The mixer is the common `virtual earth` mixing amplifier, and there is nothing special about it. Note that it is inverting, which complements the tone controls (also inverting) so the absolute signal polarity is maintained. As shown, the mixer also has a gain of a little over two times, and again this can easily be changed. Making R115/215 10k sets the gain at -1 (i.e. unity, but inverted). Note that R117/217 are not mounted on the board, but mount directly on the output level control.
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The circuit is very simple, and the PCB is nice and small (approx 50 x 75 mm). The idea is that one PCB would be wired with all components (Figure 1 and Figure 2), while the others only use the section shown in Figure 1. You can select the inputs you need, and add the appropriate input circuits, such as phono preamps, mic preamps, etc. Indeed, the range of uses is determined more by imagination than any "limitations" in the circuitry itself. The first stage (U1) is a buffer, but provides a gain of 2 (6dB) as shown. The gain is easily changed by changing the value of R104 (and R204 in the "B" Channel) - a higher value gives less gain, and vice versa. I don't recommend that the gain be increased beyond about 4 times (12dB), or DC offset will become a problem. A value of 2k7 (2.7k) for R104/204 will give a stage gain of 3.7 (11.4dB) which should be more than enough. A microphone preamp is a must if very low level signals are intended. If the ESP board is used, construction is very easy. It is small, but laid out very logically so it is easy to construct. No pots are mounted on the PCB - not because I like running wires (and I don't expect you do either) but because this gives you far greater flexibility for your version of the project. If I designed the board with the pots, then you would have to use the same type as I designed for, and the same spacings and layout. This is very restricting - especially if you can't get (or...
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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