Passive preamps - differences between technologies


I have been wondering what are the main differences in the way some passive preamps are designed. 

Some have resistors, some are transformer based.. What are the pros/cons?

More specifically, I'm looking at Music First Classic/Baby Reference V2 vs Hattor the Big or a Tortuga.

I'm looking for an upgrade from Audio Research LS16, considering looking for ARC Ref3 or a nice passive. My amp is ARC Ref150 (which is a lovely thing and I feel like the LS16 is holding it back) and phono pre is RCM sensor2 mk2 - so there's enough gain from the phono, the power amp has 300k ohms input, my DAC can output 1-3V rms, I use interconnects up to 1m so a passive could be an option. 

Thank you. 

Greetings from Prague with the first snow



My Tortuga Audio LDR preamp has never disappointed me.

It has a very clean transparent sound, nice detail, clarity is a strong point. It images very well too.

It has a pitch black back ground too that I attribute to its battery power supply.

Very impressive, especially for the $$ 👍

If you have adequate gain, I say the same thing to anybody who will listen, get one of Dave Slagle’s autoformers and be done with typical resistor type volume control.