Moving coil cartridge preamp

This is a discrete component “Op-amp” using Matrix Geometry Transistors for minimal thermal noise generation. From figure 6 of Diodes Inc. (Zetex) Application Note 23: http://diodes.com/_files/products_appnote_pdfs/zetex/an23.pdf A discrete component opamp circuit like this circuit is useful for low noise pre-amplification of uV level signals from low impedance sources (e.g. the head amplifier for a HiFi moving coil pickup cartridge). A discrete implementation allows the designer to employ relatively large area, high gain input devices. These devices present a low value of base spreading resistance to the input circuit, which minimises the amount of thermal noise generated. The output of this simple little preamplifier circuit can be connected straight into the moving magnet cartridge (RIAA equalised) input of any HiFi amplifier. Of course, two channels are required for stereo! :)