IMHO it takes a heavy arm for that low compliance (I use a Jelco 750 for them). Proper use of a step-up transformer really helps as well, and there is a lot of disinformation around. Some hints:
1) a transformer has no set impedance; it reflects the load impedance back to the source as a function of turns ratio. There are calculators on line.
2) You lower the load impedance from the MM's typical 47k by adding resistors in parallel. Some people solder resistors across RCA plugs and insert them into Ts at the preamp's MM In. Others find or make a switchbox for this purpose.
3)The thumbrule for desired reflected impedance at the cart is to start at 2x the DC resistance and go up.
4) For a DL-103 (40 ohms) you want to start around 80 ohms. A common turns ratio for use with DL-103s (and others) is 1x10. A 47k MM input would reflect as 470 ohms; we need 8k, to reflect as 80. A standard E96 1% value of 9.76k in pararallel will give you 80.1. I usually wind up at about 100 ohms (Denon says >100); 12.7k yields 99.98 ohms. 15.8k yields 118 ohms...
A caveat:
The reflected impedances only work that neatly (factors of 10) for 1x10 transformers - there are square roots in the formula.
All vintage Denon SUTs are 1x10 or have that option via switch.
1) a transformer has no set impedance; it reflects the load impedance back to the source as a function of turns ratio. There are calculators on line.
2) You lower the load impedance from the MM's typical 47k by adding resistors in parallel. Some people solder resistors across RCA plugs and insert them into Ts at the preamp's MM In. Others find or make a switchbox for this purpose.
3)The thumbrule for desired reflected impedance at the cart is to start at 2x the DC resistance and go up.
4) For a DL-103 (40 ohms) you want to start around 80 ohms. A common turns ratio for use with DL-103s (and others) is 1x10. A 47k MM input would reflect as 470 ohms; we need 8k, to reflect as 80. A standard E96 1% value of 9.76k in pararallel will give you 80.1. I usually wind up at about 100 ohms (Denon says >100); 12.7k yields 99.98 ohms. 15.8k yields 118 ohms...
A caveat:
The reflected impedances only work that neatly (factors of 10) for 1x10 transformers - there are square roots in the formula.
All vintage Denon SUTs are 1x10 or have that option via switch.