Transformer Matchbox 50 to 600 ohms

$114.37 ($95.30+VAT)

XLR transformer box to match older 30 and 50 ohm microphones to modern preamps. Standard 50 to 600 ohm model will suit most applications but custom options are available – please ask.

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Ribbon microphones often generate a lower output than condenser and dynamic mics. It is important to squeeze every last bit of performance out of the signal chain when recording quieter sound sources, 

Many older ribbon and dynamic microphones  have a 30 ohm or 50 ohm output impedance. However, most modern mics have a higher impedance and consequently many studio preamps give best performance with microphones of 200 to 600 ohms.

The transformer matchbox will connect older 30/50 ohm microphones to modern preamp inputs. It contains a high quality, custom wound Extinct Audio transformer and will give a 12dB increase in level without noise penalty. The transformer is housed in a robust metal enclosure, with gold plated Neutrik XLR connectors.

The frequency response is flat from 15Hz to beyond 60KHz, when used into a >2kΩ preamp load.

We can also supply custom transformers for microphones with unusual impedances.


  • Gold plated Neutrik XLR sockets
  • Rugged aluminium housing
  • 50 ohm input, 600 ohm output impedance.
  • Approximately +12dB increase in output voltage
  • Passive transformer. No active circuitry and no power required.
  • May be placed close to the microphone or close to the preamp.

Suitable for all 30 and 50 ohm microphones including Melodium 42B, STC 4033, and older 4038, and many others.

Please ask about your application.

Additional information

Weight 0.3 kg

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