1990 to Current

1990 – Audio Research releases the SP-14 preamplifier. This hybrid design is similar to the SP9 Mk.II with one 6DJ8 dual-triode vacuum tube in the second gain stage of the phono section. The line section is all-FET, using a circuit similar to that in the SP15, the then-current top-of-the-line model. The SP-15 includes absolute phase, phono high-pass filter, and front-panel impedance selection for cartridges, which the SP-14 omits.

1990 - Michael Elliott and his company Counterpoint release their SA-5000 hybrid preamplifier which was sold until 1993. Counterpoint declared bankruptcy in 1997 (Stereophile writeup from July 1998: https://www.stereophile.com/news/10202/), and Mike’s follow-on company, Alta-Vista Audio which serviced, supported and upgraded many of the Counterpoint products is also long gone since his retirement and departure from the industry in 2012.

While it showed incredible innovation and thinking, it—like many of their other products—reportedly exhibited poor reliability. The SA-5000 is a complicated design with a myriad of low-wattage, low-voltage elements, being floated 360V and/or 240V above ground, on a rubberized-physically-floating chassis as well (in which at least the first production run reportedly featured too-short of physical cabling across the gap). It is fairly unique in the use of BUF-03 video buffers on a +/-24VDC power supply riding in the midst of high-voltage vacuum-tube circuitry with a rather ingenious floating bias supply for manual DC-offset correction.

Properly shipping an SA-5000 back to the factory for needed repairs appears to have required the user to scrupulously follow the directions regarding which length screw went where (in order to secure the mechanically-floating subchassis for transit). Deviating from these directions could enhance any existing damage.

Speculation has rested on dealers turning their backs on Counterpoint over the mid-1990s based on reliability concerns, as well as the cratering of the Far East audio market after the October 1997 Asian currency crisis, as being either principal, or contributory, drivers to Counterpoint’s ultimate failure. We can only imagine what a disappointing endeavor it must have been to have participated in, no matter the proximate cause(s).

The SA-5000 service manual appears to have notes showing that it was laid out in early 1989 directly into a production PCB from a near-clean sheet of paper. Minor tweaks were laid in based on the prototype, and it would appear to have been released to the market. It is pure speculation to assume this was related in any way to “infant mortality” failures. However, in general, we try to be aware of straying too close to designs that could be considered “too clever”. Just because you “can” do something does not mean that you “should” do something. Tradeoffs are part and parcel of the experienced designer’s repertoire and second-guessing is inevitable. To balance this out, we do hear occasionally from clients who have the follow-on SA 5.1 model and state that it has been running for years with no issues, but do comment on its tremendous power consumption. Consensus from this handful of clients converges on our MP-7 outperforming the SA-5000 and SA 5.1 in their MM modes, at much lower power consumption, heat generation and space.

We don’t know to what extent, if any, the SA-5000 and similar products from this manufacturer relied upon computerized modeling in the design phase. However, the line between complexity and reliability is one reason that we tend not to reply upon electronic SPICE modeling for our designs. We prefer intuition, Ohm’s law, breadboarding, real-world objective measurement, and testing, followed by iterative live auditioning.

While this is unrelated particularly to Counterpoint, the analysis and discussion of the SA-5000 reminds us that on surprisingly-too-frequent of occasions, a designer will think they’ve invented something absolutely, positively amazing, and have never seen anything like it before. Then they are chagrined to uncover some very-obscure minor reference to it in a circa-1959 schematic that clearly shows the same concept being applied, but, to the best of the designer’s knowledge, they’d had absolutely no previous exposure to it. We have been able to find other examples (going back decades) of this happening elsewhere, sometimes not seen or discussed until decades after "finding the prior art”, which is, depending on your perspective, rather modest comfort.

1991 - Digidesign offers Pro Tools, a 4-channel, 16 bit non-linear audio editor for $6000.

1991 - Orban introduces the Optimod 8200, their first digital FM broadcast audio processor. The Orban 8200 offers a mode emulating the 8100 two-band processor with phase rotation, or a Purist 8100 mode. It also offers a 5-band processing structure which will become standard in American broadcasting via future Orban models 8400, 8600, and 8700.

Utilizing 32kHz internal sampling on Motorola 56001 DSPs, the 8200 kicks off the processor war of the early to mid-1990s between Orban and their principal competitor Omnia who offer the Unity 2000 processor, which despite digital control, is actually an analog processor internally. Aphex Systems offers their 4-chassis Aphex Audiophile Air Chain combining the 320 Compellor, 700 Dominator, a stereo LF/HF Exciter and Stereo Generator. These will be later combined into the Aphex Model 2200 FM broadcast processor, a 2-RU high dedicated unit. It’s “Photocell-based HF limiter” will later be replaced with a faster-responding unit as an optional update.

Digitally-compressed STL (studio to transmitter links) will be introduced by Moseley, using APT-X Lossy encoding. A 1991 Stereophile article mentions this, although not by name, in an interview with Richard Cabot, Vice President of Oregon-based audio analysis test equipment maker Audio Precision. https://www.stereophile.com/interviews/850/index.html. Stereophile Technical Editor Robert Harley and Dr. Cabot talk about the Phillips TDA1541/SAA7220 Digital Filter combo, and how one of his clients is using the Philips chipset in a broadcast application and had figured out how to correct the typical 6dB or greater of low-level non-linearity by simply re-squaring-up the digital pulse waveforms going-into and coming-out-of the chips. Some stations will deploy these and keep them on-air for a few months, later pulling them off and returning to a traditional analog composite STL for more natural sound quality.

1991 - Hovland introduces the MusiCap, a polypropylene-and-aluminum-foil high-end capacitor which will go on to be utilized by more than 200 audio companies.

1992 - Vacuum Tube Valley (VTV) magazine is introduced which publishes through the year 2000.

1992 - Sound Practices magazine is introduced by Joe Roberts which will publish 16 issues and articles for an incomplete 17th issue slated for 2000.  Back issues are available in PDF format on CD via eBay.

1992 – J. C. Morrison publishes his DIY Siren Song RIAA phono preamp.

1992 - The Russian 6H30 tube is introduced by Balanced Audio Technologies

Soviet tube technology is becoming available in the secondary marketplace, which will be further enhanced by the development of on-line auction sites in a few years as availability and interest in the Internet spread worldwide.

1992 - Burr Brown releases the OPA604 series of op amps, including the dual OPA 2604. They will run on rails up to +/-24VDC. The datasheet contains multiple references to sound quality of J-FETs and a box labeled “distortion cancellation” which was patented. Sound quality impressions appear to be sharply divided into supporters and detractors, as with many other of the 1990’s Burr Brown op-amps.

1992 - The POOGE-4 series of articles is published in TAA The authors significantly improve the performance of the Phillips DAC-960 DAC converter, which is a standard Philips 4X Oversampling design executed with the selected Crown TDA-1541-S1 DAC chip and SAA7220 digital filter. 

1993 – Analog Devices develops their XFCB (Complementary Bipolar) 24V process which will create op-amps such as the AD8610.

1993 – Melos SHA-1 Headphone Amp and Line Amp employs 1 x 6DJ8 with an IRF-730 single-ended output stage. It gains traction at Stereophile where JA uses it as part of his reference system for a year or two. Years later, independent analysis (available online) reveals quite substantial technical flaws in the basic circuitry. Unstable power supply regulation with high noise and ripple, when corrected, elevate the performance. Like Counterpoint (above) Melos’ reported questionable-reliability and repeated failures may have contributed to the downfall of the company by the late-1990s. We have observed hand-drawn schematics and layouts of the SHA-1 series that appear to be factory-created; very ’back-of-the-envelope’ in style. It is unknown to us whether-or-not these were leaked or redrawn by a consumer, but their supposed official nature does give us pause, when CAD design was well established by the mid to late 1980s.

1993 – Rotel’s High End Series is introduced. The RHQ-10 Fully Discrete phono equalizer will be sold through 1997. It features an emitter-follower power supply, double regulated, but as no power supply feedback is used, the regulator output is of moderate impedance.  The signal path consists of two cross-coupled stages with combined passive/active EQ.

1994 – On the new, larger January Cover of Stereophile – “If One Is Right, the Other Must Be Wrong” – the Single Ended Triode phenomenon from Asia is examined. It is a harbinger of the commercial arrival of newly produced SETs - the phenomenon is no longer limited to old Western Electric theater amplifiers from the 1930s and 1940s and the Do-It-Yourself hobby.

Stereophile moves back from the small-format magazines to the larger 8 ½ x 11” format, returning to its old roots and old size which were introduced in 1962 by J. Gordon Holt and ran until the original downsizing to digest-format in 1968.

1994 – The Zen Amplifier is published by Nelson Pass in TAA 2/94.  Together with the matching Bride of Zen preamp in the next issue (3/94) show the continued interest in, and fine audible performance of, simple and unique solid-state (in this case, MOSFET) circuitry. They are offered for “non-commercial use only”.

1994 - Rotel introduces a stand-alone mid-price phono preamp, the RQ-970BX Phono Stage.  It is a hybrid discrete and IC op-amp based design, using an input low-noise differential BJT pair feeding an Analog Devices AD744 to an NE5534 per channel with multi-stage equalization.  It has an unusually long life in their product line, remaining in production through 2012.

1994 - Digidesign is acquired by Avid Technolgies of Burlington, MA. The Digidesign brand (Pro Tools being their flagship product) will eventually be phased out by 2010 in favor of branding as Avid.

1994 - Leonard Feldman passes away, and an industry-focused memorial is published in the JAES by then-still-editor of AUDIO magazine, Gene Pitts. The same year Ralph Hodges also passed away; Ralph had a long-time column in Popular Electronics called “The High End”. JGH also had a column in Popular Electronics in the early 1970s.

1995 - The original Lehmann Black Cube Phono Preamp is introduced, using a SSM2017 input op-amp and 1 x OPA2604 output op-amp, with passive RIAA in between.  It will be replaced in 2006 with a new unit at a similar price point, using 2 x THAT1510P input amplifiers and 2 x OPA134 output op-amps. A notably-similar DIY design will be published in an Italian website in 2002.

1995 – Gene Pitts forms The Audiophile Voice after editing AUDIO magazine for more than twenty years.  AUDIO will go through additional editors, ending with Corey Greenberg (formerly a reviewer for Stereophile in the early 1990s) and will end publication in February 2000 after continuous publication since 1947 (in a previous incarnation).

1995 – A famous Single-Ended Tube amplifier manufacturer located in North Carolina copies the Zen amp and Bride of Zen preamp from last year’s TAA articles and sells them as commercial products.  The manufacturer’s name, as well as town, bear striking resemblance to an upbeat song on Joni' Mitchell’s 1971 Blue LP. This action is called out by Nelson Pass and the models are promptly discontinued.

1995 - Creek introduces the OBH-8 and OBH-9 phono preamplifiers. Music Hall requested the design of a small add-on RIAA stages (from Musical Fidelity) to support turntables, as built-in phono stages were declining, and separate mid-level phono stages were rare.

1995 - Rolls/Bellari of Salt Lake City, Utah introduces the dual microphone preamp model RP-220. It is based on the Dynaco PAS preamp circuit with a small microphone input transformer. It includes a +250V B rail to a unity-gain balanced op-amp output buffer based on a single Rohm BA-4560 op amp per channel, running on one single 12V power supply rail, which also supplied the tube filament directly from a noisy 7812 regulator. The same basic circuit is used in the smaller MP-105 and MP-110 single channel preamps.

They also introduce hybrid Moving Magnet Phono Preamps, beginning with the VP-529, later VP-530 and current VP-530 MkII. The VP-529s that we have examined have a rather non-flat frequency response, up 3 to 4dB in the bass and down 2 to 3dB in the treble (the specs were tighter). Switching in the optional VP-529 rumble filter (18dB/octave) caused a peak in bass response at 50Hz. The VP-529 schematic shows a textbook 1:3 RIAA network, but it is fed by a complex impedance from the tube plate which was not taken into account. Such iteration and trimming in the design stage would be necessary to achieve a relatively flat RIAA response.

1995 - Conrad Johnson Reference Series is introduced, using the unusual approach of zero feedback with 10 paralleled 6H30s to deliver a low output impedance from a conventional amplifier stage, while not using an output cathode follower.

1995 - The Woodside SC26 preamplifier is positively reviewed by Larry Greenhill in Stereophile. Woodside was a continuation of the British manufacturer Radford, whose principal Arthur Radford retired in 1986. Former staff formed the Woodside entity, but the STA-25 Mk III amplifier received a poor review from Dick Olsher in Vol. 10, No. 6 (1987). They went back to the drawing board with assistance from American Arnold Weisenberg who helped design the SC26. It used nine 12AX7s and one 12AT7, each tube being operating on a separate (solid-state-regulated) power supply. The RIAA gain stage was feedback-based with a return-to-zero capacitor between V1 and V2.

Double-regulation was employed, each of these secondary regulators being sourced from a primary 310V supply. Filaments were separately regulated. The SC-26 used SEPP-connected 12AX7s in gain blocks which were followed by 12AT7 cathode followers. Low noise Moving Coil operation was via Sowter input step-up transformers into the first 12AX7 phono gain stage.

The SC-26 was intended as a companion to the Woodwide MA-50 amplifier, which itself was a substantially reworked and modernized STA-25. The MA-50 was positively received by LG in a 1994 Stereophile.

1996 - Professional Audio Company dbx introduces hybrid mic preamps. Some reviewers find them to be rather bright and transistory-sounding.

1996 – Robert Harley leaves Stereophile and becomes editor of The Absolute Sound

1997 - TLE2072, the second generation of the TL072 series of op-amps. Texas Instruments ‘Excaliber’ series is based on a modern architecture that produces PNP transistors of high gain and high transition frequency.

1997 - Burr Brown releases the OPA134 series, to be used widely in Proceed and Mark Levinson gear as well as others. Some characterize it’s sound as “smooth” and “laid-back”.

1997 – Late October brings the height of the Asian Financial Crisis. Sonic Frontiers subsequently declares bankruptcy and is purchased by Paradigm Electronics (related to the speaker company) in Canada. 250 people and 4 plants are affected. The DIY branch reforms with a slightly different name.

1997 – Lynn Olsen provides excellent analysis of feedback-free and Single-Ended-Triode amps.

1998 - Ron Sutherland’s Acoustech PH-1 phono preamp, built at the request of Chad Kassam of Acoustic Sounds, was reviewed by Wes Phillips in the June 1998 Stereophile. Ron will eventually go on to found Sutherland Engineering to produce a broad line of similar phono preamplifiers.

1999 - Brian Damkroger of Stereophile comments on the state of the mid-price phono preamp market. He states that, in his view, the Audio Research PH3 ($1495), the Linn Linto ($1500), and the Acoustech PH-1 ($1200) are all ‘great choices’ in the $1000–$2000 price range.

1999 - Sonic Frontiers Phono One ($1999) hybrid design uses a single JFET per channel as an input, followed by a 6922-based triple-series amplifier as a second stage. The output stage uses another 6922 as a cathode follower to lower the unit's output impedance. The circuit is noninverting and uses frequency-dependent feedback for equalization, with a single compensation network being "fed from a fairly low impedance, thereby avoiding slew-limiting at high frequencies." 54dB of gain is standard, but 44dB and 62dB are also available as special orders from the factory. Stereophile provides a lukewarm reception.

2000 – In February, AUDIO magazine ceases publication after 51 years.

2000 - Hovland introduces the HP-100, a one-box, all-tube line stage ($4995) with optional built-in MM ($5995) or MC ($6495) phono stage.

2000 – Spectral releases their DMC-30 Reference Preamplifier. Upgraded modules are released through next few years, and the basic platform remained current two decades later.

2000 - Jim Fosgate of Fosgate Research (specializing in surround sound processors) publishes two of his reference preamp designs, one very similar to the Harmon Kardon Citation IV, and one of his own designs, in what would have been Sound Practices Issue 17 when it ceases physically publishing. (Issue 17 material is included in PDF reprints). Both use feedback around tube stages with the Citation IV using passive RIAA in the middle, or in two stages with active feedback.

His introductory quote is worth reading:

“Like most people, I went “Solid State” when it came along. I remember wondering why my collection of records didn’t sound as good as I thought they once did. I thought it was because my listening abilities had improved or my taste in music had somehow changed.

In the late Seventies, I invited a friend over to audition my system, a setup that I was quite proud of. This guy was a classical musician and tube listener. After listening for a while, his only comment was: “If you have a chance, you should listen to some tube equipment again.” This stuck in my mind and one day at a garage sale, I found a Dyna Stereo 70, PAS Preamp, and FM-3 Tuner for nine bucks, similar to the ones I had once owned. The amp needed a 5AR4, and a fuse, but the tuner and preamp were working, so I decided to give them a listen.

I was really surprised! This old stuff was blowing my solid state stuff away! My mind was boggled. My old records even sounded the way I remembered them. There was only one thing to do: sell all my solid state equipment, go back to tubes, and never look back again.”

2001 - Daniel Cheever publishes his Master’s Thesis which is a fascinating and in-depth analysis of solid state vs. tube audio amplifier technology, focusing especially on the relative proportion of high-order harmonic distortion and how it compares to the human ear’s own distortion and audibility profile. It examines in detail a Hafler DH-500 MOSFET amplifier, rated at over 200W/ch, with a single-ended Type 45 tube amp with only a few watts and concludes that the tube amplifier has a sonic signature that is more closely aligned with the ear’s masking profile.

2002 - A passive EQ FET preamp design with BF245s and 24VDC supply is published on a hobbyist Spanish internet site. It has low headroom and significant design constraints including high measured distortion but does not require any component matching.

2002 - An inverting FET/BJT Line Amp design is published on TNT Audio. It uses a 40V rail.

2003 - Joseph Norwood Still Passive EQ RIAA FET preamp is published in Audio eXpress’s April 2003 issue. It is later modified in private correspondence (2006).

2005 – Price inflation in high-end audio appears to take hold. 

See comments at: https://cdn.stereophile.com/content/superphon-revelation-preamplifier (April 2019)

2006 - A new Version of the Lehmann Little Black Cube is introduced, at a similar price point. This version uses 2 x THAT1510P input amplifiers and 2 x OPA134 output op-amps. The original input amplifiers (SSM2017s) were discontinued by the manufacturer, and the expensive OPA2604 will eventually be discontinued as well. The new model adds additional custom cartridge loading options.

2008 – Audio Research is sold to a private equity firm.

2009 – Jim Thiel passes away; Thiel Loudspeakers is sold in 2012 by Kathy Gornick to a group of non-audio investors, goes through a series of CEOs and designers, moves from KY to OH in 2014, and is bankrupt in March 2018.  Longtime employee and engineer Rob Gillum https://www.coherentsourceservice.com/ provides quality service to the Jim-Thiel-era models.

2009 - Hovland Corporation closes its doors in early 2009. Originally known for custom tonearm, interconnect, and speaker cables, dating back to 1979 , and then introducing the Hovland MusiCap capacitor in 1991, they had more recently introduced a small line of striking-looking electronics, beginning with the HP-100 tube preamp in 2000. One of their employees was Robert Morin, who will later go on to found Lounge Audio in 2011.

2009 – In February, The Absolute Sound Interviews Spectral's Richard Fryer and Keith Johnson.

2010 – Jan Didden starts Linear Audio magazine which continues through 2015.

2010 – SimAudio MOON 110LP introduced and sold through 2018.  It is an op-Amp based design augmented with 4 discrete transistors, and utilized an 18V external DC supply.  It is replaced in 2018 by the 110LPv2 which uses a 24V external DC supply.

2011 - Edward T. Dell sells Audio Xpress to Elektor Publishing and reluctantly agrees to retire.

2011 - Lounge Audio introduces the LCR phono preamp for $200. Housed in a striking wooden box with brass nameplates front and rear, and gold hardware, it is positively reviewed by Tone Audio.

2011 - Ron Sutherland’s Sutherland 2020 Phono Preamplifier is reviewed in Stereophile. It features two +48V switching wall warts and substantial passive R/C filtering. The gain circuitry relies on conventional op amps which are preceded by a mic preamp chip.

It uses a Texas Instruments INA163, followed by a Burr-Brown OPA134 FET-input op-amp, and a Burr-Brown OPA627 op-amp as a DC servo. This is conceptually similar to the Lehmann designs.

Frequency response rises sharply above 20kHz in an attempt to conform to what hobbyists call the Neumann “5th RIAA Time Constant” at 50K. Allen Wright, since deceased, claimed in 1995 that it was present in Neumann cutting lathes and “was designed to prevent the cutterhead from burning itself out”.

Neumann cutting lathes feature a second-order Bessel high frequency filter set far above 50kHz which primarily tackles Radio Frequency Interference (which in Europe’s Long Wave service begins at 150kHz). The filter is designed to have minimal impact to the RIAA curve. In any case, a second-order filter could not be accurately replicated by a single order “F5" pole”, even if it is placed low in frequency close to the audio band.

A design of this type may be prone to high frequency transient overload and slew-rate limiting from LP ticks and pops. It also provides significant phase lead from 5kHz to 50kHz which some listeners may find sounds pleasantly “zippy” on certain program material, but others may perceive as over bright.

2011 – Coincident Statement Phono Preamp. A high gain, all tube unit employing MC step up transformers. 2 tube gain stages are used per channel. RIAA curve is implemented passively with zero feedback. The price is US $6499.

2012 – ‘Sam Tellig’ discontinues writing for Stereophile in late 2012 after becoming irate over late payments made to writers. Editor John Atkinson attributed these issues to the change in accounting system at the new corporate parent. John remained typically gracious in on-line exchanges with ‘Sam’ as they parted ways.

Many former Stereophile reviewers are still active and sought after in other publications, including Robert Harley, longtime editor of The Absolute Sound (since the mid 1990s); Dick Olsher of EnjoyTheMusic.com, George Graves and Anthony Cordesman with The Audiophile Voice (published by former longtime AUDIO editor Eugene Pitts), and others. JGH passed away in 2009 after parting ways with Stereophile in 1997. Larry Greenhill appears to be one of the longest term Stereophile reviewers, with more than 30 years of reviews in print. HIs audio reviews were first published nearly forty years ago in Ed Dell’s Audio Amateur (which later became Audio eXpress).

2012 – U-Turn Pluto Preamp is released to support the new U-Turn Audio turntables, produced in Lexington, MA. It is a single NE5532 design, operating on a single regulated voltage rail of 11V, and appears based on a 1983 design note. At least 7500 units appear to have been shipped.

2013 - Edward T. Dell, longtime publisher of The Audio Amateur, Audio eXpress, Glass Audio, Voice Coil, and Speaker Builder, passed away at the age of 90 in Peterborough, NH. He sold the aX magazine empire in 2011. ETD first published a DIY article in JGH’s Stereophile in 1966, a substantial rebuild of a Dynaco amplifier. Stereophile reader feedback was vicious and DIY wasn’t well accepted by the readers. ETD would start TAA in 1970 which became one of the premier magazines for advancing the state of the audio art, especially from the mid 1970s through the mid 1990s. It has now (as of this writing) been refocused on Pro Audio and Consumer Audio Integration and is doing well. Darlington Labs owns a nearly complete set of TAA from 1970 to current date, as well as Stereophile 1966 to present as part of our extensive reference library.

2013 - Shannon Parks of Parks Audio in Washington state releases his tube-type MM-style phono preamp, the Budgie. It is a 6DJ8-based design running on 75VDC power rails sourced from an internal switching power supply. Active feedback EQ was utilized around both tubes. Metalized film capacitors bypass the power supply rails and couple the signal between stages and to the output. Due to the lack of output buffering or an output cathode follower, output impedance was specified at 6 kilohms.

We measured ripple at 2.4mV AC on the main power supply rails in a 2015-production sample, similar to the range of a typical cartridge input signal. It is a testament to the active current loading at the tube plates, employed via TO-92 transistors which are biased with large red LEDs, that some of this noise is rejected. The tubes receive operating bias from an unbypassed small-signal silicon diode in the cathode circuit. Note that this fixed bias arrangement results in unusual sensitivity to tube changes or “rolling”, with the bias point varying between 32V and 46V on a random sample of 6DJ8s we had close at hand. Measured gain is 38dB at 1kHz with quite accurate RIAA equalization. External power is provided by a 12VDC switching power supply.

Midway through the production run, in an attempt to reduce interference from RFI (due likely to the unshielded and RFI-prone frame-grid high frequency vacuum tubes operating completely outside of the die-cast aluminum chassis) a 15pF ceramic capacitor was placed from the grid to the plate of each input stage of the 6DJ8. This resulted in a marked increase in effective input capacitance to more than 400pF. Audible upper-midrange-peaking and subsequent dulling of the frequency response with most traditional highly-inductive moving-magnet phono cartridges would be the expected result, and was reported by users, some of whom enjoyed this type of sound.

Note that such frequency response disturbance would not be found in most bench testing because the signal generator presents a low impedance to the tube grid. This is unlike the phono cartridge - some of which are 40 kilohms or more in the top octave due to resonant-tank-circuit effects.

This model was discontinued by the manufacturer in May 2018, who moved exclusively over to an NJM2114 op-amp-based input stage, opeating flat - with no EQ - directly into an active A/D, DSP, and active D/A output, using the same Hammond die-cast enclosure. Readers can find an analysis of the headroom challenges of this topology (“RIAA entirely via DSP EQ”) and other measured performance of the unit in a review on the ASR (Audio Science Review) website.

2015 – Dick Olsher reviews the Jadis entry level phono stage in The Absolute Sound.  http://www.theabsolutesound.com/articles/jadis-dpmc-phono-preamplifier/ $6900. It has a tube regulated B+ rail using a tube-based series pass regulator consisting of an EL84 beam power tube and an EF86 pentode, and 4 x 12AX7 tubes in a feedback configuration. He concludes that “as the DPMC amply demonstrates, there is plenty of magic left in the classical approach, especially when coupled with a modern, well-regulated power supply.”

2015 – Doug Sax of The Mastering Lab passes away. Chad Kassem is reported to have purchased most of the gear (primarily tube-type, designed by Doug’s brother Sherwood) and moved it to his Kansas headquarters of Acoustic Sounds.

2015 - Blaupunkt GmbH, the car audio manufacturer, files for liquidation and bankrupcy. Owned by Robert Bosch GmnH from from 1933 until March 2009, it was sold to Aurelius AG.

2016 – McIntosh introduces two new stand-alone modern phono preamplifiers, for the first time ever (since their short-lived moving coil step-up sold from 1983 to 1987)

The MP-100 sells for $2,000. The MP-1100 sells for $8,000 with 2 x 12AX7 per channel for total of 4 x 12AX7.

2016 - Schiit Audio releases their Mani phono preamp. The unit undergoes 3 revisions, internally denoted as 1.0, 1.1., and 1.2, one of them appearing to attempt to fix a larger-than-expected susceptibility to RFI (radio frequency interference) and another addressing an “end of life” issue for one of the critical op-amps.

2017 – Mark Levinson’s No. 526 is reviewed by Larry Greenhill of Stereophile. The current Mark Levinson line uses a combination of Folded Cascode circuit topology—built with junction field-effect transistors (JFETs) and bipolar junction transistors (BJTs)—with a fully balanced, dual-mono, and ultimately direct-coupled signal path, which is “intended to achieve high gain, low noise, wide bandwidth, and excellent linearity”. This model is compatible with moving magnet and moving coil cartridges.

2017 – PS Audio BHK Signature in the May Issue of Stereophile.  https://www.stereophile.com/content/ps-audio-bhk-signature-preamplifier.  The PS Audio ($5999) is 37% cheaper than the Pass—but I've found that the BHK Signature performs above its price class. That made for a good comparison.

Compared to Pass XP-22 $8600 and the PS audio outperformed it.  Pass also offers a $38,000 preamp.  Unknown result to compare that model against BHK.

Read more at https://www.stereophile.com/content/pass-laboratories-xp-22-line-preamplifier-page-2#04xhCTzsxzLSFq8j.99

The BHK Signature preamplifier ($5999 in black or silver) marks a surprising turn for PS Audio: It has tubes. That's surprising because CEO Paul McGowan has long been anti-tube. "It's not that I do not like the sound of tubes, I always have," he recently wrote on the company's website. "I just never felt their frailties were worth their sonic virtues, and I was convinced we could do as well without them."

He recently changed his mind, thanks to amplifier guru Bascom H. King—the BHK in the name of the company's BHK Signature line—who was recently lured from semi-retirement to create two new power amplifiers and this preamp.

Why the change of heart? The story, as told in videos on the PS Audio website, is that McGowan asked King to design a preamp, and King accepted, on one condition: tubes. There's just something magical about a tube, King says—something intangible. McGowan listened, agreed, signed off, and the BHK Signature preamp was born.

Read more at https://www.stereophile.com/content/ps-audio-bhk-signature-preamplifier#gw5Fx1xwFTMAp16y.99

Bascom King was a long-time reviewer and columnist for AUDIO magazine in addition to his other pursuits.

2018 – In March, Thiel Loudspeakers declares bankruptcy. According to reporting by https://www.strata-gee.com/ $10 to $12 million had been sunk into the company, and it had suffered through 5 separate CEOs since the new owners purchased it in 2012 (after Jim’s death in 2009). Kathy Gornick, Jim’s longtime business partner, had exited rapidly after getting to know said new owners. The Kentucky factory was sold along with much of the tooling and parts in 2014 and most staff was let go. Existing stock was sold down through 2016.

We had the misfortune of encountering a chief marketing representative of the “new” Thiel April 2017 in their AXPONA exhibit room. We overheard him actively belittling the entire Jim Thiel philosophy of phase linearity and the “Coherent Source” topology to a potential client. More than one other audience member was visibly uncomfortable. Meanwhile, egregiously overpriced, blandly-finished, textbook “designed-in-Canada with high-crossover-slope” speakers were on static display. Thiel was curiously absent at AXPONA April 2018, and we discovered that they had declared bankruptcy the month before.

A major magazine had auditioned the smallest pair of the new line and tried very hard to give it a good review, based on 35 years of goodwill towards Jim and his staff. Memories of Julian Hirsch (longtime reviewer for Stereo Review) flashed in our mind: “of all the speakers I have reviewed, this is certainly one of them.”

The “new Thiel line” was refusing to hit their reserve price of less than 10% of retail on eBay a few months later. Perhaps thankfully, its chief designer had already left the now-failing company.

Longtime Thiel employee and engineer Rob Gillum https://www.coherentsourceservice.com/ services the Jim Thiel era units (we can personally recommend him) and classic-era Thiel’s not only remain the cornerstone of some extraordinarily fine systems, they are true “sleepers” in the used market. Models to particularly look out for include the CS 2.2 and CS 3.6, both of which have amazingly linear impedance curves and mate well with vacuum tube amplifiers. Those models contain tweeters which are custom versions of Vifa metal domes with an extra low primary resonance, and a 4 ohms coil winding. They have, unfortunately, proven to be prone to delamination after many decades. Rob can rebuild the driver with new butterfly assemblies, and this would appear to be a solid investment.

2018 – John Atkinson retires from editing Stereophile at age 71, and Jim Austin assumes the duties, younger by about 15 years.

2018 – David Wilson of Wilson Audio passes away; his son continues the business.

2018 – Conrad Johnson is sold by Lew Conrad and Bill Johnson to the head of their marketing department.

2018 - In May, Parks Audio releases their Puffin, a DSP-based phono preamp utilizing NJM2122 op-amp preamp stages with flat gain structure, and all EQ in DSP courtesy of a TI PCM1808 A/D and TI PCM5102A D/A stage. It features a 20mV input overload at 1 kHz (40dB gain setting as measured by Audio Science Review) which is exceeded by many Moving Magnet cartridges playing heavily modulated records, or during transients caused by ticks and pops. By comparison, the overload of Darlington Labs products at 40dB gain is typically 140mV, or 17dB higher than the Puffin.

DSP functions such as those built into this unit may lessen the audibility of gross-input-overload on surface noise, although probably not wholesale clipping on program material. Decreasing the input gain (instead) will further compromise the signal-to-noise ratio of the input A/D and output D/A converter as well as produce lower-than-desired overall listening levels in many systems. This nearly-insurmountable bottleneck is perhaps why this “all-EQ-in-DSP” approach, as advocated by a few commentators, is relatively rare in the marketplace.

Certain reviewers and some owners have found this Parks unit to be a fun device with many flexible EQ settings and a treasure trove of adjustability, particularly for collectors of very old pre-RIAA LPs or records which are heavily damaged or otherwise deploy this unit as “second” to a primary phono preamp, or at line level for its DSP. Reviews in advertising-supported publications seem to emphasize the “fun” aspect.

It has been reported that Puffins with serial numbers 1020 to 1122 have ESD diodes on the input for extra protection. These are not 1N914 or 1N4148 diodes as typically seen when protection is needed, as they lead to an input capacitance of 300 pF instead of the specified 50 pF (which denotes a power rectifier type). This could certainly explain some of the variable reactions to the unit. Interesting to note that late Parks Budgies (the tube unit) had approximately 400pF input capacitance due to an RFI capacitor that was added long after production had started.

2019 – Jack Renner, co-founder of Cleveland-based Telarc Records, passed away at the age of 84 in June. His label pioneered the wide commercial use of the 50.4kHz, 16-bit Soundstream digital recorder in 1978. He was known for his widely-spaced orchestral recordings using primarily Schoeps omnidirectional mics to produce a big and powerful (and detractors might say vaguely imaged) sound quality.

2020 - In October, Darlington Labs opens to the public and introduces the all-discrete high-voltage J-FET MM-6, MM-5 and MM-3 phono preamplifiers, using their unique intellectual property which was more than four years in active development.

2020 - Six Acoustics, a new Canadian audio manufacturer based in Toronto, Ontario, Canada, debuts their York Acoustics phono preamplifier for ~USD $400. US-based manufacturer Hagerman Technologies alleges that the York Acoustics unit directly copies the Hagerman Bugle (op-amp-based) phono preamplifier, with extremely minor changes, which is available from HagTech for about half the price in a different enclosure.

Jim Hagerman, in a Stereophile forum, stated that the Canadian unit is a “near clone” with “goop on top of the PCB” to disguise the origins. The York phono preamp appears to have started life as a failed Kickstarter campaign.

Six Acoustics claims +/-0.01dB RIAA tolerance but the “original designer” says that this is impossible in normal production, +/-0.1dB being optimistic using 1% tolerance resistors, and +/-0.4dB being typical using 5% tolerance components. Six Acoustics website advertises that “What we value here is honesty and integrity in engineering and performance“.

2021 - McIntosh introduces a newly-reimagined version of their MI-3500 350 watt/channel tube amplifier which originally sold between 1969 through 1971, and was featured as part of the Woodstock August 1969 PA system as well as the 1973/4 Grateful Dead “Wall of Sound”.

2021 - In May, Darlington Labs introduces the MP-7 phono preamplifier.

2022 - Schiit Audio released a new version of their Mani phono preamp in late February. Pricing increased from $129 to $149, and the WIMA polyester capacitors have made way for surface-mount units. It is referred to as the Mani 2 on the underside, although the prior version went through three “internal” revisions (noted as 1.0, 1.1 and 1.2) in attempts to deal with RF susceptibility and end-of-life for one of the originally-specified (12V-max-supply) op-amps.

Gain ranges have been increased by approximately 5dB. It is also reportedly significantly quieter. The power supply rails have been raised from +/-5V to +/-16V, which will improve input overload specifications, a particular limitation of the earlier unit. This completely revised design remains all-op-amp-based, as expected at this price point (for non-Darlington Labs units) and uses a single set of bipolar IC voltage regulators.

2022 - In March, Darlington Labs introduces their line of Moving-Coil Active Step-Ups, beginning with the SU-7, and quickly followed by the SU-6 and SU-5. In April, Darlington attends its first trade show as a corporate entity at AXPONA in Schaumburg, IL (a suburb west of Chicago), exhibiting at a booth in the Expo Hall. Staff attended the 2017 (old location near the airport) and 2018 (current location), skipping 2019 in favor of planning for the company rollout; the trade show was postponed multiple times and canceled during calendar year 2020 and 2021 due to local and global restrictions on travel.

2022 - In December, Parasound owner and founder Richard Schram sells the company to David Sheriff who has a 30-year career in running manufacturing and distribution companies as well as being a systems consultant, but who appears to be new to the mid and high-end audio space. Designer Darren Meyers leaves PS Audio and goes to work for Parasound, potentially assisting John Curl with primary design responsibilities.

2022 - In December, James M. Fosgate passes away at the age of 85. Jim Fosgate invented the aftermarket car stereo power amplifier in 1973 with Rockford-Fosgate, and after his departure from R/F in 1981, remained active in audio, and particularly in surround-sound decoding technology, leading the team that developed Dolby Pro-Logic II.

2023 - MQA declares bankrupcy in April - https://www.creditman.co.uk/company-notices/company/09123512

https://www.whathifi.com/features/mqa-has-gone-into-administration-what-does-this-mean-for-tidal-and-supported-products

Interestingly, a former design consultant for Darlington Labs was insistent in 2016 that we must absolutely, positively get on the MQA bandwagon. We looked at licensing costs and acquired proprietary information to be considered as a manufacturer. In the end, we parted ways with this consultant in early 2020 as we launched the company. We consider the bankruptcy of the MQA IP shell a welcome sight, as we found that it was not at all transparent to the high resolution source.

Our former consultant’s ideas of what was necessary in the marketplace ended up being diametrically opposed to what the majority of our other interested partners believed. In the end, for us, the marketplace has spoken.

We note, with some amusement, that the proprietor of the ASR website, who owns a turntable that was given to him (which he has never installed) yet loves open-reel tape on an Otari 5050-B-II, was a huge proponent of the MQA technology in 2017, declaring it “the only proper thing going”. This ASR owner, in his prior capacity as a senior Microsoft director, enabled that company to pay a huge sum of money to Pacific Microsonics for their HDCD algorithm in 2000. Microsoft then promptly deep-sixed the technology and dropped Windows playback support for the format in short order.

Tidal, who had made their name on ‘high resolution’ MQA Audio, indicated that on July 24, 2024, they were replacing all of the music in TIDAL’s MQA catalog with FLAC versions.

2023 - In August, Avid Technolgies is taken private in a USD $1.4B deal. The Burlington, MA company known for it Media Composer broadcast production editor and Pro Tools audio software will now be owned by STG Capital, a private equity firm based in California.

2023 - PS Audio debuts a new version of their high-end speaker at the AXPONA audio show in April, near Chicago, IL. It receives quite the industry comment.

2023 - In September, Parks Audio decommissions the Puffin in favor of the Waxwing, which has similar architecture inside but moved to a wireless-app-based controller.

2023 - Mastering engineer Bob Ludwig stops taking orders for new work on June 30, 2023, and will wind down his existing projects through the end of the year. Formerly of A&R, Sterling Sound, and Masterdisk NYC, he founded Gateway Mastering Studios in Portland, ME in 1992, which he operated for 30 years.

One of his most famous early cuttings by Ludwig was the Led Zepplin II album in 1969, which the band desired to be “the loudest record in the world.” His new Neumann SX-68 cutting head, the first to be helium-cooled, helped him meet the band’s wishes.

Bob is in the rarified league of mastering engineers that include Bernie Grundman; Ted Jensen, and Greg Calbi of Sterling Sound; the late Doug Sax of The Mastering Lab; the late George Piros of Fine Sound, Fine Recording, and Atlantic Records; the late George Marino of Record Plant and Sterling Sound; and numerous others.

2023 - Audio Research, the original company founded in the greater Minneapolis area by William Z. Johnson in 1970, is dissolved and refounded as a new entity, similar in concept to the GM bankrupcy and creation of the “New GM” in 2009. https://trackingangle.com/features/valerio-cora-of-acora-acoustics-corporation-to-lead-new-corporation-for-audio-research-brand. https://www.ecoustics.com/news/audio-research-acquired-2023/. TAA editor ETD conducted an extensive interview including photos with WZJ in a 1975 TAA issue.

2024 - On January 15, Darlington Labs introduces a refreshed MP and MM lineup on their website, including the new top-of-the-line MP8B, fully loaded, for $999, a revised MP7B, and MM6B, featuring higher rail voltages, enhanced power supply technology, and more. The MM5 also updated but moved to eBay only as an MM5A, derived from the MM6B but with no user adjustments. It is intended to meet the company’s committment to new or entry-level audiophiles with a USD $199 offering.

2024 - Anthony ‘Tony’ Cordesman passed away on January 29th, at age 84. Longtime AUDIO magazine reviewer, Stereophile reviewer from the mid-1980s to 1992, with TAV (The Audiophile Voice, fromer AUDIO editor (1973-1995) Gene Pitts’s follow-on magazine founded in 1995, and with The Absolute sound from 1992 through 2023. He was better known to the non-audio community as a distinguished military and political analyst first receiving widespread video coverage in the 1991 Gulf War.

2024 - On May 23rd, the Boston-area electronics retailer You-Do-It Electronics, in business for 75 years, announced its intention to close its doors and sell through their remaining inventory. In business since 1949 (as a radio and TV repair shop in Boston’s South End, and, since 1965, at the current location). A staple of the independent small parts and accessories-focused electronics, it outlasted Radio Shack and decades of internet competition, and its original founder passed away in 2022, with generations of family still working actively in the business.

In the past few years, they had reintroduced a very wide selection of NOS and used vacuum tubes for sale along with classic audio and test gear. Presumably the property value of their land parcel, well-situated off I-95 in Needham and right underneath what used to be called the FM-128 radio and TV antenna towers, contributed to the decision.

In 1965, when that location was selected, Route 128 (co-signed with I-95 for a significant portion from near Braintree to the North Shore split) was only a two-lane-per-side regional highway. This was well before the ‘Massachusetts Miracle’ of the late 1970s and 1980s resting on a foundation of electronics and computers in that area.

2024 - In mid-June, the music streaming service Tidal advised that next month (on July 24), they would be replacing the music all of the MQA-encoded music in their catalog with FLAC versions.

2024 - In mid-June, Rondi D’Agostino, president of Krell, passed away unexpectedly. She had recently hired a new CEO (although this had not yet been announced) as she was taking care of her ailing husband (both Dan and Rondi had remarried) and needed time away from the role. In September 2009, Dan and his family were removed from the original Krell in a shake-up by the Private Equity investors. A few years later, one of Krell’s automotive partners bought out the PE folks and reinstalled Rondi as CEO, as she was originally a co-founder of the company in 1980. Dan started his own company, Dan D’Agostino Audio Designs with its steampunk-looking architectural flavor.

2024 - Revox reintroduces the third revision of their B77 open-reel deck, the B77 MkIII.