A FET impedance converter for use with the Fishman pickup on my Kay orchestra bass. As shown in the schematic below, the circuit is divided into two sections, so that the input section can be mounted inside the head shell of a 1/4` plug. This puts the active circuitry right were it counts, on the instrument. Two isolated output circuits are shown, but you can have more. The prototype I use in performance has three
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outputs: 1/4" phone, RCA phono, and XLR. For the XLR output, I used a TRW/UTC #O-2 mic-line transformer, inside a #O-17 magnetic shield, to get even lower output impedance. For an improved version of this circuit with better headroom and reduced harmonic distortion, see my Active Plug Bootstrap page. For applications where battery power isn`t required, I`ve also developed a Vacuum Tube Direct Interface, using triaxial cable to connect to the instrument. The circuit is optimized for low current drain with a single 9 Volt power supply. Distortion is 1% or less up to 1 Volt RMS output. Gain is set at unity, which makes the circuit very stable with transient inputs, and matches up well with most instrument and sound reinforcement amplifier inputs. With no equalization provided, frequency response is flat allowing the circuit to be used with almost any instrument. Equalization, if needed, can be done on the mixing board or instrument amplifier. Here are some snapshots of the JFET input circuit mounted on a Switchcraft SilentPlug 1/4" phone plug, and of the battery box with additional circuitry and mic-line transformer. Magnetic pickups, consisting of many turns of fine copper wire wrapped around a permanent magnet, are found on almost all solid body electric guitars and basses. They are highly inductive, and require an impedance conversion before being connected to line level circuits. The conversion may be done by onboard...
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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