Edcor MX2 Transformer in Royer SDC

I need some help. I'm a noob to DIY stuff. I built a Royer SDC out of an MXL 993, except instead of using the Jensen transformer I used an Edcor MX2 (1:2) and wired it in reverse to make it a 2:1 step down. The mic sounds fantastic, except there is a slight buzz. I assume this could be because I have nothing connected to the C.T. pins of the transformer

Here is a pin out diagram:
https://www.edcorusa.com/content/images/thumbs/0001897_mx2.png

What I have configured right now is:

Pin 8 to C8
Pin 6 to R5
Pin 3 to XLR Pin 2
Pin 1 to XLR Pin 3

How should I connect the C.T.'s (Pins 2 and 7) in my circuit? Should I connect Pin 2 to XLR Pin 1 and Pin 7 to R5 also? I would try it out myself right now, but I blew my 24VAC 2A wall wart trying to eliminate the buzz so I'd like to get some advice before I blow another one, or myself for that matter!

I don't think the center taps are your problem as those don't need to be connected. You seem to have the polarities reversed on both sides of the transformer, so you could try switching those. You say that pin 6 is to R5 but you should have the + tap (pin 6) to the output capacitor and the - tap (pin 8 ) to ground. Kind of hard to troubleshoot not knowing more, but given that you've fried a wall wart I suspect it could be more related to power and grounding. Check voltages (be careful). Make sure that the shield on the mic cable is only connected on the mic side and unconnected on the psu, as you could have a ground loop. The Royer mod PSU can be finicky about grounding.

I had the same problem and fixed it by shortening all the connecting wires and making sure the leads from the transformer to the 3 pin XLR are twisted together cleanly and completely out of the way of any power wires.  The noise disappeared  after I did those 2 simple things.

Hope this helps.

Heath

Thanks for the advice folks.

I rewired the mic and the noise reduced by about 90%, so I guess I had some wires connected improperly. A guy at Edcor said I shouldn't bother with the center taps at all with this circuit. There is still a slight hum/buzz, but it's not that noticable when I play my acoustic. I do have pin 1 on the PSU XLR jack grounded to case. PH, are you suggesting that I disconnect this?

As far as polarities go, that is intentional so that the transformer is 2:1 instead of the 1:2 it is speced for. The mic has proper phase.

Thanks!

I've been thinking that the length of my cable has something to do with the buzz/interference. One of the two mics has longer leads inside and is noisier. I'm thinking that my 25 foot 5 pin cables might be long enough to let some interference in. Would I see better results/less noise by cutting my 25 foot cables down to say 15 feet?