M A Cotter MK-2 transformer differences?

Does anyone here know the difference between P, S, Etc. models of this MK-2 Moving Coil Pickup Transformer? I have one that does not have the designating model sticker and would like to know what its application is. Thanks in advance!
Think they are just for different impedance cartridges. I have a "verion" P (predessor to him calling the company cotter) that was meant for 3 ohm cartridges. All the models are re-wireable to other settings (plate where hook-ups are comes off & reveals 9 or 12 pins which are jumpered to create specific impedance)My verion is also blue and appears identical other than brand name. Think he OEM'd it to Bryston for awhile too
Great, so would anyone happen to have information regarding the setup of this unit, or know where I can get it? I couldn't find any information whatsoever on this company except for links taking me to this forum.
I emailed an on line service manual company lets see what they can dig up


Groovey Records
I may have the jumper diagram somewhere, don't think unit had a manual, you just bought the version applicable to your cartridge, plugged cartridge into transformer & transformer into phono in. The screws to take it apart are under the rubber feet (hex?)Pull the screws out & unit slides out of blue sleeve. Nothing to really look at though, just a sealed epoxy filled steel shell. Pins are accessible by taking end plate off (ins & outs)
All I got back in response was a form email repeating my request that I had emailed to him. His name was Tom doubt if the email was even read.

I wish I could do better for you HiFi engine had nothing and other then there I could only think of you researching who might of been their retail or wholesale distributor.

Regards Groovey

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Thanks for all your replies, someone did email me the diagrams for the MK-1, but the configuration I had did not match that of the ones listed for the MK-1. I also tried to contact a guy In Louisiana that says he has all the documentation for this unit, but have not been successful so far(phone and email).
This is from Arthur Salvatore's Website an excellent reference source from a passionate audiophile http://www.high-endaudio.com/RC-Step-ups.html

Hope it is of some use to you



These models were the finest moving-coil transformers ever made at one time, and the best I heard, overall, before the Expressive Technology came into existence. They had excellent sound; natural, detailed and dynamic, though with both of the frequency extremes rolled off a little.

It came stock with its own (4') output cables already attached, which was a strong advantage, but now it is a decided disadvantage. The cable's excessive length and (now) mediocre quality both compromise the Cotter's inherent performance. A competent technician must be found to remove and replace them with good quality RCA females, which would then allow the use of any superior phono cable.

There are different models of this transformer that have different input impedances. The model with the lowest input impedance (2L) is usually the most desirable version with current cartridges.

The Verion was the exact same transformer as the Cotter, before the name changed due to legal reasons. However, unlike the Cotter, no version of the Verion was ever offered with the lowest (L) input impedance, as far as I know.

FURTHER: The original Bryston transformer (black) was the exact same model as the Cotter, with just a different name and color. It was even built by Cotter.

However, the current Bryston transformer, with the model name TF-1, is a different design. Chris Russell, the CEO of Bryston, claims this model "has a wider bandwidth and 40% of the measured distortion of the Cotter/Verion unit." I am sad to admit that I haven't heard this unit, despite the fact that it is made in Canada.

I have some scematics but they don't match the service-manual I found on vinyl engine.

The Cotter MKII have 5 pins horisonataly (1-5) and 4 pins vertically (A-D). Mine is wired like this:


+ meaning they are connected.
The wiring instruction I have says this is the type "P" or "I" (bad copy), made for 25-40 ohm.
There is an other option calltd "X" or(P-P) for source impedance <20ohm. Does anybody know how I should wire to match my XV-1s (6ohm). In the owners manual the X and P-P are two different models.

The problem is that the wiring instruction and the owners manual don't state the same impedances for the different types of the Cotter.
I've read the Mk 2L is not variable (has only 1 impedance setting) but do not know step up ratio.