A high quality microphone preamplifier using a single power supply, suitable for dynamic or electret microphones. The opamp used can be any low noise, high performance type, e.g. NE5534,TL071, OPA 371 etc.
In recent years, following CD introduction, vinyl recordings are almost disappeared. Nevertheless, a phono preamplifier is still useful for listening old vinyl discs from a well preserved collection.
This preamp is very simple, and will work under tough conditions. The input impedance is pretty high, so it won't load down electric guitars.
A passive linestage is simple to build and makes an excellent first audio project. Building one is a good way to practice soldering skills and construction techniques, and as no power supply or active components are required it is also a safe project for beginners.
It has an exceptionally fast high frequency response, as demonstrated by applying an 100kHz squarewave to the input.
Passive preamps have gained popularity in high-end audio circles. Provided that a high quality volume control is used, a passive preamp is often the easiest and cheapest way to reach high-end sound quality.
The preamplifier is the device that has always attracted me, from a circuitry point of view. The main duty of a preamplifier is to raise the signal from a source's output level to an amplifiers input level.
The general idea is to build a basic line stage preamplifier that allows for a number of different designs and valves to be experimented with. Initially it should be built with good commercial components, nothing fancy.
The maximum unclipped output should be around 25V into 600Ohm and up to 50V into higher loads. Also driving 600 Ohm will not roll of the bass as it will do with most Preamplifiers nor will it unduly increase the Distortion.
The purpose of this report is to describe an experimental RIAA phono preamp that uses several different concepts to derive a high quality RIAA compensated phono preamp.