Loading for Air Tight PC-1 Supreme

Both your phono stages have internal stepup transformers, so Rushton's setting (based on his active phono stage) will not apply.

Loading of LOMC's with stepup transformers is both more critical and more complex than with active stages. The optimal load depends on the turns ratio of the transformer, and small adjustments can make large sonic changes.

I'd suggest checking with your phono stage manufacturers or dealers for guidance (though in my experience many offer less help than they should). Let them know the internal impedance of your cartridge (2.5 ohms) and they should be able to give you a starting place.

BTW, the brochure claims the Artemis ATE-2001's MC inputs are switchable to 3 ohms or 20 ohms. It's only the MM input that's fixed at 47K. Use the MC inputs and try both settings, just to give yourself some reference points.

With any stepup, you also have to decide whether to use primary or secondary side loading, another complex issue which was discussed on on a recent thread here. Look that thread up for an overview from someone who understands this difficult topic. I fine tuned LOMC's through stepups for several years with success, but it always took considerable experimentation to fine tune results and if I took the same cartridge and SUT to another system the optimal load was never the same.

If I'm making it sounds like there's no simple answer, it's because there's no simple answer. Loading with active gain stages is much easier.

pardon my ignorance. Does it mean that once a Phono stage utilise a step up transformer, I will have to set the loading based on the internet impedence of the cartridge?

With a low output moving coil cartridge (LOMC) you always have to set impedance based on the internal impedance of the cartridge - no matter what kind of phono stage you have.

An active gain stage just makes calculating a reasonable value simpler.

With the PL-1 I seem to be only able to set the impedance based on the loading impedance and not internal impedance. From the leaflet that came with my PC-1 Supreme cartridgem, airtight seems to suggest a loading of 100ohm to 800ohm and preferrably 400ohm. But that leaflet is met for the PC-1 i believe. I wonder if the loading for the PC-1 Supreme is the same as PC-1

Ianchang, The data that came with the PC-1 no doubt refer to the final load the cartridge "sees" when it looks at the phono stage input. With no SUT, all you need to do is insert a resistor in that range of values in parallel with the input of the phono stage. With a SUT, as Doug says, it's a bit more complex, because the cartridge "sees" first the SUT and then the load resistor on the other side. The intervention of the SUT will affect the load impedance by a factor related to the square of the turns ratio of the SUT. This sounds arcane, but it's really no big deal to calculate the value of a load resistor that will at least be in the ballpark. After that, again as Doug says, you may want to fiddle with the value to get optimal results, OR you may be perfectly happy. For formulae on how to calculate the load resistor, go to the Jensen transformer website or Google the question. You do have to know the turns ratio of your particular SUT, however. All of the foregoing applies to the choice of putting the load resistor on the phono preamp side or the secondary of the SUT, with the cartridge connected to the primary. I myself am not familiar with placing a load resistor between the cartridge and the SUT, and you can ignore that for the moment, just to get started. It just would change the value of the impedance reflected across the SUT. (Output R of the cartridge in parallel with the load R all on the primary side.)