Why upscale, and why a separate scaler

Upscaling and the M Scalers

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Everything he said on this topic (47)

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2016-03-05Watts says the Blu upsampler upgrade adds a second powerful FPGA for WTA processing, but only listening tests will show the benefit, and it ships only if worthwhile. Head-Fi, Mar 2016
2017-01-07Watts presents the Blu Mk2 slides: why ringing worries are mistaken, the 16-bit case for about 1M taps, delaying launch to reach 1M, and why the scaler is separate. Head-Fi, Jan 2017
2017-05-08Watts says the M scaler is 0.234 dB louder (-2.766 dB insertion loss, +3 dB volume) and its 10 A signal-dependent FPGA ground current forces a separate, isolated box. Head-Fi, May 2017
2017-10-20Watts says the 200T FPGA draws 10 A processing versus 2 A idle, so it sits in a galvanically isolated Blu 2 rather than DAVE, keeping DAVE's ground plane clean. Hifistatement 0
2017-10-20Watts says an external scaler reduces ground-plane noise through galvanic isolation, and that how the isolation and power supply were implemented made a substantial change to sound quality. Hifistatement 55
2018-02-23Watts says putting this FPGA in Dave would inject signal-correlated noise from 528 DSP cores into the ground plane, peaking at the smallest signals and degrading depth perception. MajorHiFi 20:02
2018-02-23Watts says a separate, galvanically isolated M Scaler keeps that noise out of Dave, isolation took two prototypes, another M Scaler is in progress, and timing recovery reaches 16-bit accuracy. MajorHiFi 20:49
2018-03-17Watts says never upsample at the source into his DACs; cascading two DAVEs via DX helps slightly versus an M scaler's huge change; isolating FPGA noise was essential for DAVE. Head-Fi, Mar 2018
2018-07-23Watts explains Hugo 2's dual data link (two 384k cables), says FPGA RF noise keeps the scaler separate, shows his homemade flight cable, and rates USB and optical equal. Head-Fi, Jul 2018
2018-07-26Watts says Qutest, Hugo 2, TT2 and Dave share the post-scaler process (WTA2 to 256FS, third-order filter to 104 MHz), notes diminishing returns, and previews DX amps' transparency. Head-Fi, Jul 2018
2018-08-02Watts says Blu 2 and M scaler filter code is identical, explains that upscaling recovers transient timing rather than adding information, and why pulse array needs DSD converted to PCM. Head-Fi, Aug 2018
2018-08-06Watts says the M Scaler uses the exact filter and the same FPGA as the Blu, pulled straight across, because the filter took too long to design to change. Pursuit Perfect System 5:42
2018-08-31Watts says the original is the unsampled analog signal; the M scaler's million taps match ideal sinc to better than 16 bits, recovering transient timing regular filters get wrong. Head-Fi, Aug 2018
2018-10-23Watts explains the M scaler matches sinc to 16.7 bits, fixing transient timing, but cannot repair aliasing from modern half-band ADCs, possibly why 1960s recordings sound amazing. Head-Fi, Oct 2018
2018-11-06Watts says servers bring no sound-quality gain, their perceived transparency being RF noise raising noise floor modulation and brightness, while the M scaler transforms musical performance. Head-Fi, Nov 2018
2018-12-27Watts says the M scaler unexpectedly improves reverb and depth perception, normally tied to small-signal accuracy, speculating about its 1.438 s of data versus concert-hall RT60, unconvinced. Head-Fi, Dec 2018
2019-01-27Watts says the M scaler makes CD equivalent to a 705 kHz recording to 16 bits; with native 705 input both it and DAVE's 164,000-tap WTA1 pass through. Head-Fi, Jan 2019
2019-03-26Watts disagrees that 24-bit files benefit less from M scaling than 16-bit, saying reconstruction makes bit depth theoretically irrelevant; 24-bit files just start out better. Head-Fi, Mar 2019
2019-07-22Watts says the M scaler converts 48k to 768k with 16-bit sinc accuracy, each doubling of rate quarters the transient error area, and WTA2 timing gains above 768k remain audible. Head-Fi, Jul 2019
2019-07-23Watts says WTA1 changes bass, pitch, timbre and separation while WTA2 affects only note starts and stops, names the RME ADI-2 Pro for test recordings, and describes IIR final stages. Head-Fi, Jul 2019
2019-12-14Watts tells a TT2 owner every DAC upsamples, the M scaler matches sinc to 16 bits for accurate transients, blind tests are insensitive, and he uses Aeon Closed on planes. Head-Fi, Dec 2019
2020-04-11Watts says the M scaler preserves a recording's HF noise, being flat to FS/2 like an ideal sinc, so the DAC's HF filter, run from 16FS to 2048FS, removes it. Head-Fi, Apr 2020
2020-06-25Watts says an M scaled 44.1 kHz recording beats an unscaled 192 kHz one, PCM timing is fully recoverable with enough processing, and he wishes recordings were 768 kHz. Part-Time Audiophile 40:28
2021-04-02Watts says ferrites and inductors in the analog path cause level-dependent phase shift and hysteresis that upset transient timing, and a noisy M scaler FPGA inside a DAC is unwise. Head-Fi, Apr 2021
2021-04-03Watts says supply ferrites are fine, any trace of noise floor modulation seems audible so he expects desktop two-box, and stock cables with a battery M scaler matched Wave Stream. Head-Fi, Apr 2021
2022-03-19Watts says above 64FS timing becomes almost unimportant, 768 kHz recordings would make scalers unnecessary, and the one 768 kHz recording he heard sounds like an M Scaler. MFG Audio Reviews 52:53
2022-08-19Watts says the M Scaler is separate because its processing creates gigahertz ground-plane noise that is very hard to filter inside a DAC, so an external scaler will always help. AVstore 29:50
2022-08-19Watts says the scaler is galvanically isolated and separate from the DAC so that the gigahertz noise is, he hopes, removed by the isolation. needs context AVstore 30:36
2023-03-02Watts says scalers are separate units to keep FPGA noise from the DAC, as the Hugo M Scaler injects 12A of noisy current into its ground plane. Head-Fi, Mar 2023
2024-05-10Watts poses the question of why they run at 768 kHz. Reactcore 9
2024-05-10Watts names 16FS at 1.6 MHz as an alternative rate and says there is a sweet spot. needs context Reactcore 14
2024-05-10Watts says the amount of data the upsampler is looking at is also critically important for sound quality, and begins to describe a trade-off. needs context Reactcore 47
2024-05-10Watts says the sweet point is 16FS and that DAVE takes up 16FS. Reactcore 1:00
2024-05-16Watts says interpolation does not create new information. The Speaker Shack 2:51
2024-05-16Watts says they are maintaining the information content originally there, not distorting it. needs context The Speaker Shack 2:56
2024-05-17Watts says separating it reduces processing noise and isolates Quartet from the DAC: RF filters in the supply and Quartet's input stage make it behave like a battery. AVstore 1:38
2024-05-17Watts says reducing noise improves sound markedly, and that scaling is about transient timing, which the brain uses to separate instruments, perceive timbre and hear notes start and stop. AVstore 2:08
2024-05-31Watts says he is not under contract with Chord, a scaler needs physical separation from the DAC, DSD sounds unreal, and subjective impressions can be characterized objectively. Head-Fi, May 2024
2024-09-29Watts says Quartet reconstructs transient timing more accurately, aiding timbre and instrument separation; digital mis-times transients, only the M Scaler approach recovers them, and it put DAVE in a new game. The Source AV 15:46
2026-03-17Watts says a regular interpolation filter distorts a CD's information content, while his aim is to preserve it fully; the key information is transient timing embedded in the samples. ecoustics 15:16
2026-03-17Watts says DAVE's filter is 164 thousand taps; an M Scaler adds a million taps, converting 48 kHz to 768 kHz (16 times), and DAVE then upsamples to 2048 times. ecoustics 23:40
2026-03-17Watts says the signal reaches analog via the noise shaper; a scaler replaces the DAC's front-end filter, and every DAC from a $600 Mojo to a $20,000 DAVE benefits. ecoustics 24:23
2026-03-17Watts says 768 kHz recordings he has heard sound as if played through an M Scaler: very spacious, with tight, well-defined bass and good timbre variation. ecoustics 26:03
2026-10-14Watts says one could upsample 48 kHz to 768 kHz with one's own filter into a chip DAC; ESS measure well, but he rates chip DACs as similar sounding. Part-Time Audiophile 34:54
2026-10-14Watts says a perfect 768 kHz filter would improve a chip DAC but not match his FPGA DACs, which filter up to 104 MHz, leaving 9.6 nanoseconds of uncertainty. Part-Time Audiophile 35:47
2026-10-17Watts calls one chassis a nightmare because processing noise upsets the DAC; hence separate supplies and a new two-way pinch-off RF filter of about 200 components each. needs context article, Oct 2026
2026-10-17Watts says keeping it separate with its own supplies avoids the issue, and he compared against a large lithium-ion battery, meeting his target of equal sound quality. article, Oct 2026