Blackspade UM25C Tube Microphone Description

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 create a true high performance microphone with the demanding professional in mind, custom built with a design focus placed solely on 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 we made minor modifications to the original to accommodate the different tube whilst remaining 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 straight forward, with the AMI "Hiller" style T14 already an industry standard and a great match for the design. Finally for the capsule we contacted Tim Campbell and asked him to make some modifications to his handmade CT12 to tune it to our circuit, and increase the performance of the microphone system as a whole through customization of his already very well known product.

For the accessories, a beefy vintage "NG" style power supply handmade by AMI power the mic, providing 3 different polar patterns; omni, cardioid and figure 8. The cable provided is a Gotham GAC-7 and every mic ships with a Rycote 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, the UM25C sounds remarkable similar to an historic Ela M251 with a smooth top end and the ability to capture details even as a room or overhead mic.

Blackspade UM25C Features

• Oliver Archut designed amplifier circuit (USA)
• Tim Campbell custom built capsule (Denmark)
• AMI T14 transformer (USA)
• Telefunken tube (USA)
• AMI NG style power supply (USA)
• Rycote shock mount (UK)
• Gotham GAC-7 cable (Switzerland)
• Neutrik / Switchcraft connectors (CH/USA)
• Built in the USA
• 5 year transferable warranty (tube = 6 months)

• Type: Condenser pressure gradient
• Capsule: Tim Campbell CT12, CK12 style
• Polar Patterns: Selectable omni, cardioid and figure 8
• Frequency Range: 20hZ to 20kHz
• Impedence: 200ohm