Blu Mk2: everything he said

156 posts and passages, oldest first, as one-line summaries in our words. Each link opens the original.

• 2016-10-18Watts says he paused Davina to finish the new Blu for a show, hopes to finish the Davina PCB by end of October, and will publish test recordings. Head-Fi, Oct 2016
• 2016-10-20Watts says 768/705.6 kHz 24-bit is best and 32 bits unnecessary, reports noise shaping beat Gaussian and triangular dither on the Blu Mk2 prototype, and Davina will study 44.1/16 losses. Head-Fi, Oct 2016
• 2016-11-01Watts says his reward is enjoying music with Mojo and DAVE, and blames himself for Blu Mk2's delay: the August prototype worked, but an improvement cost two or three months. Head-Fi, Nov 2016
• 2016-11-01Watts says he uses JRiver on his laptops, and that Blu Mk2 is CD only, using the same mechanism as the original Blu. Head-Fi, Nov 2016
• 2016-11-01Watts says Blu Mk2's optical output reaches only 176.4 kHz, so 705.6 kHz reaches DAVE via dual BNC, whose outputs are RF isolated with optional full galvanic isolation. Head-Fi, Nov 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
• 2017-01-08Watts says Davina's bi-directional USB can send 768 kHz M scaler output to a PC, but Dave is meant to receive 768 kHz via isolated BNC, as with Blu Mk2. Head-Fi, Jan 2017
• 2017-01-08Watts says the M scaler outputs any multiple of the input rate, benefiting DAVE most through its 256FS and 2048FS filtering; other DACs improve by an amount he cannot say. Head-Fi, Jan 2017
• 2017-01-08Watts says the taps are used only when upscaling, so a 768 kHz signal would pass through another M scaler unchanged, and that Moore's law is running out of steam. Head-Fi, Jan 2017
• 2017-01-08Watts reports CES demos where listeners reacted strongly within seconds of the M scaler being plugged in, saying everything improves. Head-Fi, Jan 2017
• 2017-01-08Watts says Blu got the M scaler first because Chord still sells Blu and Dave out-tapped Blu 1; the work feeds Davina, and he travels with Blu and Dave. Head-Fi, Jan 2017
• 2017-01-09Watts says he uses Hugo 2 on planes and Dave with the M scaler in hotels; Hugo 2 should ship late February or early March and appear at CanJam Singapore. Head-Fi, Jan 2017
• 2017-01-09Watts says WTA processing is identical from 44.1 to 384 kHz, explains mounting the FPGA core switching regulator underneath to limit ground-plane noise, and Blu Mk2 needing 12A. Head-Fi, Jan 2017
• 2017-01-09Watts says 384/24 is distinguishable from 48/24 but recording method matters more, praises 1960s Decca recordings, calls the M scaler 'a great equalizer', and says Davina will measure losses. Head-Fi, Jan 2017
• 2017-01-09Watts says in the early 1980s he believed digital needed 16-bit sinc accuracy and a million taps, thought that impossible, and the M scaler shows his intuition was right. Head-Fi, Jan 2017
• 2017-01-09Watts says listeners find the M scaler a bigger change than Dave, believes on another DAC it would be an ordinary tap-length gain, and wonders why sixfold taps transform sound. Head-Fi, Jan 2017
• 2017-01-09Watts says Blu's video mode cuts latency from 0.66 seconds to 100 mS, and a -0.56 second JRiver delay gives him lip sync with the full 1M taps. Head-Fi, Jan 2017
• 2017-01-09Watts confirms a poster is correct about the M scaler and Dave delay. needs context Head-Fi, Jan 2017
• 2017-01-15Watts recounts M scaler development and CES demos, discusses judging the scale of changes, lists gains in timbre, bass pitch and depth, and describes improving stop-band rejection. Head-Fi, Jan 2017
• 2017-01-23Watts says Hugo 2's 256FS filter matches Dave's, and the HF filter is best off with the M scaler and Dave since stop-band rejection is already 130 to 150 dB. Head-Fi, Jan 2017
• 2017-01-23Watts says Dave's 26,000 to 164,000 tap step disappointed him, algorithm and 16FS mattered more, 0.5M taps was transformational, and explains reducing errors until inaudible with a biscuit-barrel analogy. Head-Fi, Jan 2017
• 2017-01-24Watts says Blu Mk2's design came from Davina, which started first, the code is shared with Davina's M scaler mode, and proper SRC needed a powerful FPGA. Head-Fi, Jan 2017
• 2017-01-28Watts explains peak error, why 16-bit accuracy needs about 1M taps, why doubling sample rate only halves conventional filters' error, and that taps are not the whole story. Head-Fi, Jan 2017
• 2017-01-29Watts says HD recordings benefit too but recording quality matters more than format, and a 16M-tap scaler would need cascaded FPGAs drawing 32A at 5V. Head-Fi, Jan 2017
• 2017-01-29Watts says the only digital-mode task Davina can do that Blu cannot is converting 768k down to 44.1k, and notes family members named David. Head-Fi, Jan 2017
• 2017-02-01Watts says the M scaler connects to Dave's dual BNC inputs (1 and 2 or 3 and 4); DX outputs are dual BNC 705/768 kHz SPDIF carrying volume data. Head-Fi, Feb 2017
• 2017-03-05Watts cautions one laptop test proves little: Hugo 1 improved enormously with isolation from a Dell PC, while galvanic isolation on production Blu 2 with DAVE gives a substantial improvement. Head-Fi, Mar 2017
• 2017-03-19Watts says Blu Mk2 took its M scaler design from Davina, so 1M taps is Davina's limit, and Davina will show how much quality the M scaler loses. Head-Fi, Mar 2017
• 2017-04-07Watts says Hugo 2 with the white filter has a tonal balance like his DAVE and M scaler reference, avoids hardness, and the 16FS filter suits hard headphones. Head-Fi, Apr 2017
• 2017-04-08Watts says his posting shows he is no longer in bug-solving or panic mode on Blu 2 or Hugo 2. needs context Head-Fi, Apr 2017
• 2017-04-24Watts declines a technical rebuttal and asks the poster whether they have actually heard what an M scaler does. needs context Head-Fi, Apr 2017
• 2017-04-27Watts says image upscaling like RAISR does not carry over to audio, where only transient timing must be recovered with longer filters, and plans Davina tests of 1M-tap losses. Head-Fi, Apr 2017
• 2017-05-01Watts describes Jude recognizing the M scaler at the Tokyo show despite unfamiliar headphones, says its effect is audible even on unfamiliar recordings, and that it simply sounds real. Head-Fi, May 2017
• 2017-05-06Watts says the cited figure is FPGA leakage current, 0.4 A; Blu Mk2's low power mode switches off DSP cores at digital silence, drawing 2A against 10A normally. Head-Fi, May 2017
• 2017-05-07Watts notes a phone recording's poor mic, simple ADC and AAC compression, and is amazed the 164,000 versus 1,000,000 tap difference is audible through it. Head-Fi, May 2017
• 2017-05-08Watts says he hears the M scaler in phone clips via bass, warmth and soundstage, and Davina will let him post better clips once its USB works. Head-Fi, May 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
• 2017-05-16Watts notes the M scaler's 2.76 dB insertion loss and says 0.5M versus 1M taps, or video mode, changes depth greatly, hypothesizing coefficient truncation over reverb-length periods. Head-Fi, May 2017
• 2017-05-19Watts confirms Blu 2 has a USB input and a BNC coax input. Head-Fi, May 2017
• 2017-06-10Watts says a native 768 kHz test recording from Chord's Japanese distributor sounded like M-scaled playback, unlike DXD so far, though its high ADC noise made DAVE's HF filter matter. Head-Fi, Jun 2017
• 2017-06-11Watts says DAVE sounds better via the M scaler not from a WTA fault, citing Verilog simulation and -301 dB tests, and video mode's two-thirds million taps shrinks the soundstage. Head-Fi, Jun 2017
• 2017-06-12Watts points to the million-tap WTA M scaler, which uses 528 DSP cores in parallel on a 7A200T FPGA about 20 times more powerful. Head-Fi, Jun 2017
• 2017-06-14Watts says that with DAVE, and more so DAVE with the M scaler, differences between headphones grow and rankings shift unpredictably. Head-Fi, Jun 2017
• 2017-06-21Watts describes airport X-ray checks of his roughly 20 kg carry-on of DAVE, Blu 2 and two laptops, saying only London Heathrow stops and swabs him every time. Head-Fi, Jun 2017
• 2017-08-03Watts says there is no danger of clipping even at +7 dB when using Blu 2, so clipping is only possible at +8 dB. needs context Head-Fi, Aug 2017
• 2017-08-10Watts notes Benchmark's website omits galvanic isolation, disputes that Hugo 1 sounds different, praises its musicality with archive recordings, and says 1960s Decca sounds real via Blu 2 and DAVE. Head-Fi, Aug 2017
• 2017-08-11Watts says the million-tap M scaler exceeds 16-bit accuracy, Hugo 2 takes 768 kHz dual BNC, better analog parts put DAVE ahead, and he flies with DAVE and Blu 2. Head-Fi, Aug 2017
• 2017-08-12Watts says Davina will measure the audible losses of decimation and re-interpolation, recalls underestimating the M scaler's gain, and expects 44.1/16 Davina recordings to beat conventional ADCs. Head-Fi, Aug 2017
• 2017-08-13Watts says Davina will test how many taps are enough and whether ADC bandwidth limiting matters, noting sinc reconstruction is required and his IIR decimation filter gives 300 dB rejection. Head-Fi, Aug 2017
• 2017-08-26Watts says audible timing errors are non-linear, not fixed delays; the M scaler's 1,015,808 taps match ideal sinc to 16 bits, Hugo 2 about 13; doubling taps adds a bit. Head-Fi, Aug 2017
• 2017-08-26Watts says Blu 2's low-latency video option cuts delay from 630 mS to 104 mS via an asymmetric filter but degrades sound, so he sets -630 mS in JRiver. Head-Fi, Aug 2017
• 2017-10-11Watts says WTA reconstructs transients regardless of origin; DAVE's 164,000-tap delay is about 0.2 s and 1M taps 1.4 s, and his RT60 explanation for depth is speculative. Head-Fi, Oct 2017
• 2017-10-11Watts says aliasing from modern ADCs' half-band filters (-6 dB at FS/2) is irreparable, yet every track in his 5 TB library sounds better on BluDave with longer taps. Head-Fi, Oct 2017
• 2017-10-13Watts says a Xilinx FPGA family launched about 3 years ago went into Mojo and Hugo 2; he used it for Davina, then ported that work into Blu 2. miceblue425 23:55
• 2017-10-13Watts says Blu 2's FPGA has 740 DSP cores and about 200,000 logic cells, enough for just over a million taps; he calls this first million-tap filter the M Scaler. miceblue425 24:38
• 2017-10-13Watts says the DAVE filter took nine months and sounded only a bit better, so he expected little from the M Scaler and first built an easy half-million-tap version. miceblue425 29:37
• 2017-10-13Watts says the 512,000-tap filter compared with DAVE gave his biggest shock in 5 years, partly due to an improved WTA filter and moving from 8FS to 16FS. miceblue425 30:21
• 2017-10-13Watts says the modular design cut coding eightfold, and going from half a million to a million taps massively changed sound quality, in a way every M Scaler listener notices. miceblue425 32:31
• 2017-10-13Watts says the M Scaler deepens the soundstage enormously, which puzzles him because filter changes never altered depth before; depth depends on small-signal nonlinearity, which filters can avoid. miceblue425 33:17
• 2017-10-13Watts suspects the soundstage opens because the filter now spans 1.4 seconds, about a hall's RT60 reverberation decay time, and reverberation is an important depth cue. miceblue425 34:01
• 2017-10-13Watts says Davina will record at 768 kHz, the M Scaler's rate, letting him check how good the M Scaler is. miceblue425 39:48
• 2017-10-13Watts says a million taps gives 16-bit sinc reconstruction; 24-bit would need 256 million taps and minutes of delay, which will never happen and which he doubts is audible. miceblue425 40:07
• 2017-10-13Watts says he can decimate the bandlimited file to 48 kHz, rescale it to 768 kHz through the M Scaler, and compare, finally knowing how big the problem is. miceblue425 41:33
• 2017-10-17Watts says taps are simply taps, rivals' short or minimum-phase filters misreconstruct transient timing, Blu 2 sounds profoundly better, and he predicts marketing pseudo tap counts. Head-Fi, Oct 2017
• 2017-10-17Watts gives the filter delay formula; for the 1,015,808-tap Blu at 48 kHz the delay is 0.661 s while the filter processes 1.323 s of music. Head-Fi, Oct 2017
• 2017-10-17Watts says Blu 2 uses code originally written for Davina, and that code will not change for Davina. Head-Fi, Oct 2017
• 2017-10-19Watts confirms the WTA window forces coefficients beyond 1.4 seconds to zero, and the ignored sinc coefficients are much smaller than 16 bits, giving better than 16-bit accuracy. Head-Fi, Oct 2017
• 2017-10-20Watts says the Xilinx XC7A200T, launched about three or 4 years ago, became buyable only about 18 months ago; he used it for the Davina project, and it allows a million taps for Blu 2. Hifistatement 0
• 2017-10-20Watts says he did not expect a big sonic change from this project; moving DAVE from 26,000 to 164,000 taps took nine months and 3 redesigns over timing closure. Hifistatement 2:10
• 2017-10-20Watts says he expected only incremental gains, so designed a half-million-tap filter on the new FPGA in a couple of months, heard a huge change, and decided to use more taps. Hifistatement 3:36
• 2017-10-20Watts says the FPGA has only just enough processors and memory for a full million-tap filter, but he delayed the project to push on with a full million taps. Hifistatement 4:24
• 2017-10-20Watts says the filter needed a new architecture; 528 processors at 208 MHz met timing closure with 740 DSP cores available, but memory efficiency was the problem. Hifistatement 0
• 2017-10-20Watts describes one coefficient ROM and one data memory feeding eight DSP cores, giving about 97 percent memory efficiency and easier coding of half a million lines. Hifistatement 45
• 2017-10-20Watts says, coding alone, he designed blocks of 8 cores running as separate threads, and that going from half a million to a million taps made an enormous change. Hifistatement 1:22
• 2017-10-20Watts says longer taps improved bass definition, timbre and pitch as usual, but the million-tap M Scaler also opened up depth and soundstage beyond DAVE's. Hifistatement 2:03
• 2017-10-20Watts says the USB video mode, two-thirds of a million taps on the same architecture, collapses the soundstage, though architecture and small-signal work carried over from DAVE also matter. Hifistatement 2:57
• 2017-10-20Watts hopes the Davina project will explain why extra taps change depth, calling the soundstage opening with the Blu an unexpected shock revealing a hole in his knowledge. Hifistatement 5:17
• 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
• 2017-10-20Watts concludes that the million-tap filter is by far the most advanced filter technology, others use a few hundred taps, and it gives 16-bit CD accuracy for the first time. Hifistatement 0
• 2017-10-20Watts says sinc ripples drop below 16-bit level near a million taps; doubling adds 1 bit. DAVE is about 13 bits, Blu beyond 16, NOS 1, MQA 3 or 4. Hifistatement 24
• 2017-10-20Watts rates a typical high-performance DAC at 6 or 7 bits accurate, Hugo 12, DAVE 13.5, Blu beyond 16, and says ringing is irrelevant because it comes from non-bandlimited impulses. Hifistatement 1:12
• 2017-10-22Watts says CPUs struggle even with DSD512 DoP, 'input related' tap figures are meaningless pseudo numbers, cascaded FIR stages differ from one flat stage, and only real taps count. Head-Fi, Oct 2017
• 2017-10-28Watts says going from Hugo's 26k to DAVE's 164k taps changed little until WTA algorithm tweaks did; for a given algorithm, doubling taps doubles accuracy against the ideal. Head-Fi, Oct 2017
• 2017-11-15Watts says the M scaler's WTA coefficients match an ideal sinc to 16 bits, needing about 1 million taps and the right algorithm, which PC up-samplers lack. Head-Fi, Nov 2017
• 2017-11-29Watts says USB cables sound identical or, if audiophile, add RF, brightness and noise floor modulation; USB ferrites did nothing, but 2.5 GHz ferrites sounded marginally better on Blu Dave. Head-Fi, Nov 2017
• 2017-11-29Watts explains that 2 GHz ferrites improve depth by blocking signal-correlated ground bounce from FPGA logic transitions, while random RF causes noise floor modulation and brightness. Head-Fi, Nov 2017
• 2017-12-03Watts says his ferrite tests were on Blu 2 to DAVE, USB ferrites made no difference, and the warmer, smoother-sounding ferrite with better depth is the more transparent choice. Head-Fi, Dec 2017
• 2017-12-05Watts says skeptics bought Chord and upgraded Mojo to Hugo 2 to DAVE, every DAVE buyer buys a Blu 2, and this first show presentation aims to explain his technology. RMAF 55:28
• 2017-12-05Watts says John Franks opposed Blu 2, but Watts wanted a million taps, expected a small gain, spent six months, and got a tremendous change, which only listening reveals. RMAF 58:11
• 2017-12-09Watts names DAVE, over 2 and a half years of work, and the M scaler on Blu 2, having envisioned needing 1,000,000 taps in the 1980s, as his hardest designs. article, Dec 2017
• 2017-12-11Watts says hi-res files need the same tap length, since doubling the sample rate cuts timing error area fourfold (2 bits) while the M scaler gives about a 16-bit improvement. Head-Fi, Dec 2017
• 2017-12-16Watts says DAC64 split WTA and pulse array across FPGAs, and stresses the WTA algorithm, coefficient quantizing and internal truncation as more important than raw tap length. Head-Fi, Dec 2017
• 2017-12-24Watts says he plans long term: he foresaw a million-tap M scaler ten years ago, designed 1M-tap filters five years ago, and built in features like Dave's DX outputs. Head-Fi, Dec 2017
• 2017-12-31Watts reviews 2017: the M scaler (half-million taps Aug 2016, 1M Dec 2016, heard at CES 2017), Brilliant Classics and Oistrakh recordings, and his MrSpeakers Aeon closed. Head-Fi, Dec 2017
• 2018-01-11Watts describes balancing warmth and transparency: DAVE sounded too dark until the 256FS WTA filter, cheaper products degrade evenly from BluDave, and Mojo was set warmer for cheaper headphones. Head-Fi, Jan 2018
• 2018-01-12Watts says BluDave, his untuned reference, came from minimizing aberrations; going from 0.5M to 1M taps is audible, and Davina will show how far BluDave is from perfect. Head-Fi, Jan 2018
• 2018-01-14Watts says coefficient memory is the limit, so a mono mode would not double the taps, and Davina will establish how close the M scaler is to perfection subjectively. Head-Fi, Jan 2018
• 2018-01-16Watts says the ear/brain keeps proving more sensitive than expected; the M scaler gives better than 16-bit accuracy at 16FS, and Davina will show whether that is enough. Head-Fi, Jan 2018
• 2018-01-16Watts expects no further significant gains from the finely tuned WTA and M scaler, asking whether 20-bit (16,000,000 taps) or 24-bit (256,000,000 taps) accuracy is needed; 16M is extremely expensive. Head-Fi, Jan 2018
• 2018-01-16Watts says the M scaler is not 100% accurate but guarantees reconstruction of the original bandwidth-limited analog signal to better than 16-bit accuracy, or 99.9985%. Head-Fi, Jan 2018
• 2018-01-16Watts says Dave would be about 99.988% accurate, yet connecting an M scaler to Dave is audible within 3 seconds, so these tiny errors are extremely important. Head-Fi, Jan 2018
• 2018-01-18Watts says the 49,152-tap WTA 1 matches an ideal sinc to 12 bits, its coefficients diverging below that level; with the M scaler divergence occurs beyond 16 bits. Head-Fi, Jan 2018
• 2018-01-22Watts describes a planned transient-error measurement, fearing 164,000 versus 1M taps may measure small, and recounts how cutting Dave's harmonics from -130dB to -150dB was unexpectedly audible. Head-Fi, Jan 2018
• 2018-02-07Watts says the M scaler treats the BNC input like any other; which input sounds best depends on source noise and system sensitivity, and he hears no difference between inputs. Head-Fi, Feb 2018
• 2018-02-08Watts says DAVE is unbeatable for transparency and depth over Hugo 2, but Blu 2 plus Hugo 2 wins on timbre, rhythm, bass and instrument power. Head-Fi, Feb 2018
• 2018-02-09Watts says in Blu 2 truncator tests TPDF dither sounded worst, losing depth, and Gaussian came halfway to noise shaping; he suspects software volume beats analog volume. Head-Fi, Feb 2018
• 2018-02-21Watts says Hugo 2 is about 99.76% of an ideal sinc while conventional filters bear no similarity, yet adding an M scaler to Hugo 2 is a huge change. Head-Fi, Feb 2018
• 2018-02-22Watts says Chord announced at the Blu 2 launch that other M scaler units would come, but says no more; Qutest uses a 4-layer PCB of Hugo 2's spec. Head-Fi, Feb 2018
• 2018-02-23Watts says after Dave's modest gain he chose 512,000 taps for the Blu upgrade as easy to place and route; it took about three months and sounded completely different. MajorHiFi 15:26
• 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
• 2018-02-23Watts calls the filter the most advanced filter technology, redefining CD, and says he listened alone, sometimes with his sons, first hearing 512,000 taps in August or September. MajorHiFi 21:37
• 2018-02-23Watts says he needed others to confirm what he heard; the million taps worked by Christmas Eve, launched at CES, where Jude was the second person to hear it. MajorHiFi 22:30
• 2018-02-24Watts says the poster's situation 1 technically forms a mains ground loop but he heard no change with the charger connected; Blu 2's isolated BNC outputs remove the problem. needs context Head-Fi, Feb 2018
• 2018-02-27Watts says the FPGA draws 10 or 12A at 1V, a 12W peak; the M scaler draws about 15W from mains, well isolated and RF filtered, as on Blu 2 and Dave. Head-Fi, Feb 2018
• 2018-03-06Watts says Hugo 2/Qutest use 67.5mS of data versus 1mS for conventional filters, minimum phase sounds soft, the M scaler uses 1.37 seconds, and more M scalers will follow. Head-Fi, Mar 2018
• 2018-03-08Watts gives sinc-equivalent accuracy as 12.2 bits for Hugo 2, 13.9 bits for Dave and 16.6 bits for the M scaler, below which WTA coefficients diverge from the ideal sinc. Head-Fi, Mar 2018
• 2018-03-13Watts says Dave's superior transparency comes from many factors beyond its noise shaper, which dominate given Hugo 2 and Qutest's noise shapers, and both benefit enormously from an M scaler. Head-Fi, Mar 2018
• 2018-03-13Watts says Blu 2 already has a video latency mode, hints at new DAC developments in years, and aims to remove digital and mains cable sensitivity; analog cables only partly. Head-Fi, Mar 2018
• 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
• 2018-03-17Watts says ideal reconstruction needs an infinite-tap sinc; DAVE's WTA matches ideal to 13.9 bits and the M scaler to 16.6 bits, an unexpectedly large audible step. Head-Fi, Mar 2018
• 2018-03-29Watts says nothing in DAVE exceeds 75 deg C and Blu 2's die reaches only 60 deg C, as the die mounts to the thick aluminum chassis. Head-Fi, Mar 2018
• 2018-04-04Watts says that in the 1980s sampling theory told him a 1,000,000-tap filter was needed to guarantee 16-bit performance, then inconceivable; today the M scaler has 1M taps. article, Apr 2018
• 2018-04-04Watts says DAC chips have few FIR taps, perfect reconstruction needs infinite taps, and a brain-matched filter needs 1,000,000, realized last year in WTA M scaler technology (1,015,808 taps). article, Apr 2018
• 2018-04-04Watts lists tap lengths: DAC64 (1999) 1,024, Hugo (2013) 26,000, DAVE (2015) 164,000, Blu MKII (2017) 1,015,808; each increase plus WTA algorithm improvements raised sound quality. article, Apr 2018
• 2018-04-04Watts expects desktop models to stay ahead; on taps alone, Hugo 2 and Qutest have 49,152 versus Blu MKII's 1,015,808, which he calls 'a 20 times capacity advantage.' article, Apr 2018
• 2018-04-04Watts repeats that a filter matched to the brain needs 1,000,000 taps, says Blu MKII achieved 1,015,808, and says the longer tap length substantially improves sound quality. article, Apr 2018
• 2018-04-04Watts weighs DAVE, the M scaler (1M taps, a lifetime dream) and Mojo (musicality he has heard from no non-Chord DAC), picks Mojo, and says Hugo most changed his listening. article, Apr 2018
• 2018-04-04Watts says all headphones improve further up the chain to Blu Dave, but each headphone's strengths and weaknesses become more exposed, so favorites may change. Head-Fi, Apr 2018
• 2018-04-04Watts says since Hugo bad recordings became enjoyable, concluding the brain copes with noise, harmonic distortion and frequency response but not digital's unnatural distortions. Head-Fi, Apr 2018
• 2018-04-08Watts says USB ferrites changed nothing for him; Hugo 2's 300 MHz chip ferrites made USB sound like optical on headphones, so try 300 MHz types. Head-Fi, Apr 2018
• 2018-04-14Watts says ADCs may not resolve cable differences; compression tests on poor tracks prove little, but MP3 or AAC 320 sound softer and warmer than redbook, obvious on BluDave. Head-Fi, Apr 2018
• 2018-05-07Watts says Hugo 2's DSD filter exceeds 200 dB at 88.2 kHz, used on Blu 2; he heard only brain break-in; the M scaler outputs 705.6 kHz PCM from DSD. Head-Fi, May 2018
• 2018-06-09Watts says doubling a WTA filter's tap length doubles reconstruction accuracy, but how much accuracy the ear needs is open; Davina will show how close the M scaler is. Head-Fi, Jun 2018
• 2018-06-17Watts says BluDave cannot voltage clip at +6dB but can current limit into 8 ohms (4.1V RMS, 2.1W), making +5dB the danger zone; quiet recordings may explain the poster's level. Head-Fi, Jun 2018
• 2018-07-17Watts agrees the goal is reducing ground currents, which that filter cannot touch as ground is unfiltered; only ferrites reduce Blu 2 and Dave RF common-mode ground currents. Head-Fi, Jul 2018
• 2018-07-18Watts says extra shielding will not help; ferrites, like BNC galvanic isolation, raise the RF coupling impedance between Blu 2 and Dave grounds, with the worst problem around 2GHz. Head-Fi, Jul 2018
• 2018-07-21Watts says the M Scaler's million-tap WTA core is identical to Blu's, lists isolated USB, BNC and optical inputs and dual BNC, BNC and optical outputs, adjustable rate and pass-through. c w 23:19
• 2018-07-21Watts says the M Scaler's code and performance are exactly the same as Blu 2's, and he has eliminated the need for ferrites. c w 30:23
• 2018-07-21Watts says improved isolation on the BNC output drivers removes the need for ferrites, which in listening tests made it sound slightly worse; the code is identical. c w 30:37
• 2018-07-21Watts says Dave owners have the Blu 2, or could use Davina, the AD converter, which will have an M scaler built in. c w 31:16
• 2018-07-22Watts says it is absolutely fine with Dave, its benefit over Blu2 being no need for ferrites on the BNC cables, which were only the top layer of icing. Head-Fi, Jul 2018
• 2018-07-26Watts reports no difference, says Blu 2 avoided problems he had with the Hugo M Scaler, and never needed USB isolation since the noise comes from the FPGA. needs context 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
• 2018-08-06Watts says he spent a lot of time fine-tuning the filter to get the best sound on the Blu, and once that project was sealed it should not be changed. Pursuit Perfect System 5:55
• 2018-08-13Watts says Blu Mk2 has the same DSD filter, and the Hugo M Scaler began as a copy of the Blu 2 project with only control code changed. Head-Fi, Aug 2018
• 2018-09-06Watts says Blu 2 uses USB VBUS only as an RF-filtered logic flag, so removing it just disables the USB input and cannot change sound quality. Head-Fi, Sep 2018
• 2018-10-01Watts says a DPLL removes optical input jitter, output uses a low-jitter analog PLL, the M scaler auto powers down, and Blu 2 standby affects only the CD mech. Head-Fi, Oct 2018
• 2018-11-02Watts says it matches Blu 2 with 3 dB headroom, pass-through is volume matched, the main change is musical and takes time, and the supplied SMPSU is fine. Head-Fi, Nov 2018
• 2018-12-13Watts explains 2 GHz ground-plane noise crossing the BNC isolation's 5pF; clip-on ferrites help Blu 2 but degrade the Hugo M Scaler, solid-core help slightly, cables beyond 2m don't. Head-Fi, Dec 2018
• 2019-12-04Watts describes a show where Blu 2 Dave outperformed a costlier vinyl setup in spaciousness, separation and engagement, and says he does not get vinyl. Head-Fi, Dec 2019
• 2019-12-18Watts says M scaler output is 11th-order noise-shaped to 24 bits at 768k for -301 dB accuracy, ranks Gaussian dither above TPDF, and advises keeping the source bit perfect. Head-Fi, Dec 2019
• 2020-05-27Watts says certified USB cables work at any length, he heard no difference among them, doubts audiophile cables, and found longer BNC cables better through reduced ground loop currents. Head-Fi, May 2020
• 2020-08-10Watts says 2 m BNC cables beat 1 m, solid-core 2 GHz ferrites help most, clip-on ferrites hurt with the M Scaler, and battery power breaks its ground loop. Head-Fi, Aug 2020
• 2026-10-02Watts says every module must reproduce a -301 dB signal within a thousandth of a dB or depth suffers; in 2017 he took Blu 2 from 0.5M to 1M taps. HiFi Buys 1:24:04

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