Firstly this is an old post that I moved here from the main page as I am working towards updating it.
 | Recently I built one of the U47 Copies that are out there. I have built many mics over the years but I have to say this was satisfying. The Kit if you will is an amalgam of several different sourced items. First the body and the mic PCB's, BV8 transformer and the circuit concept are designed and fabricated in Austria by one Max Kircher AKA, IOAudio with the exception of the head basket that comes from Flea Microphones which uses a magnetic relay for pattern switching. The capsule which is an M7 BlueLine PVC skinned unit comes from Germany and is machined and skinned by Thierch Elektroakustik. The PSU PCB is designed and manufactured by a person who goes by Zayance in France. The new concept at play here is the dual tube topology. The mic employs a circuit that is true to the original except instead of using a single (outrageously expensive and unobtanium) VF14 it uses two (2) 4o8a tubes wired filament in series and tube path in parallel. Thus the voltage for the mic can be kept to the original concept of one supply voltage (105VDC) and a drop down resistor used to get the filament voltage. UPDATE: I have since sold this mic and moved on from the two tube concept. I still have some mics that use it but I have come to the opinion that the 408a tubes are just not reliable or quiet enough for studio use! Sadly it is more problematic than it is worth. |