The Denon 103R is a low output (.25mV) MC (moving coil) cartridge that retails for $379. It is a low compliance cartridge and is not compatible with all tonearms. It is a great bang for the buck cartridge, provided it gets along with your tonearm and you have a phono pre amp you can pair it with. You need sufficient gain (50dB or greater) and be able to adjust the input impedance to the manufacturer suggested 100 Ohms.
The basics. Getting rid of the plastic body on the Denon 103R changes the physical resonance of the cartridge and will have an effect on the sound. You can run the cartridge nude, but many folks report that adding a wood or aluminum body is a very good thing. The added mass is said to improve broad-band resonance suppression compared to the light plastic body. Folks say it transforms this cartridge from a very good to a great one, CP members Carl (schwarcw) and Larry (analog97) among them. Adding mass also increases compliance with the tonearm.
The process. Note that you can easily render your cartridge useless by breaking the coil wires, knocking the stylus off or bending/breaking/removing the cantilever. I didn't stop to take pics while nuding mine; didn't want any break in concentration.
A nude your Denon body video on you tube.
Some of the best cartridges use boron, ruby, or diamond cantilevers. If you want your re-bodied Denon to be able to get into the ring with cartridges costing thousands of dollars, send it to Soundsmith to replace the aluminum cantilever with a Ruby cantilever/ Nude "Contact Line" diamond ($250) or their top of the line Ruby cantilever/Nude "Optimized Contour" Contact Line Diamond ($350). They also have a wood body with brass plate option they will sell you and install for a fee.
IIRC Zu Audio was the first to offer a Denon 103 with an aluminum body. They also tested and graded cartridges, with the better matched channel ones selling for a premium price. Wood bodies such as Uwe were/are offered in a variety of hardwoods (Ebony, Panzerholz, African Rosewood). Wood bodies are said to be softer or relaxed in presentation compared the aluminum bodies. Zu also potted them, that is using a small amount of epoxy (not completely filled) to securely hold the cartridge to the new body. Most DIY folks just go with a friction or press fit into the replacement bodies. I've also seen a tiny Allen screw used in an aluminum body that tightens against the cartridge frame.
Since I am a detail freak with esoteric tastes (extremely dynamic, neutral with shades of warmth) I went with an aluminum body. I used wood glue to secure the cartridge to the body in the event I wish to remove the cartridge (hopefully anyway). ISOkinetic is a popular supplier of quality aluminum bodies available in three colors for the Denon priced at 79.99 euro ($101). Knock offs of wood or aluminum bodies are also available on ebay but you would have to research if they are quality.
ISOkinetic web site.
I purchased my Midas aluminum body from David (daiwok), a Lenco Heaven forum member whom lives in Hong Kong. It ran me 105 euro ($132). Shipping was free to Lenco Heaven forum members. It is priced higher than other aluminum bodies but I liked his rounded corner design shape (he offers both squared and rounded corner bodies) and it was supplied with a stylus guard. The stylus guard is also sold separately for 18 euro ($23) and fits Uwe and ISOkinetic bodies. I like a guard as I do swap between two arms and it helps keep my stylus/cantilever safer. Some tape on the sides of the guard prevents marring of the body.
Lenco Heaven web site (but you have to be a member to view the Market Place/Traders forum).
My Turntable. Rest of gear in sig.
A heavy plinth, trimmed top plate heavy platter Lenco idler drive named Beveley in Cadillac Black. If done properly, there isn't an arm or cartridge a modded Lenco could not run. (The list of tables folks gave up when they got their modded Lenco is pretty impressive). My mods include a heavy layered Baltic Birch glued and screwed plinth with a larger aftermarket stainless spindle and bearing. Table, metal idler and Swiss made motor disassembled and re-lubed. The field coils were precisely adjusted around the motor armature to ensure minimum vibration and maximum speed/torque.
An Advanced Analog MG-1 air bearing liner tracking tonearm is installed. The MG-1 has the option of damping but I'd prefer to not damp a tonearm. I run two mats to further isolate the idler drive platter from the record. A rubber mat sits on the platter and then a Boston Audio Mat 1 on top of that which is made of carbon graphite. The spindle hole on the Mat 1 is large enough so it can be adjusted to not contact the spindle. The table has a very dynamic sound and speed is constant no matter what a record groove throws at it.
My Lenco build thread.
Jennifer Warnes /Famous Blue Raincoat 180g 45rpm 3LP Box Set.
Steely Dan / Gaucho 200g Universal Japan pressing.
Rob Wasserman / Duets 180g German pressing.
Madonna / Something to Remember German pressing.
After 75 hours of break in, I did some serious listening to the listed LP's then modded the cartridge. Compared to the Denon plastic body, the 103R with aluminum body sounds cleaner and more solid in the overall presentation. To me it sounds like more information with less distortion from top to bottom. Mid band clarity and high frequency extension became greater and more refined yet still remained musical.
My other cartridge is a Dynavector Karat 17D3. Compared to the Midas bodied Denon, it has even better defined bass, and a more fleshed out and articulate midrange (much better detail and transparency) along with an even more refined top end. I can also run less VTF (tracking force) with the Karat (1.5g per Soundsmith, 1.9g mfr suggested versus the 103R's 2.3 g).
The Karat does retail at a higher price compared to what I have in the Denon (Denon 103R with aluminum body $512 retail versus Karat at $1150 retail). Since I have the Karat, I won't invest any more in the Midas bodied Denon. I had my Karat inspected by Soundsmith and they say it has another 1K hours left in it if I don't abuse it. Unsure of what the economy will be like at that time, but I'd surely consider a Soundsmith Ruby cantilever upgrade for my Denon to get more out of it versus plunking down $1K or more on a cartridge.
In summary, doing the Denon body mod is worth it if you have the nerve to nude it. It got me closer to my better cartridge with a small investment. Your tonearm may need additional counterweights added due to the increased mass added by the body. I cobbled an added weight to get me by until I am able to figure the exact weight of the proper counterweight needed and order one.