone (the T5P), he said an external amp would degrade transparency "with absolutely no drive benefits" Head-Fi, Apr 2018. In January 2021 he wrote: "If you need more power for headphones go for a TT2." Head-Fi, Jan 2021 For a softer sound, he said in February 2017 that he added the filter adjustments on Hugo 2 so there would be "the possibility of a more forgiving sound" Head-Fi, Feb 2017. In January 2024, on the Mojo 2 thread, he said some headphones are said to sound better with external amps even though Mojo 2 and Hugo 2 can easily drive them to ear-splitting levels Head-Fi, Jan 2024.
Hugo TT 2. In May 2018 he said TT2 was meant to drive any headphones; he gave 18 watts Darko Audio 50. In October 2018 he wrote that it "strikes me as completely insane to use a headphone amp, which will only destroy transparency" Head-Fi, Oct 2018. In July 2020 he said an external amp fed from TT2's DAC mode "often sounds warmer due to distortions" Head-Fi, Jul 2020. Asked in March 2022 how he would run a Susvara from TT2, he said he would use the single-ended outputs and "would never use an additional amp for headphones" Head-Fi, Mar 2022. In February 2023 he said: "That way you do not need a separate headphone amplifier because the power is innately in there." Soundnews 13:10
Dave. In January 2018 he said that with a headphone connected and Dave's volume below +4 (+7 for BluDave), it "will not clip nor distort - ever" Head-Fi, Jan 2018. On the Susvara he leaves the choice open: Dave reaches 92 dB SPL, which would be just fine for him, but "to many listeners 92dB would not be enough, so it really depends upon the listener" Head-Fi, Jan 2022. In 2023 he said Dave is fine for 99% of headphones Soundnews 12:37. In June 2023 he named the Susvara as "the only situation where it may make sense" Head-Fi, Jun 2023. In January 2025 he said any additional amp is "guaranteed to distort the sound", and that he would only use one if Dave lacked drive, adding that Dave drives the Stealth to ear-damaging levels Head-Fi, Jan 2025.
Qutest. In January 2018 he said it was "designed principally for speaker based systems", that some like the coloration of external headphone amps, but that for transparency with refinement "it's gotta be Hugo 2 or Dave" Head-Fi, Jan 2018. The same day he said: "If you want to drive HP, get a Hugo 2." Head-Fi, Jan 2018 In February 2018 he said Hugo 2 "easily out performs" Qutest with a separate headphone amp, adding that some like the sound of their amps, "and that's OK" Head-Fi, Feb 2018. In March 2019 he called TT2 an order of magnitude simpler than Qutest plus a headphone amp Head-Fi, Mar 2019.
If your headphone sounds too bright or too lean. His suggestions were EQ or different headphones, not an added amp: in 2014 replacing the headphone, gentle EQ, or other cables Head-Fi, Aug 2014; in 2016 EQ or warmer headphones such as the AQ Nighthawks Head-Fi, Dec 2016; in 2018 EQ or better headphones Head-Fi, Jan 2018.
What he has not said. He does not review or recommend any named external headphone amp, or anything on this question about the original Mojo; Mojo 2 is covered by one post Head-Fi, Jan 2024.
Quotes
“Adding an extra headphone amp will only make things worse as extra components degrades transparency.”2014-04-15 Head-Fi, Apr 2014
“Unless the 'phones are crazily insensitive, I would not use an external amp - you will only lose transparency.”2016-12-09 Head-Fi, Dec 2016
“That way you do not need a separate headphone amplifier because the power is innately in there.”2023-02-05 Soundnews 13:10
“to many listeners 92dB would not be enough, so it really depends upon the listener”2022-01-04 Head-Fi, Jan 2022
Dated positions
| When | Products | Position |
|---|---|---|
| 2014-04 to 2014-08 | Hugo (original) | He said an extra headphone amp makes things worse, but that adding one for more power is acceptable. Head-Fi, Apr 2014Head-Fi, Aug 2014 |
| 2016-12 to 2017-02 | Hugo (original) | He said Hugo has plenty of power for headphones unless the volume is at white, and that he would not use an external amp unless the headphones are very insensitive. Head-Fi, Dec 2016Head-Fi, Feb 2017 |
| 2018-01 to 2018-04 | Hugo 2 | He said Hugo 2 will not clip or distort below white volume, that pretty much all amp use he had seen was not about power, and that an external amp degrades transparency. Head-Fi, Jan 2018Head-Fi, Jan 2018Head-Fi, Apr 2018 |
| 2018-01 to 2019-09 | Qutest | He said Qutest was designed mainly for speaker systems and to feed easy loads such as pre-amp inputs, that Qutest plus an amp would apply for those who like an external amp's coloration or whose headphones need added warmth, and that for headphones he would point to Hugo 2 or Dave, or TT2 as a simpler path than Qutest plus an amp. Head-Fi, Jan 2018Head-Fi, Jan 2018Head-Fi, Feb 2018Head-Fi, Mar 2019Head-Fi, Sep 2019 |
| 2018-05 to 2023-02 | Hugo TT2 | He said TT2 was made powerful enough that a separate headphone amp is not needed, that adding one destroys transparency, and that an amp fed from DAC mode often sounds warmer due to distortion. Darko Audio 50Head-Fi, Oct 2018Head-Fi, Jul 2020Soundnews 13:10 |
| 2021-01 | Hugo 2, Hugo TT2 | He said an extra stage always degrades transparency, and that if you need more power for headphones, go for a TT2. Head-Fi, Jan 2021 |
| 2015-12 to 2025-01 | DAVE | He said Dave drives headphones without an external amp, with the Susvara as the case he leaves to the listener, and that any additional amp distorts the sound. Head-Fi, Dec 2015Head-Fi, Jan 2022Head-Fi, Jun 2023Head-Fi, Jan 2025 |
| 2022-03 | Hugo TT2 | Asked how he would run a Susvara from TT2, he said he would use the single-ended outputs and would never use an additional amp for headphones. Head-Fi, Mar 2022 |
| 2024-01 | Mojo 2, Hugo 2 | He said some headphones are said to sound better with external amps even though Mojo 2 and Hugo 2 can drive them to very loud levels. Head-Fi, Jan 2024 |
Caveats and open points
- Several posts are replies whose original question is not shown, so the exact headphone or situation in a few cases (for example the 2024 Mojo 2 post) is not fully visible.
- The original Mojo is not covered by any statement found on this question, and Mojo 2 is covered by one post.
- No named external headphone amp is evaluated by him in this material.
Topics: Driving headphones and IEMs, Transparency, musicality and design goals