Very well said Stephen, although this was posted 12 years ago I found it today googling for reviews etc on cheap transformers for ribbon microphones.

Here in Sweden we have Jörgen Thuresson who makes exellent if not the world’s “best” condenser mic’s like CM402 and others, I also have 2 of his 20dB preamps intended for dynamic and ribbons and they really open up and you have the sweetspot on your consoles input micpres as well w. these that sound far better than any other on the market!

Cheers Kristian Lakeson

Thx for this info though; I’m not at all inclined to a DIY mic, but the cost savings and interest in ribbon mics means I might try this. Also I have heard good things about the se X1R ribbon which is only about $230 FYI.

Stephen, where is your blog with recommendations, tests and what not? I want to buy everything you recommend.

There was perhaps a 1 dB increase in sensitivity but otherwise no discernible change in frequency response or S/N ratio. I did not measure distortion so can’t speak to that.

On the other hand a friend used a Lundahl transformer on his R144 and this appears to have had a large impact on sensitivity and actually improved the S/N ratio and reduced “hiss”.

Incidentally I also tried removing the protective mesh screens (no significant change to frequency response) and retensioning the ribbon (mine was a bit saggy, and this increased sensitivity about 1.5 dB).

The original transformer has its wires coming out from the bottom which makes it easy to feed the wires through the cap. The Edcore mounts its wires from the sides and I spent an hour maneuvering the wires so the transformer could mount deep enough in the cap so the cap could be screwed back in place on the mic housing. Backing off the screw that mounts the PCB board helped allot. I then tacked the PCB in place with two small drops of CA glue.

The frequency response definitely increased in the upper mids and highs which is what makes the signal louder. Recording results were much brighter sounding more like a Condenser.

I’m not sure I like the results for vocals yet. In retrospect I should have done this mod to the R144 instead of the R40. I liked the results I got with the R40 over the R144 because it gave me a rich tone to my voice. I bought the 144 cheap because it had a broken ribbon and replaced it with 2.5 micron which gave it a midrange bump that sounded a bit metallic. I replaced the R40 with a 1.6 micron ribbon and it was ideal for my voice.

I may wind up swapping the Edcor transformer into the R144 then either using the R144 transformer in the original transformer in the R40.

I will need to do a little more experimentation first. I wasn’t happy with the first results with the Edcor in the R40 but having listened to a finished recording and comparing it to another done with the original transformer it does stand out in the mix better. I did have to EQ it more but the final results for that particular song weren’t bad.

I may have to take a song recorded with the original transformer, then add a track using the new transformer so I can A/B compare the two more closely using a frequency analyzer. I like being able to use minimal processing to get good results when mixing because transparency is preserved.

I will say this upgrade will be ideal if the mic is used for recording instruments, especially guitar or drums. Its just my particular voice already has too much upper mids and the original transformer scooped them right where they were needed

Just as a note for anyone else doing this, it may be worth your time to take the head basket off and look at the ribbon itself; my was loose and sagging, sagging as far as being almost out of the magnets at the deepest part of the sag.

I was able to re-tension the ribbon by loosening the top clamp piece and pulling on a bit of the tab that was left by the manufacture. You just need to tighten it enough to remove the sag, but NOT pull the pleats out of the ribbon material. A

Word of caution, keep positive control of your screwdriver when near the magnets, or it will pull the screwdriver into the ribbon, then you will be replacing the ribbon material…

Great website and thank you for posting this modification, I had performed the same transformer modification to a NADY RMS-4 a number of years ago with outstanding results.

http://riikari.fi/mark

Here is a comparison between transformer mods in an MXL R-144 recording drums you can hear the difference between the original transformer and the mods;
https://www.youtube.com/watch?v=RRCFZY3wH4o