Vintage Audio Technology for the Modern Studio
UM25C Microphone


For the second installment in our UM Series, we looked to move in a different direction from the 47/49 inspired UM17R, towards the historic Ela M250/251 microphones. The aim was to ceate a true high performance microphone with the demanding professional in mind, custom built with a design focus placed solely only sound quality and reliability.

The UM25C’s design process began with the selection of a suitable tube and circuit.  For the tube, we opted for an NOS Telefunken model that has so far not been used in any other microphone. It approaches the tone of the historic 6072a, with similar sound quality and performance, and more importantly, is easier to source as good quality replacements remain more available.  For the circuit, it is identical and no modifications are needed to exchange the classic Telefunken with an 6072, either tube the mic is true to the 250/251 tone. For optimum sound quality, we chose to go for point-to-point assembly of the circuit on a Plexiglas board. The transformer choice was straightforward, with the AMI ‘Hiller’ style T14 already an industry standard and a great match for the design.

For the accessories, a beefy vintage ‘NG’ style power supply, handmade by AMI, powers the microphone providing 3 different polar patterns- Omni, Cardioid and Figure 8. The cable provided is an US made Accusound with 7 pin Neutrik cable ends.Every microphone ships with a custom shock mount built to the exact weight ratings of the UM25C. The entire system is covered by our 5 year limited warranty with all units burnt-in and tested for 3 days prior to delivery.

In terms of its performance, as a guideline only, the UM25C sounds remarkably like an historic Ela M251 with a smooth top end and the ability to capture details even as a room or overhead mic. As with all our microphones, we highly recommend you contact your dealer for a demo in your own room, to experience it firsthand. 




Product features
  • AMI 47RP PSU, made in the USA
  • Made in the USA Accusound cable with Neutric cable ends
  • Custom shock mount
  • Historic Ela M251 circuit updated by Oliver Archut
  • AMI T14 transformer made here in Gaylord, Kansas US
  • NOS Telefunken tubes
  • Point to point wiring
  • Flight Case
  • Microphone Amplifier made here in Gaylord/KS USA
  • 5 year limited warrenty (tube excluded customers pays for shipping)


Product Specs:
  • Type:  Condenser pressure gradient
  • Polar Patterns:  Remote 3-position switch;  Cardioid, Figure 8 and Omni
  • Frequency Range:  20Hz to 20,000Hz
  • Impedance:  200Ω
  • SPL:  133dB
  • Sensitivity: 12mV/pa
  • Equivalent Noise:  less than 7dBA
  • None linear Distortion: 1% THD @ 1000 Hz (134dB)
  • Mic Dimensions: 47 x 237mm/1.85 x 9.33 inch 
  • Weight:  750g/24.11Oz


 List price:  $2999.

Historic Ela M251 (top) and UM25 in AMI's anechoic chamber

More UM25(C) pictures