Voltage measurement of balanced outputs
“dB” It is common practice to measure balanced outputs with unbalanced voltmeter. This article discuss how it is the right way to do that. Lets start with several definitions about the output levels. Definitions decibel Abbr. dB Equal to one-tenth of a bel. [After Alexander Graham Bell.] 1. A measuring system first used in […]
Noise performance analysis of Op-Amps
I. INTRODUCTION In a previous research we discuss the design and performance of J-FET discrete input ultra low noise preamplifier with voltage noise less than 0.3nV/ЦHz [1]. The circuit has significant benefits compared to the simple op-amp use but it is not suitable for some low scale and low power devices. Front transistor used […]
Time constant mod for the Revox B750 MK-II
Revox B750MK-II is very interesting amplifier. It integrates nice RIAA EQ preamp for MM cartridges. After changing all of the capacitors and transistors, its sound is very impressive. First of all it is a current feedback amplifier. The power amps sound pretty at all. This post is purposed to the RIAA EQ of the […]
LNA2104 – Ultra Low Noise Preamplifier
The amplification of low signals from inductive transducers is not an easy task. Existing integrated amplifiers are good enough but in some applications the requirements are for better signal to noise ratio and high gain. For example the LT1028 / LT1128’s voltage noise is less than the noise of a 50Ω resistor. Here we […]