The two stage tube preamp I built for a client required and moving coil preamp. I chose the Le Pacific jFet based schematic for my build.

The battery pack and components are all on the one piece of veroboard (no PCB). Russian PIO caps are used for the output and a "Sungold" epoxy enamel cast Al encases this compact unit.

There should be 100hours of play between battery changes. The preamp has been tested with a Audio-technica AT-F3/III MC cartridge. The cartridge output is 0.35mV but there is plenty of gain in the preamp.

Comments

• AmpDoctorJos
• 29 December 2011 at 04:13AM
• What about the noise? Do you know the S/N ratio?
  Some people use very big input transistors with a lot of current for this application, but if your batteries really work for 100 hours the current in the input transistor cannot be too big.