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DIY U48 schematic with EF800 tube Condenser Microphones
Old 7th March 2018
Here for the gear

Looking for DIY U48 schematic with EF800 tube

I have built a couple of microphones over the last year and a half and my next project is a stereo microphone based on the U48 schematic. Finding a schematic and a power supply seem to be problematic. I am (again) making the mic body myself. It will be a 2-1/2" body tube with capsules fixed at 90% angles. I like the EF800 tube because I can fit a pair of them adjacent to each other to save room. Heat might be a problem there, not sure. I prefer pattern switches on the body as opposed to remote pattern switching here and can live with Cardioid and Figure 8 but omni would be a nice addition but not necessary. alternately I can do a remote pattern control and a switch for dedicated Cardioid pattern. Oliver's alternative tube U47 schematic would work here but I would need a dual power supply. It seems that adding the Figure 8 pattern to the U47 schematic would entail adding a 105 volt leg but the high impedance resistor value is not something I know how to calculate. If any of you learned folks have some good advice I am all ears...
Here are some pics of my recent projects.

Last edited by Nollman; 7th March 2018 at 03:17 PM.. Reason: pics did not upload
Old 20th March 2018
Here for the gear

Does anybody think this will work out. I am no expert here and welcome any suggestions.
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