The PhoneAxe is an original design by the author of a passive filter network built into a 1/4` phone plug/coaxial cable, and is designed to allow electric-guitar matching to the magnetic-phonograph input on common hi-fi amplifiers. Most guitar amplifiers have `high input impedance` typically greater than 200 kohms. The reason for this is that the
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typical electric guitar pickup is a inductive magnetic transducer with frequency-dependent impedance. At high frequency, the mutually induced pickup voltage is dropped across the pickup-coil self-inductance (back EMF) if the pickup load impedance (i. e. amplifier input) is too low. Therefore, a high impedance amplifier input is required to prevent high frequency "loading" effects which are audible as a high-frequency attenuated "dull" sound. Most hi-fi audio amplifiers have two types of signal inputs: the line-level auxiliary inputs (for tuner, tape, CD etc. ) typically require 200 mV or more signal-level for efficient output power, have a nominal flat frequency response from 20 Hz to 20 kHz and an input impedance <= 30 kohms. This input by itself is not well matched to the guitar pickup output because of : The typical active solution for guitar/line-in matching is a flat- response dual op-amp circuit which provides impedance buffering and sufficient gain (typically 10 dB) for driving the line-level input. This is generically the type of input stage used in most solid-state guitar amplifiers. A simplified schematic diagram is shown below: The second type of hi-fi amplifier input is the classic magnetic-phono input. A simpler solution for guitar to hi-fi amplifier interfacing can be realized using this phono input. The phono input is characterized by : Since there is abundant gain at the phono-input, a simple compensating...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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