Best transformer for a u47 style MXL 2001 (Royer Mod)? Basically a Tube Mic.
- Thread starter 777funk
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dmp
Well-known member
The Royer mod is a very different circuit than a u47, so you don't have to limit the choice to "u47" transformers.
It's cathode biased and it doesn't have a bypass cap, while the u47 is fixed bias using the heater supply. And different tubes.
The u47 uses a lower ratio transformer than what Royer recommends, and lower than most other plate output designs.
I built a pair of mics based on the Royer circuit using 10:1 Beyer transformers and edge terminated capsules. They are excellent mics.
You may just want to experiment with the output coupling cap value and type to dial it in with a particular transformer. I think I ended up using a smaller value than Royer.
So, I'd suggest trying any high quality ~10:1 transformer.
Ioaudio & AMI both make great transformers, imo.
It's cathode biased and it doesn't have a bypass cap, while the u47 is fixed bias using the heater supply. And different tubes.
The u47 uses a lower ratio transformer than what Royer recommends, and lower than most other plate output designs.
I built a pair of mics based on the Royer circuit using 10:1 Beyer transformers and edge terminated capsules. They are excellent mics.
You may just want to experiment with the output coupling cap value and type to dial it in with a particular transformer. I think I ended up using a smaller value than Royer.
So, I'd suggest trying any high quality ~10:1 transformer.
Ioaudio & AMI both make great transformers, imo.
