Trying to understand compliance/tonearm weight (RE: choosing between carts for my Technics SL-Q202)

[mumblethief]

Hello!

So I recently peeked my head back into the world of Vinyl (after some clueless experimentation a number of years ago). This is my first time trying to educate myself enough to "do things right," and I could really use some help as the minutia of this stuff can get overwhelming pretty fast!

So here's my current situation: I recently acquired a used Technics SL-Q202 fitted with a Stanton 680 EE cartridge and a D680 stylus. I have read that, first off, I should replace my used stylus (it plays pretty well to my un-calibrated ears, but I want to make sure I'm not damaging my new records).

I had read that the AT95e is a solid cart, but was hoping to find a replacement stylus for my Stanton, more for aesthetic reasons than anything else, since I don't have much personal experience to go on in terms of difference in sound.

I am in Canada, and, in my search for a cheap replacement stylus I found THIS (with the Stanton d6800 (681eee) being the one compatible with my cart) and THIS AT95e.

I emailed the seller, asking some basic questions. Their response that the compliance of the AT95e might better match my tonearm, but that the Stanton is better, was quite thorough and helpful, but has it forced me to try and figure out just what compliance is and how to apply this knowledge to my decision, which has not proved to be less than simple. I believe I now understand the basic concept just fine, but when I try to use tools such as THIS, I get completely lost.

Which brings me to now, trying to figure out how to match a tonearm with a cartridge in general, and specifically, trying to figure out whether I should buy the replacement Stanton stylus (I have been assured they are new and original, sourced from JICO, and simply without logo), or the full AT cartridge for my turntable.

Any help will be thoroughly appreciated!

Thanks,

- chris

BONUS QUESTION:
Semi-relatedly, if I do end up with one new and one used Stanton stylus, is it a good of bad idea to swap them in and out as I play records in better or worse condition (using the old one for random thrift store curiosities, etc)? Basically, is there any harm in repeatedly plugging and unplugging styli like that (presuming careful removal/storage/etc)?

 

[bang4buck]

Hi and welcome to the forum.

The easiest answer first, no, repeatedly installing and removing the stylus is not harmful. Some cartridges make it a lot easier than others, though. Stantons are among the easiest.

Compliance versus mass is a lot like springs on a car. Light car plus stiff springs means a very rough ride (think British roadster), heavy car and soft springs means it feels cushy most of the time but can easily bottom out on a real bump (think 70s American). Those are the extremes, of course. A milder mismatch means you’re not harming your stylus or the record, but you’re not getting the best results in terms of sound quality.

To use one of those calculators, you need to know the effective mass of the arm, and the compliance value of the exact stylus you’re using. Those two should intersect within the green area.

Your Technics tonearm is probably on the higher mass end, being S-shaped with a detachable headshell, and the Stanton stylus is probably too soft for that. You could use a “stiffer” (low compliance) stylus but Stanton originals are difficult to find. The Jico is NOT original.

I would agree that the AT95E is almost guaranteed to work better. They have just announced a completely revamped model lineup, so you may want to wait for those to hit the market, or grab the discontinued model if you find a sale price.

Lastly, the used stylus may still be perfectly fine, but it takes a microscope and lots of experience to tell for sure. Buying new is a good idea.

 

[bang4buck]

By the way, your first embedded link up there is not working for me.

A great first stop for reliable stylus information is http://www.thevoiceofmusic.com/catalog/phono_needles.asp

Often called TVOM around here. Don’t worry about the antiquated look of the website. It’s a very active and reliable source. I believe Gary, the owner, runs the business all by himself, but he really knows his stuff and keeps the site up to date. Highly recommended. Hopefully postage to Canada is not a deal-killer. Pfanstiehl numbers 822 and 824 fit your Stanton. So does 606 for the Pickering XV-15, but they look different (Stanton and Pickering were the same company).

For a new cartridge, another Audio-Technica that should work very well at under $30 US is the AT91.

 

[mumblethief]

First off, thanks for the warm welcome!

Second, sorry about the broken link -- should be fixed now!

Thirdly, thanks so much for the thorough answers bang4buck! That it /is/ all right to swap in and out the stylus makes me want the Stanton to work even more, but I suppose in the end having one good stylus is better than two sub-par XcP

Thanks as well for the recommendations of both website and models. The shipping + conversion rate does threaten to push most US sellers out of my hopeful price range, but it's always worth a look (and could certainly come in handy in the future when budget is less of an issue!).

I think I'll start by taking another crack at parsing those calculators to confirm whether I should avoid the Stanton. If that is the case, then I'll do some more research on the difference between the two Audio-Technica models.

Thanks again!

 

[tnsilver]

Which brings me to now, trying to figure out how to match a tonearm with a cartridge in general, and specifically, trying to figure out whether I should buy the replacement Stanton stylus (I have been assured they are new and original, sourced from JICO, and simply without logo), or the full AT cartridge for my turntable.

Welcome to AK!!!

I'm not going to answer your question directly. Instead, I'm going to teach you how to answer this on your own for any tonearm and any cartridge.

It's not tonearm weight nor tonearm mass - it's effective mass which is the layman term for inertia. The tonearm can weigh 400 grams while it's EM can still be just about 12.5 grams. It's a number that basically tells us by how much the tonearm resists the movement of the stylus while it vectors in it's own directions as it reads the groove modulations. The number is an indication of suitable carts. EM plays together with the cart's compliance, which is just a fancy word for the springiness of the cantilever. Think of this interaction between inertia and springiness as the road handling of an 18 wheeler with a Toyota suspension or a VW beetle mounted on a pickup chassis. Not so good - is it? Same applies for tonearms and carts. High effective mass tonearms (commonly but not accurately related to as 'heavy') go together with low compliance carts. Low effective mass tonearms act well with high compliance carts.

To find a matching cart for your tonearm, you will need to know it's effective mass and the cart's level of compliance, plus some basic info about the cart, such as it's weight (mass). There are ways to measure effective mass of a tonearm, but to KISS it, we usually query the manufacturer's specs. The VE tonearm database is a useful tool for that purpose. Cart data can be found on the VE cartridge database. Technics common turntables tonearms (SL-1200) are about 12 grams (with the SL-Q202 probably rated at 11 grams). You will need the dynamic compliance as measured at a 10Hz frequency. This is important and I will tell you why in a bit.

Compliance is typically given in SI units (like micrometers per milliNewton or X times 10-6cm/dyne) that are meaningful to scientists but not so much for the public, so in our domain it's just referred to as 'cu' for compliance units. To make it worst, dynamic compliance (as opposed to static compliance) is how springiness reacts to a frequency and there seems to be different accepted values for the frequency used in the measurement throughout the industry. Japanese carts specs are almost always at 100Hz, while European specs are at 10Hz, all at the same time some US mfgr's (Shure) just state static compliance. There are no conversion formulas between values stated in different frequencies. It's common to multiply Japanese specified dynamic compliance at 100Hz by any number between 1.5 and 2.0 in order to convert it to dynamic compliance at 10Hz, but that's just a ballpark method and anyone can just pick a number in the range. So, for example, if an Audio-Technica AT-OC9ML cart is specified to have dynamic compliance of 9 x 10-6cm/dyne (or 9cu), because it's Japanese, we assume it's at 100Hz and this means it's probably 13.5cu to 18cu in European terms at 10Hz. A Japanese Denon DL-103 with 5cu is assumed around 10cu at 10Hz.

So why is this important? Because one common way to tell how a tonearm handles a cart is predicting the resonant frequency. The resonant frequency is an uncontrolled cascading vibrational effect that's going to plague the cantilever at some frequency. It's a fact of life for any spring induced with vibrations. We can't eliminate it but we can control (or limit) the frequency at which this happens. We want to keep it below the lower end of the audible range (20Hz - 20KHz) because above it it's too violent. However, even at the bottom end, we're restricted by some environmental frequencies such as footfall (6Hz -7Hz) and we wouldn't want to induce a resonant frequency to the cantilever every time we walk across our living room floorboards or someone slams the garage door. To mitigate it, we've come up with some sort of Goldilocks range for resonant frequency (RF) which is above foot fall but bellow the human lower audible threshold, and it's between 8Hz to 12Hz or better yet 9Hz to 11Hz. The way to nail it is to match the compliance of the cart with the effective mass of the tonearm, taking into account the extra inertia that's added with the cart's own weight at the tip of the tonearm, and get the RF in a desired range.

The way to do it, in a nutshell, is simple. Find the compliance that will yield RF in the Goldilocks range for the effective mass of your tonearm. That's more or less like finding the right suspension for a VW beetle or an 18 wheeler truck. In practice it involves some elaborate math for which we don't care too much right now. There are tools for the job just as well.

One of these excellent tools is the VE "Cartridge Resonance Evaluator" which is linked to from the effective mass column in the tonearm database. I've changed that link URL to include 11 grams of effective mass but you can do this right here. Notice the Y axis is compliance in cu@10Hz and the X axis is the total mass (yes, this is weight this time) of the cartridge plus the mounting screws and washers, which can generally be thought of as an extra 0.5 gram mass. Anything in the green zone is a good cart match for your tonearm!

More of the same is the VE Resonance Calculator as part of their cartridge database tools. Here, you are practically asked to enter your tonearm and cartridge parameters and you get the resonance frequency to be your own judge of the result.

You already know the effective mass of your tonearm. Assume it's 11 grams. All you got to do now is find out the Stan's compliance, or the AT95 or any replacement stylus for either of those. Just make sure it's in cu@10Hz, then use the tools above to figure out the resonance frequency. Once you know how it works, the hardest part sometimes is just collecting the data.

Best of luck with it!

 

[sqlsavior]

Seeing as how original Stanton styli are becoming scarce, I wouldn't be too quick to assume yours is worn out. Non-visual clues that may indicate a worn-out stylus are excessive sibilance, and a need to clean the stylus often. If you don't have these problems, you can play it until you do.

 

[mumblethief]

Thank you so much for putting in the time to teach this new skill @tnsilver It is very satisfying to seek out the data and work it through the various tools. Also, thanks @sqlsavior -- I very much like the idea of that being the case, though I'm not sure I would recognize an excess in sibilance? Any tips?

Regardless, I would still like to figure this out. At first I got different results with each calculation tool, but I seem to have worked out whatever error I was making, and they now yield these results:

When using the Cartridge Resonance Evaluator, I make sure that the tonearm effective mass is set to 11 (which is indeed correct according to the maintenance manual PDF I dug up). The Stanton 680EE cartridge is listed as having a mass of 5.5, and a dynamic compliance of 18 x10-6cm/Dyne (aka 18 cu I believe?). I add the .5 grams for the mounting hardware, bringing the cartridge and mounting hardware total mass up to 6. I then consult the chart output from the Cartridge Resonance Evaluator, going to the 6 gram column and the 18 cu row, which lands at 9Hz, as perfectly in the middle of Goldilocks' green belt as possible.

With the AT95e, I do the same thing, keeping the mass the same (though it is really .2g heavier, the chart moves in .5g increments), and estimate the 10Hz compliance to around 11 (it is listed as 6.5 in the database). Consulting the chart, this lands us at 12Hz, in Goldilock's midriff, just above her green belt.

The resonance calculator yields similar, though more precise results: 9.09 for the Stanton and 11.56Hz for the AT cartridge.

I am a bit surprised by this, as the unanimous response has been that the Stanton would be a bit too high compliance, and the AT more closely matched. My results show the opposite, though I wonder if my compliance upscaling (due to the Japanese standards you mentioned) might be off, or perhaps some other error? I hope not though, as I like these results :0D

 

[tnsilver]

You pretty much nailed it!

I'd go with 13cu@10Hz for the AT95 but your guess is as valid as mine and it doesn't make that much difference.
Although the cartridge database mentions the Stanton figures are static compliance,
the 18cu figure for the 680ee is dynamic, as confirmed by the Stanton product catalog (p-15).

The higher compliance Stanton carts are the 681eee (25cu) and the 881/991 (30cu), not the 680.
For better or for worst, you got your self the correct answer!

BTW: Static compliance, according to some sources, needs to be halved to reflect dynamic compliance at 10Hz.

 

[bang4buck]

Excellent, so whoever picked the cartridge back then did know what they were doing. 11g eff. mass is a lot less than I would have thought, that’s working in your favor. You should check that you have the original headshell, though.

Unfortunately this still doesn’t help you find a new Stanton stylus as they haven’t been in production for probably 20 years or more. Aftermarket styli for Stanton/Pickering are rarely worth it, but some recommendations can be found in various threads here on AK. Our search function actually works!

One last thing, keep in mind that the VE database is basically a wiki. Take it with a grain of salt.

 

[mumblethief]

I'm away from my computer so forgive my brevity and typos, but I think we've uncovered some fresh potential ignorance in my part!

What I'm wondering now is if I've misunderstood how the terms "cartridge" and "stylus" apply to calculating resonance?

I've been entering the information of the 680ee cartridge I currently have installed on my turntable as, if I understand correctly, I would still be using it with the replacement d6800 (681eee) stylus from my initial post installed inside if I went that route.

Should I in fact be entering the data you reference above corrisponding to the 681eee? Basically is it the cartridge, or the stylus in the cartridge that must be taken into account when calculating resonance? Or am I misunderstanding those terms altogether?

Also, many thanks for the cautions about static compliance and wiki-level database reliability!

 

[tnsilver]

It's the cantilever that determines the compliance. If you were to mount a 681eee stylus in the body of a 680ee, it would be 25cu.

 

[mumblethief]

Ahh! Thanks for the clarification! When one pauses to think about it, I suppose that's the only thing that really makes sense xvP

In any case, I went for the 681eee! I figure it's cheap enough, worst case I just resell it and move on. I'm also excited for the opportunity to easily compare and contrast it to my current needle to help get a feel for how different stylus' effect sound (and hopefully help divine how damaged my previous one is).

Again, thanks so much to you all for giving so much patient and thorough help and information!

- chris

 

[tnsilver]

I went for the 681eee! I figure it's cheap enough

by all means, lemme know where one could obtain a cheap enough 681eee stylus...

 

[mumblethief]

Hmm, perhaps I misspoke? The stylus I'm getting is the one listed HERE. I'm still not quite solid on correct nomenclature, so maybe it's technically a Stanton d6800, which is a replacement for a 681eee? Is that how this works? Despite having learned quite a bit over the last day or so, much still alludes me!

 

[the_nines]

Welcome to AK!!!

I'm not going to answer your question directly. Instead, I'm going to teach you how to answer this on your own for any tonearm and any cartridge.

It's not tonearm weight nor tonearm mass - it's effective mass which is the layman term for inertia. The tonearm can weigh 400 grams while it's EM can still be just about 12.5 grams. It's a number that basically tells us by how much the tonearm resists the movement of the stylus while it vectors in it's own directions as it reads the groove modulations. The number is an indication of suitable carts. EM plays together with the cart's compliance, which is just a fancy word for the springiness of the cantilever. Think of this interaction between inertia and springiness as the road handling of an 18 wheeler with a Toyota suspension or a VW beetle mounted on a pickup chassis. Not so good - is it? Same applies for tonearms and carts. High effective mass tonearms (commonly but not accurately related to as 'heavy') go together with low compliance carts. Low effective mass tonearms act well with high compliance carts.

To find a matching cart for your tonearm, you will need to know it's effective mass and the cart's level of compliance, plus some basic info about the cart, such as it's weight (mass). There are ways to measure effective mass of a tonearm, but to KISS it, we usually query the manufacturer's specs. The VE tonearm database is a useful tool for that purpose. Cart data can be found on the VE cartridge database. Technics common turntables tonearms (SL-1200) are about 12 grams (with the SL-Q202 probably rated at 11 grams). You will need the dynamic compliance as measured at a 10Hz frequency. This is important and I will tell you why in a bit.

Compliance is typically given in SI units (like micrometers per milliNewton or X times 10-6cm/dyne) that are meaningful to scientists but not so much for the public, so in our domain it's just referred to as 'cu' for compliance units. To make it worst, dynamic compliance (as opposed to static compliance) is how springiness reacts to a frequency and there seems to be different accepted values for the frequency used in the measurement throughout the industry. Japanese carts specs are almost always at 100Hz, while European specs are at 10Hz, all at the same time some US mfgr's (Shure) just state static compliance. There are no conversion formulas between values stated in different frequencies. It's common to multiply Japanese specified dynamic compliance at 100Hz by any number between 1.5 and 2.0 in order to convert it to dynamic compliance at 10Hz, but that's just a ballpark method and anyone can just pick a number in the range. So, for example, if an Audio-Technica AT-OC9ML cart is specified to have dynamic compliance of 9 x 10-6cm/dyne (or 9cu), because it's Japanese, we assume it's at 100Hz and this means it's probably 13.5cu to 18cu in European terms at 10Hz. A Japanese Denon DL-103 with 5cu is assumed around 10cu at 10Hz.

So why is this important? Because one common way to tell how a tonearm handles a cart is predicting the resonant frequency. The resonant frequency is an uncontrolled cascading vibrational effect that's going to plague the cantilever at some frequency. It's a fact of life for any spring induced with vibrations. We can't eliminate it but we can control (or limit) the frequency at which this happens. We want to keep it below the lower end of the audible range (20Hz - 20KHz) because above it it's too violent. However, even at the bottom end, we're restricted by some environmental frequencies such as footfall (6Hz -7Hz) and we wouldn't want to induce a resonant frequency to the cantilever every time we walk across our living room floorboards or someone slams the garage door. To mitigate it, we've come up with some sort of Goldilocks range for resonant frequency (RF) which is above foot fall but bellow the human lower audible threshold, and it's between 8Hz to 12Hz or better yet 9Hz to 11Hz.

The way to do it, in a nutshell, is simple. Find the compliance that will yield RF in the Goldilocks range for the effective mass of your tonearm. That's more or less like finding the right suspension for a VW beetle or an 18 wheeler truck. In practice it involves some elaborate math for which we don't care too much right now. There are tools for the job just as well.

One of these excellent tools is the VE "Cartridge Resonance Evaluator" which is linked to from the effective mass column in the tonearm database. I've changed that link URL to include 11 grams of effective mass but you can do this right here. Notice the Y axis is compliance in cu@10Hz and the X axis is the total mass (yes, this is weight this time) of the cartridge plus the mounting screws and washers, which can generally be thought of as an extra 0.5 gram mass. Anything in the green zone is a good cart match for your tonearm!

More of the same is the VE Resonance Calculator as part of their cartridge database tools. Here, you are practically asked to enter your tonearm and cartridge parameters and you get the resonance frequency to be your own judge of the result.

You already know the effective mass of your tonearm. Assume it's 11 grams. All you got to do now is find out the Stan's compliance, or the AT95 or any replacement stylus for either of those. Just make sure it's in cu@10Hz, then use the tools above to figure out the resonance frequency. Once you know how it works, the hardest part sometimes is just collecting the data.

Best of luck with it!

Awesome post, sir.

 

[Thomas_AA]

Note that the 8-12 or 9-11 hz ”optimal” resonance frequency is a simplification. Looking at the vertical resonance it should be at least one octave above the warp frequency. The records have warp frequencies in the range of 4-6 Hz meaning that 12 Hz or higher is a ”safe” resonance fr in the vertical direction. The upper limit is the music content which is around 100 Hz for the vertical movement. The vertical resonance fr should be at least one octave below the lowest fr in music. So in the end it should ideally be somewhere between 12 and 50 Hz.

Looking at the horizontal movement the resonance should be between the 0.55 Hz and the lowesr bass notes 15-20 Hz (or 40 Hz since most records do not contan info below 40 hz).

In conclusion a vertical resonance of 20 Hz and horisontal resonance of 5 Hz is perfectly fine and can be achieved with a tonearm that has different effective mass in horisontal and vertical direction. It will also have benefits such as lower noise induced by record warps.

 

[tnsilver]

Note that the 8-12 or 9-11 hz ”optimal” resonance frequency is a simplification

Perhaps, but 50Hz sounds excessively high. It would render what we experience and call 'sub-sonic' frequencies, well... 'sonic'. The 1977 paper "Audible Effects Of Mechanical Resonances In Turntables" by Poul Ladegaard from B&K, calls for 15Hz - 18Hz (see conclusion if it's TLDR). Possibly, today's standards had taken it up a notch to what VE uses (9Hz - 11Hz).

 

[Thomas_AA]

Yes 50 hz is high but arms with heavy horizontal effective mass such as some liear trackers and eg moerch dp-8 may be in the 5 hz region. And dp-8 is around 20 hz inthe vertical.

Edit mixed up directions