Xaudia M-series mic matching transformers
These transformers can be supplied in any required impedance ratio; 50 to 600 ohms is a commonly requested ratio that is perfect for Melodium 42B and other 30 to 50 ohm ribbon mics. This will give a 10dB increase in level without noise penalty, and a flat response from 15Hz to beyond 60KHz.
Let us know about your microphone and preamp and we will advise on the optimum transformer type.
Approximate dimensions: 25.7 mm x 19.5 mm x 18.5 mm