Actually it is not so simple to get DL-10-3 sound properly with some random mc-transformer and phono stage.
Here is the 20 years old post by Thorsen that summarize it nicely. Hope that helps.
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Before I cover the differences between modern MC pickups and the 103 one or two more comments, the 103 will never be the last word in extreme LF or HF nor quite in resolution, still, it does at least as well as MANY modern High End pickups do in average setups, if placed into a context in which it works well.
Differenes are many....
1) Difference in mechanic - modern MC (and some MM) cartridges rely on "dumping" unwanted mechanical energy into the tonearm, which thus requires high rigidity, extremely close coupling of the whole mechanical system and very tight bearings.
The denon was designed in an age when rigid arms simply did not exist. A Denon would bolt into the plastic removable headshell of a EMT Arm, onto the small contact area of an Ortofon Arm "G" type removable headshell or onto an SME 3009/10/12 removable headshell. That means several mechanical breaks and soft couplings between cartridge and finally the Turntable. The Denon is actually designed to work well under such conditions. Bolt it into a modern rigid arm and you losse a large degree of the perfomance.
The 103 actually REQUIRES arms that by modern standards are crappy. If you cannot find a suitably crappy arm (as they tend to fetch prices that are obscene on e-gay) use two small plastic washers between the cartridge body and the actual headshell mounting surface and do not overtighten the cartridge screws, the whole idea to avoid coupling the cartridge rigidly to the arm.
A little story, without the "washer" trick the 103 sounded exteremly "grey" in my Originb Live RB250 and the Silver 250 and while using a fairly modern headshell on a very cheaply picked up MKII UNIMPROVED 3009 I still did not get the sound that I knew was possible. Before actually laying down the long green to buy an old 3012 I managed to snag an original 3009 Headshell off a friend and voila, all fell into place.
2) Difference in electric - modern MC cartridges (the better ones anyway) have very low impedances (< 10 Ohm is common) and use very strong magnet systems. The 103 uses an old style Alnico magnet and has coils that are no heavier than modern cartridges, but wich are wound with much finer wire and have more turns, meaning the DCR is 40 Ohm and the inductance is notable.
Now that means that the 103 cannot be used with (most) modern MC Stepup transformers, they usually are optimised for very low impedance sources and loose extension at the frequency extremes (already a somewhat weak area) and due to the relations to the magnetic core also resolution is lost.
What this means is that the 103 is actually MUCH more at home with a studio Microphone stepup transformer with a nominal 200 Ohm primary impedance (common types are 200:10..15K) and it should be loaded quite lightly with something in the 500R - 1K region. Getting good medium impedance microphone stepup transformers is not easy, meaning you may be better off using active stepups.
Finally, if you use modern Valve Phonostages you have another problem. Old MM Phono's tended to be variants of the Marantz or Dynaco feedback equalised designs. They have fallen out of favour for good reasons but have one particular feature that makes them different and more suited to the 103 than the non-nfb equalised modern types. That feature is that the input capacitance is much reduced by the NFB. At high frequencies where the input capacitance of conventional ECC83 (> 200pF) or of a WE 417A (>200pF) starts causing potential trouble the NFB equalised valve ponostage actually reduces this input capacitance due to the very large amount of NFB applied (around 40db more than at 20Hz).
Now 200pF are not a bad load onto the 103, but if you use a 1:10 stepup transformer the actual capacitive load onto the 103 becomes in effect around 2nF enough to cause audible problems (I tried).
The expensive solution is an old, nonimproved SME Arm or equivalent with the right type of transformer (certain old german mike stepup transformers are rumored to be the ultimate) and a low input capacitance MM Phonostage which would have to be most likely DIY as few commercially available ones exist that make sense.
Considering that the 103 only costs < 200 Bucks in an age where "quality" cartridges retail for at least 10 times that and considering it's peculiar requirements it will always remain a well kept secret and as long as enough reviewers get their setups dramatically wrong this state will thankfully remain, keeping the 103 cost down, as only people with right setup and studio's want it.
Ciao T
