How do I make sure my player sends bit-perfect data at the native sample rate?
Short answer
Watts says to send his DACs the original file untouched, with no resampling, upsampling, EQ or format conversion by the player Head-Fi, Nov 2024Head-Fi, Apr 2018. His checks: the sample rate light should match the file (a 96k file showing red on a Qutest has been converted), and DoP DSD playing mute-free indicates bit-perfect data Head-Fi, Dec 2023Head-Fi, Mar 2017. The one allowance he makes for Qutest, which has no volume control, is software volume in the player Head-Fi, Mar 2020.
Practical answer. In posts from 2014 to 2024 Watts gave the same core advice: feed the DAC the original file as it was recorded and keep the player from changing it Head-Fi, Apr 2014Head-Fi, Apr 2018Head-Fi, Aug 2021Head-Fi, Nov 2024. In 2018, replying about the Qutest, he put it this way: "You need to ensure that the data is bit perfect, that means the source does not upsample nor convert the data in any way" Head-Fi, Apr 2018. He wants the DAC's own filter, not the computer, to do the upsampling Head-Fi, Jan 2024. Asked in an interview recorded by December 2019 (part 4 published January 2020) whether to upsample in Roon or JRiver, he said "they should let the DAC take care of all of that", adding that this rested on owners' reports, not his own listening Passion for Sound 15:20.
What to set up
- Native sample rate. In April 2014, on the Hugo, he said "keep the file to whatever it was originally, don't let the player mess with the bits" Head-Fi, Apr 2014.
- DSD. In November 2024 he said that if the file is DSD, "don't let the source convert it to PCM" Head-Fi, Nov 2024. In February 2017, in the Dave thread, he also advised against converting to DSD Head-Fi, Feb 2017. In February 2022, in the general Watts Up thread, he said DoP DSD is fully supported up to DSD 256 on Linux and macOS, with DSD 512 (native) limited to Windows via ASIO; the post names no product Head-Fi, Feb 2022.
- No EQ, volume or upsampling in the player. The 2024 reply says the source should not "mess with PCM via EQ, volume or upsampling" Head-Fi, Nov 2024. For the Hugo in 2015 he said the source should be set to bit perfect "unless you really need some EQ" Head-Fi, Apr 2015.
- Bit depth. Over USB the Qutest always receives 32 bits, and a 16-bit source has its bottom 16 bits set to zero (2018) Head-Fi, Apr 2018. Replying about the M Scaler in 2019, he said never to set the PC to 16-bit output, because 24-bit sources get truncated and re-dithered Head-Fi, Mar 2019. In a 2022 reply that concerned the TT2, he said 32-bit integer data reaches the FPGA but 32-bit floating point is not supported Head-Fi, Mar 2022.
How to check
- Sample rate light. On the Qutest, with a 44.1k file you should see red Head-Fi, Apr 2018. In December 2023 he said the display shows the true input rate, so a 96k file shown as red "has been sample rate converted by the source" Head-Fi, Dec 2023. On the Hugo M Scaler in 2018, a 44.1k file showing orange (48k) is being converted by the player Head-Fi, Aug 2018.
- DoP DSD test. In March 2017, in the Hugo 2 thread, he said to test with DoP DSD: if it is mute free, it is bit perfect Head-Fi, Mar 2017. In October 2017 he said drop-outs on DoP DSD mean it is not bit perfect Head-Fi, Oct 2017. In a February 2023 talk he said a JRiver or Roon bit-perfect report can be trusted, and a DSD file is the check if you are worried; he added "We're not recommending you listen to DSD" Dusty Audio 1:05:36.
What counts as altering the data
In March 2016 he wrote that even a single stage of gain scaling "will make a big difference to the sound" Head-Fi, Mar 2016. He qualifies volume. In March 2020, on the Qutest, which has no volume control, he said to keep the source bit perfect "apart from when you have to do volume control", and that Roon volume beats a preamp or passive control Head-Fi, Mar 2020.
In August 2018 he advised to "ignore MQA and always go for the unchanged original file" Head-Fi, Aug 2018.
By product
- Hugo (2014 to 2015): keep native rates; PC sample rate conversion washed out the sound Head-Fi, Sep 2014.
- Mojo, Mojo 2 and Dave: in 2016 he said the Remedy, which uses a sample rate converter chip, is not bit perfect and is possibly "the fastest way to destroy the sound of Mojo or Dave" Head-Fi, Dec 2016. In the Mojo 2 thread in January 2024: "do not use SRC or upsampling" with his DACs Head-Fi, Jan 2024.
- Hugo M Scaler (2018): send it bit perfect data, because PC upsamplers cannot match its filter Head-Fi, Jul 2018Head-Fi, Jul 2018.
Drivers and modes
In August 2016 he said Windows drivers that ship with Chord DACs resend faulty packets, which driverless systems (iOS, Linux, Android) do not Head-Fi, Aug 2016. Later he played this down: in October 2017 he suspected driverless is OK in practice, and in 2022 he said he did not think resending is actually needed Head-Fi, Oct 2017Head-Fi, Feb 2022. In December 2016 he said that if the app is bit perfect, ASIO and WASAPI both are Head-Fi, Dec 2016. In 2022 he relayed Chord's advice to use exclusive mode on Mojo 2 Head-Fi, Feb 2022Head-Fi, Jul 2022.
What he has not said: no step-by-step settings for specific players, Apple Music, Android or iOS. In 2021 he said he has "zero experience of using Apple myself" Head-Fi, Mar 2021.
Quotes
“my advice is always send my DACs the original recording in the format that it was mastered in. If DSD, don't let the source convert it to PCM”2024-11-11 Head-Fi, Nov 2024
“You need to ensure that the data is bit perfect, that means the source does not upsample nor convert the data in any way.”2018-04-25 Head-Fi, Apr 2018
“But to test it use DoP DSD - if its mute free, it's bit perfect.”2017-03-28 Head-Fi, Mar 2017
“So unfortunately a 96k file that is displayed as red has been sample rate converted by the source.”2023-12-16 Head-Fi, Dec 2023
Dated positions
| When | Products | Position |
|---|---|---|
| 2014-04 to 2015-04 | Hugo (original) | Give Hugo the file at its original rate and do not let the player or PC resample it; set optical and coax to 24 bits and HD USB to 32 bits, with the source bit perfect unless EQ is needed. Head-Fi, Apr 2014Head-Fi, Jun 2014Head-Fi, Sep 2014Head-Fi, Apr 2015 |
| 2016-03 to 2016-12 | DAVE, Mojo (original) | Even one stage of gain scaling changes the sound (general thread); the Remedy, built on a sample rate converter chip, is not bit perfect and possibly the fastest way to destroy Mojo or Dave sound; Windows Chord drivers resend faulty packets while driverless systems do not. Head-Fi, Mar 2016Head-Fi, Aug 2016Head-Fi, Dec 2016Head-Fi, Aug 2016 |
| 2016-12 to 2017-10 | DAVE, Mojo (original), Hugo 2 | If the app is bit perfect, ASIO and WASAPI both are; DoP DSD playing mute free is his test for bit-perfect data; he advised against converting to DSD. Head-Fi, Dec 2016Head-Fi, Mar 2017Head-Fi, Oct 2017Head-Fi, Feb 2017 |
| 2018-04 to 2019-03 | Qutest, Hugo M Scaler | Source must not upsample or convert; the sample rate light shows what the DAC receives (44.1k is red, 48k orange); do not set the PC to 16-bit output. Head-Fi, Apr 2018Head-Fi, Aug 2018Head-Fi, Mar 2019Head-Fi, Jul 2018 |
| 2018-02 to 2020-03 | Qutest | Software volume adds some distortion and noise, but he suspected (2018) and then said (2020) it was better than an analog volume control; with Qutest he allowed volume control in Roon as the exception to keeping the source bit perfect. Head-Fi, Feb 2018Head-Fi, Mar 2020 |
| 2019-12 to 2020-01 | Playback software (JRiver, Foobar, Roon) | Interview recorded by December 2019 (part 4 published January 2020): let the DAC do the upsampling rather than Roon or JRiver; he said this rested on owners' reports, not his own listening. Passion for Sound 15:20 |
| 2022 to 2024-11 | Mojo 2, Hugo TT2 | Do not use sample rate conversion or upsampling; send the original format, DSD unconverted; 32-bit integer is supported, 32-bit float is not; exclusive mode advised by Chord for Mojo 2. Head-Fi, Jan 2024Head-Fi, Nov 2024Head-Fi, Mar 2022Head-Fi, Feb 2022Head-Fi, Jul 2022 |
| 2022-02 | General | Chord's USB supports DoP to DSD256 on Linux and macOS, and native DSD512 only on Windows via ASIO (no product named); he did not think Windows resending of faulty packets is actually needed in practice. Head-Fi, Feb 2022 |
| 2023-02 to 2023-12 | Playback software (JRiver, Foobar, Roon) | Check by DSD conversion or a JRiver trial, trust player bit-perfect reports (talk), and read the sample rate display. Dusty Audio 1:05:36Head-Fi, Jan 2023Head-Fi, Dec 2023 |
Caveats and open points
- He gives the principle and two checks (sample rate light, DoP DSD) but no step-by-step settings for specific players or operating systems.
- The 32-bit integer versus float remark (Head-Fi, Mar 2022) was a reply about the TT2 in a general thread; it is not stated for other products.
- The Hugo bit-depth and maximum-rate settings (Head-Fi, Apr 2015) are from 2015 and apply to the original Hugo.
- Volume handling is qualified by him: bit perfect except where software volume is needed (Head-Fi, Mar 2020).
- The interview advice against PC upsampling (recorded by December 2019, part 4 published January 2020) rested, he said, on owners' reports rather than his own listening (Passion for Sound 15:20).
- His 2016 point that Chord's Windows driver guarantees bit-perfect delivery was softened in 2017 and 2022, when he said driverless USB is probably fine in practice (Head-Fi, Oct 2017, Head-Fi, Feb 2022).