Hugo 2
What it is
Watts describes Hugo 2 as a transportable device Head-Fi, Feb 2017 whose "primary use is on trains, planes and automobiles" (January 2017) Head-Fi, Jan 2017. In January 2017 he expected Chord to ship in late February or early March Head-Fi, Jan 2017. On 2017-03-30 he said production code had been issued in late February, guessed at supply chain issues, and named design issues on his side as the primary reason it was late Head-Fi, Mar 2017.
He calls the step from Hugo 1 "frankly a complete re-design" Head-Fi, Jun 2017, and in a 2018 written interview said "90% of the technologies implemented on Hugo 2 was referenced or adopted from DAVE" article, Apr 2018.
Design
In February 2018 he gave the Hugo 2 and Qutest signal path as a 16FS WTA1 filter of 49,152 taps, a 256FS WTA2 filter, a third-order 2048FS filter, then a pulse array noise shaper at 104 MHz Head-Fi, Feb 2018. The tap figure covers only WTA1; WTA2 and later filters are extra Head-Fi, Mar 2017Head-Fi, Mar 2017.
On the analog side he listed a 10 element pulse array (Hugo 1 had 4), a second-order analog noise shaper output and a digital DC servo Head-Fi, Jun 2017, with no coupling capacitors in the audio path Head-Fi, Jan 2018. Volume is digital, noise shaped at 705/768 kHz Head-Fi, Feb 2018. A DPLL re-clocks incoming data Head-Fi, Jun 2017 (see Does source jitter matter with a Chord DAC, and would a reclocker,…).
The filter button sets two things: white is HF filter off and WTA2 on, green both on, orange both off, red HF filter on and WTA2 off Head-Fi, Mar 2022. He ties WTA2 to perceiving when notes start and stop, and the HF filter to lower noise floor modulation, heard as warmer and smoother Head-Fi, Mar 2017Head-Fi, Mar 2022. DSD is filtered to 705.6 kHz PCM, with over 200 dB attenuation in January 2018 Head-Fi, Jan 2018 and over 220 dB in November 2018 Head-Fi, Nov 2018. In March 2017 he called the crossfeed the same as the original Hugo's Head-Fi, Mar 2017; in April, identical in code to DAVE's PCM+ crossfeed Head-Fi, Apr 2017.
Inputs, outputs and power
Inputs are USB and optical Head-Fi, Feb 2017, plus two coax inputs on 3.5 mm jacks, for desktop convenience and for dual data mode with M scalers at 768 kHz Head-Fi, Feb 2017Head-Fi, Jul 2018. In 2017 he said USB is not galvanically isolated because the USB chip would flatten the source battery, but its ground and VBUS are RF filtered Head-Fi, Jan 2017Head-Fi, Jun 2017.
He gave maximum output as 5.3 V RMS, where THD reaches 1% into 300 ohms (2017), repeated at 1 kHz in 2018 Head-Fi, Apr 2017Head-Fi, Mar 2018; a one-line 2019 TT2 comparison gives 5.4 V RMS with no condition stated Head-Fi, Jan 2019. Into 8 ohms it is 1.05 W RMS at 1% THD Head-Fi, Oct 2019. Output impedance is 0.025 ohms Head-Fi, Feb 2018; the stage is Class A into 300 ohms at 5 V RMS and Class AB into lower loads Head-Fi, Jan 2020.
The charger runs at 1 A (cyan) or 2 A (white) and enters desktop mode after more than 24 hours of power Head-Fi, Mar 2017Head-Fi, Sep 2018, holding the battery at about 80% charge Head-Fi, Jun 2018. It shuts down after 10 minutes without SPDIF lock or valid USB 5V Head-Fi, Aug 2017, but not in desktop mode Head-Fi, Jun 2018.
How he says to use it
"I run with green all the time," he wrote in 2017 Head-Fi, Mar 2017. In 2021 he recommended filter 2 for DSD and all PCM, with smaller benefits at 44.1k Head-Fi, Aug 2021 (see Which filter setting should I use on Hugo 2, TT2 or Qutest, and…). He finds crossfeed "absolutely essential to get good depth" Head-Fi, Apr 2017, and in 2020 said he uses it all the time, set to max Head-Fi, Dec 2020, which is blue on Hugo 2 Head-Fi, Jan 2023 (see What does crossfeed do, which setting should I use, and why didn't…).
In July 2018 he said that on Hugo 2 over headphones optical sounds the same as USB, but not once the connection is grounded, and that with a simple low power source USB sounds the same as optical, "so use the optical as your benchmark" Head-Fi, Jul 2018. His statements on USB against optical changed between 2014 and 2022 (see Which input sounds best on a Chord DAC (optical, coax, USB or…, Which Chord inputs are galvanically isolated, and which setups…). The source must not up-sample Head-Fi, Sep 2017. For 768 kHz from an M scaler he describes 3.5 mm to RCA cables with RCA to BNC adaptors Head-Fi, Jul 2018 (see Which Chord DACs accept 705.6/768 kHz from an M Scaler, and how do…).
He advises against an external power supply Head-Fi, Mar 2017; in 2021 he said the charger can make it sound brighter, recommending a power bank for desktop use Head-Fi, Oct 2021. His advice on leaving it on changed: keep it on (2017) Head-Fi, Jun 2017, a rule by hours of use (2020) Head-Fi, Mar 2020, off when not in use, particularly for 12 hours or more (2022) Head-Fi, Oct 2022, and off if unused for two days or more (2024) Head-Fi, Jul 2024 (see How does desktop mode work on Hugo 2 and Mojo 2, and will Mojo 2…, Why does my Hugo 2 switch itself off, and how does standby work on…). "Any external amp will degrade transparency" Head-Fi, Jan 2018 (see Should I add an external headphone amp to a Chord DAC?).
Compared with other Chord models
Against Hugo 1 he called it more incisive and more refined, crediting lower noise floor modulation and distortion, better noise shaping and the 256FS WTA Head-Fi, Apr 2017. It delivers 1050 mW into 8 ohms against about 750 mW for the original, "if memory serves" Head-Fi, Nov 2019.
In January 2017 he called DAVE "still a very big change up from Hugo 2", with Hugo 2 much closer to DAVE than the original Hugo Head-Fi, Jan 2017. In 2018 he said DAVE is unbeatable for transparency, particularly soundstage depth, while Blu 2 with Hugo 2 wins on timbre, rhythm, bass and instrument power Head-Fi, Feb 2018. Qutest shares common circuitry and identical audio code, but Hugo 2's output stage is more advanced Head-Fi, Feb 2018. TT2's FPGA is double the size, with a noise shaper about 100 times more effective Head-Fi, May 2018. In 2021 he took TT2 to hotels but not on aircraft, the difference being too small Head-Fi, Jul 2021. Mojo 2 has four fifths of Hugo 2's tap length and no WTA2 Head-Fi, Jan 2022, and no second-order analog noise shaper; "Hugo 2 is still superior" Head-Fi, Jan 2022. In an interview he said Mojo 2 aimed at two-thirds of the way from Mojo (0%) to Hugo 2 (100%) HiFi Buys 2:29:40. In 2022 he said the next product would not be a Hugo 3 Head-Fi, Feb 2022.
What he has not said
He gives no noise shaper order for Hugo 2 itself; he gave 12th order for TT2 Pursuit Perfect System 35:36.
Release and official documents
- Announced at CES in January 2017, "available early 2017". Source: Poly, Hugo 2, and Blu Mk. II Announced at CES 2017, Chord Electronics, 2017-01-06.
From Chord Electronics. Links open Chord's own copies; reviews hosted on Chord's site are left out. Chord's Hugo 2 page.
Manuals and guides
Drivers (Windows)
Other
Key figures
His own figures, dated. Where he gave different figures at different times, each appears.
Show all 40 figures
| Figure | Value | When | Source |
|---|---|---|---|
| WTA1 filter taps (1FS to 16FS) | 49,152 taps; he says WTA2 and later filters are not counted | 2017-03 | Head-Fi, Mar 2017Head-Fi, Mar 2017 |
| WTA2 filter output rate | 256FS, a resolution of 88 nS | 2017-03 | Head-Fi, Mar 2017 |
| Pulse array elements | 10 (Hugo 1 had 4) | 2017-06 | Head-Fi, Jun 2017 |
| Pulse array noise shaper clock | 104 MHz | 2018-02 | Head-Fi, Feb 2018 |
| Master clock | 104.25 MHz crystal oscillator, which he says all of his DACs have | 2017-05 | Head-Fi, May 2017Head-Fi, May 2018 |
| Internal module accuracy (truncation noise shapers) | tested to over 350 dB; each module must pass a -301 dB sine | 2018-02 | Head-Fi, Feb 2018 |
| Volume control accuracy | -400 dB accuracy (Jan 2018, describing Hugo 2's volume control as used in Qutest); change in distortion and noise below -350 dB, run at 705/768 kHz (Feb 2018) | 2018-01 | Head-Fi, Jan 2018Head-Fi, Feb 2018 |
| Residual noise | 2.6 uV, half of Hugo 1's | 2017-04 | Head-Fi, Apr 2017 |
| Noise floor | -177 dB (Apr 2017); static -175 dB (Aug 2017) | 2017-04 | Head-Fi, Apr 2017Head-Fi, Aug 2017 |
| Noise shaper resolution | 260 dB, against 140 dB for the best delta-sigma | 2017-08 | Head-Fi, Aug 2017 |
| Source jitter tolerance | jittered by 2,000 nS with no measurable effect | 2017-08 | Head-Fi, Aug 2017 |
| Channel separation | 144 dB in his presentation (the published separation spec is a worst-case figure) | 2017-02 | Head-Fi, Feb 2017Head-Fi, Jan 2018 |
| Noise relative to theoretical | within 0.5 dB of theoretical (as is Qutest) | 2018-01 | Head-Fi, Jan 2018 |
| Dynamic range effect of resistor tolerance and clock jitter (October 2017 RMAF talk, video published December 2017) | 126 dB goes to 126.5 dB | 2017-10 | RMAF 43:11 |
| THD at 2.5 V output | 0.00007% | 2018-01 | Head-Fi, Jan 2018 |
| Maximum output voltage | 5.3 V RMS, where THD is 1% into 300 ohms (Apr 2017); 5.3 V RMS at 1 kHz (Mar 2018); 5.4 V RMS (Jan 2019, against 6.6 V for TT2 XLR in low gain) | 2017-04 | Head-Fi, Apr 2017Head-Fi, Mar 2018Head-Fi, Jan 2019 |
| Power into 8 ohms | 1.05 W (Jan 2018); 1.05 W RMS at 1% THD (Oct 2019); 1050 mW (Nov 2019) | 2018-01 | Head-Fi, Jan 2018Head-Fi, Oct 2019Head-Fi, Nov 2019 |
| Power into 80 ohms | 350 mW, voltage limited | 2017-11 | Head-Fi, Nov 2017 |
| Output current limit | 0.5 A RMS; he adds Hugo 2 can be voltage as well as current limited depending on load | 2018-01 | Head-Fi, Jan 2018 |
| Output impedance | 0.025 ohms | 2018-02 | Head-Fi, Feb 2018 |
| Frequency response with load, 20 Hz to 20 kHz | within +/- 0.1 dB at 8 ohms and +/- 0.05 dB with no load | 2017-07 | Head-Fi, Jul 2017 |
| HF filter | second order, -3 dB at 40 kHz (Mar 2017); LPF time constant changed from 0.7 uS (227 kHz) to 2.8 uS (57 kHz) (Jul 2017); about -1 dB at 20 kHz (May 2020) | 2017-03 | Head-Fi, Mar 2017Head-Fi, Jul 2017Head-Fi, May 2020 |
| DSD filter attenuation | over 200 dB (Jan 2018); greater than 200 dB at 88.2 kHz (May 2018, in a DAVE-thread post about the new Hugo 2 DSD filter); over 220 dB, for a filter that runs at 705.6 kHz (Nov 2018) | 2018-01 | Head-Fi, Jan 2018Head-Fi, May 2018Head-Fi, Nov 2018 |
| Sinc accuracy | about 99.76% of an ideal sinc (Feb 2018); 12.2 bits sinc-equivalent (Mar 2018) | 2018-02 | Head-Fi, Feb 2018Head-Fi, Mar 2018 |
| Data used to recover the analog signal | 67.5 mS at 44.1k | 2018-03 | Head-Fi, Mar 2018 |
| WTA filter latency | 34 mS (Jul 2017, sample rate not given); about 31 mS for 48 kHz input (Apr 2018); 16 mS at 96 kHz (Jul 2019) | 2017-07 | Head-Fi, Jul 2017Head-Fi, Apr 2018Head-Fi, Jul 2019 |
| WTA1 overload margin | 2.75 dB (Mar 2018); 2.76 dB, which he says all the WTA1 filters have (Apr 2022) | 2018-03 | Head-Fi, Mar 2018Head-Fi, Apr 2022 |
| FPGA resource use | 100% memory, 100% DSP cores, 98% logic (Feb 2017); all DSP cores, all memory, 99.8% logic, about 800 mW (Mar 2017); 45 DSP cores at 208 MHz, 99.8% fabric (Sep 2017) | 2017-02 | Head-Fi, Feb 2017Head-Fi, Mar 2017Head-Fi, Sep 2017 |
| FPGA family | 7 series | 2020-11 | Head-Fi, Nov 2020 |
| Battery full charge voltage | 8.4 V | 2017-03 | Head-Fi, Mar 2017 |
| Desktop mode battery voltage | 8.1 to 8.2 V (14 Mar 2017); 8.0 to 8.2 V, mostly 8.1 V (20 Mar 2017) | 2017-03 | Head-Fi, Mar 2017Head-Fi, Mar 2017Head-Fi, Mar 2017 |
| Desktop mode charge level | about 80% charge (Jun 2018); charges to 80% capacity (Nov 2020) | 2018-06 | Head-Fi, Jun 2018Head-Fi, Nov 2020 |
| Battery cut-off voltage | 6.5 V | 2017-04 | Head-Fi, Apr 2017 |
| Charge currents | 1 A (cyan) and 2 A (white) (Mar 2017); 1.9 A worst case 'from memory', 2.1 A specified (Jan 2018) | 2017-03 | Head-Fi, Mar 2017Head-Fi, Jan 2018 |
| Power consumption | 2 W in desktop mode (Jun 2017); 2.25 W when not charging (Mar 2018) | 2017-06 | Head-Fi, Jun 2017Head-Fi, Mar 2018 |
| Auto shut-down delay | 10 minutes without SPDIF lock or valid USB 5V | 2017-08 | Head-Fi, Aug 2017 |
| Desktop mode entry | charger power uninterrupted for more than 24 hours | 2018-09 | Head-Fi, Sep 2018 |
| Crossfeed settings | blue 700 Hz 4.5 dB; green 700 Hz 6 dB; red 650 Hz 9.5 dB; IIR at 705/768 kHz | 2017-04 | Head-Fi, Apr 2017 |
| Highest input rate | 768 kHz via USB and via the dual coax inputs | 2019-03 | Head-Fi, Mar 2019 |
| Failure rate (relayed from Chord's production director) | of the order of 0.1% | 2017-08 | Head-Fi, Aug 2017 |
Quotes
“Hugo 1 > Hugo 2 is frankly a complete re-design”2017-06-17 Head-Fi, Jun 2017
“For 99.9% of the time I just run with green.”2017-07-25 Head-Fi, Jul 2017
“Any external amp will degrade transparency”2018-01-10 Head-Fi, Jan 2018
“Hugo 2 is still the perfect match for portable/transportable use”2021-07-18 Head-Fi, Jul 2021
Caveats and open points
- Nearly all evidence is Head-Fi forum posts, many of them replies to questions that are not shown, so a reply's exact subject is inferred from the thread. Posts in other products' threads (Qutest, TT2, Mojo 2) are used only where he names Hugo 2.
- His FPGA usage figures differ between posts: 98% logic on 2017-02-21 Head-Fi, Feb 2017, 99.8% logic on 2017-03-15 Head-Fi, Mar 2017 and 99.8% fabric on 2017-09-03 Head-Fi, Sep 2017. They are listed as stated, not reconciled.
- His HF filter figures differ between posts (-3 dB at 40 kHz in 2017-03, time constants of 0.7 to 2.8 uS in 2017-07, about -1 dB at 20 kHz in 2020-05), and his DSD filter figure moves from over 200 dB (2018-01) to over 220 dB (2018-11); the only frequency he ties to the attenuation is 88.2 kHz (2018-05 Head-Fi, May 2018), while 705.6 kHz is the rate the filter runs at (2018-11 Head-Fi, Nov 2018). Desktop mode voltage is 8.1 to 8.2 V on 2017-03-14 and 8.0 to 8.2 V on 2017-03-20. Maximum output is 5.3 V RMS in 2017 and 2018 Head-Fi, Apr 2017Head-Fi, Mar 2018 and 5.4 V RMS in 2019 Head-Fi, Jan 2019, the last in a one-line comparison with TT2 that states no measurement condition; the posts do not say the maximum changed. The WTA1 overload margin is 2.75 dB in 2018 Head-Fi, Mar 2018 and 2.76 dB in 2022 Head-Fi, Apr 2022.
- Sinc accuracy is given two ways, about 99.76% of an ideal sinc (2018-02) and 12.2 bits (2018-03), and the posts do not say how they relate. Volume accuracy is -400 dB in 2018-01 and below -350 dB in 2018-02.
- He described the crossfeed two ways in spring 2017: the same cross-feed as on the original Hugo, 'the only piece of code coming from Hugo' (2017-03-15 Head-Fi, Mar 2017), and code identical to DAVE's PCM+ crossfeed (2017-04-12 Head-Fi, Apr 2017). The posts do not say how the two relate.
- His advice changed over time. Leaving the unit on: keep it on (2017-06 Head-Fi, Jun 2017), a revised rule by hours of use (2020-03 Head-Fi, Mar 2020), turn it off when idle (2022-10 Head-Fi, Oct 2022), turn it off after two days (2024-07 Head-Fi, Jul 2024). Charger audibility: he could not hear the charger on headphones (2018-08 Head-Fi, Aug 2018) but wrote that the charger can make it sound brighter (2021-10 Head-Fi, Oct 2021). Warm-up: no burn-in needed (2017-03 Head-Fi, Mar 2017), about 10 minutes of warm-up (2018-09 Head-Fi, Sep 2018), then in 2023-02 Head-Fi, Feb 2023 and 2024-01 Head-Fi, Jan 2024 he attributed the 10-minute change to his ears or headphones on flights. Battery removal: works without it but not recommended (2017-03 Head-Fi, Mar 2017), the output stage relies on the battery (2021-10 Head-Fi, Oct 2021), may or may not work (2024-11 Head-Fi, Nov 2024).
- Posts from January to early March 2017 describe pre-production or newly finalized units, and on 2017-04-05 he noted that an earlier measurement predated changes in late January and early February Head-Fi, Apr 2017. Some later figures may supersede them.
- The 0.1% failure rate is Watts relaying what Chord's production director told him, in a post that also discusses user reports of failures Head-Fi, Aug 2017; it is not a measurement by Watts.
- A bare 'Hugo' in older posts can mean Hugo 1. No post describes a balanced output on Hugo 2. A reply of 2018-07-22 giving 'typically 12W' Head-Fi, Jul 2018 does not name its product and is not used as a Hugo 2 figure.
- Limits of this archive: his CanJam slides (2017-03, 2018-02) are images that the archive does not hold, so the figures on them are only those he repeated in text.
- Scope: the 104.25 MHz clock is a figure he gave for all of his DACs Head-Fi, May 2017, the -400 dB volume figure comes from a Qutest-thread post about Hugo 2's volume control Head-Fi, Jan 2018, and the 2.76 dB overload margin is stated for all WTA1 filters Head-Fi, Apr 2022. The 2018-02 signal path is stated for Hugo 2 and Qutest together Head-Fi, Feb 2018.
Indicator colors
What each light means on the Hugo 2, from Chord's manual: Indicator colors: Hugo 2.
Questions about this product
Owning and setting up
- How do Mojo 2 and Hugo 2, or TT2 and DAVE, compare?
- How does desktop mode work on Hugo 2 and Mojo 2, and will Mojo 2 drain on the shelf?
- Which headphones, speakers and sources does Rob use himself, and which pair well with Chord DACs?
- Why does my Hugo 2 switch itself off, and how does standby work on the battery-powered DACs?
- Can I take DAVE, Hugo 2, an M Scaler and a power bank on a plane, and how does Rob listen on flights?
- Can I use Hugo, Mojo or Mojo 2 while it is charging, and is it OK to leave it plugged in all the time?
- What do the colored indicators mean (volume, sample rate, charging), and is a volume color the same level across Chord DACs?
- Do I need the Chord driver on Windows, should I use ASIO or WASAPI, and will my DAC work with Mac, Linux, Android or an iPhone?
- How good is Bluetooth on Hugo and Hugo 2, and are aptX HD or LDAC lossless?
- Is Chord working on a DAVE 2, Hugo 3, Mojo 3 or TT3, and when might the Ultima DAC arrive?
- Should I add an M Scaler to my Qutest or Hugo 2, or upgrade to TT2 first?
- Should I add an external headphone amp to a Chord DAC?
- What does crossfeed do, which setting should I use, and why didn't the original Mojo have it?
- What does the M Scaler actually do, and is it worth adding to my DAC?
- Why do I hear a buzz or feel a tingle when the charger is connected, and should I earth my unit?
- Has Rob published his own recordings, and how were they made?
- How loud is safe, and does hearing loss make high-end gear pointless?
- Is my Chord DAC powerful enough for my headphones?
- My DAC drops out, clicks or loses lock. What should I check before returning it?
- Should I put ferrites on my BNC or USB cables, and which kind?
- Should I send DSD as DoP or native?
- Should I use balanced or single-ended headphone drive, and why are Chord headphone outputs single-ended?
- 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?
- Why does Rob use a digital DC servo instead of coupling capacitors, and is there anything worth modding?
- Can I stack TT2 and an M Scaler, and how hot is too hot?
- 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?
- Should I leave my Qutest, TT2, DAVE or M Scaler switched on all the time?
- Should I use a pre-amp (tube or solid state), or run the Chord DAC straight into a power amp?
- What DSD rates does each input on a Chord DAC accept?
- Which kind of source does Rob recommend feeding a Chord DAC?
- Why does my DAC mute or click when the track or sample rate changes?
- Why won't Rob comment on other brands' products?
In depth
- Which filter setting should I use on Hugo 2, TT2 or Qutest, and what does the HF filter do?
- Does source jitter matter with a Chord DAC, and would a reclocker, external clock or USB-to-SPDIF converter help?
- How are Chord's filter stages split across 16FS, 256FS and 2048FS, and what does each stage do?
- How do Chord DACs handle DSD, and does Rob consider DSD better or worse than PCM?
- 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 might a brighter or more detailed change actually be a step backward?
- Do Chord DACs need burn-in or warm-up?
- Do measurements tell you how good a DAC sounds, and is Rob an objectivist or a subjectivist?
- What is noise floor modulation, how does Rob measure it, and why does he say it is audible below what can be measured?
- Will a USB purifier, JitterBug or USB isolator improve my DAVE, TT2 or Hugo?
- How do microphones, studio conversion and mastering limit what a DAC can reproduce?
- 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 battery power better than mains, and can I power the M Scaler or Qutest from a power bank?
- 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?
- What do noise shaper order and speed buy, and why does DAVE's 350 dB noise shaper matter?
- What does Rob mean by 'starting and stopping of notes', timbre variation and 'sense of flow', and what causes them?
- What does Rob mean by depth, and what in a DAC improves or collapses it?
- What is the WTA filter, how was it tuned, and how does it differ from a conventional windowed sinc filter?
- Do Chord DACs decode MQA, and what does Rob think of it?
- Does hi-res audio sound better than CD, and should I buy the 96k or the 44.1k release?
- 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 audio processing dither or noise-shape, and is 64-bit floating point transparent?
- Which Chord inputs are galvanically isolated, and which setups short the isolation out?
- Why are half-band decimation filters and studio sample-rate conversion a problem, and how much aliasing rejection is enough?
- Why does Rob design to -301 dB, how can that be verified, and how does small-signal accuracy relate to depth?