Hugo M Scaler
What it is
Watts describes the Hugo M Scaler as a separate box holding a bigger interpolation filter for the DAC: one million WTA taps that take 44.1 kHz to 705.6 kHz and 48 kHz to 768 kHz, with no sample rate conversion Head-Fi, Jul 2018Head-Fi, Aug 2018ecoustics 23:40. Before it shipped, "M scaler" named the same engine in Blu 2 units heard at shows Head-Fi, May 2017; the March 2018 figures below were stated for "the M scaler" before the July 2018 launch, with identical filter code Head-Fi, Mar 2018Head-Fi, Mar 2018Head-Fi, Aug 2018.
He says it improves tempo, pitch, timbre variation and instrument separation Head-Fi, Sep 2021, and that what a listener hears depends on the listener and the system Head-Fi, Oct 2018HiFi Buys 2:24:19. In 2022 he said his intent was Chord DACs, and that the big benefit needs 768 kHz AVstore 25:51AVstore 26:46.
Design
He says the coefficients match an ideal sinc function to 16.6 bits (March and July 2018) or 16.7 bits (October 2018), so bandwidth-limited signals are reconstructed to better than 16 bits Head-Fi, Mar 2018Head-Fi, Jul 2018Head-Fi, Oct 2018, with 99.98 percent as the worst case Head-Fi, Sep 2018. In January 2025 he said a transient test he did not pursue showed "the M scaler" 22 bit accurate, but that a raw number does not show perceptual accuracy Head-Fi, Jan 2025.
The filter uses about 1.4 seconds of music: 1.37 s (March 2018), 1.42 s (July 2018), 1.438 s (December 2018) Head-Fi, Mar 2018Head-Fi, Jul 2018Head-Fi, Dec 2018. The FPGA is the 28nm Xilinx 200T Head-Fi, Mar 2025.
The 56-bit result is cut to 24 bits by 11th-order noise shaping at -301 dB, with no dither at the full 1M taps Head-Fi, Apr 2019Head-Fi, Dec 2019Head-Fi, Mar 2019; at 2x and 4x he uses high-level Gaussian dither Head-Fi, Jul 2022. DSD is handled as on Hugo 2 and TT2, converted to 705 kHz 24 bit PCM that leaves only on the dual BNC Head-Fi, Jul 2022Head-Fi, Mar 2019.
It is a separate box to keep the FPGA's noise, "12A of correlated current with large amounts of 2GHz noise", away from the DAC Head-Fi, Jul 2018Head-Fi, Mar 2023. The BNC outputs are galvanically isolated, with 2GHz chip ferrites in the drivers Head-Fi, Dec 2018Head-Fi, Aug 2020.
Inputs, outputs and power
Inputs are galvanically isolated USB, two BNC and two optical; outputs are dual BNC, single BNC and optical (talk) c w 23:19. The OP SR button sets the output: red pass-through, green 176.4/192, blue 352.8/384, white 705.6/768 at the full 1M taps; only white enables dual data Head-Fi, Sep 2018. Output is 2.5v pp terminated, 75 ohm Head-Fi, Nov 2019Head-Fi, Aug 2018.
Power is 12W typical, 13W elsewhere Head-Fi, Jul 2018Head-Fi, Aug 2018Head-Fi, Jan 2025. The input is regulated to 5v internally Head-Fi, Jun 2022Head-Fi, Jan 2025; his supply limits differ (see caveats).
How he says to use it
- Feed it bit perfect data; PC upsamplers lack its processing and the WTA algorithm Head-Fi, Jul 2018 (see Should I upsample in software (HQPlayer, PGGB or my player) before…).
- Optical is his reference input Head-Fi, Apr 2019AVstore 42:56. In April 2019 he said that with DAVE and a pre-production prototype scaler he heard no consistent change between USB and optical, though results may vary with the source Head-Fi, Apr 2019; in an interview published August 2022 (recording date not stated) he said USB can sound as good as optical or a little harder, and to start with optical AVstore 41:06AVstore 42:56. His wider view of USB versus optical changed over the years Head-Fi, Jan 2018 (see Which input sounds best on a Chord DAC (optical, coax, USB or…).
- Use 75 ohm BNC; 2 m beats 1 m; clip-on ferrites sound worse, solid-core ferrites help, and Wave cables or an isolated battery break the ground loop Head-Fi, Aug 2018Head-Fi, Oct 2021Head-Fi, Nov 2018Head-Fi, Apr 2021Head-Fi, Jun 2023 (see Which BNC cables, and what length, should I use between an M…, Is battery power better than mains, and can I power the M Scaler…).
- With DAVE, the right dual BNC output goes to BNC 2 or 4 and the left to the bottom pair, OP SR white Head-Fi, Feb 2019Head-Fi, Apr 2020Head-Fi, Sep 2018 (see How do I connect the M Scaler to DAVE, and why does dual BNC only…, My DAC drops out, clicks or loses lock. What should I check before…). Hugo 2 and Mojo 2 also take dual data Head-Fi, Jul 2018Head-Fi, Jul 2023 (see Which Chord DACs accept 705.6/768 kHz from an M Scaler, and how do…).
- In January 2023 he said he runs DAVE's HF filter off with the scaler, partly from system synergy and his usage (mostly 44.1/16, a warm-sounding office system), and that the scaler's HF rejection with 44.1 is significantly better Head-Fi, Jan 2023Head-Fi, Jan 2023. In February 2025 he advised filter 1 or 2 with TT2, not 3 or 4, and said he uses 2 Head-Fi, Feb 2025 (see Which filter setting should I use on Hugo 2, TT2 or Qutest, and…).
- Pass-through is "not bit perfect" and carries the same 2.76dB loss Head-Fi, Oct 2019 (see Is M Scaler pass-through bit perfect, and why is the scaled output…).
- Video mode cuts delay to 104 mS Head-Fi, Aug 2018; he plays ripped Blu-rays in JRiver with video delayed to keep full taps Head-Fi, Mar 2018.
- Power the scaler or DAC before the source Head-Fi, Jul 2023. In February 2019 he wrote that it "just needs 10 minutes of warm-up"; in March 2023 he said there is no warm-up time on the scaler and put his in-flight change down to ear pressure Head-Fi, Feb 2019Head-Fi, Mar 2023 (see Should I leave my Qutest, TT2, DAVE or M Scaler switched on all…, Do Chord DACs need burn-in or warm-up?).
- In 2022 he said TT2 and the scaler can stack but are better apart with Wave or solid-ferrite cables; in 2023 he said he never noticed a difference Head-Fi, Apr 2022Head-Fi, Dec 2023 (see Can I stack TT2 and an M Scaler, and how hot is too hot?). He advises against linear supplies Head-Fi, Sep 2018Head-Fi, Jan 2025 (see Should I replace the supplied power supply with a linear or…).
Compared with other Chord models
He said it uses the exact filter and FPGA of the Blu Pursuit Perfect System 5:42, with better BNC isolation Head-Fi, Aug 2018. DAVE's filter has 164,000 taps AVstore 6:55; TT2's 98,304 taps switch off when the scaler is connected Head-Fi, Dec 2018. An M scaled DAVE beats an M scaled TT2 Head-Fi, Mar 2019 and easily beats an M scaled Qutest Head-Fi, Sep 2018. In 2020 he preferred TT2 plus scaler to a bare DAVE for musicality, adding that many would prefer DAVE's transparency Passion for Sound 24:16. Quartet has 4M taps Head-Fi, Jun 2024, which he called four times the Hugo M Scaler's, with three isolation stages to its one Hifi Pig TV 1:28ConvinceMeAudio 11:00. He called Quartet "a major advance on Hugo M scaler", while in June 2024 the Hugo M Scaler was still his "goto on flights" Head-Fi, Jun 2024, and said it would not replace the Hugo M Scaler The Source AV 5:05. In July 2024 he took both the Hugo M Scaler and the prototype Quartet traveling, and in September 2025 found flying with only an M Scaler disappointing Hifi Pig TV 4:13Hifi Pig TV 4:39The Source AV 15:46.
Release and official documents
- Presented at CanJam London in July 2018, where the host said it would be available in the autumn.c w 3:16
From Chord Electronics. Links open Chord's own copies; reviews hosted on Chord's site are left out. Chord's Hugo M Scaler 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 58 figures
| Figure | Value | When | Source |
|---|---|---|---|
| WTA filter taps | 1M taps (one million) | 2018-07 | Head-Fi, Jul 2018Head-Fi, Jul 2018 |
| Match to ideal sinc | 16.6 bits (March 2018, said of "the M scaler" before the July 2018 launch, same filter code as Blu 2; restated July 2018) | 2018-03 | Head-Fi, Mar 2018Head-Fi, Jul 2018Head-Fi, Aug 2018 |
| Match to ideal sinc | 16.7 bits | 2018-10 | Head-Fi, Oct 2018 |
| Worst-case match to perfect sinc | 99.98% (guaranteed better than 99.98%) | 2018-09 | Head-Fi, Sep 2018 |
| Transient reconstruction test | 22 bit accurate for "the M scaler" (test not pursued; test date and which M scaler not stated) | 2025-01 | Head-Fi, Jan 2025 |
| Music data used by the filter | 1.37 seconds (said of "the M scaler" before the July 2018 launch; same filter code as Blu 2) | 2018-03 | Head-Fi, Mar 2018Head-Fi, Aug 2018 |
| Music data used by the filter | 1.42 seconds at 44.1 kHz (0.71 s delay) | 2018-07 | Head-Fi, Jul 2018 |
| Music data used by the filter | 1.438 seconds | 2018-12 | Head-Fi, Dec 2018 |
| Delay, video mode off | 0.63 s with a 48k source (said of "the M scaler" before the July 2018 launch; same filter code as Blu 2) | 2018-03 | Head-Fi, Mar 2018Head-Fi, Aug 2018 |
| Delay, video mode off | 0.63 S at 1M taps (input rate not stated); video mode 2/3M taps, 0.1 S | 2018-07 | Head-Fi, Jul 2018 |
| Delay, video mode off | 0.71 s at 44.1k; 0.65 s at 48k | 2018-07 | Head-Fi, Jul 2018 |
| Delay, video mode off | 0.71 s at 44.1k; 0.65 s at 48k | 2018-12 | Head-Fi, Dec 2018 |
| Delay, video mode off | 0.661 s with a 48k source; half at 96k; 0.165 s at 192k | 2020-04 | Head-Fi, Apr 2020 |
| Delay | 0.7 of a second | 2025-05 | Audiophile Junkie 17:12 |
| Video mode delay | 104 mS | 2018-08 | Head-Fi, Aug 2018 |
| Video mode filter | asymmetric; future part cut, delay 0.104 S | 2018-12 | Head-Fi, Dec 2018 |
| Video mode taps | 98,304 future plus 507,904 past, 606,208 total | 2022-05 | Head-Fi, May 2022 |
| Original samples per interpolated sample | 63,488, going 1FS to 16FS | 2022-08 | Head-Fi, Aug 2022 |
| FPGA | 28nm Xilinx 200T | 2025-03 | Head-Fi, Mar 2025 |
| FPGA count | one (Quartet has five of the same type) | 2024-05 | AVstore 21Audio Force 24:08 |
| DSP cores | 528 | 2018-07 | Head-Fi, Jul 2018Head-Fi, Jul 2018 |
| DSP cores in the FPGA chip | 740 on the Xilinx A200T | 2018-07 | c w 17:48 |
| DSP cores in the FPGA chip | 720 on the Xilinx 200T | 2025-05 | Audiophile Junkie 16:33 |
| DSP cores | something like 600; 525 'I think' | 2020-06 | Part-Time Audiophile 28:53 |
| Filter code | half a million lines | 2018-07 | Head-Fi, Jul 2018 |
| Output rates (OP SR) | white 705.6/768 kHz 1M taps (dual data); blue 352.8/384 (1/2 M taps); green 176.4/192 (1/4 M taps); red pass-through | 2018-09 | Head-Fi, Sep 2018 |
| Optical rate limit | 192 kHz, 0.25M taps | 2018-07 | Head-Fi, Jul 2018 |
| Output word length | 56-bit output reduced to 24 bits by truncation noise shapers guaranteeing -301 dB | 2019-04 | Head-Fi, Apr 2019 |
| Noise shaper order | 11th order, -301 dB accuracy at 768k | 2019-12 | Head-Fi, Dec 2019 |
| Truncator noise floor at 16FS | -390 dB (he says set by his test vectors) | 2021-07 | Head-Fi, Jul 2021 |
| Insertion loss | 2.76 dB | 2019-10 | Head-Fi, Oct 2019 |
| Insertion loss | 2.75 dB | 2020-06 | Head-Fi, Jun 2020 |
| Output level | 2.5v pp terminated | 2019-11 | Head-Fi, Nov 2019 |
| Power draw | 12W typical while playing | 2018-07 | Head-Fi, Jul 2018 |
| Power draw | 13W total | 2018-08 | Head-Fi, Aug 2018 |
| Power draw | 12W when working | 2019-06 | Head-Fi, Jun 2019 |
| Power draw | 13W | 2025-01 | Head-Fi, Jan 2025 |
| Current from supply | 1A at 12v | 2020-09 | Head-Fi, Sep 2020 |
| Input voltage | 9 to 15 volts (Nintronics open day talk, November 2018, published December 2018) | 2018-11 | Pursuit Perfect System 14:11 |
| Input voltage maximum | 15v maximum input rating | 2018-11 | Head-Fi, Nov 2018 |
| Input voltage range | about 5v lower value; upper 15.5v | 2019-10 | Head-Fi, Oct 2019 |
| Input voltage damage | 18v and above destroys the protection diode | 2020-01 | Head-Fi, Jan 2020 |
| Input voltage damage | damage only at 16v and above | 2020-10 | Head-Fi, Oct 2020 |
| Input voltage rating | rated 15v input | 2025-01 | Head-Fi, Jan 2025 |
| Thermal trip | 65 deg C case | 2019-05 | Head-Fi, May 2019 |
| FPGA temperature rating | 85 deg C (timing tools worst case) | 2019-05 | Head-Fi, May 2019 |
| FPGA die temperature, stacked | 45 deg C (die rated 125 deg C) | 2019-01 | Head-Fi, Jan 2019 |
| Low power mode | after ten minutes of digital silence | 2019-10 | Head-Fi, Oct 2019 |
| USB draw from source | about 250 mW | 2019-02 | Head-Fi, Feb 2019 |
| Galvanic isolator capacitance | about 2pF on the BNC drivers | 2021-03 | Head-Fi, Mar 2021 |
| Galvanic isolator capacitance | 2pF on USB and another 2pF on the BNC outputs, about 80 ohms total at 2GHz | 2023-03 | Head-Fi, Mar 2023 |
| Dimensions | 40.5 mm tall, 235 mm wide, 236 mm deep including BNC; PSU 140 x 50 x 30 mm | 2018-08 | Head-Fi, Aug 2018 |
| DAVE volume before clipping with scaler | +6 dB | 2019-04 | Head-Fi, Apr 2019 |
| DAVE volume before clipping with scaler | +7 for 0 dBFS sources | 2022-01 | Head-Fi, Jan 2022 |
| Battery run time | nearly 10 hours from a Bixpower BP90-12v (12v unregulated output) | 2023-01 | Head-Fi, Jan 2023 |
| Battery run time | about 10 hours from his BixPower | 2025-01 | Head-Fi, Jan 2025 |
| Project origin | started as a copy of the Blu 2 project; only control code changed, core audio processing identical | 2018-08 | Head-Fi, Aug 2018 |
| Firmware and audio | no firmware change has affected audio or measured performance; production designs are frozen for audio | 2022-07 | Head-Fi, Jul 2022 |
Quotes
“the M scaler is not an upgrade - it's transformational, in that you get that master tape feeling, or being in touch with the musical performance.”2018-07-24 Head-Fi, Jul 2018
“Please remember that pass-thru is not bit perfect - it's intent is to allow one to easily hear the effect of the M scaler.”2019-10-18 Head-Fi, Oct 2019
“dual BNC operation is only for the full 1M taps at 705/768 kHz. Otherwise it is single data mode at max rate of 352/384 kHz.”2018-09-22 Head-Fi, Sep 2018
“You need to send the M scaler bit perfect data.”2018-07-26 Head-Fi, Jul 2018
Caveats and open points
- Several of his figures differ between posts and he did not reconcile them: data window (1.37 s in March 2018, 1.42 s in July 2018, 1.438 s in December 2018) Head-Fi, Mar 2018Head-Fi, Jul 2018Head-Fi, Dec 2018; delay (0.63 s at 48k in March 2018; 0.63 S at 1M taps, rate unstated, on 22 July 2018; 0.65 s at 48k on 26 July and in December 2018; 0.661 s at 48k in 2020; 0.7 of a second, rate unstated, in a 2025 talk) Head-Fi, Mar 2018Head-Fi, Jul 2018Head-Fi, Jul 2018Head-Fi, Dec 2018Head-Fi, Apr 2020Audiophile Junkie 17:12; video mode taps (2/3M in July 2018, 606,208 in May 2022) Head-Fi, Jul 2018Head-Fi, May 2022; sinc match (16.6 and 16.7 bits) Head-Fi, Mar 2018Head-Fi, Oct 2018; insertion loss (2.76 and 2.75 dB) Head-Fi, Oct 2019Head-Fi, Jun 2020.
- DSP cores: 528 used by the filter (July 2018 forum) Head-Fi, Jul 2018Head-Fi, Jul 2018, and 'something like 600 DSP cores, 525 I think' in a 2020 podcast Part-Time Audiophile 28:53. The 740 (2018) and 720 (2025) figures, both, are what he said the FPGA chip itself contains c w 17:48Audiophile Junkie 16:33.
- Supply limits: 15v maximum input rating (2018-11) Head-Fi, Nov 2018, upper threshold 15.5v with a lower value of about 5v (2019-10) Head-Fi, Oct 2019, 16v 'could destroy the protect diode' (2019-11) Head-Fi, Nov 2019, damage at 18v and above (2020-01) Head-Fi, Jan 2020, damage at 16v and above (2020-10) Head-Fi, Oct 2020, 16v could cause damage (2022-06) Head-Fi, Jun 2022, rated 15v input (2025-01) Head-Fi, Jan 2025, and 9 to 15 volts in a talk (Nintronics open day, November 2018; published December 2018) Pursuit Perfect System 14:11.
- Isolation capacitance on the Hugo M Scaler: about 2pF (2021-03 and 2023-03) Head-Fi, Mar 2021Head-Fi, Mar 2023, and in a 2022 interview 'two picofarads' corrected to 'three' AVstore 42:06. The 5pF in Head-Fi, Dec 2018 (2018-12) is said of the Blu 2's BNC output, before he describes improving the isolation for the Hugo M Scaler; it is not a Hugo M Scaler figure.
- FPGA temperature rating: 85 deg C for worst-case timing (2019-05) Head-Fi, May 2019 and 'the die is rated at 125 deg C - continuous operation' (2019-01) Head-Fi, Jan 2019; he did not say how the two relate.
- DAVE volume limit with the scaler: +6 dB in April 2019 and +7 for 0 dBFS sources in January 2022, and, in March 2025, +7 dB suggested as the limit with a Hugo M scaler for a DAC the item does not name; he did not explain the differences Head-Fi, Apr 2019Head-Fi, Jan 2022Head-Fi, Mar 2025.
- Warm-up: in February 2019 he wrote that the M scaler/TT2 setup 'just needs 10 minutes of warm-up' Head-Fi, Feb 2019; in January 2023 he said portable setups on flights, with or without the scaler, sound bright for the first 10 minutes Head-Fi, Jan 2023; in March 2023 he said there is no warm-up time on the scaler and put the in-flight change down to ear pressure Head-Fi, Mar 2023.
- The 22-bit transient figure (January 2025) names only 'the M scaler' and gives no test date; by then the Quartet scaler was in development, so which scaler it describes is not stated Head-Fi, Jan 2025.
- Exact tap count: in an April 2018 interview he gave Blu MkII as 1,015,808 taps article, Apr 2018, and he says the Hugo M Scaler uses the identical filter core c w 23:19Head-Fi, Aug 2018; no Watts item in this archive gives that exact figure for the Hugo M Scaler. At the launch a host gave 'one million fifteen thousand and Three hundred and eight' c w 1:09.
- Names change with date. Before July 2018, 'M scaler' in his posts names the million-tap engine in the Blu Mk2 or a planned product, not the shipped Hugo M Scaler; from 2022 a bare 'M scaler' can mean the Choral/Quartet scaler. Head-Fi, Mar 2018, Head-Fi, Mar 2018 and Head-Fi, Mar 2018 (March 2018) predate the launch, and he did not say whether their figures changed for production.
- Dates estimated from post IDs: Head-Fi, Jul 2018, Head-Fi, Jul 2018, Head-Fi, Oct 2018, Head-Fi, Dec 2018, Head-Fi, Jan 2019, Head-Fi, Feb 2019, Head-Fi, Oct 2019, Head-Fi, Apr 2022. Head-Fi, Mar 2025 is only bounded (after 2025-03-27, before 2026-03-03); its key figure date is the lower bound.
- The launch-talk statements on price and availability are a host's, not Watts's; the host's affiliation is unverified in the archive c w 1:09c w 3:16.
- His effect claims (flow, separation, soundstage) are his own listening reports; he said he cannot fully explain the depth and soundstage change and that results depend on the listener and the system Head-Fi, Dec 2018Pursuit Perfect System 20:30Head-Fi, Oct 2018HiFi Buys 2:24:19.
Indicator colors
What each light means on the Hugo M Scaler, from Chord's manual: Indicator colors: Hugo M Scaler.
Questions about this product
Owning and setting up
- Can I stack TT2 and an M Scaler, and how hot is too hot?
- Does an M Scaler help Mojo, Mojo 2 or a non-Chord DAC?
- Is M Scaler pass-through bit perfect, and why is the scaled output quieter?
- Why does my M Scaler give no output with native DSD?
- How do I connect the M Scaler to DAVE, and why does dual BNC only work with the output set to white?
- How does the Quartet M Scaler differ from the Hugo M Scaler?
- Should I add an M Scaler to my Qutest or Hugo 2, or upgrade to TT2 first?
- What does the M Scaler actually do, and is it worth adding to my DAC?
- Can I take DAVE, Hugo 2, an M Scaler and a power bank on a plane, and how does Rob listen on flights?
- Why do I hear a buzz or feel a tingle when the charger is connected, and should I earth my unit?
- 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?
- Is TT2 plus an M Scaler as good as DAVE?
- Should I put ferrites on my BNC or USB cables, and which kind?
- Which headphones, speakers and sources does Rob use himself, and which pair well with Chord DACs?
- Why does my DAC mute or click when the track or sample rate changes?
- My DAC drops out, clicks or loses lock. What should I check before returning 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?
- 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 do Mojo 2 and Hugo 2, or TT2 and DAVE, compare?
- How many taps and pulse array elements does each Chord DAC have?
- Should I leave my Qutest, TT2, DAVE or M Scaler switched on all the time?
- Should I send DSD as DoP or native?
- 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?
- Why won't Rob comment on other brands' products?
- Will existing Chord products get firmware or code updates, and can DAVE be upgraded?
In depth
- Is the filter algorithm more important than the tap count, and would more than a million taps keep improving the sound?
- Should I upsample in software (HQPlayer, PGGB or my player) before a Chord DAC, and can it match an M Scaler?
- Which Chord inputs are galvanically isolated, and which setups short the isolation out?
- 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?
- 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 can upscaling to 705.6/768 kHz improve sound if the recording has nothing above 22 kHz?
- 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?
- What does Rob mean by depth, and what in a DAC improves or collapses it?
- Why does tap length matter, and why a million taps?
- Do Chord DACs decode MQA, and what does Rob think of it?
- How do Chord DACs handle DSD, and does Rob consider DSD better or worse than PCM?
- How were Chord's current DACs and the M Scaler developed, and how long did each take?
- If the data reaching the DAC is bit perfect, can the source (laptop, phone, streamer, CD transport or network gear) still change the sound?
- 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 does Rob mean by 'starting and stopping of notes', timbre variation and 'sense of flow', and what causes them?
- Which filter setting should I use on Hugo 2, TT2 or Qutest, and what does the HF filter do?
- Why does Rob design to -301 dB, how can that be verified, and how does small-signal accuracy relate to depth?
- Why does Rob distinguish perception from hearing, and why does he distrust psychoacoustic thresholds?
- Why might a brighter or more detailed change actually be a step backward?
- Do measurements tell you how good a DAC sounds, and is Rob an objectivist or a subjectivist?
- How do microphones, studio conversion and mastering limit what a DAC can reproduce?
- What does Rob think of Class D amplifiers, and how do his pulse array power amps differ from them?
- What is Davina, and what happened to the pulse array ADC?
- Why are half-band decimation filters and studio sample-rate conversion a problem, and how much aliasing rejection is enough?