Cartridge/arm matching

>>The 103R is similar in compliance to the Shelter...

Actually, no. The compliance for the Shelter 501 MkII is 9 x 10-6 cm/dyne, while the compliance for the Denon DL-103 is 5 x 10-6 cm/dyne. That's quite a difference. There are very few if any, modern cartridges with lower compliance than the DL-103 family, which makes them a difficult challenge for use with most light, short tonearms (like the RB-250.

Resonance compliance is a complicated subject- it's not just about cartridge/tonearm weight or damping. Adding a heavier counterweight or mass to the headshell will not make a DL-103 sing on an RB-250 arm.

The Shelter should work with the RB-250, although as Stringreen mentioned you will need some method to adjust VTF, and you have few good options for azimuth adjustment, which is critical in order to achieve best sound with any MC cartridge.

Actually, yes. ;-)

The compliance Denon quotes for the DL-103 is based on a measurement at a 100Hz, which is not industry standard (or particularly useful). When measured at the industry standard (and more useful) 10Hz, the DL103's compliance works out to be approximately 11x10-6cm/dyne, which is actually a bit higher than the Shelter's.

Fully agree with the rest of your post.

Again, no. The adjusted compliance for the Denon DL-103 at 10Hx is often mistakenly quoted at 11x10-6cm/dyne. The fact is that no standard formula that works for converting compliance from all cartridges due to differences in construction and materials. Although Denon has always listed the compliance for the DL-103 at 11x10-6cm/dyne, the actual demonstrated compliance is a little less. The base rule of thumb for converting from 100Hz to 10Hz is to multiply by 1.5. Assuming that the actual compliance is 4.5, multiplied by 1.5 comes out to 6.75 calculated. I use 6 as a planning rule.

From 1973-1978 I worked for a Southern California audio dealer with several stores. We were also a distributor for Nippon Columbia, Denon's parent company. Among other brands we also carried Denon turntables and cartridges, but not the DL-103. One day in 1975 (as I recall), a technical engineer for Denon visited and made a training presentation for the sales teams. Shugita-san referred to the suspension and aluminum cantilever on the DL-103 as having the lowest compliance and being the most stiff and unbendable of any other cartridge on the market. He also stated that this cartridge was completely unsuited for any of the tonearms that we were carrying, including Denon, Luxman, Micro Seiki, Philips, Sansui and Thorens.

I have tried, many times, to get a DL-103 to work (aka sound good) mated with a medium compliance tonearm, always unsuccessfully. It simply does not sound the way the cartridge was designed to sound by the manufacturer.
I would not recommend that combination to my customers.

**** The base rule of thumb for converting from 100Hz to 10Hz is to multiply by 1.5

Audiodistinction, i'm not a technician but are you sure that multiply by 2 is incorrect when converting @100Hz compliance to @10Hz compliance?

**** I have tried, many times, to get a DL-103 to work (aka sound good) mated with a medium compliance tonearm, always unsuccessfully.

I have the same feeling when i tried higher compliance cartridges on heavier tonearm designed for Denon DL103 family (Thosam Schich "12 Tonearm). But i can't find effective mass for Shick tonearm anywere, i wish to know.

***** DL-103 as having the lowest compliance and being the most stiff and unbendable of any other cartridge on the market.

Except Ortofon SPU probably: 8 µm/mN (10Hz)

For adding weight/mass to a tonearm, a model train store will sell you some little squares of lead you can put on the headshell (or even between it and the cartridge, to damp the cartridge body's vibrations somewhat).