switchable SUT?

[AstromanoftheFuture]

I've been eyeing the Eros II kit, particularly because it has a provision for adding SUT's for LOMC. I do not currently have any LOMC carts, but I've been looking to try them. I'm considering the purchase of one of the Denon 103 variants, and I am most interested in trying out the "budget" Ortofon SPU-- the #1 SPU. While looking at the Ortofon, I'm also looking at their external SUT's... but having the SUT's internal to the Phono pre seems more elegant...

I hope this question isn't too naive, ill-informed, etc...

When one adds the SUT's to their Eros, do they also add a switch (on SUT, off no SUT)? Is having a "switch" to go between no SUT and SUT (or to switch one of the variable SUT's) considered undesirable? My limited research seems so... and I can't see from the online documentation that the SUT addition is something "switchable" or it's just meant to be on all the time, (or just depends on how the owner builds their kit)

The Ortofon #1 has an output voltage of only .18mv...Internal impedance of 2 ohm, and a recommended load impedance  > 10 ohm. I'm looking at the Sowter SUT's, they do recommend several different models, I just haven't figured which one would be the best (still need to crunch all the numbers).

[Paul Birkeland]

When one adds the SUT's to their Eros, do they also add a switch (on SUT, off no SUT)?

I suppose this is possible, and there is a 1/4" hole that could be used for this purpose.

Is having a "switch" to go between no SUT and SUT (or to switch one of the variable SUT's) considered undesirable?

Oh yeah, you've undoubtedly stumbled across the 100,000 online posts talking about how terrible this is.  You could certainly give it a shot and make this determination on your own though.

The Ortofon #1 has an output voltage of only .18mv...Internal impedance of 2 ohm, and a recommended load impedance  > 10 ohm. I'm looking at the Sowter SUT's, they do recommend several different models, I just haven't figured which one would be the best (still need to crunch all the numbers).

Whew, 0.18mV is ultra low!  The Sowter 1590 is the only step-up from Sowter that is suitable for using that cartridge with the Eros 2.

If you haven't bought a cartridge yet, you can look at the Sowter phono step-up page and note just how many cartridges will work with a 9570 or 1990.  In general, if you plan to use a 1:10 step-up, I would recommend a cartridge with 0.4mV of output or more if at all possible. 

The amount of work that it takes to dial in your tonearm when you switch cartridges should be something you consider if you're planning to do switchable transformers, as the inconvenience of setup may be enough motivation to just stick to one cartridge.