Specs for Cotter MK 2L

Anyone know what the step-up ratio is for this SUT?

I’m looking to pair it with my Koetsu Blue Lace and Shindo Vosne-Romanee and Shindo 604 speakers.

I’ve heard that the Cotter’s are known to pair well with Koetsu’s, but it’s not clear to me if that pairing is primarily for the wood or stone bodied Koetsu’s. Also, I’m told that the Vosne-Romanee is different than most pre-amp’s, so what works "in general" won’t necessarily translate to a Shindo pairing due to it's different loading characteristics.

Bob from Bob’s Devices recommends a ratio of 1:30 based on the published specs of the Vosne-Romanee, so curious what the Cotter ratio might be. I’ll probably try out his SUT, but wouldn’t mind getting a few that work best on paper and comparing to see which has the tone I like best. He offers a 30 day trial and I figure anything vintage I buy can be resold later if his wins out.

Koetsu Blue Lace
Body: Blue Onyx
Output Volts: 0.3mV
Inner Impedance: 5 Ohm
Recommended Impedance: 30 Ohm
Compliance: 5 x 10-6 cm/dyne at 100 hz

Shindo Vosne-Romanee
Phono Input‐Switchable
Phono MC(RCA Pin Jack)Input Sensitivity/Impedance:0.2mV/2 - 100Ω.
Phono MM(RCA Pin Jack)Input Sensitivity/Impedance:3mV/100KΩ.
Output(XLR Jack) Impedance: 8V/600Ω.
Phono Max. Input Voltage:1,200 mV.
B27d49d2 9038 4ccb b2a2 5643b52436c7bgupton
Dear bgupton: Maybe I'm missing something but IMHO you need not any SUT for that cartridge/phonopream combination. You can't connect directly to your Vosne-Romanee.

Who tell you that you need it?

Regards and enjoy the music,
Very low output, max= 0.1 mV
The way I understand it , is that SUT step-up ratio is inversely proportional to the input impedance, it presents to the cartridge
Your Koetsu has 5 Ohm impedance, so it likes "to see" the load, that is approximately 10 times higher, 50-100 Ohm
if the SUT (Cotter MKII L), is designed specifically for Koetsu, that means, it has highish step up ratio, likely 25-30.
BTW, I have Vosne Romanee and Koetsu Urushi cart myself.
I'm getting Ypsilon MC 10 L SUT (1:10 ratio) and 500 Ohm input impedance, but you can load it down to required by Koetsu 100 Ohm with additional resistors.
I'm going to try and see how it works