Hi Chris,
you can load your MC cartridge with resistors (and capacitances) applied in the input of an integrated MC phonostage or by using a SUT with no additional tuning of the load by added resistors and/or capacitances) to the SUTs secondary winding or with.
From a technical perspective none of these variants change anything in the MC generators behaviour. It remains always an alternating current generator with a tendency to oscillate and resulting in a high-frequency resonance. This is clearly a non changeable rule in electronics and physics.
At same time one should be driven and motivated by manufacturers specification: HMD025/TMD 25 -> 24 ohms impedance and recommended load at 200 up to 300 ohms because this specification point at what is achievable most: a linear frequency response
A SUT ratio of
- 1:20 will result in 118 ohms seen by the MC cartridge, what´s far too low
- 1:10 will result in 470 ohms seen by the MC cartridge, what´s seems to be too high, but even EMT is using a 1:10 SUT in the 155ST phono stage in order to be operated together with their TSD15 (also 24 ohms imedance)
- 1:13 results in 297 ohms seen by the MC cartridge, what would be right in the specs limits
- 1:15 results in 297 ohms seen by the MC cartridge, what would also be right in the specs limits
Cartridge sound changes with how it´s beeing loaded, what equals directly to the SUTs step up ratio, but it´s not telling you anything about the SUTs quality. Furthermore cartridges always sound best when loaded for a linear frequency response, but you won´t detect this in auditioning by having a look at hights or bass performance; differences are with details, timbre and spatiality only.
I´d given several 1:10 as well as other SUTs and capsules a try with my TSD-15 with 1:10 beeing not any nicer/ smarter or bad than SUTs and capsules that are not that easy and cheap to source as 1:13 or 1:15
On other hand you might be lurking for names of capsules and SUTs you might get you hands on and audition them. If so I´d go with
- entré ET-100 (in its 1:10 setting)
- Bryston TF-1 (in its 1:13 setting)
- Tamura TKS-83 (in its 1:10 setting)
- Tamura TKS-22 (in its 1:14 setting)
- Shure inout matching transformer with a ratio of 1:12.5
- Sennheiser TM-003 (1:10)
- Fidelity Research XG-5 (in its 1:13 setting)
- Ortofon T-30 (in its 1:14 setting)
- Denon AU-320 (in its 1:10 setting)
- Technics SH-305 (in its 1:10 setting)
