The Thorens will take others but this is just fine. |
The Shure V15VMR is a moving magnet design -- one of the best, moderately priced MM's available (although superceded by the V15VxMR). Your cartridge has an output of 4-5 millivolts.
Here's a simplified explanation of the difference between moving magnet (MM) and moving coil (MC) cartridges.
In a cartridge, an electrical signal is generated by the magnet or coil moving in relation to one another. As the stylus/cantilever moves, it alters the flow of electrical energy created in the field between the magnet and the coil (in effect, creating an electrical analog, or representation, of the movement of the stylus/cantilever assembly). The electrical signal which is generated then passes to a phono preamp stage, which boosts the signal enough to drive the input stage of the main preamp.
The way in which an electrical signal is generated by movement of the stylus/cantilever assembly differs between the MM and MC design. With a MM design, the magnet structure is attached to the end of the cantilever, which is surrounded by the coil. As the magnet moves inside the coil assembly, it changes the electrical flux of the coil.
With a MC design, the coil (made up of wire windings) is wound around the end of the cantilever, which is surrounded by the magnet structure. As the coil at the end of the cantilever moves, it changes its position in relation to the surrounding magnet structure, thereby generating the electrical signal.
The theoretical advantage to the MC design is that the wire windings on the end of the cantilever have much less mass than a magnet structure, and the lower mass is easier to move. Hence, the MC design should be more sensitive and move more quickly, thereby improving transients, high frequency response, etc. (In a MM design, the coil can have many more windings, since it is in a fixed position that does not move. More windings = more gain.) The downside to the MC design is that it generates a weaker electrical signal than a MM design, thereby requiring more "boost" from the phono preamp stage.
Many of the theoretical advantages of the MC cartridge over the MM cartridge prove to be less than touted in actual use. All other things being equal, the MC should outperform the MM design, but the mechanism by which the cartridge generates a signal is not the only factor. Cartridge body resonance, tracking ability, the amount of boost required by the signal (weak signals require more preamplification), etc., all play a role in how well a cartridge performs.
In actuality, there are a number of very good MM (Shure, Grado, Rega, Picering, etc.) and MC (ClearAudio, Dynavector, Sumiko, Ortofon, etc.) designs, and your eventual choice depends in part on your personal listening tastes and the rest of your system.
Your Thorens turntable comes with its own arm, which is a decent arm, although not the best available. (It is held by many that the turntable and tonearm are actually more important factors in the overall result than the cartridge.) It will probably perform just fine with either MM or MC cartridges, provided the cartridge compliance/tonearm resonance point (the point at which the tonearm starts to vibrate and cause mis-tracking) is compatible. Without getting too technical, the issue here is one of tonearm mass vs. the cartridge compliance. What is necessary is for a tonearm to remain stable, without movement, thereby allowing the cantilever to move freely in relation to the grooves in the LP. If the tonearm also moves, the cartridge cannot track properly. All cartridge/tonearm combinations have a point at which resonance sets in, and this resonance point should be in the 10-12 Hz range. If the resonance point is above this point, it will be audible, and if lower than this point, there will be mistracking problems (potentially severe). Therefore, the mass of the tonearm must be compatible with the compliance of the cartridge.
Based on my recollection of the mass of the tonearm of the Thorens 125, the tonearm on your table should work fine with the majority of MM cartridges (including your Shure), and medium to higher compliance MC designs. The tonearm will probably NOT work well, however, with low-compliance moving coil cartridges.
Hope this helps. If you have more questions, please post a follow-up for me or others to answer. |
Nice to see someone taking 15 minutes out of their day to explain cartridges like this. Sweet piece of work. |
The cartridge you have is the best of the shure V15 series. Don't replace it - but if necessary get a new stylus assembly - make shure it is for that particular series of cartridge. email me for more info if you like....bravo a Sdcampbell.. |
Thank you for spending your valuable time to teach me the basics involved in tt reproduction of sound. I really appreciate the information as well as the effort you all provided. As far as tone arms go, I believe I have an SME replacement arm. Not sure what model, but the cool guy who sold the Thorens unit assured me he knew what he was doing. I haven't set up the unit yet because I don't have a dustcover, and I don't think my inexpensive stereo rack can support the tt. But my vinyl collection continues to grow, through donations and shopping sprees. Can't wait to set it up. If I put up a WTB for the cover, what are they worth? Sorry to stray from the topic. Thanks again,
Steve |
Hi, Steve:
Glad to help. We were all virgins once (some of us a very long time ago, and we may have forgotten how it felt...).
If I were re-writing my post a bit, I would have made the point to say that in an audio system that has an analog front end, there are two sets of transducers (a device which converts energy from one form to another): the phono cartridge (which converts the motion of the cantilever into an electrical current), and the speakers (which convert the electrical/audio signal back into the motion of the cone/panel/ribbon, thereby creating sound waves).
Transducers are the most problematic items in the audio chain, since they are subject to non-linearity and other forms of signal distortion and anomaly. Hence, it should be no surprise that cartridges and speakers have such significant differences from one brand/model to another. Just as people buy speakers that sound best to their ear, so with cartridges...
I mentioned in my first post that the tonearm/cartridge combination has a resonant frequency. This is because the cantilever acts like a spring. The cantilever shaft passes through a suspension system -- think of it like a rubber donut -- and as the cantilever moves up and down, and side to side, it interacts -- like a spring -- with the tonearm.
Let me close by adding that the Thorens turntable line is a very good one. The audiophile community tends to be a bit snobby when it comes to turntable brands, but the Thorens models offer a lot of performance for a reasonable cost -- not to mention some convenient features that many high-end turntables lack (such as easy changes from one speed to another). If you want to buy a dustcover for your turntable, you should be able to get it for $25-40 used.
I have one question for you in return: do you have an entire SME tonearm assembly, or just a replacement arm tube? If the former owner threw in an entire SME tonearm, you may want to seriously consider replacing the stock Thorens arm with the SME, which is much better arm. If you want to discuss this more fully, please let us know which SME tonearm you have.
Enjoy, and good listening to you.
Scott C- |
Actually the TP16 arm on a 125 mkII is a great arm. The SME is a good arm also - there is more panache to the SME (probably a type 3) but many prefer the stock arm. |
Steve: You probably have a version of the 3009 arm, or if you are lucky a 3012 (12"). The Sure "V" that you have should sound very nice, on either, if it is in good shape. Might be best (as mentioned above) to just replace the stylus (if this is even needed) and listen to it "as is" cartridge wise for starters (these combo's are quite good). In your situation I would upgrade the IC's (just the interconnects - not the tone arm cabling) if this has not been done. Also, if it has the stock Thorens rubber mat, a Linn felt mat is a big step up. A felt mat will not only improve the sound (on Thorens) but will also cut down (considerably) on static build up. I am currently using a Thorens TD165, but did the above to a TD160II in the 80's (this one had the 3012 arm, Linn mat and your exact cartridge). Though the TD165 is a budget table (and me being on a budget:-), I have still replaced the IC's with 47 Labs OTA cable and made a DIY felt mat (even on this table - much better sound). I have not gone into setup (also crucial) and you might try researching this @ Audioasylum.com in the Vinyl Forum. Good luck and have fun. |
Scott: Dekay is right. If I remember correctly, the SME arm is a 3009. And when I said that I hadn't set up the "unit" yet, I hope I wasn't unclear: I meant hooking up the whole turntable to my system, not the tonearm -- the SME is already installed. I think the guy who sold the Thorens to me may have included the original tonearm as well, but it's all packed away in storage right now so I can't quite check.
Dekay: when you suggest the Linn felt mat, you mean the mat that the record rests upon, right? Where can I find one and how much can I expect to pay? I think I'm still kind of incompetent at DIY stuff, even if it only involves tracing a circle on felt and cutting it out. You suggest upgrading the interconnects, as well. I wasn't given any in the package, but I've been saving a Coincident IC that was recommended to me when I had more cash available. Do you think this cable would be too unflatteringly neutral for the Thorens? Are there any ICs usually mated with Thorens? I'll ask Steve at the Cable Co. next time I talk to him, too. What I'm really concerned about are the female RCAs on the TT: They are old, and not gold plated. Where can I go to update these connections? Lastly, the ground wire has a few knicks and cuts in its shielding, and if I remember correctly, some wire is exposed. Does it matter sound-wise if I just wrap some electrician's tape around these spots, or would you recommend replacing the wire entirely? Would radio shack wire do the job _well_, or are there proven audiophile ground wires, too?
Thank you all very much for your input.
--Steve |
Steve: Yes it is the platter mat. The last time I researched the Linn mat it was around $80 (which may have been @ a discount). Perhaps the members here have a source for a less expensive (but just as good) felt mat? Also research TT IC's as it seems that you will be starting fresh. The cable (IC) that I am using is part of a "kit" that costs $600 and I use the same cable throughout my system (even for speaker cable). I tried to hand cut my first DIY mat (I agree that doing this is not easy), but cut the second one on a direct drive turntable @ a thrift shop. I just punched a center hole, placed the felt square with some tape on the bottom side of it on the TT platter, started up the beater TT while wrapping my hand, which was holding a razor knife, around a shelf post for support and let her rip/cut. I consider this to be potlicking @ its best, but the guys @ the shop didn't mind and I got a nice circle out of this one. The 1/8" felt that I used was from McMaster-Carr and cost approx. $15 (enough material to make two mats). They are online @ (mcmaster.com/) though I have a branch 30" away from where I live. I hardwired my IC's to the table, but feel that you are on the right track upgrading the old Thorens RCA's. I have been replacing the RCA's on some new/vintage gear with good results and I am just using cheap gold plated ones. The gear that I end up keeping will get better RCA's down the line, but for now I am using some mystery ones that I purchased in bulk (a baggie full of them) @ a thrift shop for a few dollars. I still need to research these connectors as I am not certain as to what's hot and what's not. TT setup is too detailed to go into here (for me anyway), but there is tons of info on this @ Audioasylum, which also has a very nice search engine. The basics may even be in the FAQ section on the first page, but there is detailed info (on your model(s) - both TT and arm) in the forums. I used to have other people set up my TT's in the past, but have found (this time around) that it is really not that hard (time consuming yes, but not hard:-), plus I feel better knowing how to do this myself as I can now change things @ a whim. What you will need is a protractor (or cartridge gage) and a small mirror, a VTF gage/scale (to double check tracking force), some main bearing oil (Singer sewing machine oil is what I use and it's $2 a tube), a bubble level to place the deck on an even keel and perhaps some metric allen wrenches to adjust VTA. If some of this stuff came with the table, then all the better. I use elctrician's alcohal for general degreasing and cleaning the belt. Again this sounds complicated, but it's not once you start reading and doing it. The result is much better sound without spending much. |
Mobil One (or an equivalent synthetic) is a great bearing Oil. One of the lighter viscosities is the ticket. It's also good in your car engine.... |
It's great to find someone who seems to know anything about the Thorens TD 125, so I'll take my chance and ask my question. I own a Thorens TD 125, original version, with SME 3009 arm and a rather new Ortofon MC 15 Super cartridge. I had the deck rewired with Van den Hul Cable. My question concerns the SME-arm, which has rather loose bearings. What arm would be the best to replace it with? Since I'm a little short on money please don't tell me only a SME series V would do.... I would like to keep my Ortofon cartridge.....
Michiel. |
For about 125 american plus shipping SME will totally rebuild your arm. Mine is over there now. Here's the service email address
Service@sme-ltd.demon.co.uk |
