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Showing posts with the label Preamplifier

Multimedia RIAA Preamplifier

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Even if a large number of album titles once available on vinyl are now, little by little, being proposed as CDs, not all are available and far from it. You may have treasures in your collection that you would like to burn on CDs. First, preserving a CD is easier than preserving a vinyl record, and second, we have to admit that turntables are disappearing, even on fully-equipped Hi-Fi systems. From a point of view of software and PCs, converting from vinyl to CD is not a problem. A large number of programs, whether paid for freeware, are available to re-master vinyl records with varying degrees of success and to eliminate pops, crackles and other undesirable noises. All of these programs work with the sound card of your PC and that, admittedly, is where the problem starts. Most high-quality turntables are equipped with a magnetic cartridge which typically delivers just a few mV. The cartridge signal requires a correction of a specific frequency, called RIAA correction. If our older read...

Phonon Preamplifier Circuits Diagram

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In recent years, following CD's introduction, vinyl recordings are almost disappeared. Nevertheless, a phonon preamplifier is still useful for listening old vinyl discs from a well preserved collection. This simple but efficient circuit devised for cheap moving-magnet cartridges, can be used in connection with the audio power amplifiers shown in these webpages , featuring low noise, good RIAA frequency response curve, low distortion and good high frequency transients behavior due to passive equalization in the 1 to 20KHz range. Transistors and associated components provide ±18V supply to the op-amp, improving headroom and maximum output voltage. Phono Preamplifier Circuits Diagram  Notes: R2, R3, R4, R7, R8, C4 & C5 should be low tolerance types. Schematic shows left channel and power supply. For stereo operation R1, R2, R3, R4, R7, R8; J1; C1, C4 & C5 must be doubled. Numbers in parentheses show IC1 right channel pin connections. Technical data: Sensitivity @ 1KHz : 2....

Band 2 Preamplifier

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This is a VHF amplifier for the Band 2 Radio Spectrum tuning approximately 88 - 108 Mhz. Band 2 Preamplifier Circuit Diagram Notes: The circuit uses two 2N3819 FET's in cascode configuration. The lower FET operates in common source mode, while the upper FET, operates in common gate, realising full high frequency gain. The bottom FET is tunable allowing a peak for a particular station. Coil details follow: L1 4 turns of 18swg air spaced with a 1cm diameter, the tap is one turn up from earth end... L2 4 turns of 18swg air spaced with 1 cm diameter. The coupling coil is 1 turn interwound from the supply end. Enamel coated wire must be used.