Hugo (original)
What it is
Hugo, later called Hugo 1 Head-Fi, Apr 2017, is the portable DAC and headphone amplifier Watts designed for Chord Electronics; in 2018 he called it "my first portable DAC" Head-Fi, Mar 2018. He dates the project to autumn 2012 article, Aug 2014. He called it "kind of an accident": it got six years of rewritten code meant for a reference-class DAC article, Aug 2014article, Aug 2014.
In a 2018 written interview he said Hugo launched in 2014 as a fun project, that he expected to sell a couple of hundred, and that it sold over 10,000 article, Mar 2018. In 2014 he said its amp cannot be judged alone, as there is no separate headphone stage Head-Fi, Apr 2014. He said "Hugo has never been tweaked or voiced to sound a certain way" Head-Fi, Feb 2015. In March 2015 he said Hugo was "gaining traction with mastering engineers" Audiophile Style, Mar 2015.
Design
In 2015 he gave the filter chain: a 26,368-tap WTA stage from 1FS to 8FS, a second WTA stage to 16FS that also does volume, a linear interpolator to 2048FS, then two low-pass filters Head-Fi, Mar 2015. The taps run on 16 parallel DSP cores at 208 MHz Head-Fi, May 2014. More taps, he says, reconstruct timing more accurately Head-Fi, May 2014.
The DAC is a pulse array with discrete flip-flops at the analog output, driven by a noise shaper in the FPGA at 104 MHz from a low-jitter crystal, and he said the DPLL "effectively eliminates source jitter" Head-Fi, Apr 2014Head-Fi, Jun 2014. It has 4 elements; QBD76 has 16 Head-Fi, Apr 2014. In 2016 he called 200 dB the Hugo standard for the noise shaper Hifistatement 3:05. The FPGA is a Xilinx Spartan-6 LX9 article, Aug 2014. In talks he said the design already used 95 to 98% of the FPGA before crossfeed, so he slimmed the noise shaper, still 200 dB, and it sounded better, with more depth RMAF 20:51Pursuit Perfect System 20:32Passion for Sound 12:06Passion for Sound 12:52.
The analog section has one active stage, a fast op-amp with a discrete Class A output stage inside a single global feedback loop, and two resistors and two capacitors in the direct signal path Head-Fi, Feb 2015. There is no analog volume control Head-Fi, Apr 2015, and the design is single-ended Head-Fi, Aug 2014. Output impedance is 0.075 ohm Head-Fi, Apr 2014. Volume is digital, 51 bits internally, truncated at 16FS by noise shaping and dither that adds only fixed noise at -180 dB Head-Fi, Jan 2015.
Inputs, outputs and power
Input limits (2015): SD USB and Bluetooth 16 bits at 48 kHz, HD USB 32 bits at 384 kHz, optical 192 kHz, coax 384 kHz Head-Fi, Apr 2015. DSD is accepted through DoP only Head-Fi, May 2016, decoded after input selection so any input works Head-Fi, Apr 2014. DSD becomes PCM at 16FS through a filter he gave 140 dB of rejection in 2014 Head-Fi, Apr 2014. From an M Scaler, Hugo 1 cannot take dual data mode; he advised the single BNC output at 352/384 Head-Fi, Dec 2018 (see Which Chord DACs accept 705.6/768 kHz from an M Scaler, and how do…).
One output stage feeds every connector, so there is no fixed DAC output Head-Fi, Nov 2014. He gave 5V RMS and 0.5A RMS Head-Fi, Sep 2014; preset mode measured 2.996V RMS at 0dBFS Head-Fi, Jun 2014. For loudspeakers he said they must be 8 ohms or more and efficient, as "you only have 1W" Head-Fi, Apr 2014.
Power comes from two 4.2V batteries, an 8.4V supply Head-Fi, May 2015, giving about 8.5 hours on HD USB and 10.5 hours on other inputs, with low-power headphone output Head-Fi, Apr 2015. He heard no significant change with the charger in or out (2014, 2017), though with 8 ohm loads flat out it sounded fuller Head-Fi, Jun 2014Head-Fi, Dec 2017Head-Fi, Jun 2014. With Hugo on and the charger connected, trickle current matches its draw Head-Fi, Jun 2014. Over-voltage chargers other than the supplied one damaged its protection circuit Head-Fi, Jul 2014. Switching regulators sounded better to him than linear ones Head-Fi, Jan 2016Head-Fi, Mar 2018.
How he says to use it
He preferred optical on Hugo from 2014 as "smoother and warmer" Head-Fi, May 2014, confirmed in a June 2014 retest against coaxial Head-Fi, Jun 2014, and wrote "Optical is best on Hugo" in July 2015 Head-Fi, Jul 2015. Yet in September 2014 he told an owner to "Use the USB inputs" rather than let the PC resample, since "the difference in SQ in using optical is small" by comparison; a 44.1 to 48k conversion once washed out "the Hugo magic" Head-Fi, Sep 2014. He said he thinks Hugo works well with any source so long as it is bit perfect Head-Fi, Jun 2014. His USB versus optical statements changed over the years (see Which input sounds best on a Chord DAC (optical, coax, USB or…, If the data reaching the DAC is bit perfect, can the source…, Does source jitter matter with a Chord DAC, and would a reclocker,…). In 2014 an isolator on the SD USB input improved depth and separation with his Dell, but works only up to 48 kHz Head-Fi, Jun 2014Head-Fi, Oct 2014 (see Will a USB purifier, JitterBug or USB isolator improve my DAVE,…, Which Chord inputs are galvanically isolated, and which setups…).
He advises feeding power amps directly with no pre-amp Head-Fi, Jun 2014 (see Should I use a pre-amp (tube or solid state), or run the Chord DAC…). He says external amps degrade transparency, and below white volume he believes there is plenty of power for all headphones Head-Fi, Sep 2015Head-Fi, Feb 2017 (see Should I add an external headphone amp to a Chord DAC?, Is my Chord DAC powerful enough for my headphones?, Can Hugo, Hugo 2, Mojo, TT2 or DAVE drive loudspeakers directly…). On the very sensitive Shure SE846 he said the 5uV residual noise would be just audible Head-Fi, Sep 2014 (see Will sensitive IEMs hiss on a Chord DAC?).
He left his plugged in and on, in 2014 and again in 2016 Head-Fi, Apr 2014Head-Fi, Jan 2016. A fully depleted unit enters safety charge mode and must then be charged with Hugo switched off Head-Fi, May 2016 (see Can I use Hugo, Mojo or Mojo 2 while it is charging, and is it OK…, Should I replace the supplied power supply with a linear or…). He said crossfeed suits older hard-panned recordings, and on Hugo 1 gave regular recordings no depth benefit Head-Fi, Sep 2017 (see What does crossfeed do, which setting should I use, and why didn't…, What do the colored indicators mean (volume, sample rate,…).
Compared with other Chord models
Qute is technically very similar to Hugo, yet he found Hugo radically different musically and was unsure why article, Aug 2014. In 2016 he said Hugo TT adds extra batteries, supercaps, USB galvanic isolation and a better reference supply, cutting distortion and noise by some 4 dB Head-Fi, Jan 2016. He said Mojo shares Hugo's 4-element pulse array, noise shapers and truncators, so their depth is similar Head-Fi, Feb 2018.
Hugo 2 he called a complete redesign: 10 pulse array elements instead of 4, better DSD filtering, a second-order analog noise shaper output and a digital DC servo Head-Fi, Jun 2017. Its first WTA stage has 49,152 taps to 16FS, then a second to 256FS Head-Fi, Jul 2017. He gave Hugo 2 residual noise as 2.6uV, half of Hugo 1 Head-Fi, Apr 2017, and 1050 mW into 8 ohms against about 750mW for the original, recalled "if memory serves" (in 2014 he had said "you only have 1W" for loudspeaker use Head-Fi, Apr 2014) Head-Fi, Nov 2019. He said galvanic isolation made huge differences with Hugo 1, a benefit reduced by an order of magnitude on Hugo 2 Head-Fi, Jun 2017.
What he has not said
His "5th order or better" noise shaper figure describes pulse array generally, not Hugo by name Head-Fi, Apr 2014.
Release and official documents
- Launched in 2014, in his words.article, Mar 2018
From Chord Electronics. Links open Chord's own copies; reviews hosted on Chord's site are left out. Chord's Hugo (original) page.
Manuals and guides
Drivers (Windows)
Key figures
His own figures, dated. Where he gave different figures at different times, each appears.
Show all 44 figures
| Figure | Value | When | Source |
|---|---|---|---|
| WTA filter taps, first stage (1FS to 8FS) | 26,368 taps | 2014-05 | Head-Fi, May 2014Head-Fi, May 2014Head-Fi, Mar 2015 |
| WTA filter taps, as stated in a later post | WTA 1 of 26,368 taps (1FS to 8FS), then WTA 2 from 8FS to 16FS | 2017-07 | Head-Fi, Jul 2017 |
| Filters in the chain | 5 filters: 2 FIR WTA stages, a linear interpolator 16FS to 2048FS, 2 IIR low-pass filters | 2014-04 | Head-Fi, Apr 2014 |
| DSP cores for the WTA filter | 16 parallel custom cores at 208 MHz | 2014-05 | Head-Fi, May 2014 |
| Filter delay | 1,648 samples, 34 mS at 48 kHz | 2014-06 | Head-Fi, Jun 2014 |
| Filter latency (sample rate not given in the post) | 38 mS latency, interpolation based on 76 mS of data | 2015-03 | Head-Fi, Mar 2015 |
| Filter delay, later post | Hugo 1 had a delay of 34 ms | 2018-10 | Head-Fi, Oct 2018 |
| Oversampling before the noise shaper | 2048 times | 2014-05 | Head-Fi, May 2014 |
| Pulse array elements | 4 | 2014-04 | Head-Fi, Apr 2014 |
| Pulse array elements, later posts | 4 (Hugo 2 has 10) | 2017-06 | Head-Fi, Jun 2017Head-Fi, Feb 2018 |
| Noise shaper clock | 104 MHz | 2014-04 | Head-Fi, Apr 2014 |
| Noise shaper clock, later post | 104.25 MHz (a fixed 2364 times, and 2172 times for 48K) | 2015-03 | Head-Fi, Mar 2015 |
| Noise shaper performance | 200 dB, the Hugo standard | 2016-01 (recorded about then; published 2016-07) | Hifistatement 3:05 |
| Noise shaper performance, later statement | worked to 200 dB, 32-bit accuracy | 2023-02 | Dusty Audio 21:41 |
| Internal volume accuracy and truncation noise | 51 bits internally; fixed noise at -180 dB after truncation at 16FS | 2015-01 | Head-Fi, Jan 2015 |
| Volume range | +18 dB (white) to -70 dB (dark brown); typically three 1 dB steps per color | 2014-05 | Head-Fi, May 2014Head-Fi, Sep 2014Head-Fi, Mar 2015 |
| Output voltage, maximum | 5V RMS | 2014-04 | Head-Fi, Apr 2014 |
| Output voltage at clipping | 5.25V RMS at +18dB; just over 5V RMS before clipping | 2014-09 | Head-Fi, Sep 2014Head-Fi, Sep 2014 |
| Output voltage, unclipped into 300 ohms | a little over 5V RMS | 2015-04 | Head-Fi, Apr 2015 |
| Output voltage at 0dBFS, preset mode | 2.996V RMS measured at 1kHz; 3V RMS preset | 2014-06 | Head-Fi, Jun 2014Head-Fi, Sep 2014 |
| Output impedance | 0.075 ohm (75 milliohm) | 2014-04 | Head-Fi, Apr 2014Head-Fi, Jan 2015 |
| Output current | 0.5A RMS | 2014-09 | Head-Fi, Sep 2014Head-Fi, Sep 2014Head-Fi, Apr 2015 |
| Output power (stated for loudspeaker use) | 1W | 2014-04 | Head-Fi, Apr 2014 |
| Output power into 8 ohms, as recalled for the original | about 750mW ("if memory serves") | 2019-11 | Head-Fi, Nov 2019 |
| Residual noise | 5uV A-weighted; dynamic range 120.0 dB +/- 0.1 dB | 2014-08 | Head-Fi, Aug 2014 |
| Dynamic range, same on all inputs (APx555) | -120.7 dB; jitter artifacts below 500 fS | 2015-07 | Head-Fi, Jul 2015 |
| THD with load, at 3V RMS line level | 0.0004% rising to 0.0007% into 33 ohm | 2014-04 | Head-Fi, Apr 2014 |
| Output bandwidth | 50 kHz -3 dB | 2016-01 | Head-Fi, Jan 2016 |
| Input limits | SD USB and Bluetooth 16 bits/48 kHz; HD USB 32 bits/384 kHz; optical 192 kHz; coax 384 kHz | 2015-04 | Head-Fi, Apr 2015 |
| DSD decimation filter rejection | 140 dB (designed 2014) | 2014-04 | Head-Fi, Apr 2014 |
| DSD decimation filter, 2018-01 description | aliasing visible at -150 dB in Hugo 1's filter (Hugo 2's is better than -240 dB) | 2018-01 | Head-Fi, Jan 2018 |
| DSD decimation filter, 2018-06 description | aliasing performance better than -130 dB; a one-line reply with no visible context says Mojo is the same | 2018-06 | Head-Fi, Jun 2018Head-Fi, Jun 2018 |
| DSD decimation filter, further description | -130 dB rejection, worst-case aliasing -150 dB | 2019-05 | Head-Fi, May 2019 |
| Crossfeed processing | own 16FS, 48-bit DSP cores, first-order EQ | 2014-08 | Head-Fi, Aug 2014 |
| Batteries | two 4.2V cells (8.4V supply); two 2.2AH Li-ion | 2014-06 | Head-Fi, May 2015Head-Fi, Jun 2014 |
| Power supply parts | batteries, 9 regulators and 12 RF filters | 2014-06 | Head-Fi, Jun 2014 |
| Battery life | about 8.5 hours on HD USB, 10.5 hours on other inputs (with low-power headphone output) | 2015-04 | Head-Fi, Apr 2015 |
| Power dissipation, maximum | 2W max, chassis 3.2 deg C per W | 2014-06 | Head-Fi, Jun 2014 |
| Power dissipation, FPGA (against DAVE FPGA 5W) | 0.8W | 2015-05 | Head-Fi, May 2015 |
| Power draw, left on | about 1.5W | 2016-01 | Head-Fi, Jan 2016 |
| Over-voltage protection trigger | 12.8V | 2014-07 | Head-Fi, Jul 2014 |
| FPGA capacity used before crossfeed was added | 98% | 2018-11 (open-day talk; published 2018-12) | Pursuit Perfect System 20:32 |
| FPGA capacity used before crossfeed was added, other account | 95% | 2019-12 | Passion for Sound 12:06 |
| Units sold | over 10,000 | 2018-03 | article, Mar 2018 |
Quotes
“Hugo is the first product I have designed in my 30 odd year career where the strategy of making it as transparent as possible has paid off enormously with musicality.”2014-10-20 Head-Fi, Oct 2014
“Hugo has never been tweaked or voiced to sound a certain way.”2015-02-02 Head-Fi, Feb 2015
“I leave mine permanently plugged in.”2014-04-16 Head-Fi, Apr 2014
“Hugo was the first digital device that actually worked for me musically”2015-12-30 Head-Fi, Dec 2015
Caveats and open points
- Naming: before Feb 2017 a bare 'Hugo' in the Hugo thread means this unit. Later posts that say 'Hugo' were read as the original only where he says Hugo 1 or contrasts it with Hugo 2. A 2020 podcast gives Hugo a power budget of two and a half watts and a 2023 one gives about 4 watts it can dissipate, both after 'Hugo' with no number and in talks that also discuss Hugo 2, so neither is listed as a Hugo 1 figure Part-Time Audiophile 29:37Soundnews 26:15.
- Dates of origin differ: he gave autumn 2012 for the project start article, Aug 2014, 'Oct 2012' for first hearing it Head-Fi, Jun 2017, Sunday 20 Oct as the first listening test of finished code in a post dated 2014-10-20 that calls Hugo one year old Head-Fi, Oct 2014, 2013 as its year in a tap-length list article, Apr 2018, and 2014 as launch article, Mar 2018HiFi Buys 25:30. In 2023 talks he dated the change and the larger FPGAs to 2015 Dusty Audio 15:25Dusty Audio 16:13.
- The Music Photo Life item is a written Q&A as published by the interviewer; its wording (launch year, units sold) may be edited.
- Maximum output voltage varies by post and by load: 5V RMS (2014-04), just over 5V RMS (2014-09), 5.25V RMS at clipping (2014-09) and a little over 5V RMS into 300 ohms (2015-04). The manual's 2V RMS preset figure was to be corrected to 3V RMS Head-Fi, Sep 2014, and he said to ignore a 37V figure as a spreadsheet entry Head-Fi, Apr 2015.
- Power figures differ by post and measure different things: 2W max dissipation (2014-06), 0.8W for the FPGA (2015-05) and about 1.5W draw when left on (2016-01). He did not reconcile them.
- Original Hugo output power into 8 ohms is 1W in a 2014 aside about speaker use and about 750mW in a 2019 recollection ("if memory serves"); he did not reconcile them Head-Fi, Apr 2014Head-Fi, Nov 2019.
- Charger: in 2014 AB tests on a fully charged unit he heard no significant difference with the charger in or out Head-Fi, Jun 2014, while driving 8 ohm loads flat out he said adding the charger helped Head-Fi, Jun 2014Head-Fi, Apr 2014.
- DSD decimation filter figures differ: 140 dB rejection when designed (2014), aliasing better than -130 dB (2018-06), -150 dB aliasing visible (2018-01), and -130 dB rejection with worst-case aliasing at -150 dB (2019-05). He did not reconcile them. The Mojo figure rests on a one-line reply with no visible context, which the Mojo page does not use Head-Fi, Jun 2018.
- Filter delay is 34 ms at 48 kHz in 2014 and 2018 posts, and 38 mS latency in a 2015 post that gives no sample rate; he did not reconcile them.
- The FPGA capacity before crossfeed is 98% in a 2018 talk and 95% in a 2019 one; a 2017 transcript says only that the code was too big to fit.
- Tap figures are given as 26,368 (exact, 2014-05 onward), 26k (2014-04), over 26,000 (2015-03) and 26,000 (2018) Head-Fi, Apr 2014Head-Fi, Mar 2015c w 15:36, all for the first stage. The 1M-tap figure for 16-bit accuracy in 2014 is a guess he labeled as such Head-Fi, Apr 2014.
- Pulse array element counts for Hugo are 4 across 2014, 2017 and 2018 posts Head-Fi, Apr 2014Head-Fi, Jun 2017Head-Fi, Feb 2018. A 2015 post explains the pulse array principle using a 16-element array and does not say Hugo has 16 Head-Fi, Apr 2015.
- German Hifistatement interviews are the publisher's translation; they were not quoted. Japanese and Chinese press items quoting him were not used as his words.
- His comparisons with Hugo 2, TT and Mojo were made after those products existed; most are design and listening statements rather than measurements.
Indicator colors
What each light means on the Hugo (original), from Chord's manual: Indicator colors: Hugo (original).
Questions about this product
Owning and setting up
- How good is Bluetooth on Hugo and Hugo 2, and are aptX HD or LDAC lossless?
- How loud is safe, and does hearing loss make high-end gear pointless?
- Is my Chord DAC powerful enough for my headphones?
- Should I add an external headphone amp to a Chord DAC?
- Should I send DSD as DoP or native?
- Can I use Hugo, Mojo or Mojo 2 while it is charging, and is it OK to leave it plugged in all the time?
- Do lossy or streamed files sound worse than local files on a Chord DAC?
- How do I make sure my player sends bit-perfect data at the native sample rate?
- How many taps and pulse array elements does each Chord DAC have?
- Is Chord's digital volume control transparent, and does it lose resolution at low volume?
- My DAC drops out, clicks or loses lock. What should I check before returning it?
- Should I use a pre-amp (tube or solid state), or run the Chord DAC straight into a power amp?
- Should I use balanced or single-ended headphone drive, and why are Chord headphone outputs single-ended?
- What DSD rates does each input on a Chord DAC accept?
- What do the colored indicators mean (volume, sample rate, charging), and is a volume color the same level across Chord DACs?
- What does crossfeed do, which setting should I use, and why didn't the original Mojo have it?
- Which Chord DACs accept 705.6/768 kHz from an M Scaler, and how do I connect Hugo 2 or Qutest to get the full 1M taps?
- Which kind of source does Rob recommend feeding a Chord DAC?
- Why do I hear a buzz or feel a tingle when the charger is connected, and should I earth my unit?
- Why does my DAC mute or click when the track or sample rate changes?
- Will existing Chord products get firmware or code updates, and can DAVE be upgraded?
In depth
- Does source jitter matter with a Chord DAC, and would a reclocker, external clock or USB-to-SPDIF converter help?
- How do Chord DACs handle DSD, and does Rob consider DSD better or worse than PCM?
- What does Rob mean by depth, and what in a DAC improves or collapses it?
- Which input sounds best on a Chord DAC (optical, coax, USB or BNC), and why does Rob prefer optical when it is said to have more jitter?
- Why are half-band decimation filters and studio sample-rate conversion a problem, and how much aliasing rejection is enough?
- Why does Chord use FPGAs and discrete conversion instead of DAC chips or a custom ASIC?
- If the data reaching the DAC is bit perfect, can the source (laptop, phone, streamer, CD transport or network gear) still change the sound?
- Is the filter algorithm more important than the tap count, and would more than a million taps keep improving the sound?
- What does Rob mean by 'starting and stopping of notes', timbre variation and 'sense of flow', and what causes them?
- What is the WTA filter, how was it tuned, and how does it differ from a conventional windowed sinc filter?
- Why does Rob distinguish perception from hearing, and why does he distrust psychoacoustic thresholds?
- Why does tap length matter, and why a million taps?
- Will a USB purifier, JitterBug or USB isolator improve my DAVE, TT2 or Hugo?
- Do Chord DACs need burn-in or warm-up?
- Does hi-res audio sound better than CD, and should I buy the 96k or the 44.1k release?
- How are Chord's filter stages split across 16FS, 256FS and 2048FS, and what does each stage do?
- How can upscaling to 705.6/768 kHz improve sound if the recording has nothing above 22 kHz?
- How do microphones, studio conversion and mastering limit what a DAC can reproduce?
- How does a pulse array DAC work, how does it differ from R2R and delta-sigma, and why is it insensitive to jitter?
- How were Chord's current DACs and the M Scaler developed, and how long did each take?
- Should I replace the supplied power supply with a linear or aftermarket one, and will that affect my warranty?
- Should I upsample in software (HQPlayer, PGGB or my player) before a Chord DAC, and can it match an M Scaler?
- Should audio processing dither or noise-shape, and is 64-bit floating point transparent?
- What are the DX outputs for, and what happened to the pulse array power amplifiers?
- What do noise shaper order and speed buy, and why does DAVE's 350 dB noise shaper matter?
- Which Chord inputs are galvanically isolated, and which setups short the isolation out?
- Which kinds of error does Rob consider audible, and which does he consider benign?
- Why might a brighter or more detailed change actually be a step backward?