Audie, My use of the word "illegal" was meant to be taken as humor. Nothing more than that.
The device described on the website appears to be electrically identical to a 12AX7 tube (except I did not see a rating for "mu", which parameter best describes the gain of a vacuum tube). Does AMT have high and low mu versions of this product? Do you know the mu values for both or either? |
Lewn, what is illegal about it ? The guy said that he developed it about six years ago but put it away. Finance was his problem to push it further. He did acknowledge the fact that somebody put a patent on a similar thing but the application is different from what he is doing. He went further to say that the patent has expired but that he has the first right to the technology since his was on his site before the patent was granted. Lew the way I see it is that no circuit change is required and it might solve problems for we guys that are in love with tube phonostage. Reduced noise floor. |
Fleib, thank you for pointing out the AMT website. You are more than Google.All the descriptions on that site about the product is what I heard during the very short period of listening. The guy said that he has two versions of the product, a high gain one and a low gain. This is the reason why I want to try the high gain one on the Marantz 7c. I do not want my excitement to cloud my judgement but to have an extended home listening. Solid state or no solid state does not matter too much to me.I was not able to detect that it is not a tube. |
Holy cow! That's illegal! Perhaps the reason I could not find it under "12AXT" is the fact that its name is "12AX7-WS". What a clever idea. Has anyone besides Audpulse heard one of these devices? Based on specs, it should not give any more gain than a 12AX7 vacuum tube, but if one were to replace an aging 12AX7 with a WS, then it would subjectively appear to have more gain. And I was wrong; the OEM Marantz 7C does indeed use 12AX7s (not 12AT7s).
From the blurb, it would appear that AMT has also made solid state replacements for other tube types. |
Lew, here it is - a solid state replacement: http://amtelectronicsusa.com/productpage12AX7WS.html
Regards, |
Follow-up: A Google search on "12AXT" brings up nada about any such device. I then tried searching on "12AXT tube", then "12AXT transistor", again with no result except a list of references to the "12AX7" vacuum tube that we all know about. Aud, what's up? Thanks. |
Dear Audie, Is the 12AXT a vacuum tube or a solid state device? (If it has no filament, it MUST be solid state, actually.) If the latter, do you know for a fact that it can be dropped in a 7C to replace the 12AT7s or the 12AX7s? (I forget which tube type is used in the 7C, thought it was 12AT7.) Where and in what context did the "12AXT" blow your mind?
As to modifying a 7C, sure, there are many ways to upgrade it with modern parts that did not exist back then. But I personally would not mess with the tube types originally chosen, unless I wanted to change the sound altogether. Just my $.02 |
I picked up a Signet MR 5.0 ML. The MR series has the same basic generator as the 440 - 490mH, 790 DC, 3200 ohm imp. I really bought it for the stylus which is beryllium/ML, to replace the 152ML I broke in transplant. The MR series has a 120/440 series plug, but requires a slight plastic trim on the side, to fit.
The Signet only sounded so-so. The DC was off, being around 809 in one ch and 830 in the other. It also has a small metal body. I put the stylus on my 440 and it was excellent, much like the 152 stylus. I was trying to figure out why the MR body is subpar. Just a bad sample or does the metal body have something to do with it? My 440 measures close ch to ch on DC resistance.
All the ATs I've messed with seem to be greatly improved with a boron or beryllium cantilevered stylus. High inductance ones are easier to manipulate. Like Timeltel's 13Ea with a 155LC stylus is greatly improved, and I think without having to change loading. I used to load my stock 440 at 32K to tame the high end. With the exotic stylus it sounds great at 47K.
Heavier aluminum cantilevers resonate in the audio band and often augment response peaks. The exotic ones resonate near the limit, or past the audio band and also have greater detail/resolution. A lower inductance generator like the 150MLX (350mH) will be harder to manipulate. If it's too aggressive I suspect judicious lowering load resistance is the answer. All AT MMs need < 200pF shunt capacitance which is important to keep the high frequency resonance from being lowered and augmenting treble. Regards, |
Lewn, I have the Marantz 7c as a back-up full function preamplifier for over a decade and has only been used once after changing the captive power cord on the unit. But recently I came across what is called a solid state 12AXT tube that totally blew my mind. This tube has no filament and does not need any warm up. Not much to report on that tube at the moment till I install it in the Marantz 7c. With the high gain of the tube and the performance that was demonstrated to me, I think that my search for a dedicated TOTL MM phonostage may be over. I know that I read on one of the Audiogon threads about a modified Marantz 7c that aroused my curiosity but I cannot remember the thread. |
Audpulse, So far as I know, the phono stage in the Marantz 7C in completely original form IS MM-ready. There was no such thing as an MC cartridge back in its day. It probably does develop higher than average gain compared to a typical modern MM phono stage, because of the bass and treble and other contour controls built into it; such filters suck up some gain, so a little excess is needed. |
Regards All, I do not know if it is in this thread or another that somebody modified the Marantz 7c to be specifically used as a MM phonostage. Can someone please point me to it. |
Lew, if you're still interested in a budget phono stage let me know. I have some comparative user reports on the top contenders.
Nandric, if you're still looking for X-1 replacement styli TurntableNeedles.com has what I believe to be an Astatic. Like the Jico replacements it's a straight aluminum cantilever with a bonded tip. #673-DQ. ($38) Jico doesn't have the stylus. Regards, |
Dear Banquo, The modesty is not a qualitity of a person but depends from the circumstances. I first thought that there are no aftermarket styli for the JVC-X1 available and than come 4 of them across by pick-upnaalden in Holland. All of them are marked as 'JVC DT-X1-MK 2'. Neither is with the so called 'tension wire', alas. My comrade Don who is familiar with Jico will investigate what Jico has to offer. My original cantilever is broken in such a way that a new cantilever/stylus combo can be glued on the remainder. So it is probably that I will end with at least 3 new styli. What is anyway certain is : I will never again try to straighten any cantilever whatever. |
Is the tonar stylus body shaped like the x1 original, Nandric, or like the x1 mk2? If the latter, then you have a few more choices: jico makes a mk2 shibata replacement and lp gear has their own 'vivid line' replacement. I have both. The jico is very good, although sadly not nearly as good as the original. I haven't mounted the lp gear one.
Does the tonar have the tension wire? |
Good news for those who own the JVC-X 1. I discovered 4 styli which can be used as substitute for the original. By 'pick-upnaalden.com' named as 'JVC DT-X1-MK2'. I purchased the 'Tonar 00740-DE' for 52 euro and am surprised with its quality.
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My Technics EPC-P100CMK4 is listed for sale at ebay. 130 hours use and suspension rebuild from Axel. I think a few may be still trying to find one so thought I would mention it here.
Regards |
Dear Bangue, This is my third MM cart with the so called 'tension wire' behind the cantilever. Grace 9 and Technics U 205 mk 3 the other two. Jcarr mentioned tension wire in one of his previous post. I think that this tension wire may 'explain' their superiority. By JVC there is a kind of 'joint pipe' behind the cantilever but very difficult to reach. Otherwise a re-tip would be no problem at all. My sample has about 3 mm of the original cantilever left so I will ask Axel to glue a new cantilever/stylus combo on this 'stump'. |
Dear Nandric,
In addition to philosophy we now share the misery of having broken a TOTL Victor cantilever. In my case, the X-1/ii (I thought it was clearly the best MM I had heard in my system). I believe both use beryllium rods. AFAIK, no vendor sells NOS replacements. pickupnaalden sold their last x-1/ii needle a day or so before I broke mine :(. Your best bet, in addition to the one Pbnaudio linked to, is to visit yahoo japan. I believe I saw an x-1 a month ago. Good luck. |
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Does anyone own the JVC X-1? This cart is one of the best MM carts I have ever heard. Alas I broke the cantilever by my attempt to straithen the thing. I thought that the cantilever is made from aluminum but it is a kind of metal rod. Are there any replacement styli available? |
Pkoegz, Perhaps you have seen my posts several days back where I noted my (current) puzzlement as to how to judge my Grace Ruby cum SS OCL stylus. It had a promising first few hours in my system and then became and remains rather shrill and irritating, compared to my other completely OEM Grace Ruby and compared to another very good MM (or IM), the Acutex LPM320. So, I have questions for you: What tonearm are you using? What VTF? Did you have the opportunity to listen to your Ruby prior to the re-tip, with its standard elliptical stylus, and if so, how did it compare? I guess also it's relevant to ask how you are loading the re-tipped Grace; I am using 100K with no added capacitance, which works great with my OEM Grace. Thanks. |
Pkoegz, I am a supporter of G. Marx: "if you don't like my principle I have other''. What about this chef by Maxime: 'nothing can compare with a good cooked potatoes'. I would prefer prime rib with green peas. But in some other domain some may prefer the simple Grace above Anna.
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Nandric, "The whole country is covered with manufacturing towns... a region of fire; reeking with coal-pits, and furnaces, and smelting-houses, vomiting forth flames and smoke." The squire is apt to wax eloquent on such themes. "He had the genius of taste except at certain moments when the Massenet slumbering in the heart of every Frenchman awoke and waxed lyrical."
Time for you to wane lyrical and (just)stop! |
Pkoegz, In a similar context I addressed our (rich) member Thuchan with the story about his compatriot Marlene Dietrich. She was wondering why the American women are so badly clothed. 'At present' (the 60is) she stated ' one can get decent clothing for only $ 100000'. |
I have had a lot of very expensive phono cartridges. Including but not limited to, goldfinger, atlas, xs-1, PC-1, 9000 and now an Anna. My favorite the atlas but the Anna very very strong competition. Betters the atlas in a few ways. So it was much to my surprise when I came across this thread and bothered to read some of it. Long story short I bought a grace ruby used and the bought a soundsmith stylus ruby-OCL(red) for $500. After proper set up and dialing in on my pass labs Xp-25 phono stage, wow! What a shock. All this for about $750, no way. I have compared repeatedly to the Anna. Anna a little smoother and some of the bottom tighter. I have been in this hobby for a long time and I have made some very good purchases but none better then the grace ruby. Now I am looking out for some other potentially great mm's. Live and learn. But don't get rid of your atlas's or your Anna's. Still in my view the best you can do. Just not for the money. |
Donde esta el Mejicano? +1 |
Enough theory already. I want more cartridge recommendations. This thread used to be cartridge of the month/week. I know there are others out there awaiting my ears. MM/MI/MC bring it on!!! Donde es el Mexican? |
Dear Acman3, There is this old prejudice about 'absent-minded' teachers. My English teacher explained those new punctuation signs but, alas, in the wrong thread. By accidence I discovered his expalanation in the 'Vintage DD turntables'. The new punctuation signs are called 'emoticons'. So, I would think, one reason more to save my money for a new cart instead to buy a new laptop. Thanks for your support. I also hope you like the MC's more than the other kind? |
I would also keep the old laptop and buy more cartridges or tonearms! I think you have your priorities correct. Who cares if you can't see the symbols, when your listening to great music, |
Acman3, There is this old (confused) conecption about the difference between 'quality and quantity'. Well if one is an obssesed collector of carts the savings must come from somewhere. Besides I think that the 'good old punctuation' is already very complex. BTW my laptop is 'as new'. Only 4 years young. Dover, I am usualy joking but if you want me to read your post 'all the way' you should write shorter stories. And I am sorry. I should write that I disagree with the proposition but agree with Dover. I think that nobody has problem with the subjective preferences for either; MM or MC. But this seems not to be satisfying so the strategy is to assume better technical capabilties for either kind. Some among us even evented new punctuation signs to make their 'point(s)'. I just learned from Acman3 that those are to find on the new laptops. |
I see 2 rectangular objects like windows... well my computer is 4 years old. Actually I have never really trusted computers, that´s why I prefer analog :) |
Nandric, The symbols I see, on Halcro's post, on my home computer are a Thumbs up, and a smiley face smooching. On my older beat up work computer I just see blocks of goobledygook. Your computer must see it as a Hammer???? It might be time for both of us to update. |
08-21-14: Nandric Dear Dover, See Dover 07-13-13: ''the essence = does one prefer the 'rising high end' of the MC carts or...'' Nandric, that was a proposition, not a personal view, for the purpose of discussion. If you read the post in full I pointed out that not all MC's have rising top end. Indeed my Koetsu Black ( current model ) has no rising top end and my Dynavector Nova 13D is only 1 db up at 20kh. I suspect that the ensuing step up device or phono stage probably generates more variation in ones perception of top end than the actual cartridge, hence the wide variation in opinions on said same cartridge in many instances. Same with tonearm and its set up, the impact on the cartridges "sound" or sonic signature is significant in my view. |
Nandric, I think Halcro is indicating his agreement with Fleib, as regards the idea that both MMs and MCs can have merit, and cartridges should be evaluated on an individual basis, not based on their mechanism of action. I agree with Fleib, too |
Dear Dover, See Dover 07-13-13: ''the essence = does one prefer the 'rising high end' of the MC carts or...''
Halcro, I amdire your creative mind but your punctuation innovations are not yet explained to me by Lew. However I deed recognise the hammer symbol which you introduced instead of your question marks . I assume that the intention of this hammer is to give more force to your MM arguments? |
Years ago I thought MCs were better than MMs, now I don't think either one is superior. They're different. This....👍😘 |
I think we like record players because of the differences and the possibilities those differences afford. Not all differences are assets or shortcomings, sometimes they're just different. Different flavors, as Jcarr said.
Understanding something about how cartridges work can enhance enjoyment. Knowing how to load certainly helps, and seeing a frequency response graph can give us a better idea of response, than a purely subjective review without it.
I thought you'd talk about what you like about some of your carts, instead of making another list. We all have our preferences and our personal rankings may or may not coincide with someone else's preferences. Years ago I thought MCs were better than MMs, now I don't think either one is superior. They're different. I tend to like accurate carts, but nothing's perfect and there are other aspects of performance. To each his own. Regards,
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08-20-14: Nandric This also imply that I disagree with Dovers 'theory' that MC carts are prefered by persons who like 'exaggerated' (+ 3 dB at 20 Khz ?) I have never said that and do not subscribe to that theory. |
Addendum. Fleib ,I forget the DVD player. Not for me. I think that music is meant for our ears while violence, love stories and other adventures for our eye. Besides I always listen to the music with my eye closed. This way I can imagine to be the singer in front of me. Even with Maria Callas. This way I discovered the female part of my personality. I also discovered that one need a special kind of art to enjoy a life performance. I have seen Pavarotti and Montserrat Caballe with my own eye. The mentioned 'art' is the art to pretend to like what you see. |
Dear Fleib, Because of Jcarr I was polite. I should address you only and rephrase my 'menace': If you continue with revealing the shortcomings of (all) carts I will buy a (SA) CD player. Now regarding Raul and my favorite carts I like the distortions of my TRX II, AT 150 ANV and Glanz/Astatic 61 of the lesser kind and Kiseki Goldspot, Miyabi, Magic Diamond, LP S, Shiraz , EMT LZi (thanks Thuchan) , Blue Oasis and Shinon Red boron from the better sounding kind. This also imply that I disagree with Dovers 'theory' that MC carts are prefered by persons who like 'exaggerated' (+ 3 dB at 20 Khz ?) high frequency. I am totally deaf for anything above 11 Khz. |
Nandric, "If you and Jcarr continue with revealing the complexity and faults of carts I will buy a CD player (grin)."
Is that another one? Maybe you should get one of those Denon all-in-one DVD players that Raul likes so much. I take it you sold your AT170 ? Do you have a favorite cart? What is your favorite(s) and why do you like it more than the others? Feel free to wax poetic. I'm genuinely curious. Regards, |
There's an old thread on VE - Cartridge Loading Explained. For anyone interested in this subject: http://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=6674&sid=a26d56af50fa28225f39fa0073dbb465&start=60
In response to a comment about electrical models (Hagerman and a Spice electrical model), Werner (same one as on TNT) said: "And both are near-useless as they don't take the (inevitable) cartridge's mechanical resonance and treble losses into account. With MMs this is all happening around 10-20kHz, and electrical resonance (through loading) is used to compensate for this."
"Mechanical resonances and mechanical treble losses (how fast can you wiggle a given mass?) don't show up in electrical models of cartridges. Both phenomena happen between 10 and 20kHz with MM cartridges.
Sadly cartridge manufacturers don't publish the electrical equivalents of their products mechanical properties."
People who used electrical models for loading inevitably had to abandon those results. The part that's tricky is capacitance. As a general rule I keep capacitance to a minimum and use resistance loading as much as possible. In the case of the Ortofon M20FL Super, 53K and around 250pF was preferable to 47K, 400pF. Capacitance lowers high frequency resonance and normally augments treble just as it did in the TNT M97 article, only not as extreme. BTW, the M97 goes through a remarkable improvement with a Jico SAS stylus. Regards, |
"This could be because cutting lathe amplifiers almost never contain resistors that are accurate to 0.1%, or capacitors that are accurate to 0.5% (according to the LP cutting engineers that I have spoken with), this could be because the RIAA lookup tables (that an EE would use to help design phono stages or cutting-lathe electronics) in various engineering articles didn't always agree with each other. Whatever the reasons, differences between the RIAA EQ curve (as defined by equations rather than look-up tables) and what individual cutting lathes are wont to produce should be expected."
Wish I could have cited that paragraph to Raul in connection with my several arguments with him about the necessity for absolute RIAA accuracy in a phono stages. For a given LP, a slightly inaccurate phono RIAA filter might serendipitously result in a "flatter" frequency response during playback than would a "perfect" phono RIAA filter. This was in the context of his insisting that only SS phono stages are worth thinking about, because of the probability that they would be more RIAA-accurate than tube types. This is not to say that I support sloppy RIAA design; I only maintain that the long term accuracy of a very well designed tube phono stage is sufficient. |
My experience with test LPs is that they often don't agree; sometimes the differences are minor, sometimes they are bigger. Use two different test records (of good quality) and you'll get two different frequency response curves. Likewise for crosstalk, distortion, IMD etc.
This could be because cutting lathe amplifiers almost never contain resistors that are accurate to 0.1%, or capacitors that are accurate to 0.5% (according to the LP cutting engineers that I have spoken with), this could be because the RIAA lookup tables (that an EE would use to help design phono stages or cutting-lathe electronics) in various engineering articles didn't always agree with each other. Whatever the reasons, differences between the RIAA EQ curve (as defined by equations rather than look-up tables) and what individual cutting lathes are wont to produce should be expected.
For example, two days ago I received a set of test measurements from a highly-regarded tonearm manufacturer. These were of the Etna, tested in his latest tonearm. Comparing his measurements to Stereoplay's Etna measurements, and you would think that a different cartridge was involved. This doesn't necessarily prove that either test is better, or less valid. But it is proof that test measurements do not always give the same (or even similar) results, and this is neither unique nor a surprise.
OTOH, the differences between cartridges tested at the same facility should be comparable (unless X cartridge was tested in January and Y cartridge was tested in August). For example, going back to the HiFi News group test, the lift in the presence band shown by the 17D3 does not appear with any of the other 6 cartridges tested, so that particular observation may be applicable to situations outside of the HFNRR test.
Then again, the important question is - how much of these measured differences are apparent to the ear? Based on my own experiences (including blind testing with various listening panels), I don't think that there is a single answer. What I can say is that cartridge body construction (materials, shapes, voids, densities etc.) and magnetics have a big impact on the subjectively perceived frequency response. A measured frequency response that sounds neutral with one body construction may not provide the same subjective response with a different body construction.
Conversely, the same measured frequency response (or very similar) may not sound the same at all if the body construction or magnetics are different.
Case in point - the Delos and Kleos have very similar frequency response measurements, but they sound strikingly different, and that includes the treble range. The Kleos has a very pure and quiet-sounding top end that is kind to worn records, while the Delos sounds more exuberant at the top, and is more likely to reveal that a given LP has seen better days.
So why the sonic differences from such similar FR measurements? First, the magnetics are different on the two - a permalloy armature on the Delos as opposed to a chemically purified iron armature on the Kleos. Second, the Kleos is machined from a harder alloy than the Delos, and adds internal resonance traps that have been strategically placed to prevent the spent mechanical energy (originating from the stylus and cantilever) from being reflected back into the coil region, and funnel that energy into the headshell and tonearm.
As another example of how materials and construction can affect the subjectively perceived sound, normal LPs are mastered on an lacquered disc, while DMM LPs are mastered on a copper disc. This change results in a very different sound for DMM (as compared to traditional lacquer-based LP masters), to such an extent that the choices taken during the mastering processed need to be changed (or at least should be changed) in order to produce acceptable sound quality.
Measurements are very useful, but due to differences in test LPs, LP groove diameter (of the test track), operating temperature, tonearm setup and whatnot, it can be misleading to read too much into the importance or validity of one particular test. My recommendation would be to perform multiple tests in multiple setups, and hope that the average of those multiple tests will provide some objective understanding.
And, there is much more to the sound of a cartridge than what test LPs are designed to measure.
kind regards, jonathan |
Jcarr, My comments are based on an article that appeared in Audio magazine 3/83. It's called Phase Testing in Phono Cartridges, by Kevin Byrne of Ortofon. In the article there are actual plots of amplitude and phase. These are measurements not calculations.
Phase vs amplitude is shown for the MC200 with varying amount of damping. There are also plots for 5 unnamed MMs. The MC200 has a boron cantilever and primary HF resonance is 27KHz. At that frequency there is a phase shift approaching 180°. We don't know what the MMs are, but all had phase shift close to 20KHz. The MC200 phase discrepancy extended down to 7 - 8K, The worst case MM phase was down to 1 - 2K.
This is the only measurement of phase vs amplitude I've seen. I have a copy on a PDF. I can't post it here, but I can send it as an attachment on an email. It would be interesting to read your comments. Regards, |
Hi Fleib:
>The mechanical performance overwhelms the electrical and shunt capacitance combined with inductance serves to lower high frequency resonance.
Overwhelm is not the appropriate word. I have some experience designing MM cartridges (for other brands), and in a nutshell, what you do is counterpoise the electrical parameters against the mechanical performance. The client commissioning the design is not always open to a wide range of output voltages (or cantilever materials), so the designer may need to operate within a fairly limited range of inductances and moving masses, but the general idea is to manipulate the electrical parameters to counteract what goes on in the mechanical domain, and vice versa.
>Someone (not Hagerman) assumed there is a phase shift at electrical resonance, but this appears to not be the case.
Not sure why you think that electrical resonance won't cause a phase shift - normally it does. I see electrical phase shifts all the time in my work with amplifiers, and I see the same at ultrasonic frequencies with MC cartridge loading. Nevertheless, just to double-check the situation with MMs, I entered Werner Ogier's first schematic from the following page into my circuit simulator (which I use on a daily basis).
http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html
I see a frequency peak at 8.05kHz, and at the same frequency the phase has shifted by about 50 degrees (compared to 20Hz). Incidentally, the phase shift starts occurring at a much lower frequency than the electrical resonance peak occurs at, which is again what I would expect (and have observed many times). At 4kHz the electrical phase has shifted by 21 degrees, at 2kHz the electrical phase has shifted by 10 degrees, and at 1kHz the electrical phase has shifted by 5 degrees.
>Just thought I'd mention it as there seems to be a lot of confusion about this.
I accept your word that there is confusion about this, but I honestly don't understand why this should be the case, as any well-practiced EE knows that both resonances and filter poles will normally have accompanying phase shifts.
The Oikawa RLC calculator limits the number of components that can be used to 3, and unfortunately 3 components won't allow you to resistively load the phono cartridge that you are simulating. A full-fledged circuit simulator is far more powerful and flexible, but the Oikawa simulator is considerably better than nothing (smile).
kind regards, jonathan |
Dear Fleib, If you and Jcarr continue with revealing the complexity and faults of carts I will buy a CD player (grin). |
Hi Jcarr, Yes indeed most interesting.
"Cartridge suspensions should only allow vertical, horizontal and 45-degree flexing modes, but in reality nearly all cartridge suspensions also allow twisting, and if a given suspension doesn't contain a tension wire, fore-aft motion as well."
Microscope photos of grooves show walls that vary from 45°. (BTW for ° sign hit Alt + 248) I've only seen a few such photos, but most seem consistently steeper. It seems to me the motion would be within an arc of 90°. To confuse things further there is also simultaneous vertical angling of the groove. I haven't quite gotten my head around the possibilities, but motion doesn't seem limited to vertical, horizontal and 45° flex modes.
My point about the MC305 was if the stylus mount isn't rigid. I guess it doesn't matter much, performance will still be compromised. I don't have experience with this cart or have lab test to verify if this is actually the case.
Interesting links of the Accuphase carts. The Monster cantilever/tips look like the AC3, but without the beryllium in the middle. About 6 months or so after the 1000 came out there was some kind of change in the cantilever and response was extended past 100K. I think diamond dust coating was added at that time and a change in tip mounting. This was back in '88 and I can't remember the details. Original response was to 75K. Thanks for the calculator it looks interesting. I'll have to check it out.
Hagerman's calculator for HO carts is of limited value for loading purposes. The mechanical performance overwhelms the electrical and shunt capacitance combined with inductance serves to lower high frequency resonance. Someone (not Hagerman) assumed there is a phase shift at electrical resonance, but this appears to not be the case. Phase shift occurs at high frequency resonance. Just thought I'd mention it as there seems to be a lot of confusion about this. Regards, |
Jcarr Thank you for the informative post. I am interested in your view on cantilever flex on eccentric records. My experience with a tangential air bearing tone, the Eminent Technology ET2, is that even with the horizontal mass reduced significantly by using a totally decoupled counterweight ( in the horizontal plane ) I can observe the cantilever flexing back and forth as the arm moves in and out. I have observed the same phenomena with conventional pivoted arms including my Naim Aro, Dynavector 501 and FR64. An argument has been put forward that because the frequency of oscillation navigating the eccentric record is so low, that the cantilever and arm move as one and the cantilever does not flex. Kuzma uses this for his rationale on employing a very high mass arm. Bruce Thigpen has stated this would defy physics. My own physical observations with low compliance MC's ( Koetsu Black, Denon 103 Garrott among others suggests lateral flex occurs when playing eccentric records. What is your view or experience on this. |
Hi Fleib: Cartridge suspensions should only allow vertical, horizontal and 45-degree flexing modes, but in reality nearly all cartridge suspensions also allow twisting, and if a given suspension doesn't contain a tension wire, fore-aft motion as well.
If you measure crosstalk on an oscilloscope using a test LP, you will see that it causes the test signal waveform to break apart and spreads the sections over both channels rather than one. Breaking a waveform apart is never a good idea for sonics, since doing so generates high-order distortion products which are unpleasant to the ear. For this reason I consider cartridge crosstalk to be a type of distortion, rather than merely a channel separation problem.
No matter how rigid the cantilever and secure the the stylus tip mount, the flexible nature of the cantilever suspension allows the cantilever and stylus to rotate as a unit, leading to worsened crosstalk. As opposed to normal crosstalk which is due to misalignment of generator and stylus, crosstalk such as this is dynamic in nature, and increases and decreases as the LP groove modulations rise and fall.
Therefore, although a cartridge with a lurking dynamic crosstalk issue will probably measure OK and sound OK on simple music, on big orchestra peaks, congestion and imaging problems may occur.
The farther the stylus protrudes from the centerline of the cantilever, the more effective it is as a crank, making it easier for the LP groove to twist the cantilever and generator around (with the suspension acting as the pivot). A very short stylus reduces the level-dependent twisting effects by being less effective as a crank. At the other end of the cantilever, a large surface-area boss (typical of many MCs and the Audio-Technica MMs), combined with a large diameter damping system will act in a similar manner as a disc brake, reducing cantilever and generator twisting.
Although not much can be done with rigid cantilevers (sapphire, boron, diamond etc.) to reduce the twisting effects other than shortening the distance that the stylus protrudes from the cantilever centerline, it is possible to design an alloy tube cantilever to circumvent this effect - if the cantilever is made with a kink in it (corresponding to the VTA angle) which starts to bend a little farther back than is normal for alloy tube cantilevers, the patch where the stylus contacts the LP groove can be placed directly on the cantilever longitudinal axis. This avoids the dynamic crosstalk issue by removing the crank effect of the stylus.
In more ways than one, it is easier to make a high-quality phono cartridge when the cantilever is made from a ductile material rather than the rigid, brittle materials that are commonly viewed as "better". Rigid cantilever materials have no "give", meaning that the slot, hole or surface for the stylus mounting must be made larger than the stylus, and this necessary oversizing forces the mounting tolerances to be poorer. A ductile cantilever material can be fitted with an undersized mounting hole so that the stylus is press-fit into place, and this will help keep the position (front-to-back, side-to-side) and angle (azimuth, SRA) of the stylus closer to the intent of the cartridge designer. And since the ductile cantilever can be bent without damage during forming, it is possible to cancel out some of the geometrical effects that would otherwise occur (per the above paragraph).
Returning to rigid cantilevers, please look at this.
www.accuphase.com/cat/ac-3en.pdf
If you compare the photo of Technics cantilever to the cantilever cross-section drawing in the Accuphase AC-3 pdf, the Accuphase drawing suggests that the contact point between stylus and LP groove was kept closer to the center axis of the cantilever, and it also shows that the stylus block passes through both upper and lower cantilever walls, which should help keep consistent stylus mounting accuracy.
This doesn't mean that a long stylus only has downsides to - it confers advantages as well. A longer stylus makes it feasible to reduce the cantilever length (for a given cantilever rake angle), so if the designer's top priority is to reduce cantilever length, a longer stylus (and/or higher cantilever rake angle) will be effective.
Most notably, a longer stylus will be far more resistant to jamming due to dirt accumulation than a shorter stylus would be, and this is important for a volume-sales product that may see a fair amount of casual use. Back when Lyra was making cartridges with 0.06x0.06mm stylii (smaller than what is on the Technics, and up there with the Denon DL-1000A), we'd get back cartridges where the user claimed that the stylus was broken off. In many cases, the stylus was intact and perfectly fine - it was simply that the tiny stylus size made it prone to vanish in accumulated dirt, and once that happened, the cartridge wouldn't play - the cantilever would just slide across the LP as though the stylus was missing.
Here is also a link for the AC-1 pdf. You can see how it used an alloy tubular cantilever which was bent into shape (although for crosstalk purposes it would have been better if the bend started a little further back).
www.accuphase.com/cat/ac-1en.pdf
FWIW, tubular cantilevers are not more rigid than rod cantilevers of the same material, unless the outer diameter of the tubular cantilever is larger than the OD of the rod cantilever. But a larger OD will cause the stylus to protrude by a greater distance from the cantilever centerline, which we have seen is a disadvantage when it comes to crosstalk.
Finally, allow me to point out that most design choices in a phono cartridge bring side-effects. Very few design choices only confer advantages with no negatives. As one example, it is no accident that the great majority of phono cartridges ever made have converged on a cantilever length of around 6mm. Any designer can specify a shorter cantilever, but doing so brings direct and indirect performance penalties which need to be carefully considered, and doing so also inevitably forces design work-arounds in various areas which may upset the balance of the design as a whole.
On a different topic, here is an online simulation tool for RLC circuits.
http://sim.okawa-denshi.jp/en/RLCtool.php
It allows for the user to enter their own values for resistance, capacitance and inductance (thereby making it feasible to do a simple electrical modeling of an MM, MI or MC phono cartridge), and it can show the phase response, step response, overshoot and other parameters in addition to the frequency response. This is a nice tool to complement Jim Hagerman's cartridge loading page, to get a better idea of phono cartridge behavior in the electrical domain.
Hope this was of interest.
kind regards, jonathan |