So we have a new ribbon.
Now let's install the fabulous and justly famous Lundahl LL2912 microphone transformer!
This is one of the two most popular transformers for the Apex ribbons. The other transformer being the Cinemag CM-9888.
We just need to remove the stock transformer and put the new one in its place. However it's critical that the new transformer is wired correctly so that proper polarity is observed.
You can see the primary and secondary leads identified in the photo on the right.
It's easy to figure out the secondary connections by tracing them to the XLR connector. I marked my PC board to make it easier to identify when I connected the new transformer.
Desolder the leads and unscrew the can from the chassis frame.
Note that the cable shield ground was soldered to the tab on the chassis - you will need to get all of the solder off to remove the can.
Primary positive is white, negative is red.
Secondary positive (to pin 2 of the XLR) is green. Cold (pin 3) is black. And pin 1, ground goes to the tab on the right.
Then the transformer can be removed. In my case, the cover 'lid' of the transformer didn't want to budge, so I threaded the nuts back on and used them to leverage the cover off.
Plunk it in your parts bin.
I put some green shrink tubing on the primary lead so I didn't get confused when connecting it.
Just pass the leads through the holes. I used a piece of copper shielding tape to hold the transformer in place. Any kind of tape would be fine I think.
I confess that I did this after I soldered the transformer connections. It seemed more logical, but I had less room to maneuver the screws. It worked fine though.
The board helps clamp down the leads.
Note the cable screen now soldered to the ground.
Here's how I routed the leads - right along the edge of the ribbon motor assembly, held in place with wire ties.
Be very careful threading the wire ties near the ribbon so you don't tear it!
The other low noise hint I learned is to twist the respective positive and negative leads from the ribbon together. Meaning, the red lead on the left side of the motor with the blue on the left and the same on the right. The idea being that they will cancel out RFI.
I got maybe 2 twists on each, so I'm not sure how much it helps, but I did it, so there!
Remember, though that BOTH of the red leads (negative) still go together to the same terminal on the board, and likewise for the blue (positive). You can see this on the larger version of the image.
You can also see how I used a small piece of shrink tubing to hold both red leads together and the same for the blue leads.
Then the two reds go to the old "red" terminal and the blues to the "blue" terminal we marked earlier.
So I put some CLD tile material inside the body, and stuffed it with speaker stuffing to fill the open space. Now it's totally dead.
See also how I ran the cable through the body - I reused the factory cable sleeve and put a new cable clamp on (broke the old one taking it apart!).
There is a second headbasket mesh screen and a fabric windscreen in the basket - I decided to leave them in for now. The ribbon does need some sort of protection.
Compared back-to-back with a stock Apex 210, it's a night and day difference. Amazing!
The stock one sounds small, boxy, boomy and not a lot of high end.
The modded one is much more open, less boomy, and has much more high end. It's pretty amazing.
The difference is like having earplugs in (stock) and taking them out (modded).
And it's dead silent.
I'm running the mic through a Cloudlifter Z and I find I can use the low (12dB) setting if I wish. Plenty of gain after the Cloudlifter boost.
I think all this improvement is a combination of the thinner ribbon and the transformer. I want to convert another one and use a Cinemag transfomer to see if there is a difference. But for now, I'm super pleased with this one.