Strange Tonearm Tweak. Long

Ciao Tom,
thanks a lot, I already got an Expressimo stub and cw which satisfied me a lot! The idea behind your strange tweak intrigued me and I tried to estimate the math relationship between cartridge lateral compliance and additional rotational inertia given by your extra weights, in order to get a general solution...

I'll try to study it in a physical mood...

Ciao, Stefano

David, I like the hanging counterweight a bit better than either the stock OL counterweight or the Expressimo Heavyweight. Everything seems to be a bit more open and less "confined". A bit more "liquid". It's not a really big difference, like the HiFi mod is, but is provides a little more performance from the package. It is only suitable on the OL Silver(or Rega variants) because the Encounter and Illustrious have the different type of anti-skating mechanism and base platform differences which would interfere with the presence of the hanging counterweight. I tried to implement it on the Encounter when I had it here for audition, but it was not applicable to the Encounter.

Tom, any more musings with regard to hanging the "oblong" counterweight on the Silver in lieu of the stock counterweight?

Stefano, the end-stub kits for the RB250 are a good mod, if you don't already have that.

Ciao Tom,
thanks a lot for your kind answer!

Meanwhile, yesterday I tried with a small amount of tack and used 2 small bits of an unknown metal (each about 2,3 gr.).

I must say that, at least, I didn't hear any drawbacks with my Goldring 1042. Indeed, I seem I have listened to smoother and more extended highs. Bass are - quite - good (as before).

BTW, I'm going to some more DIY on RB250 (rewiring, remove lift, remove some paint at cartridge end), thanks for your suggestion!

Ciao,

Stefano

FWIW, I invented this mod because I cannot play in the upper stratosphere of high priced tonearms and other equipment. I have a budget, and so I only tried to make the most of what I could afford to buy. I have also tried to do stuff like this with my other equipment, so that I could have as close to "top end" sound as possible, given my low budget for purchasing. Necessity is "the mother of invention".

I would urge anyone who likes this HiFi mod, to experiment with Lowther single-driver speaker systems and low-power SET amps. That combination makes an exceedingly enjoyable result at the back-end of the signal chain too.

The mods that I've made to my Lowther EX4 equipped Voigt pipe cabinets makes a significant improvement to that design too. And the cone treatment that I used is very effective in virtually eliminating what is left of the "Lowther shout" from the current version of the Lowther speaker drivers. My cabinets only had one very noticeable flaw(within their intended spectrum range), which was a "hollow sounding" coloration in the lower mid-bass, from some cabinet resonance effects. This was totally eliminated when I placed the Sistrum SP-004 platforms under the speakers. It was miraculous in eliminating this resonance from the cabinets, and was one of the major factors in my eventually seeking employment with Starsound.

A well-tuned Voigt Pipe with Lowther drivers, using my "swinging doors" baffle mod, and placed on Sistrum SP-004 platforms, is one of the most musically enjoyable speakers that could be had for the money spent. Of course, my custom David Berning 45 SET-ZOTL is a very nice way to drive them, but any good quality SET of under 8 watts(with good output transformers) would be a nice pairing with these speakers. I am transfixed by the sound quality every time I play my system. It always puts a smile on my face, and sometimes I even have to get up and dance in the room.

I only say this, because most people have liked my tonearm mod, and I want to share some of the other things in my system that have given me equal improvement to my listening pleasure. I'm not going to make any speakers for sale, but the plans are on the internet, and anyone can email me for info about the mods, or proper tuning procedures for the Voigt Pipes, or the cone treatment.

Basically, the mods relate to eliminating the baffle-step losses associated with narrow-faced speaker cabinets, without resorting to electronic filtering, and the cone treatment stiffens the cone without adding mass which would slow down the speed. This changes the cone-breakup mode which coincides with the transition from main cone to whizzer cone in the critical upper midrange which is generally called "Lowther shout". It solves it. The SP-004 platforms are required to eliminate the cabinet resonance in the mid-bass region that happens because the lower half of the Voigt Pipes must be hollow.

Your welcome. Looking forward to even better things as this cart breaks in, too.

Thank you David. It means alot to hear accolades from someone who has heard as many analog products as you have.

That makes me feel real good!

And I'm happy that you got good results, too.

In a purely aesthetic vein, I was in the store other day to find weights for my OL Silver. In the store I visited, there was literally an array of lead and brass weights in a variety of colors. Black, which matched my arm perfectly, gold, silver, tortiose shell, neon colors. Some looked VERY cool. Guess the fish can tell a difference too!

I JUST set up the arm the other day with a Denon 103R. Tried it sans weights first and things were pretty damn good. Then, last night, I took two 1/2 oz. weights and drilled out the centers a bit and matched their weights on a digital scale until each was 11.75gr. Installed and spun again. OK, this invention is probably the biggest bang for the buck (well, actually cents) in the history of audio. The additional detail was not to be believed unless heard and the tightening of the bass was kinda scary. So much so that I wondered if it could actually be attributed to such a seemingly meager mod. But, I am not willing to take them back off to find out.

Bravo, Tom! Good work!

Stefano, thanks for your question, and I'm glad you enjoyed the thread.

In my opinion, a cartridge with a compliance of 25 is not going to move the RB250 laterally. The standard effective mass of the RB250 should be sufficient to laterally stabilize that cartridge.

I don't think that adding any additional horizontal mass would be productive in this case, and there is a possibility of causing a mismatch in mass/resonance if you do add horizontal mass to the tonearm with a high compliance cartridge, such as you have.

Hi TWL, thanks a lot for this great thread and information sharing. I just learned of your tweak. Owing a 250, with expressimo cw, and a cart with a much higher compliance 25 µm/mN (so 5 times DL103's one), I was thinking if, in your opinion, a linear model might be common sense in order to find weight lateral size.

In this case I immediately thougt of 12/5, i.e. about 2.4grams/each "stabilizer". Is it too simplicistic (apart from try and listen :-) )?
Thanks a lot, Stefano

Well Doug, it's great to be able to move up in the world. I'm real happy that the Silver and HiFi mod were able to get you through the early times with good results.

Here's to hoping it's more the latter than the former.

Both! LOL

So DougDeacon, does that rate a "Hiho, Silver. Away!" or a "live long and prosper"?

I'm sad to have to report that we have officially moved on. The TriPlanar doesn't quite match the HIFI-modded Silver for leading edge transients, as I noted above, but it excels in all other parameters. That's what you'd expect for 4x the MSRP of course, so that isn't exactly news.

What is news, and very good news too, is that a well-respected member of our little community has bought the Silver. It should enjoy an active life in a loving and appreciative home rather than doddering off into idleness in my attic. Even better, I believe it's headed off to college! Not only is the Silver rugged enough to survive that environment, I have every confidence it will help open the ears of another generation of music lovers to the musical truths of analog playback. Party on! :-)

This was our first high end arm. Thanks to Twl we started off right, with solidly implemented analog playback at a sensible price. A modded Silver is precisely on the cusp of the price/performance curve, exactly what we were seeking, exactly what Twl described. Paired with the right cartridge it represents enormous value for the money. IME that is as true today as the day this thread began.

At least we kept pictures. We will always have fond memories of those Silver days.

Thanks for the support, guys. Sometimes I just get a little tired.

Thanks, joe I was just needing a little reassurance. That's the company that I was looking at, only 5 days, AUH Yeah! When my Grado gets off auction tommorow I will have to order one, unless Doug sends that Shelter, hint,;)-~. Hey TWL don't let the nay-sayers get you down, just set up your force fields with positive energy and healing thoughts. They can't affect you if you don't let them. Remember it's all a reflection of themselves, that they are projecting, don't take it on. AAAUUUUUUUUUUMMMM:)

Oh, and I'm gonna try this tweak on a Rega/OL arm with the Denon, as soon as I decided upon and buy the arm.

Joe - Thanks for the 103R link. I ordered one of these today.

Colitas,

Get the 103r through Audiocubes 2. Look here:

Audio Cubes II

The price went up to $249 + shipping, but I think that's the best deal you'll find. I got mine from them, and it arrived in about 5 days. Not bad from Japan.

If you have not figured it out from this thread, Tom's tweak is a must do. Probably the most dramatic improvement you will ever make, especially for the money.

Tom,

I know what you mean. It has taken a lot of effort not to post on the Beta testers thread until I actually finish my tests. A prime example of how far off topic and ridiculous some posts can get. While I like to get sarcastic once in a while, as Paul did in his excellent "ninja" reply, the temptation to to actually call someone an asshole instead of just alluding to it as I did, is almost overwhelming.

Mr slate I'll be right over with those papers! Anyway, I still want to do the mod, but now need a good MC to use. I have started a new business with my wife, and plan on rollin' in the dough in a few weeks. Well at least as much as selling cookies to teenagers will allow. I believe I will go with a Denon 103r, just need to decide who to go through. Any suggestions? Then I will be ready to mod out my 250 to the final tilt. I believe I will leave the re-wire last, after reading Mr slate's post.

Doug, I really like the ZYX Airy. It is a great cartridge all-around. I have been recommending the ZYX cartridges for quite awhile. I'm sure you've seen my posting about them.
Right now my finances don't allow me the luxury of moving in that direction. I'm pretty much stuck where I am until things pick up financially for me.

Joe, I haven't been doing much posting here lately, because frankly I've been a little tired of some of the argumentative posters. It made being here much less fun than it used to be.

Ah, the magic of low level detail and micro-dynamic nuance. Yum. These allow the real humanity in the music to come through.

I "knew" this intellectually but had never really heard it until we got a new cartridge. Comparing the ZYX Airy to the Shelter 901 is perhaps something like comparing your amp/speakers to mine. There's little or no loss of macro-dynamics, but the Airy's ability to play down to very soft levels with subtlety and nuance really breathes life into the musicians. It's at least the equal of a Koetsu RSP in this regard, probably better, but without the syrupy warmth.

From what little I've found to read about them, all the ZYX models seem to share this trait, to varying degrees I suppose. I don't recall if you've heard one but I urge you to try. (That 501 can't last forever!)

Of course I should follow my own advice and consider changing directions with our speakers and amplifier. We're not quite ready to give up "full" frequency response though, particularly since we enjoy stuff like organ music with its low pedal notes. If you'll forgive the obscenities, would either a sub or active X-overs work in a setup like yours?

Thank you, Doug.

As you know, I am very sensitive to dynamics in general, since it is my belief that dynamics is where much of the emotion in the music lies. As music is an emotional expression, it is very important to me, to have this emotion properly conveyed. The power of macro-dynamics, and the subtle nuances of micro-dynamics, and their attendant emotional contexts really bring the intent of the composer and musicians to the forefront, and I need to have that in my musical presentation, as effectively as possible.

This is why I strove to find an improvement in that area for the tonearms. I just wanted to get that information off the record, and into my system.

It is also why I use very high efficiency speakers, which have an extremely low dynamic threshold. These speakers with 100db efficiency move at the slightest electrical impulse, and therefore have extremely good microdynamic performance. It would take a much higher level electrical signal to even get an 80db efficient speaker starting to move. This low-level signal resolution of high efficiency speakers is another key to hearing all the music available on the disc. I effectively reach down 10-20db deeper into the dynamic range of a recording with a system like this. Low level detail really comes out. My speakers are producing details which don't even get a "normal" speaker into motion.

Also, low power SET amps are very delicate in their presentation of the low-level details and can only power high-efficiency speakers like I use. The combination of these items together really makes a very enjoyable listening experience. Of course, I went with an incredible combination of OTL-SET and single driver loudspeakers, which do away with crossover distortion, and effectively drive the speaker cones directly from the output tubes, which doesn't hurt any.

A system is just that: a system. If you know what you want, and know how to get it, you can assemble a very enjoyable package of products which will really rock your boat. It doesn't have to be the most expensive, it just has to be what you like.

"Just a simple use of basic materials, properly applied."

Twl comes out of hiding, and then tries to hide behind himself with a masterpiece of understatement. Nice try Tom but I'm not buying it!

In addition to a HIFI-modded OL Silver, I've heard my Shelter 901 on the following arms:
- Basis Vector ($2,895)
- Graham 2.2/IC-70 ($3,900)
- TriPlanar VII ($3,900)
- Schroeder Reference ($6,500)

These arms outplay the $900 Silver in virtually every respect, as they should. But a HIFI-modded Silver tops them all in one parameter: the speed and extent of leading edge transients. None of these kilo-buck arms holds the cartridge as steady for the initiation of a big groove modulation. Referring back to some of the early discussions above, even the unflappable TriPlanar's adjustable damping does not stabilize the arm as well as the HIFI mod for attack rise times and amplitudes.

A HIFI-modded OL or Rega may be the best arm in the world for leading edge dynamics. Just a simple use of basic materials, properly applied. :-)

Anothet off topic post, but Tom, you are being awfully quiet on the Teres/Quattro thread.

First you disappear, then you leave the Teres torch to Doug, Lary, and myself.

SHAME ON YOU!!

Good to see ou back.

Mr. Slate, glad to have been of service to you.

Just a simple use of basic materials, properly applied.

Hi guys, and sorry to Twl for the OT. I bought my RSR fully assembled from SoundFountain. I believe Rudolph's taking pre-orders for another batch.

My only niggle is that the edge was a bit rough. This doesn't affect functionality, it just doesn't look as pretty as it might. Rudolph has switched suppliers in an effort to improve this.

Joe,
My short user review is posted on the site linked by Zaikesman, scroll down to near the bottom. Short version: several worthwhile sonic positives, no sonic negatives.

I'll start a new thread (probably tomorrow) so as not to continue this hijack. I have information that will be of value to Zaikesman and perhaps of interest to others as well.

Over the last year as time/$ have permitted I worked on trying to get my system to sound like what I thought it should sound like. I played a horn growing up and used to go see the Minneapolis Symphony perform with my family along with many rock/jazz concerts. My goal was to try and duplicate what I felt an instrument sounded like when played. Sometimes because of the venue you had really good acoustics but even in a good hall there are better seats than others. I was trying to get a sound that I felt would be in the middle maybe 20 rows back. Depending on the venue and what type of music or concert it is, especially in my high school days at a rock concert in a hockey arena, then the ambiance and acoustics didn’t matter because you were so high.

Ahem, anyway, jazz, blue grass or acoustic concerts of late have been seen at The Egg in Albany, NY, which is an outstanding venue and has extremely good acoustics. After doing a lot of reading on acoustics and listening to my digital front end I decided I had to fix the room before it could ever be close to something I would enjoy. I thought about building different designs and could have since I’m fairly handy but in the end I bought manufactured bass traps called Realtraps. Spent $1300 and bought 6 bass traps and 2 high-frequency traps. The traps are sized 2’x4’ and 2” thick. I have the HF traps located approximately at the side mirror points. 4 bass traps up on the front wall and 2 bass traps on the rear wall. This made a major difference in sound quality, smoothing and dampening all frequencies without taking to much out of the room and over-dampening it. I could now turn up the gain on the pre-amp without over-whelming the room and rattling the windows and floor joists. I would like to measure the frequency response of the room but haven’t done that since I don’t have the tools yet. I’d bet there are still improvements to be had here.

I finally finished building and finishing the maple table to sit my VPI-TNT 3.5 turntable on. I anguished over where to put the table because I didn’t want to screw up the sound stage that the Gallo speakers portrayed on the front wall. In the end, I really didn’t have any good choices and with restrictions on phono cable leads to the pre-amp and room considerations I had to set the table up right in the middle of the front wall. So far, this seems to be ok and I haven’t noticed any detrimental sound stage effects.

Spent the last couple of weeks twiddling with the TNT and all the different adjustments you have to go thru to get it right. I had bought a Wally protractor to adjust the Benz Micro Lo.4 moving coil cartridge mounted to an Incognito rewired, VTA adjustable Rega RB300. I also installed the Expressimo heavy weight. I had done all of the adjustments and it sounded pretty good but the instruments semed “thin” or “light”. There was bass but not with authority. There were drums but no “snap” to them. So I bought some 10K pots and made up adjustable cartridge loading resistors and installed them in the CAT pre-amp. After experimenting with these for several days it seemed around 300 ohms gave good results so I made up fixed 324-ohm load plugs and installed them. This made a fairly large difference and things sounded much better but it still didn’t sound really great. Not bad, just not what I felt it should given the quality of components. Still sounded “thin” and “light” compared to what I felt was a more dynamic sounding CD player. This annoyed me big time! I had bought TWL’s Hi-Fi mod last fall but because my TNT was down while I built the maple table I had never installed them. I hand reamed the 12-gram lead bullets out to 21/64’s which made the side walls really thin but they now fit over the bearing cap nuts. Super glued them in place and let dry for a day. Went thru all adjustments again being particularly anal.

This next part is going to sound so much like “me too!” What can I say? Now, dynamics kick ass! Full, solid, correct sounding. Bass lines and drums sound just like you think they sounded when recorded. A full dynamic sound but not so much that you feel it’s wrong.

I’ll give a couple of examples. I have the Classic Records release, 200 gram, Cat Stevens, Tea for the Tillerman, side 1, Hard Headed Woman, huge difference in bass, acoustic guitar, voice. Very solid dynamic sound. The authority just sounds right. Even my tin-eared wife noticed it easily.

Next: Pink Floyd, Mobil Fidelity, DSOTM, side 1, Money, Us & Them - I wanted to break out my rolling papers on this change. Really fabulous!! Bass, guitar, voice, all so much more real and dynamic sounding.

Next: Steely Dan, MCA, Gaucho, side 1, Babylon Sisters, Hey Nineteen – This was fantastic! Drums sounded like they were in the room, voice, horns, guitar, just great.

Finally: The Dave Brubeck Quartet, Classic Records release, 200 gram, Time Out, side 1 – all of it. For my ears this is my test record. Fantastic sax, outstanding drum work and some fine bass lines. I actually feel Dave’s piano is the weak link on this record. Anyway, maybe 10x better. Not really sure how to quantify how much better but it goes from sounding pretty good prior to Hi-Fi mod to just plain F****** great!

Call it $1 buck for lead weight and $1 for super glue and I get this kind of improvement? I know the Incognito rewire and Expressimo heavy weight didn’t make this much difference and they cost several hundred. Yes, I think they made a difference but not to the degree these stupid lead weights made.

Maybe my best analogy would be when I installed a stage 3 hot chip in the computer of my turbo Audi S4. It went from sort of quick to bat out of hell get to know your local state trooper fast. It really made a quantum difference and that’s what these lead weights did. If Tom charged several hundred for it you would still after hearing the change think it was worth it. Thanks Tom! Now, where are those damn papers…

For pics of my system see:

http://forum.audiogon.com/cgi-bin/fr.pl?vevol&1054441548&read&3&4&

Doug,

I know you posted about the ring, but damned if I could find it. I'd like to know what it cost too.

Joe

Doug: Sorry to go off-topic for a sec, but I noticed at soundfountain.com Audio & Music Bulletin that you were using the RSR outer record ring. Did you make yours, or buy it complete? If it was the latter, what do you think of the pricing for the quality? From the text it seems implied that one could be fabricated for my SL-1200, though I don't know if it would fit in between the platter and my KAB damping trough...

Yes Doug, as you know, the HiFi mod is related to matching the cartridge to the effective horizontal mass of the arm, and can therefore be mismatched, if the cartridge has too high compliance for this mod.

It is not "universal" in application.

Thanks for your observations and comments.

Hi Tom,
A few months back someone on VA tried to compare a 103R and a Shure V15xMR on a HIFI-modded RB250. Not surprisingly, the Shure came a poor second. I told him he'd have to remove the Mod or remove the Shure. ;-)

He apparently was under the impression his modded arm would improve the performance of any cartridge. Strange that anyone could think so after reading your first post on this thread but apparently he had missed the point, so I guess it can't hurt to reiterate.

Cheers, good to see you posting again!

Very glad you all are enjoying the mod.
Thank you for your kind comments.
My satisfaction comes from knowing people are getting better sound by using my invention.

Still a 100% success rate, no dissatisfaction ever reported.

This may be the only audio item that everybody likes.
It seems that the major considerations for universal appeal are:
Great sonic results,
Very low price.

BTW, I just read on the OL website about their new "Conquerer" tonearm(new "flagship model", over $4k). It seems one of the major upgrades has been to increase the lateral(horizontal) effective mass even further.
Where have we heard that before?
It feels very good to have been on the vanguard of a trend in tonearm improvement.

"H.I.F.I" = Horizontal Inertia Force Increase

Note: Remember this mod is designed for cartridges with compliance ratings of 15cu or below. No Grado or other high compliance cartridges should be used with this mod, as it does not help with a "whippy compliance" cartridge, and may cause Grado cartridges to do the "Grado wobble" because of mismatch. It gives the most satisfying results with low compliance cartridges like Denon DL103 and 103R, Shelter, Koetsu, and the like, with below 10cu compliance rating. Cartridges with 10-15cu compliance rating will get a good improvement too, but not quite as astounding as the lowest compliance ones. The lower compliance the cartridge is, the more likely it is to "overdrive" the horizontal effective mass of the tonearm, which is why the HIFI mod works so well with lower compliance. A higher compliance cartridge may likely already be horizontally stabilized by the standard effective mass of the arm, and needs no change in that parameter.

To all, and TWL especially - changed over my cart to a Denon DL-103R, with the bullet tweak previously installed. After setting up and burning in the cartridge (TWL - no VTA adjustment needed on the Rega!), I can easily attest the DL-103R with the tweak is a wonderful match. This cart nearly nailed the HFNR Test record's torture track, and IMHO that is saying something. What a pleasure to listen to, and I'm happy to have the $$$$ in my pocket that I could have spent on much more pricey carts. TWL, thanks again for the recipe and advice, esp. on the DL-103R.

Tried this with my Rega P25/RB600/cart setup and it works great. Used the yellow "blu-tack" mentioned within the thread, and steel bullets (can't find any lead ones in NH, but if someone whats to ship me a pair, feel free to send some up here!). I also have a Denon DL-103R on order, and am interested to see how the tweak works when the Denon's installed. I know the DL-103R isn't supposed to be the perfect match for the P25/RB 600, but thread comments have convinced me using this tweak with the Rega will prove otherwise.

What a great low-cost removable upgrade - thanks!

I found this thread from a post today on the AA Vinyl Asylum.

Anyway, I came, I read, I tried the mod. I have an RB250 with the OL stub/counterweight, OL rewire, etc. I just superglued the 7/16OZ bullet weights to the bearing caps and got on with it. The results...

Wider and more 3D soundstage, initial bass impact is much snappier (but not deeper). Its like everything became more focused. The highs got a lot better - I had no idea how mushy my setup was before. Good stuff.

But the best improvement is that well-recorded pianos now have that chesty piano sound, instead of a throaty piano imitation. Real, full, reverberant piano. Shweet.

Thanks TWL and all for the best $.79 I've ever spent in audio.

Pete Fowler, Austin TX

I agree, I did it and was amazed.

I believe!!!

For less than $5, I purchased 2 fishing weights from the Bass Pro Shop and some Blu-tac equivalent from the Home Depot. It took 3 attempts to figure out how much blu-tac equivalent (actually, mine is yellow) to use, but I no longer feel the need to pull out the super glue. The weights haven't slipped for a week now.

I have noticed that my OL Silver / Shelter 501 is now even more sensitive to VTF (1.85 grams by my Shure seems to work best for me).

If you have an arm / cartridge that could benefit from this tweak, you are a fool if you do not try it. For less than $5, this non-permanent mod is a must.

Hi,
The standard RB250 has end caps which are pressed into the bearing yoke on both sides. Sometimes these are already removed. If they are still there on your arm, and you don't want to mess around with taking them out, then just apply these same principles to your application by grinding a depression in each fishing weight that approximates the curve of the brass end caps. Then glue or Blu-tac the weights right to the brass end caps, and you are ready.

Be careful to choose a fishing weight which is shaped such that it will not interfere with your cueing lever.

Twl:
I've just looked over my OL RB 250 tonearm and I don't see where one would "press fit" the weights. There aren't any real "nuts" to press them onto. Did you remove something else on the tonearm?

Speaking of what goes on behind the counterweight, that's where I would work on putting the fluid damping trough, to get the paddle farther from the pivot point than is normally possible on the platter side of things. (The Townsend trough-at-the-headshell-over-top-of-the-spinning-record design notwithstanding, which makes me nervous and seems like it would be a bit of a pain in the butt when it comes to actually playing a bunch of records, although I'm sure that it is the most effective implementation possible from a damping standpoint). So instead of having a relatively massive counterweight very close to the pivot, I'm imagining an extension of the tonearm continuing to the rear, terminating in the damping paddle, with only a relatively light counterweight needed.

I just had an intriguing thought: mightn't Tom's idea be somehow translatable to and beneficial with the Well Tempered tonearm suspension design?

Alex,
You're right with all those ideas I think. That would make an arm very broadly compatible, especially if a couple different counterweights were also included. Then one could really tune in both vertical and lateral moving mass. Whether resonances at the threads would be a problem I don't know, but quality machining and very fine theads would help, and they'd give finer adjustability too. Maybe a Delrin female thread insert to prevent metal-to-metal contact?

Another idea I'd like to see is a VTF fine-tuning adjustment screw that threads into the back of a locked down counterweight. You could quickly add or subract a few 100ths of a gram by moving the screw in or out without having to move the C/W and remeasure. Big benefit for VTF-sensitive cartridges like Shelters. We change VTF every time the weather shifts: 1.95g in January, 1.70g now, who knows in July. The screw would be quite tiny, we do small VTF adjustments on our modded Silver with a rotating paper clip mounted on the HIFI weights.

Of course I'm never retreating from my main position: Kuzma Air Line or bust!

Tom, just to clarify, what I wrote was intended to describe a tonearm having *not only* a conventional counterweight, but *also* side-weights mounted as you specify (I included the detail about bearing-axle concentricity, for instance) - *not* a counterweight with side-weights added to *it*, as it seems you may have aprehended.

Doug, thanks for making clear that you posted earlier about the idea (which I'm sure Tom must have also had from near the beginning) of making the side-weights adjustable. I've thought about this a little more, and come to the conclusion that a production tonearm with this feature would probably need both a provision for threaded-post fine adjustability, plus a small assortment - maybe three different mass values - of exchangable side-weights, to yield a practical working range of variability that's broadly compatible with cartridges of differing compliance. As far as the potential sore point of resonance at the threaded (or whatever) junction goes, I don't think this looks too bad: you already have an adjustable counterweight that's affixed to the tonearm proper, so doing something similar that's on the bearing axle - rather than directly in the tonearm 'mechanical path', such as a detachable headshell - doesn't seem overly daunting to me.

Basement, I agree that placement of mass, as well as the amount of mass in various planes, is very important to the overall success of a tonearm design. This is still an evolving art/science, even after all these years. A natural inquisitive nature is needed to spend time thinking and testing new ideas. Maybe some people will be spurred into making the next leap forward to a totally new tonearm design, or just the next evolutionary discovery, after reading some of our posts here. In any case, I think this thread has become one of the real reasons why forums can be so good for the development of the hobby.

I really appreciate all of the posts and ideas that have been presented here on this thread, in a most genuine way. Maybe all of us "tonearm geeks" needed someplace to converse. I'm glad it is working out the way it is.

Alex, as you mention, the actual lateral mass is the combined mass of the tonearm, cartridge, counterweight, bearing housing, AND my added weights. All arms, of course, have some amount of lateral mass built-in as part of the basic components. Usually it is similar to the vertical mass. But some tonearms have designed-in some additional lateral mass to give similar benefits as the HiFi mod has, notably the OL Encounter and Illustrious which do not need my mods.

Regarding your multiple resonance point theories, I think it has merit. By distributing the 2 resonance points over a wider range, it will have less additive effects resulting in lower amplitudes, but over a wider range. By keeping this range small and in the "ideal" range between 8Hz and 12Hz, the additive amplitudes can be minimized and still not have adverse audible effects. In Doug's case(Shelter cartridges) the 11Hz vertical and 9Hz horizontal both fall in the "ideal" range, and are wide enough apart to reduce additive amplitudes. This will result in significantly less mass/resonance amplitudes compared to having both(vert.& horiz.) resonating at the same freq. and causing a doubling of the resonating amplitude. In an ideal world, we could try to produce these amplitudes at the exact same point, but 180 degrees out-of-phase, thus causing cancellation of the resonance altogether. I haven't figured out how to do that yet. So this narrowly distributed resonance may be the best way to go so far.

As far as the idea you had about the counterweight with side-weights, the weights must be located exactly at the pivot axle, or else you are adding mass to the vertical component. My weights are small-diameter, and concentric with the center of the rotating bearing axle, so they have minimal(if any) effect on vertical mass. All of the HiFi mod effect is on the horizontal mass, so as to keep vertical mass unchanged, for good warp tracking. In addition, having the weights made of lead will damp any resonances that might adversely affect the performance, and the extra weight attached to the axle actually makes the axle itself less likely to become excited or chatter in the bearing clearances.

In some cases, a very simple idea or device can address a wide range of problems effectively, as long as it is well thought-out. I have resisted doing any big changes to it, since it is working so well as it is.

I think this thread is turning out to be a lot of fun.

Doug, I thought about making the weights threaded for adjustability, but finally decided that it left too much to chance. Also, any threaded pieces will set up resonance points at the joints, unless very securely locked, and even then they could still have some(ie. removeable headshell joint). They are right on the axle, so resonance could be a problem. Also, that would raise the cost noticeably. It would be worth a try for an experienced user who knows what he's doing with cartridge compliance matching.

I'd be willing to make some units with adjustability for someone, but the machining costs and labor might make them quite expensive on a small scale manufacturing basis. I've talked with the guys at Starsound about making this item in a more professional(and possibly adjustable)form, but so far it is on the back burner.

This plain model that I'm making has a pretty good working range for most cartridges(5cu-15cu), and is simple and cheap.

There are some really interesting thoughts here in the last few post, as far as thoughts or ideas that eventually turn into knowledge. It is for one useful when we attempt to measure and discover that the measurements are not exactly what we expect- we figure out there is something else going on and we learn something. One thing pointed out here is that the grooves of a record are cut at a 45 degree angle-so then how could a horizontal mass not have an effect on vertical mass? (as it relates to its affect on the suspension). I wonder how these grooves are cut into these various test records that are able to relate to being able to determine separete vertical and horizontal resonences, and wheather these are still existing the same way when the same system is playing a record with grooves cut at 45's. My ears suggest that as I listen to the differences with this particular mod is there is greater channel separation.
We all know that resonence points are important, and tonearm designers are sure to make sure they're designs fall within these parameters. There is also a definite importance on mass, and the placement of such, as it relates to the evacuation of energy, and it is clear in the more recent trends of the better tonearms that have recently added mass to they're arms in particular areas and gained improvements.
A little earlier on in this thread it was brought to our attention that the sidewieghts could be used to effect a change in anti-skate behavior. It made me think about the effects of bearing placement, as it relates to weight (or mass) placement, as it relates to the behavior and tracking ability of the arm. In both the immedia and the sme, the bearings are placed by the designers to minimize tracking error, according to the relative travel of the arm, BUT, changing the placement of the mass in a similar way, such as some of the aftermarket rega counterweights, and the upgrades on the graham, show similar results, without changing bearing placement.
The best unipivots in use today, namely the graham, the immedia, and the vpi, pay close attention to the placement of mass because they have to-it relates directly to the stability of the arm as it relates to tracking- and as designers shift and add mass, they continue to get better results. It is also, perhaps, that as the same attention is payed to pivoted arms, we get the same results, which might lead to the conclusion the while there are advantages to a unipivot as it relates to bearing quality/cost and friction, that perhaps it has more to do with the placement and attention of the mass.
Another case in point might be the popularity and performance of air bearing designs. Very complicated, and while they do show themselves capable of a high level of performance, it was a matter of time until pivoted, and unipovoted arms showed many of the positive aspects of the air bearing designs without the complications. Could very well be, that the sole advantage in actual use, of these air bearing designs is the vertical/horizontal mass relationships inherent in they're designs.
Of corse, the very best arms are very expensive, and rightly so because of the costly construction, as it seems that often certain improvements and uprades are costly to execute. There are some aspects of some costly arms where the quality of the construction relates directly to the performance. And then there are some aspects where improvements are made to the design that are by chance, or because the designer thinks the improvments are the result of what the intention is. That is why this thread is so fun. That is where this thread is at, and that is also why it is so amazing that as TWL comes up with these ideas and experiments that seem to break the rules, it not only forces us to change our perception of what a "properly" designed tonearm is, we make great sounding improvements that I am convinced would further the technology the more we understand them.