By Michael Miguest
​www.bluenote.com/artist/wayne-shorter

   By Kevin Barrett

  Abstract: Cogging torque is produced in the pre-2016 Technics turntable direct drive motors simply
because of the magnetic attraction between the rotor mounted permanent ring magnet and the steel stator.
However, the cogging torque is small at under 3 grams, competing with the frictional
drag of the bearings themselves. Cogging torque mostly reveals itself as a rumble component at 26.64Hz
at 33.33RPM. This is outside the normally weighted roll-off of the rumble measurement (100hz), and is
56dB below a standard test signal and therefore is not audible.
This paper serves to describe how the motors work and how the measurements compare between direct
drive and belt drive turntables of the day.

Technics Direct Drive Motor (1973-2010)
All the motors used in the technics 1200 series are 3 phase variable power factor Brushless DC motors.
That is, the speed is analogous to the applied power. And the power is controlled by applying a DC
Control Voltage to the motor drive circuits.
At the low operating speeds of these motors, the power factor is actually very low. And while these
motors are capable of fast start up times, at operating speed the running torque is quite low.
I think the fast start up feature is what led many to call these high torque motors. But as we will learn
later in this article, in order to optimize such a motor for turntable use, torque is a necessary sacrifice for
smooth rotation at low speed.

To control the speed of these early designs (1973-1978), an integrated(bifilar) motor coil winding was
used to develop a feedback voltage that could be used to control the speed of the motor.
This signal voltage is filtered by a simple resistor/capacitor network which converts it into a DC voltage
with a time constant of approximately 1 second.
This speed signal voltage would then be compared to a reference voltage and the resultant DC Control
Voltage would be used to hold the motor speed at the desired operating RPM. These early motors had
very good wow and flutter measurements (0.03%) but because the DC Control Voltage was developed
across simple resistors, the speed was known to drift over time and need constant re-adjustment.
Furthermore, the response time was also slow (>1 sec) needing 1/2 revolution or so to make a speed
 correction. ( A good description of this motor operation and circuitry can be found in the SL-1100 service
manual available at www.vinylengine.com)

Quartz Phase Locked Direct Drive Motor
Technics direct drive motors made after 1979 use a different kind of frequency generator to provide
feedback for platter speed control.
This generator is comprised of a flexible printed circuit coil that is placed directly around the motor
magnet making the signal it produces a true representation of platter position.
In this way, as the motor rotates, the magnetic field cuts through the coil and generates a 50.55hz signal
when the platter is moving at 33.33 rpm. This is compared against a quartz crystal reference. The crystal
frequency(4.19328Mhz) is passed through 4 dividers 1/16, 1/8, 1/54 and 1/12 to arrive at a matching
 50.55hz reference. When the platter is rotating, these two signal waveforms are maintained in perfect
alignment or phase by using a circuit called a phase lock loop (PLL). If the two signals are in phase we
know that the platter speed and position is precisely locked to the quartz crystal timing. You can think of the frequency generator and the crystal oscillator as gears that are in perfect mesh with each other
when the PLL is in a locked condition.
The PLL produces two square wave signals, a speed signal (Vo) with a fixed frequency, and a phase signal
(Po) which reflects changes in platter relative position. The two signals are combined in a circuit called an Integrator. This converts the square waves into a saw tooth wave which is then filtered again by a
simple resistor/capacitor network with a time constant of approximately 300ms. This DC voltage is
compared to a reference voltage and the resultant DC Control Voltage is use to control the power of the
motor.

To summarize, both older and newer motor designs use a DC control voltage to control the platter
speed. They just use different means to achieve the same end.
Both control systems achieve equilibrium at the set speed. And while the older method has issues with
long term drift and dynamic load response, the later method does not.
The response time to a change in platter load friction is approximately 1000 milliseconds(1/2 revolution)
in the older models and 300 milliseconds(1/6 revolution) in the later version.
The response time governs just how well the platter speed can maintain equilibrium for a change in load
as happens when the stylus encounters a loud modulation.
Ideally, you want the platter speed to remain steady during this time. A belt drive for example, achieves
load stability by using a very heavy platter. The direct drive with a PLL emulates that electronically.
Another difference between the early motor vs the later ones, is bi-directional drive. The early motors
could only push forward. The later motors could push or pull the platter allowing for an even greater
degree of control over the platter’s relative equilibrium. If you compare a 1200 original vs a 1200MK2
when switching from 45 to 33, you can immediately appreciate the bi directional drive. The
speed change is instant with the MK2, while the original 1200 has to coast slowly down to 33 due to the
inertia of the platter. As an interesting aside, the Sansui SR-838 used a unique braking scheme to speed
up the change from 45 to 33.
And while not as instant a speed change as a 1200 MK2 bi directional drive, the changeover was quite a
bit faster than the original SL1200.
The Technics 1200 MK2 spec sheet indicates that speed change due to load torque is 0% for loads up to
0.8 LB-in.(180gm stylus force)
Wow and Flutter is specified as 0.025% weighted, and 0.035% peak. The weighted W&F measurement
taken directly from the internal frequency generator is 0.01%
Speed Drift within 0.002%
Speed drift is the average speed measured over time. Audio magazine measured drift as speed change
over 42 seconds (Ed Long).
Using the 1200 MK2 drift number of 0.002%, the turntable speed can vary between 33.3339 and
33.3326 rpm (33.3333 X 1.00002 and 33.3333/1.00002)
That would allow for example, a 20kHz frequency to wander between 19.999.6kHz and 20.0004kHz, a
1kHz tone would wander between 1000.02 and 999.98 Hz. This is not audible.

From wiki page on wow and flutter:
Absolute speed
“Absolute speed error causes a change in pitch, and it is useful to know that a semitone in music
represents a 6% frequency change. This is because Western music uses the ‘equal temperament scale'
based on a constant geometric ratio between twelve notes; and the twelfth root of 2 is 1.05946. Anyone
with a good musical ear can detect a pitch change of around 1%, though an error of up to 3% is likely
to go unnoticed, except by those few with ‘absolute pitch.”
- End of wiki

This helps to put the 0.002% into real world perspective.
As a comparison, the highly regarded Well Tempered Lab belt drive turntable reviewed in Audio
magazine in July 1988, had a long term drift of 0.15% and Ed Long rated that as very good.
Cogging
Now, regarding the use of the term cogging. Let’s start here with the definition from Wikipedia:
“Cogging torque of electrical motors is the torque due to the interaction between the permanent
magnets of the rotor and the stator slots of a permanent magnet machine. It is also known as detent or
no-current torque. This torque is position dependent and its periodicity per revolution depends on the
number of magnetic poles and the number of teeth on the stator. Cogging torque is an undesirable
component for the operation of such a motor. It is especially prominent at lower speeds, with the
symptom of jerkiness. Cogging torque results in torque as well as speed ripple; however, at high speed
the motor moment of inertia filters out the effect of cogging torque.
- End of wiki

And yet, no one would look at a Technics turntable platter in rotation and suggest that the motion is
“jerky”. Just looking at the strobe display confirms that. Furthermore, simply rotating the platter slowly
by hand also shows that there is no discernable pole to pole attraction. And while these motors are
capable of fast start up times, at normal running speed, they are, by design, low torque motors; easily
stopped by hand when running at normal operating speed.
So why has the word cogging been used so often in our hobby to describe a deficiency in the sound of
direct drive turntables?
Maybe it has to do with the kind of information you encounter when you research brushless DC motors
online.

There you will find things like this:
Cogging, by definition, is a force that interferes with the continuous torque delivery of an electric motor.
In the worse situation, cogging torque can be so great that the motor will not even start up.
https://www.youtube.com/watch?v=pYa5VOaQHyo&t=911s
All DC Brushless motors that feature a steel core will exhibit some degree of cogging.
However, motors can be designed to minimize the effects of cogging torque to a degree where it
competes with the general friction of the bearings themselves.
Reducing the cogging torque
“Cogging torque is produced, in a brushless PM machine, by the magnetic attraction between
the rotor mounted permanent magnets and the stator teeth. It is the circumferential
component of attractive force that attempts to maintain the alignment between the stator
teeth and the permanent magnets”
http://www2.ece.ohio-
state.edu/ems/files/TechReportProtected/Study%20of%20Cogging%20Torque%20in%20Permanent%20
Magnet%20Machines.pdf
Cogging Torque Minimization Techniques
Cogging torque minimization techniques have been analyzed for various electromechanical machines. In
this paper, results for the following cases are provided:
(1) variation in magnet strength,
(2) variations in magnet arc length [5, 11],
(3) shifting magnetic poles [9-12],
(4) radial versus parallel magnetization [5, 13],
(5) rotor eccentricity,
(6) variations in the slot width [9],
(7) variations in the radial shoe depth,
(8) variations in yoke notch radii,
(9) permanent magnet skewing [7, 9, 11, 14-17], and
(10) permanent magnet overhang [9].
According to this paper, of the 9 items listed, the ones most obviously employed in the Technics motor
to reduce cogging magnitude are items 1 & 2, variation in magnet strength, and variations in magnet arc
length.

Further, “Another way to mitigate the effect of cogging is to select a fractional slot combination in which
the number of stator slots divided by the number of rotor poles is a non-integer number. As a result,
only one side of the rotor magnet lines up with the stator slots. The edges of the slots do not line up
with the poles, which, reduces cogging torque.”
Taken from https://www.automate.org/tech-papers/understanding-the-distinctions-among-torque-
ripple-cogging-torque-and-detent
The Technics SL-1200MK2 motor uses a 16-pole magnet and a 12-slot stator and so exhibits a fractional
slot combination, 12/16 = 0.75. It also uses a continuous low energy ring magnet with 16 integrated
poles (8 pole pairs) thus optimizing the magnet pole arc. It does not use 16 separate magnets as you
might find in truly hi torque motors.
Just rotating the platter slowly by hand and releasing shows that there is just barely perceptible cogging
torque acting on the platter: The platter comes to a near stop and then only slightly rocks backwards as
it stops; that is the extent of the pole-slot attraction. By making the number of slots divided by poles
fractional, you minimize attraction and encourage motion thus reducing cogging torque. A great
explanation of how to minimize cogging in ac motors is shown here:
https://www.youtube.com/watch?v=pYa5VOaQHyo&t=911s beginning at 6 min in and especially focus
at 8:38 – 10:36.
Measuring cogging torque
More importantly, it is possible to measure the cogging torque with a simple gram pressure gauge. I
think this reveals the true insignificance of cogging torque on Technics motor performance.
Cogging torque measured on a Technics SL-1200 MK2 with a gram pressure gauge:
Using a stock platter with the magnet removed, to measure just the bearing friction torque:
Measuring 1.5” from the spindle (the stator radius) I get 3.5 grams
Measuring 6” from the spindle at the edge of the platter I get 1.5 grams.
Using a platter with a magnet to capture bearing friction plus cogging attraction:
Measuring 1.5” from the spindle (the stator radius) I get 10 grams
Measuring at the edge of the platter I get 3.5 grams.
If you subtract the top from the bottom set of numbers:
The cogging torque alone as seen from the motor stator is 10-3.5 or 6.5 grams.
The cogging torque alone as seen from the platter edge is 3.5 – 1.5 or 2 grams
2 grams referred to the outer edge of the platter (12.0”).
6.5 grams referenced to the diameter of the actual motor/magnet (3.25”).
Calculated centrifugal force of the platter (5lb 14” at 33.33 is 501 grams
( http://www.calculatoredge.com/mech/flywheel.htm )
2 grams is 0.4% of 501 grams
It is important to note that most of the academic articles on cogging torque use examples of very high
torque motors in their discussions.

One such example
https://www.academia.edu/19661425/A_Novel_Cogging_Torque_Simulation_Method_for_Permanent_
Magnet_Synchronous_Machines?email_work_card=view-paper
shows a motor having a peak cogging torque of 203 grams. They then go on to discuss a technique that
reduces cogging torque to 6 grams(page2174). Quoting “There is a noticeable reduction of 97.5%
with respect to the 2 Nm value obtained from the proposed HMPP analysis. A significant improvement
benefit using skewing rotor has been proved quantitatively. It thus is an effective way to minimize the
undesirable cogging torque.”
https://www.unitconverters.net/torque/newton-meter-to-gram-force-meter.htm (you can use this to
convert between Newton-meters and grams)
They say, and justifiably so, that going from 203 grams to 6 grams effectively minimizes undesirable
cogging torque.
Bear this in mind when you look at the measured cogging torque of the 1200 motor at just 2 grams.
Also, since the Technics 1200 mk2 motor is stated to provide 0% speed variation with up to 180 grams of
drag, 2 grams would seem rather inconsequential.
Cogging Torque Ripple
Once the platter is in motion, the startup cogging affect is diminished and what remains is something
called cogging torque ripple.
This is calculated by first determining the cogging steps.
The angular slots = 360/12 = 30
The angular poles = 360/16 = 22.5
30 – 22.5 = 7.5
360/7.5 = 48 cogging steps per revolution.
The Cogging Frequency at 33.33rpm = (33.3333/60) * 48 = 26.64hz.
So as the platter is rotating at 33.33rpm, the motor EMF is experiencing a modulation or vibration of
26.64Hz.
From the paper listed above: “Cogging torque adds a ripple component to the desired constant output
torque from the machine. This can produce vibration and noise.”
So, this 26.64Hz signal would be seen as part of the rumble specification, but as specified rumble is
already quite low at -56dB (unweighted, 5-700hz) so it is not significant.
https://en.wikipedia.org/wiki/Rumble_(noise)

Conclusion
From this study, my conclusion is that the technics motor speed stability does not suffer from the effects
of cogging torque.
The rumble measurements may be influenced by the motor torque ripple of 26.64hz, but this too would
seem insignificant when looking at the rumble measurements.
The belt drive Well-Tempered Turntable reviewed by Ed long for Audio Magazine in July, 1988 shows an
unweighted rumble of -66dB.
When the weighted(150-700Hz) measurements are taken, the two turntables are even closer -78dB for
the Technics, -82 for the Well-Tempered Turntable.

Historical Questions
Yet there does remain this comment which M Fremer found for me in this
article: https://www.stereophile.com/content/linn-sondek-lp12-turntable-lingo-power-supply-
measurements From Stereophile back in 2002.
In describing drive system non linearities in a Linn turntable, John Atkinson wrote: "If you are thinking
that a servo-controlled direct-drive design would be the way to eliminate these spuriae, think on this: in
a direct-drive turntable, the motor acts directly on the platter spindle. There is therefore no mechanical
filter to reduce the effect of any variations from perfect rotational behavior on the part of the motor. In
addition, all servo systems will have a natural frequency around which they will 'hunt,' albeit in a
damped manner in a well-designed system. In the direct-drive turntables that were popular in the
1970s, this natural servo frequency was around 3kHz--right in the middle of the region where the ear is
most sensitive."

I inquired recently about what model he was referring to and was told “If I recall correctly, I was talking
about the original pre 1979 Technics SL-1200”. But he did not offer the authority or reference source for
this 3kHz comment.
I am still trying to get some clarification on this because if you study the original 1200 motor(a great
description is written in the SL-1100 service manual); it uses a frequency generator yes, but that signal is
rectified and filtered to create a DC control voltage with a very slow time constant of 1.12 Hz.( 6800ohm
x 33e-6 farad x 5) I use 5 time constants because it takes 5 time constants for an RC network to reach
the applied voltage level.

There is no indication in the service manual that anything in the circuitry is running as fast as 3000hz.
Servo motors with a large flywheel, such as a turntable are going to achieve equilibrium. If there is any
“hunting” of the control voltage, it is not going to be a repetitive waveform, but rather it will be random
in response to frictional changes such as encountered with dynamic stylus drag. And the time constants
of the control voltage circuitry, as discussed earlier, are not fast enough to respond at 3000hz(0.33mS).
If anyone knows the origins of this 3kHz. claim, it would be most helpful.
Also, the comment that “the motor is directly coupled to the platter spindle and there is therefore no
mechanical filter…” is not accurate as the motor power is applied through a magnetic field which, with
the mass of the platter creates a spring.

So, to one degree or another, the inertia of the platter does act as a low pass filter. Again, under normal
operation, these are low torque motors, as they would have to be to minimize the effects of cogging
torque. https://www.osti.gov/servlets/purl/100261 , Pg 3. Paragraph C & D.
In other words, the magnetic field in a direct drive is analogous to the belt in a belt drive. Both offer
compliance to the rotating mass of the platter(flywheel).
The advantage of the direct drive is that it is rotating at 33.33RPM, which keeps the frequency of most
rumble noise well below the audible range. That cannot be said for the belt drive where the motor is
likely spinning at 3600 RPM and this produces rumble frequencies which are much higher and
therefore more likely to be audible.
It is important to note that when a linear positional frequency generator is used with phase locked
control, very small changes in speed (i.e. platter position) can be detected the instant they occur
anywhere within the 360 degree cycle of rotation.
Technics calls this full cycle detection.
Because these corrections are so small, they do not produce audible artifacts because they are
infrequent and also because they are smoothed out even further by the flywheel effect of the 4-pound
platter.

​It has always seemed odd to me that the very feature that is claimed to benefit a belt drive is neglected
as a feature benefit for direct drive turntables as well.
KAB Electro Acoustics
Preserving The Sounds Of A Lifetime
www.kabusa.com
www.twitter.com/kabelectro
P.O.Box 2922
Plainfield, NJ 07062
908-754-1479 Phone
908-222-3442 Fax

By Michael Miguest

I have a Mark Levinson 390s that I use as a transport. It has a polarity feature that allows you to play your CDs with a click of a button  "Normal" or "Inverted.  For anyone who has this feature, I thought you might find this information useful.
​Here are most of the ones posted in Ultimate Audio (Summer 2000 issue):

Normal or "0" polarity: A&M, Acoustic Disc, Atlantic, AudioQuest, Blue Note, Caprice, Chandos, Chesky, Chess, Columbia, Concord, DMP, Elektra, Geffen, GRP, Harmonia Mundi, Hungaraton, Hyperian, JVCXCRD, Klavier, Liberty, Manhattan, MusicMasters, Nonesuch, Novus, Opus 3, Orfeo, Philips, Polydor, Pope Music, Reference, Reprise, Sheffield, Supraphon, Verve, Wilson. ECM also belongs in this list, IMO.

Inverted or "180" polarity: Analogue Productions, ASV, BIS, Capitol, Cypress, Delos, Deutsche Gramophone, Discovery, EMI, Epic, Impulse, L'Oiseau-Lyre, London, MCA, Mercury, Motown, Nimbus, Pangaea, Polar, Private Music, Riverside, Ryko, Shanachie, Sony, Telarc, Teldec, Vanguard, Virgin, Vox, Warner Brothers, WEA. I would presume that English Decca/Argo belong in this list.

 By Michael Miguest
     


      There is a caveat to my subjective statement that my Ken Stevens' Convergent Audio Technology (CAT) SL1 Signature upgraded MKII to MKIII is a masterpiece. Subjectivism is based on or influenced by personal feelings, tastes, or opinions. With that in mind, the CAT MKIII after some tube rolling, allows me to achieve an incredible musical presentation at a price point that in my opinion, is sane. When it plays music, it sounds like music. It's transparent, textured, neutral, inexorably revealing, insightful and along with its pace, rhythm, attack and timing (PrAt), is more life-like than virtually any other preamp that I have experienced. I'm sure the build quality contributes to CAT's incredible performance. Both the main unit and power supply feel like solid masses. It is constructed like the proverbial Brick (expletive) House.This is due to their steel chassis and the liberal use of what Ken Stevens calls a "resistive damping compound" internally -- the blue stuff you'll see adhered to much of the main chassis's internal surface area. The steel and damping compound were chosen because they control resonance, something CAT takes to great lengths. Circuit boards are made of G200, a material that's 12 times more expensive than the substrate used for many of the circuit boards in other high-end products.

       With regard to my system, my tube power amp is a VTL stereo 90 running 6550 Tung Sol power tubes with a pair of Valvo Blue Label pinched waist 12AT7 and a pair of Telefunken ECC801S signal tubes. The Cat SL1 Signature MKIII is a synergistic match created in Heaven. My Digital front-end consists of the Mark Levinson 390S which I use as a transport that feeds a Monarchy NM24 Dac that uses 6922 vacuum tubes and is powered by a Monarchy AC-Regenerator. The CAT SL1 Signature MKII used 12AU7 tubes in the V6 and V7 line stage positions which was changed to 6922 tubes in the MKIII. According to designer Ken Stevens, the 6922 is a better input tube than the 12AU7, and allows the SL-1's noise level to be reduced from -92dB to -112dB (unweighted). Apart from the noise figure, the electrical specifications stayed the same: gain is within ±0.1dB of the Mk.II; there is no change in rise time, bandwidth, or slew rate. Still, Stevens says the sonic improvement is such that he seriously considered renaming the preamp the SL-2. I ran across this information from a stereophile review:The 6922 has been part of the SL-1's tube complement, but not in the line-input stage. The SL-1's design calls for the tube in this spot to have a plate voltage of 175V, and published 6922 specifications state that the maximum allowable plate voltage is 130V. The tube that Stevens now uses as the line-input tube is made by Sovtek in Russia, and has the European designation of E88CC. Although labeled 6922, it has—as Stevens discovered when reading the instruction sheet packed with the tubes—a maximum plate-voltage spec of 220V, well within the SL-1's requirements. To accommodate the new tube, the gain was padded down. There are no other circuit changes. My Analog front-end consists of a Thorens td 126 MKIII with a Denon 103r cartridge that feeds my Allnic AUT 2000 step up transformer which feeds the CAT's phono inputs. Last, but not least, my system has a Revox a77 High Fidelity reel to reel tape player.

     When it comes to tubes, my tastes prefer NOS vacuum tubes. Ken's SL1 Signature MKIII is supplied with (Sovtek) 6922 and (EI ) 12AX7 tubes. I subsequently rolled a pair of Telefunken E88CC in the V1 and V2 positions and a pair of Telefunken ECC83 smooth plates in the V3 and V4 positions of my Phono Stage. I left the Sovteks in V6 and V7 because of the plate voltage issue but rolled a pair of Mullard MC-1s in the V8 and V9 positions in the Line Stage. You would have to hear the musical presentation with this tube combination.

       
      In conclusion, my personal feeling is a "Masterpiece" is the work of an artist who has been absorbed by the spirit of his/her times and can transform personal experience into a universal one. Masterpieces make us forget the artists, and instead direct our attention to the artist's works. We may wonder how a particular work was executed, but for the time being, we are transposed, so deeply brought into this creation that our consciousness is expanded. Thank you Ken Stevens for your Technology Serving Music !

    ​https://www.catamps.com/products


​





​

By Michael Miguest




With Lloyd’s passing the audio world has lost one of its most gifted minds, and those who knew him have lost an amazing husband, friend and confidante. If you ever had the privilege of meeting Lloyd, you know what a gift this man was to all of us. This is a really difficult season for us. For him… well, he’s at the feet of his Heavenly Father, and he was never one to complain anyway, so we’re sure he’s doing just fine. 🙂

Below is Lloyd’s obituary. To say he’ll be remembered fondly would be an egregious understatement. We don’t have any concrete plans regarding the business side of things at this point. Today we just miss him very, very much. 

Listen to some great music and smile in Lloyd’s memory. Sharing the gift of music with the world was his passion, and that’s what he’d want us to do.

Happy Listening…

This is the heavily abridged story of Lloyd Walker. Some of the tales related herein may be on the tall side, but this is how Lloyd told it, so now they’re gospel truth.

Lloyd was born in Texas City, Texas on August 11, 1943. His father was a Merchant Marine in WWII and later worked in a local oil refinery. His mother was a homemaker. Lloyd spent his life making things — starting with building target rifles with his dad from a young age. As a teenager all Lloyd wanted was a motorcycle, something his mother was disinclined to allow. So he got a hold of a motor scooter (hardly the same thing, but you work with what you’ve got), and proceeded to turn it into a rocket ship on two wheels. The bike probably would have been safer.

From there Lloyd started wrenching on cars, setting the national record in the quarter mile before computers came along and “messed the racing game up”. He graduated Dickinson High School, and shortly thereafter was drafted to serve in Vietnam.

Lloyd cheated death in Vietnam more times than he could count. He was narrowly missed by a sniper, and was the sole survivor not once, but twice when personnel carriers he was aboard were attacked. “It just wasn’t my time,” he’d say when he told the stories. Once, as he tells it, he was walking point with his unit looking for trip wires, turned around to tell his unit the path was clear, and saw directly behind him on the path a wire that was stretched across the path a full foot off the ground. There was no way he should have missed that wire. He didn’t see how it was possible. Again, the only explanation, “It just wasn’t my time.”

After being decorated with a Bronze Star and a Purple Heart for his service, Lloyd returned to Texas and began work as a pipe fitter for the oil refineries near home. That work brought him into instrumentation, making sure systems worked in concert for facilities like refineries and power plants. It took him all over the country, sometimes even the world. There are countless adventures (and misadventures) to be found between the lines here, but the greatest adventure of Lloyd’s life is one Felicia Henry Walker.

They met in September of 1978. Felicia didn’t want to date Lloyd, but he didn’t ask for a date — he offered her a ride on his motorcycle. She hopped on the back of his bike one Sunday morning, expecting a short ride. Fourteen hours later he brought her home, and they’ve been inseparable ever since.

They married on April 28th, 1979. They rode all over the country together, sometimes for work, sometimes just for fun. Lloyd and Felicia criss-crossed the map, following Lloyd’s work, until finally settling down in Pennsylvania after Lloyd was brought to the area to work at the Limerick plant.

After developing a passion for high-end audio as a hobby, and a friendship with Bob Dilger (a legendary air-bearing turntable pioneer to whom Lloyd regularly pitched design ideas for improving Bob’s Maplenoll Turntables), Lloyd eventually decided he could build the best turntable in the world. Not just a good ‘table. The best in the world. No plan, no business model, just a dream. So he and his partner Fred Law went into his garage and got to work. And over the next 26 years, that turntable became the Walker Audio Proscenium Black Diamond Mk VI Master Reference — regarded by many in the industry as exactly what Lloyd set out to build — the greatest turntable the world has ever seen.

The audio industry brought Lloyd friends and fans from all over the globe, countless stories, and immeasurable joy. He loved his work, he loved his wife, he loved Jesus (a relationship that only started after Felicia prayed for him for 25 years). He always had a glint in his eye, a smile on his face and a story to tell. Lloyd was always rough around the edges, and unapologetically himself. And those who loved him wouldn’t have had it any other way. His authenticity was infectious, and he will be missed.

In 2010, after beating throat cancer, the words remained the same, “It just wasn’t my time.” But by then he knew Jesus. And the words he heard from Him were, “It’s not your time. Don’t worry. I’ve got you.” We lost Lloyd on March 15, 2022 after a battle with leukemia and a blocked carotid artery. He went peacefully, with Felicia by his side. And while we are so very sad that he is gone, it was, finally, his time. As he goes to the arms of his Savior, one thing has not changed. “Don’t worry. I’ve got you.”

Thousands of stories, most of them at least a little true. Countless adventures — enough for ten lifetimes. And this much is certain: Lloyd Walker lived life well, and we will miss him. Rest well, Lloyd. See you soon.

By Michael Miguest

ENJOY !

​By Michael Miguest

By Michael Miguest

This review is for Herbie's RX-9 Tube Dampers. Rather than put dampers on all tubes, I chose to put a pair on my input tubes in my modified Monarchy NM24 tube dac and a pair on my tubes in the V2 and V7 positions which amplify and buffer the RIAA output in the phono section of my restored Citation 1 preamp. I wanted to hear how much difference my system's presentation would be just treating the source of my digital and my analog.

My digital consists of a Mark Levinson 390s as a transport that feeds the modified Monarchy NM24 via the Creative Concept digital cable. The Monarchy NM24 is powered by the Monarchy Regenerator that I set at 120 Hz and 117 v. The tubes in my Monarchy NM24 Dac are 1965 Siemens Halski CCa. 

My analog consists of a Thorens 126 MKIII that has a modified tonearm with a 103r cartridge which feeds an Allnic AUT-2000  SUT which feeds the phono section of the Citation 1. The tubes in the Citation 1 are 1957 Mullard MC-1s.

Herbie's RX-9 Tube Dampers resolve recorded events on a higher level demonstrating a greater revelation of that event. The dampers reveal nuances, coherence, texture, tonality, Prat, etc, which provide a greater sense of reality. The dampers enhance your system's "Musicality"  providing an emotional connection that contributes to a heightened level of musical enjoyment. 
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By Michael Miguest                                                                                                                                                                 

Last year I retired my Proceed CDD transport with a mint Mark Levinson 390S I found on ebay. The Proceed CDD was always tagged as the poor man's Mark Levinson. Feeding it to my modified Monarchy NM24 tube Dac, it provided me a formidable digital front-end for many years. However, the Mark Levinson 390S is on another level. The build quality, parts, and design are exceptional. The 390S has the HDCD decoder inside. It utilizes the 37 transport that in and of itself, is an inimitable  work of art. The 390S' sound when combined with my Monarchy NM24 Dac that uses two 1965 Siemens & Halske CCa tubes, and powered by my Monarchy AC-Regenerator set at 120 hz is very life-like, with full bodied, articulate, tuneful bass, an exceptional musical mid and airy, fluid highs with incredible 3-dimensional sound. It throws a wide and deep soundstage as it breathes the music and subsumes you in a more realistic. quasi analog presentation.

Let's talk HDCD which is the subject of this blog. This format is High Definition Compatible Digital. Professor Keith O. Johnson co-invented the HDCD technology with Pflash Pflaumer, and in 1996, they formed Pacific Microsonics to introduce the concept of high-resolution audio. In 2000, Microsoft purchased Pacific Microsonics and continues to incorporate HDCD technology into its PC offerings. Johnson now consults with Microsoft; his latest project, Speaker-Correction, uses modeled correction of speakers to improve computer sound and can be found in XP software.

In the midst of his work as a developer, Johnson's ongoing relationship with Reference Recordings gives “The Professor” a platform with which to engineer and experiment with loudspeakers, microphones and other equipment designs. To record renowned ensembles such as the Dallas Wind Symphony, Chicago Pro Musica and the London Philharmonic, Johnson uses some manufactured equipment — Tascam recorders, Microsonics Model 1 and 2 HDCD processors (he's admittedly biased) and a Neumann U47 here and there — but mainly uses gear he's either custom-built or extensively modified at his shop in Pacifica, Calif. 

 HDCD is claimed to improve Audio CD in two general ways. One is to increase the available dynamic range - from the 16bit standard of Audio CD to (a claimed) 20bits (Reference Recordings do 24 bits). This nominally represents an increase in dynamic range from around 90dB to 114dB. The other is to mimic a wider effective bandwidth and provide an audible effect that makes musical transients sound more like you’d hear using a sample rate higher than the Audio CD standard. It is important to bear in mind each of the various types of alteration it can apply are provided as options from a ‘menu’ that those recording/mastering a disc can choose to apply (or not!) when making a specific HDCD. 

The expansion of dynamic range is said to be achieved using two methods. The first is a form of soft limiting for musical peaks. The second adjusts the gain for long quiet passages of music to make the recorded sample values larger. This makes them bigger compared with the quantisation level. Effects like these may well be applied when recording and mastering anyway. But the key feature of HDCD is that it should embed ‘control codes’ into the audio data that an HDCD player can detect. They then tell it how to ‘correct’ the alterations done during recording and mastering the CD. 

The sound difference between red book and HDCD is not subtle. It is more dynamic, expansive, lively, beautiful. and 3-D. My connection to this digital presentation in HDCD is much closer to analog and as a result, listening fatigue and digital glare are markedly close to non-existent. The Reference Recordings by Professor Keith O. Johnson are exemplary and will go toe to toe with sacd or any other digital format.

In conclusion, it's ironic that this format which Professor Johnson co-invented in the mid 1990s is teetering on extinction. My thanks to Professor Keith Johnson and Reference Recordings for keeping this format on life support by continuing to record titles in this extraordinary sounding format. It's also ironic that not that long ago vinyl was in a very similar place and now is the De Facto standard of quintessential sound reproduction. This clearly brings to mind the old adage: "The more things change, the more they stay the same".

https://referencerecordings.com/