Gramophone Dreams #79: a Vintage Lenco L75 turntable & the PrimaLuna EVO 100 phono stage

My adoptive mother, Lily Mae, was a retired businesswoman and former fashion model turned stay-at-home mom and artist-painter with famously good taste in everything. She raised me to have good manners, an "active awareness of color and texture," and "an eye for form." She expected me to critique her paintings, her decorating, and her wardrobe, urging me constantly to develop "good taste in everything."

In Lil's world, a perfect day was for me to skip school and go with her clothes shopping at Marshall Field's, where it was my job to sit in a plush chair offering comments about which outfits had the best fabrics and best "complimented her form." She always said "form is bones" and fashion is about "how fabrics hang on people's bones."

After lunch at Field's, we'd have tea at her artist friend Selma's house. After tea and perusing fancy art books in the living room, we'd move to the dining room, where Selma would show us the latest additions to her blue-onion porcelain collection. After admiring Selma's dishes, we would move to her back porch painting studio. There, it was my job to notice which paintings were new since our last visit. When I cut school with Mom, my days were devoted to sitting up straight, never looking bored, and noticing how various luxury objects met my eye.

My mother equated good taste with "good breeding" and intelligence.

On the way home from Selma's, Lil would always compliment me on being "a good shopping partner"—but that was only a preface to her standard lecture on how book-learning, manners, and refined taste "get you a seat at the best tables." Invariably, she would conclude these class-consciousness sermons saying, "Anybody can have money, but only 'smart' people have taste."

Mom never let me forget that having money creates the need for taste.

Lily Mae Iverson was born in 1907, so I presumed every mother who survived two world wars, a plague, and the Depression lectured their sons like that. Fortunately, her admonishments served me well. They became the building blocks for my own version of her philosophy: What I give my attention to, and what I aspire to understand, reflects the kind of person I am choosing to be.

For me, taste is literally the thought matrix of all the things I've chosen to regard as important.

Garages and museums
I view audio gear first through the eyes of a mechanic like my dad, who, when I took him to MoMA to see art, all he saw was the pipes. Second, I see it through the eyes of an artist like my mom, who let me cut school so she could show me her favorite paintings at the Art Institute of Chicago. After I started painting, we had a show together in Chicago. At the opening, she told one of her collectors, "Pay no attention to his work, he has scrambled brains," alluding to my use of lysergic acid diethylamide.

Naturally, I grew up to love art and pipes as much as mountains, forests, bodies of water, and violent weather—but none of those things do I now love more than cars, trains, trucks, motorcycles, and boats. To my last breath, I will aspire to having good taste in everything that moves under power. I love watching long trains at railroad crossings and get excited when I spot a prime specimen of a Mack or Peterbilt truck. I love old tractors and the sounds of two-stroke dirt bikes when they downshift in corners. I love watching torque making stuff move.

Right now, my desire to watch torque in action has me exploring a mechanical subcategory of vintage audio gear referred to as idler-drive turntables. I've owned a variety of idler drives including my first turntable, a four-speed Dual 1009, a few Garrard 301s, an Elac Miracord 40, and I've never been without at least one Thorens TD124. But...

Unlike many of my friends, I never considered idler drives to be inherently superior to direct or belt drives. For years, my Denon DP-3000 direct drive sat right next to my Linn Sondek LP12 belt drive. I never thought to compare them as examples of their drive types. The notion of advocating for or believing in one form of technology over another never appealed to me—until one day last February when I heard my friend Yale's system sourced by his massive EMT 930 turntable with an EMT arm and cartridge. More than any system I'd ever heard, that system, playing Yale's really ood records, made my toes tap uncontrollably and kept my mind locked into the music. My experience at Yale's lent serious credibility to his claim that "idlers are close to god" and set me on the path of discovery I'm now on—the path where I can't afford an EMT 930, or for now, a professional rebuild of my 1957 TD124, but I could and did afford a preowned, made-in-Switzerland Lenco L75.

Lenco's rhythm-keeping holiness
Experiencing Yale's drool-worthy EMT 930, followed by my time spent with PTP Audio's Solid9 Lenco-based turntable, forced my mind to wonder: Why do idler drives inspire such fanatical devotion in their adherents? Do believers actually feel some kind of god force behind the high-torque motors, sturdy rubber idler wheels, and heavy platters? Could pushing a platter feel different to a listener, or be a more effective use of motor torque, than pulling with a rubber lead?

When the Solid9 departed, I decided to see if a stock Lenco L75 could be as exciting and PRaTish as the PTP or EMT. And because I'm a lucky guy, no sooner had I made that decision than a friend of a friend offered me his stock Lenco L75 for $750. I said yes immediately, and two days later, a 1969 L75 was sitting on my rack looking fresh and only slightly used. It came in its original box, with its original plinth, tonearm, and owner's manual. Best of all, I could start playing it immediately because it had been recently "refreshed" by turntable specialist Michael Trei, who tweaked and adjusted the drive system, oiled the platter bearing, and replaced the tonearm's rubber V-blocks with new brass ones (footnote 1). The only nonstock parts on the L75 were a bendably soft after-market aluminum headshell and Shure's iconic M3D "Stereo Dynetic" cartridge, which Shure introduced in 1958 and which, according to Shure's advertising, was the world's first "Dynetic" (moving magnet) cartridge.

I tried running the M3D into the moving magnet inputs of the SunValley SV-EQ1616D and PrimaLuna's new EVO 100 phono stage. It sounded the most fluid and detailed through the 10-tube PrimaLuna (see the description Page 2) and the most tone-correct through the four-tube SunValley equipped with smooth-plate Telefunken 12AX7s. Inexplicably, with both preamps I noticed a faint, grainy hiss that haunted the background of whatever disc the cartridge was playing. This noise wasn't obvious, and it wasn't hum. It seemed magnetic. Once I noticed it, I couldn't stop thinking about it, so I swapped in an AudioTechnica VM95E moving magnet cartridge, which dramatically raised the Lenco's excitement factor, manufacturing slurries of quick-punching, hard-hitting bass and an upper-octave transparency that made the Gen-X Lenco sound young, smartly dressed, and fully caffeinated. My Lenco fun had begun.

With the VM95E, recordings were presented with bright, clear, noise-free excitements, but vocal and instrumental tones were not as dense, intense, or real-sounding as they had been with the Shure M3D, which showed real talent in those areas. Noticing that caused me to remember how solid and colorful the PTP Solid9—an extensively rebuilt Lenco—with the Sorane/Abis SA1-2 arm sounded with a stock, plastic-bodied, moving coil Denon DL-103.

The quality of my Lenco listening jumped up several levels when I installed the 40 ohm, 0.3mV DL-103. This cartridge-tonearm marriage was ordained by the same god that blesses idler drives. At first, I connected the 103's output to the SunValley SV-EQ16161D's moving coil input, which is loaded with a 50 ohm shunt. That's a 40 ohm cartridge driving a 50 ohm load! With the SunValley and its 50 ohm load, I heard a tsunami of naturally presented low-level detail, strong rhythms, and a benign, rolled-off top end. Response-wise, the 50 ohm load caused some of the Denon's 4kHz energy to move down to 400Hz. The sound with this nearly 1:1 loading lacked the transient edge and brightness and fast, sharp resolution I've come to associate with punchy moving coil dynamics, but over time my brain adapted to this unusually rich and relaxed sound. Duke Ellington's Blues in Orbit (Columbia MOVLP 443) and Mel Tormé at the Crescendo (Bethlehem BCP 6020) sounded quieter, easier flowing, with more Duke and Mel star power. Distortion seemed lower. Which made me wonder if over all those boomer-decades my brain had adapted to the brighter, higher-presence sound of the generally accepted load of 300–400 ohms. Or maybe at 50 ohms, some Lenz's law damping was helping the Denon's conical stylus ride the groove better? More questions I can't answer.

Dave Slagle has used AnalogMagik software and test records to show that loading the DL-103 down lowers its IM distortion measurably, and that this added damping improves trackability (footnote 2).

This Lenco-Denon-SunValley front end did a fantastic job representing the voices and the hip sentiments of Duke Ellington and Mel Tormé, but how would it do with a more earthbound poet like Louis-Jacques Rondeleux? Troubadours, his fantastic album of secular 12th and 13th century song (Harmonia Mundi France HM 566), is a record I use to get a preliminary read on a new cartridge. With the SunValley at 50 ohms, Rondeleux's baritone was presented in a strikingly vibrant manner. Roger Lepauw's vielle (a largish, violinlike five-stringed instrument) came through pure of tone and LSD-detailed against deep, silent, black backgrounds. The Lenco's reproduction of the somber tones and hesitant pace of Rondeleux's singing made this recording a high point of my early Lenco listening.


Footnote 1: See lencoheaven.net/forum/index.php?topic=13.0.

Footnote 2: Recently, Herb's claim led to an interesting three-way exchange between Herb, JCA, and EMIA's Dave Slagle. Herb and Slagle both pointed to a 1980 paper by Peter Moncrieff, published in International Audio Review, which concluded on the basis of actual experiment that when a resistor loads a phono cartridge directly—not via a step-up transformer—it doesn't affect the bandwidth or damp resonant peaks (which in any case, with an MC cartridge, are very high in frequency) as is, or was, commonly assumed. Slagle has corroborated Moncrieff 's result. What loading does do, Moncrieff discovered, is reduce intermodulation distortion. The mechanism is uncertain, but Moncrieff speculates that it could be due to electromagnetic damping of subtle cartridge mistracking—hence Herb's reference to Lenz's law in the previous paragraph.—Jim Austin

ARTICLE CONTENTS

COMMENTS
Anton's picture

I was afraid a bomb would go off at the museum and, you being orphaned, would steal a painting of a small bird.

It all worked out, though!

Lovely column about the joy of classic vintage!

AudioBang's picture

After reading your well articulated column, I have a new appreciation for this....
https://www.youtube.com/watch?v=qlg5InsskW4

Thanks Herb! :)

RobChamp's picture

Herb, your recollection of diesel engine performance is correct. Compression ignition (ie diesel) engines experience 'torque rise' when you load them down. The governor in the fuel injection pump, sensing the engine speed slowing delivers an increasing amount of fuel to maintain speed and increasing torque. Spark ignition (ie gas) engines have a narrow torque band. When you go up a hill, engine speed AND torque drop, which is why you have to downshift.

Electric motors, as any Tesla driver will tell you, can deliver big torque from zero speed because the battery (or AC power supply) can deliver high current. Not sure if or how that accounts for the differences you perceive in the performance of idler TTs.

eatapc's picture

As to the findings of Moncrieff and Slagle — that loading "doesn't affect the bandwidth or damp resonant peaks" — I'd like them to show their work. This goes against pretty much everything I've ever read. I agree that correct loading will improve tracking ability and lower IM distortion, but I've seen measurements over the years that seem to show dramatic changes in frequency response vs. loading. This debate and uncertainty confirms in my mind that a transimpedance phono stage with a low-impedance cartridge is the smart way to go. That setup optimizes the parameters with no guesswork required. Here's a typical analysis of MC cartridge loading: http://www.extremephono.com/Loading.htm

dave slagle's picture
Quote:

As to the findings of Moncrieff and Slagle — that loading doesn't affect the bandwidth or damp resonant peaks"

I should clarify the above and say loading a MC cartridge doesn't materially affect the bandwidth or damp resonant peaks anywhere near the audio band.

Moncrief shows his work in IAR#5 and provides frequency plots of a Sony XL55 which is a 40Ω cartridge loaded with both 100Ω and 5Ω with no appreciable change in behavior in the frequency domain.

Mike Trei more recently notes in spin doctor #7:

I had the advantage of being able to run the Zu/DL-103 through the CH Precision P1 phono stage's loading wizard, trying dozens of load values and getting a frequency-response plot for each. I learned just how insensitive to load the DL-103 really is. There is no sign of the expected steep high-frequency dropoff as the loading value approaches the cartridge's own 40 ohm internal impedance. Even at 40 ohms, the response remained pretty flat out to 18kHz, with a fairly gentle rolloff above that.

In doing his due diligence Jim Austin reached out to me and I provided him frequency plots of both a shelter 501 and a denon 103r with both heavy and light loads. Aside from the change in amplitude, the plots were materially the same for both situations.

I would like to see the original source and documentation of this image from the site you linked since I have yet to see that type of measured behavior from loading any MC cartridge.
http://www.extremephono.com/Loadin1.gif

Quote:

This debate and uncertainty confirms in my mind that a transimpedance phono stage with a low-impedance cartridge is the smart way to go.

There is a huge disconnect in your statement above and your belief on how loading manipulates frequency response. If the referenced plot is to be trusted and loading does indeed effect frequency response in the manner proposed, then what must happen with the very aggressive load a transimpedance stage provides?

dave

eatapc's picture

Thanks for your response, Dave. I won't dispute your findings or Mike's regarding "no sign of the expected steep high-frequency dropoff as the loading value approaches the cartridge's own 40 ohm internal impedance." As Mike wrote, a change in the high-frequency response was expected. It's conventional wisdom passed on from cartridge manufacturers and reviewers for decades. Is it wrong, or is it simply that some cartridges are relatively load insensitive versus others? If it's flat-out wrong, that would be big news! Perhaps Stereophile can explore that.

As to my "huge disconnect," I'm not an electrical engineer, but my guess is that loading changes frequency response in a voltage-gain situation, not with a current-mode preamp, which uses the current, not the voltage. Is that a possibility? I agree with you, Mike and Herb that damping affects tracking ability and IM distortion. That's one of the reasons I like current-mode phono stages. From Herb:

Response-wise, the 50 ohm load caused some of the Denon's 4kHz energy to move down to 400Hz. The sound with this nearly 1:1 loading lacked the transient edge and brightness and fast, sharp resolution I've come to associate with punchy moving coil dynamics, but over time my brain adapted to this unusually rich and relaxed sound.

What Herb describes is what I've heard with my own MC cartridges as I add too much loading. However, what I've heard with a few transimpedance preamps, one of which I still own and use daily (Lino-C 2.0 with a Lyra Kleos SL), is that the virtual short does not interfere with transient edges or brightness. Tracking is improved without making cartridges sound dull or rich. I don't have the budget for a CH Precision P1 phono preamplifier, but I note that it has two current inputs and one voltage input (with loading wizard). I'd be interested in measurements of a few MC cartridges into the current inputs versus the voltage input with different loads.

Ortofan's picture

... the graphs showing the effects of various loads on the frequency response of an MC type phono cartridge would appear to be Newsletters 9+10, dated Autumn 2000, pages 4-5, from the Swiss amplifier company FM Acoustics.

https://www.fmacoustics.com/download-1/

samueljohn's picture

Herb,
Your ability to draw me into your life, backstory, or narrative is awe inspiring. Everytime I come upon your column, I am enthralled by the journey. Thank you for your prose. I look forward to every new adventure. (disclosure; I keep a log of the records you use in your columns. Another journey I enjoy taking with your guidence.)
Keep up this amazing story.
Warmest
J

Herb Reichert's picture

I am grateful for your attentions, and happy my stories have pleased you.

Your praise makes the next story easier to write.

sincerely,

herb

rockdc's picture

Loved your write up on the Lencos. I have one stock, on a stacked plywood plinth, and one corian PTP I built with parts from Peter. Moerch 12" DP6, and AT1501 12" on the plywood one, DL103 or AT 95ML carts. Amazing. Beat my (sold) 301, 401, and TD124, as well as my Linn and Merrill Heirloom........Ten years now with the Lencos..... Now, you want a real rabbit hole? I have just finished restoring two Russco Studio Pro Model B idler tables. These are amazing too, maybe more drive than my Lencos, and definitely much more fun to use. Fun to restore, too. One with the period correct wood Micro Trak arm........the other with a Syntec arm. Check them out.

Herb Reichert's picture

that sounds like so much "project car" fun.

I am jealous and impressed.

h

rockdc's picture

sounds amazing, but I could never leave the house with a tubed unit like that up and running.......

Lazer's picture

Why?

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