Transformer assembly line!

This week we have been building lots of little transformer moxes to match vintage 30 ohm ribbon mics to modern mic preamps. Correct impedance matching can deliver a +12 dB increase in level without noise penalty or loss of frequency response, which is welcome for many older microphones. Here is how a Reslo RV microphone behaves with and without the transformer:

Frequency response plots for Reslo mic with and without an impedance matching transformer

They are suitable for many old microphones including the following:

• Reslo RBL and RB 30 ohm models
• Melodium 42b
• Grampian ribbon mics (including GR1/L and GR2/L)
• Cadenza ribbon microphones (wired for low-Z use)
• RSA & Selmer ribbon mics
• STC 4033
• Altec and Western Electric ribbon microphones

More information.