Last Year I did this take on Royer mics. I did 4 mics, 2 of them based upon the Royer Mod 2 (Small Diaphragm Condenser, with the tube in the mic, and the transformer is near the power supply) and two based upon the first royer mod (Large Diaphragm Condenser.) One was using the original circuit board layout, the other was re-layed out to fit in a smaller mic.
All of them use the same power supply. The way I did this is that I created a little "interface" box to work with the SDC versions, to contain the transformer. It also accomplishes getting the transformer out of the Power Supply Box, which is good for the noise floor.
It was my first exposure to tubes, but I use the LDC's a lot, and really like them.
First circuit cards, hand drawn copies of the royer layout
Later I re-layed out the mic card to fit a short mic, and the power supply to fit a small box.
Original Royer design being built
Picture of completed Royer Mod Mic
Traditional Royer Mod, hand copied and drawn PCB
Second round mic, a modification of a big echoey MXL mic, that I shortened, opened the basket, and put a royer circuit in with a different card layout for size. Also fitting the tube inside the basket.
Plastic cup works well to protect the delicate diaphragm while you re-assemble the mic.
Shorter mic, using a mic trafo backwards for the stepdown.
Closeup, you can see how the circuit card fits up under the plate that supports the capsule. At this point the transformer was 4:1 stepdown, which made the mic much too hot, but later I put a 10:1 stepdown in there which works fine.
Finished short Royer.
You can see the tube glowing in there.
Here is the little converter box, that has the transformer in it. In Dave Royers original design this transformer was in the power supply enclosure. By taking it out of the enclosure, yøu can worry less about shielding, and you can use the SAME power supply for all these mics (but on the SDC mic's you need to use this little interface box.) This works well to reduce the amount of stuff I have to carry for on location work.
Two mics and interface boxes can fit in one case. And they will work with the same power supplies that feed a normal royermod mic.
A dual power supply and a single. I did a re-layout of the power supply card and I can fit two of them in the small box (it is tight) too with one inverted (the caps overlap).
I have to dig up some photo's of the guts of the power supply, and the little interfaces. But they are really very simple. It is Dave Royers design, but the cap, resistor and transformer are mounted in the interface box instead of the power supply. I also re-configured the pinout so that if you accidentally plug the mic in without the interface box, you are less likely to fry something.
All of them use the same power supply. The way I did this is that I created a little "interface" box to work with the SDC versions, to contain the transformer. It also accomplishes getting the transformer out of the Power Supply Box, which is good for the noise floor.
It was my first exposure to tubes, but I use the LDC's a lot, and really like them.
First circuit cards, hand drawn copies of the royer layout
Later I re-layed out the mic card to fit a short mic, and the power supply to fit a small box.
Original Royer design being built
Picture of completed Royer Mod Mic
Traditional Royer Mod, hand copied and drawn PCB
Second round mic, a modification of a big echoey MXL mic, that I shortened, opened the basket, and put a royer circuit in with a different card layout for size. Also fitting the tube inside the basket.
Plastic cup works well to protect the delicate diaphragm while you re-assemble the mic.
Shorter mic, using a mic trafo backwards for the stepdown.
Closeup, you can see how the circuit card fits up under the plate that supports the capsule. At this point the transformer was 4:1 stepdown, which made the mic much too hot, but later I put a 10:1 stepdown in there which works fine.
Finished short Royer.
You can see the tube glowing in there.
Here is the little converter box, that has the transformer in it. In Dave Royers original design this transformer was in the power supply enclosure. By taking it out of the enclosure, yøu can worry less about shielding, and you can use the SAME power supply for all these mics (but on the SDC mic's you need to use this little interface box.) This works well to reduce the amount of stuff I have to carry for on location work.
Two mics and interface boxes can fit in one case. And they will work with the same power supplies that feed a normal royermod mic.
A dual power supply and a single. I did a re-layout of the power supply card and I can fit two of them in the small box (it is tight) too with one inverted (the caps overlap).
I have to dig up some photo's of the guts of the power supply, and the little interfaces. But they are really very simple. It is Dave Royers design, but the cap, resistor and transformer are mounted in the interface box instead of the power supply. I also re-configured the pinout so that if you accidentally plug the mic in without the interface box, you are less likely to fry something.