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Lyra

WAM Engineering

Corrective brass shims

WAM Engineering
By: Brian Fisher

June 1st, 2025

Accepting the gift

WAM Engineering's brass corrective shims optimize geometry while imparting stunning sonic benefits.

Don’t ever let being a physics flunky get in the way of describing a good thing. That’s a solid headline for this quick meditation on a piece of brass. 

Ok, before I get into that, allow me to introduce myself. I am a friend of Michael Fremer’s, who some of you have read about in Stereophile. I struggled with a very expensive malfunctioning arm on my turntable and all the attendant problems that it inflicted on my even more expensive Lyra cartridge. Michael wrote about my saga with admirable journalistic integrity, and I will say for the record that both companies handled this situation with professionalism and swift action. But it doesn’t hurt having friends in proverbial high places to help escalate fixes to expensive problems. So, this little meandering riff is about just that.

Years ago when I first got the system that I still enjoy today, the person setting it up struggled with setting the antiskating on my Kuzma arm. Knowing what I do now, I should have allowed my murmuring concern to be a full-throated yell to stop and take action. But, I pushed forward and after not too long I noticed that my cantilever developed a skewed angle that might have been beneficial in other contexts, but it certainly didn’t benefit my audio playback. That’ll be enough prurience for today. 

Enter J.R. of WAM engineering. I could go on and on about him, but let’s just say that he is extremely knowledgeable, measured, and he’s doing a job for which he was made. As a teacher, I understand the level of patience that he musters for his clients. Having restraint with children is essential and not so difficult to conjure but summoning this for grown children is another matter entirely. 

After using Mr. Fremer’s personal Wally Skater (I have since bought my own- and so should you), we determined that there were bearing issues in my 4 Point 9 arm. So, off it went. And my cartridge went back to Lyra. Both came back a few months later in new condition and I enjoyed years of listening. Thanks to all involved. 

But, when it came time to step up to the new Lyra Etna Lambda, I decided to take a different approach. There has been much written about the manufacturing tolerances of audio equipment- we are talking about skewed cantlivers, crooked styli and other such horrors. One would think these issues would not be a thing in high end audio, but they are. And, they certainly sting more with the price paid and no one around to tell you that you aren't crazy and that this thing just may be…broken. 

So, I sent my brand new Lambda to J.R. for his cartridge analysis service. I figured he’d be able to aid me in deciding whether my Etna was a keeper. And, it turned out that it was! However, there were tolerances that could be tightened up with shims. So I decided to go for it and have been rewarded with the best listening experience of my life. Best of all, with J.R.’s shims, there is no need to use a microscope to adjust SRA/VTA, and you don’t need a Fozgometer to adjust azimuth. Just make sure the arm is perfectly parallel to the record in both planes (best to use the Wally Reference tool for this), set tracking force and anti-skating and enjoy. 

Yet, curiosity doesn’t always result in a dead cat, so I did wonder (over a year later) what JR’s upgraded brass shims would do to my system’s golden sounds. Initially, I was put off by the extra couple hundred dollars and went with his standard shims. But, I have experienced the benefits of adding mass to guitar necks and bridge pins over my years of playing and collecting vintage instruments. This curiosity resulted in countless hours researching the effects of a higher mass tonearm. The logic was certainly there, as was my desire to experiment. So, off my cartridge went to California for J.R.’s Kuzma mounting service. I sent him my headshell, and all he did was change the shims to brass. The brass adds an additional 5 grams of mass to the headshell over the additional 1.2 grams of mass that the resin shims add to a cartridge alone. So that’s a significant number. I reset tracking force and was ready to listen.

“To say that my wife and I were stunned (yes, I’m an audiophile who actually listens with his partner) would be an understatement. There was such a sense of blackness of background: Instruments hung in space with such weight and dimensions. There was far more thrust to the bass, but it was more tightly controlled. The high end was extended and cymbals sounded like actual cymbals in a live room. My center image was tighter and more lifelike. And here comes the classic, unsatisfying audiophile observation: Everything just sounded bigger and better. J.R. commented that “basically we are making it tougher for the groove content to modulate the headshell, thereby lowering the noise floor.” The end result was the same Lyra with identical mounting angles but with more mass. And the brass imparts a salutary influence on the mechanical impedance between the headshell and cartridge. J.R. did mention: “A cautionary note: The devil is firmly ensconced in the details: adding mass without strict adherence to standards of rigidity and placement can cause things to sound worse, not better.  WHERE you add mass, WHAT mass you add and HOW you affix that mass is critical to the results.” 

So, do I have a perfect understanding of what brought such a massive change to my playback performance? Well, that’s a big no. A sense? Yes, but it doesn’t really matter to this listener. It has never sounded so good, and I’ve learned to stop questioning things that truly work. Accept a gift. Sometimes it’s just time to say thank you and enjoy my records. 

Specifications

Manufacturer Information

WAM Engineering

Mibs Distro

Comments

  • 2025-06-01 02:26:42 PM

    Tim wrote:

    Glad to hear that you're happy with the shims. I too have been tempted with WAM's ervice.

    I am somewhat surprised that the additional 5grams is a benefit in your circumstance (and not a downgrade) - explained;

    I personally use a similar setup: Etna SL and Kuzma 4point (11inch however); which has an effective mass of 18grams.

    Although I love this combo; I do find the cart/arm resonance not ideal (around 7.5hz). Thr biggest issue being that Lyra carts are quite high compliance and the 11inch Kuzma is a relatively higher mass...

    I would have bet money that 13grams would be a much better outcome for the Etna; but perhaps I'm wrong.

    @Michael Fremer; I'm sure over the years you've had the opportunity to test your Etna on arms of varying masses; perhaps even the 11inch 4 point vs 9inch; what's your findings?

    • 2025-06-01 05:03:04 PM

      Come on wrote:

      It’s great when things work! But yeah, I had the same thoughts. Any additional mass at this distance to the bearing afaik goes into the tonearm mass equation squared. This should better go in the right direction.

    • 2025-06-01 05:45:56 PM

      WallyTools -J.R. wrote:

      I understand your hesitation to accept the approach. It does fly in the face of many decades of practice and understanding of what is "best" to aim for. Unfortunately, the landmark studies that have been done in the past (e.g. Bruel & Kjaer 1977, etc.) were performed with two highly limiting assumptions: 1. That we should tolerate warps; and, 2. That we cannot isolate our turntables from low frequency excitation from it support surfaces.

      Obviously, we can do many things to ameliorate those two limiting foundational assumptions. If we do, we can change our design limitations for tonearms. I discuss this in a few of my Sound Bite series videos and I have plans to do a multi-video series on mass and rigidity in transcription instruments - particularly the tonearm.

      The other thing I would say is that people generally (and by this I include audio reviewers, equipment designers and me) are good at identifying when a problem has been "fixed" but very frequently identify the wrong reason for the improvement. This causes us to come to conclusions that don't demonstrate repeatability across a multitude of applications. The reason we are pretty bad at identifying the "why" behind our experiences is because we neither understand how many variables are affected when we make any one change to the system nor do we understand how to rank order them in terms of their audibility. Getting through this problem is possible, of course, but it is very time consuming and tedious. This is exactly why we have been working for more than two years on our first scientific paper (but, happily, are now done collecting data and are finally ready to write it.)

      • 2025-06-01 05:50:30 PM

        WallyTools -J.R. wrote:

        I didn't make clear: the "landmark studies" I refer to are the studies which tell us to keep our cartridge/tonearm resonance between 8Hz and 12Hz. I agree with 12Hz and violently disagree with 8Hz. It should be quite a lot lower.

        • 2025-06-01 06:07:02 PM

          Come on wrote:

          I understood this means you found out that a resonance below the 8Hz wisdom so far, is only a problem when records are warped or turntables little isolated. This should be easily comprehensible (or not) when using a flat record over headphones I guess.

          But it must be said that not everyone can afford a roughly 12k+ expensive active isolation platform (which to my knowledge seem the only ones isolating deep enough).

          • 2025-06-01 06:22:17 PM

            Brian Fisher wrote:

            I’ll mention that my table sits on an iso acoustics maple platform. It’s around $500. Sounds incredible. So no need to go crazy.

          • 2025-06-01 06:22:19 PM

            Brian Fisher wrote:

            I’ll mention that my table sits on an iso acoustics maple platform. It’s around $500. Sounds incredible. So no need to go crazy.

            • 2025-06-01 07:03:47 PM

              Anton wrote:

              I admire that platform!

          • 2025-06-01 06:45:13 PM

            WallyTools -J.R. wrote:

            True, but the need for filtration at the lower frequencies is not constant across every person's system. This is the conversation we are NOT having about isolation options: What frequencies are being passed to my turntable? What frequencies are in need of the most attention? What isolation equipment is best for this application? What are the filtration characteristics of the competing brands by frequency and amplitude? This last one is addressed by almost none of the manufacturers.

            We are working on a tool to help you answer the first three questions.

            • 2025-06-01 07:29:17 PM

              Come on wrote:

              Great idea! On the other hand I’d assume what’s good for an electron microscope should also be fine for a turntable, as at the end it just has to be quiet. Well maybe in audio some higher frequencies play a bigger role than elsewhere, but I’d wonder if there are major differences in the lower regions. A very interesting topic.

        • 2025-06-01 06:09:17 PM

          Tim wrote:

          Very interesting point J.R;

          So you argue that the upper bound of resonance acceptability is valid at 12hz but the lower bound of 8hz is too high and that it should be lower?

          This would play well into arguments persuading people to a higher quality medium to high mass arm. Kuzma's latest Sapphire arm has an extremely high mass and I have personally wondered if there would be any cartridges that even come close to meeting the 8-12hz ballpark.

          • 2025-06-01 06:46:48 PM

            WallyTools -J.R. wrote:

            Correct. Respecting the 8Hz lower limit system resonance in high end audio makes no sense if one's goal is maximum faithfulness to groove content.

        • 2025-06-01 06:14:21 PM

          Tim wrote:

          Ive also heard arguments that an arm's ability to dissipate/extract resonance away from the cartridge is more important than the combined resonance frequency.

          • 2025-06-01 06:39:09 PM

            Come on wrote:

            I’m quite sure it is! And against warp effects, the counterweight closest to the bearing is also more important in my experience.

            But I assume bass control can anyway be connected to the spring/mass relation of a headshell-heavy weight distribution connected with too low compliance, even when unwrapped records are played on a well isolated table. But Wally folks’ detailed experiences will be more than interesting.

          • 2025-06-01 06:41:29 PM

            WallyTools -J.R. wrote:

            I have heard these claims before. It is among the most ill-advised tonearm/headshell design parameters one could conceive. I cannot imagine why it would be a good thing to TAKE energy away from the cartridge motor, particularly when you consider that doing so requires the dampening system to displace the structure holding the precious cantilever pivot location - which will inevitably lead to that displacement becoming part of the signal. Designers who claim such things are making changes to their designs, listening, hearing an improvement and ascribing the "improvement" to the wrong thing. It is a multivariate and highly dynamic environment (that of the cartridge motor and its tonearm) which makes making determinations on WHY and HOW to improve the system fraught with potential errors of omission and commission. We need to approach design claims made by tonearm manufacturers with a good deal of skepticism. Tonearms ONLY screw up the sound of a cartridge to greater or lesser degrees. They will never improve upon what the cartridge is capable of.

            • 2025-06-01 07:24:12 PM

              Come on wrote:

              Wow, I think this is one of your most spectacular assumptions, as it not only questions the principles of many tonearm manufacturers but also those of many cartridge and turntable manufacturers, where the dissipation speed of the material and the quality of the bearings (not only to guide the arm in the best way but also to ensure best resonance dissipation) is a key point. As I thought it is in most turntable designs from top to bottom up to the level where dissipation is intentionally lowered to my knowledge. I was sure resonance energy that arrived from cantilever at the headshell body isn’t something we’d want to keep around there. Your theory really turns everything I heard so far regarding the physical basics of cartridge/arm/turntable design upside down with no alternative idea I have yet. But what do I know ;-)

            • 2025-06-02 07:05:15 AM

              Tim wrote:

              I think the argument is (as I understand it):

              A cartridge, as a converter of energy (mechanical to electrical); is poorly inefficient as there is much that is lost (as either heat or vibration)...

              The argument is that what gets done with this 'lost' energy is important.. From a cartridge manufacture's point of view, which I believe Lyra argues, they try to repel as much of this lost energy out of the cartridge body as possible.. I believe Lyra achieve this in two main ways:

              1. Prevent internal reflections of this mechanical / vibration energy
              2. Mount the cantilever directly to body to more closely couple the generator to the thing that's holding it.

              In this sense, one could argue that taking this lost energy away from the generator is important?

              Very keen to hear your thoughts on this JR?

  • 2025-06-02 05:57:01 AM

    Tim wrote:

    @MF;

    I've said it before, I'll say it again: this site needs a forum... For exactly these kind of discussions. Let's bring the discourse forward!

    • 2025-06-02 09:25:38 AM

      Michael Fremer wrote:

      Certainly this subject needs to be further discussed! As for a forum, we just installed a "carousel" feature on the home page so one step at a time...

    • 2025-06-02 11:30:04 AM

      Come on wrote:

      The fun thing is…we’re getting “re-educated” every now and then, partly be the same people. Even JR over time revised certain previous theories (which I count as strength, not problem). At the end it’s probably simply physics and obvious (for a physicist, which I am not).

      If embankment dams would be built upon theories, guesswork and experiments as most turntable equipment is designed, then we’d be worse off. The good thing with turntable stuff is: as completely controversial or even antagonized some theories used are…the result more often than not sounds not that different ;-).