AM Radio Circuits

AM Radio Circuits

AM radio began with the first, experimental broadcast on Christmas Eve of 1906 by Canadian experimenter Reginald Fessenden, and was used for small-scale voice and music broadcasts up until World War I. AM radio technology is simpler than Frequency Modulated (FM) radio, Digital Audio Broadcast (DAB), Satellite Radio or HD (digital) Radio. An AM receiver detects amplitude variations in the radio waves at a particular frequency. It then amplifies changes in the signal voltage to drive a loudspeaker or earphones.

The earliest crystal radio receivers used a crystal diode detector with no a

mplification.  As a result, many broadcast stations are required as a condition of license to reduce their broadcasting power significantly (or use directional antennas) after sunset, or even to suspend broadcasting entirely during nighttime hours.  Medium-wave and short-wave radio signals act differently during daytime and nighttime.  However, in the late 1960s and 1970s, top 40 rock and roll stations in the US and Canada such as WABC and CHUM transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. Early experiments with stereo AM radio involved two separate stations (both AM or sometimes one AM and one FM) broadcasting the left and right audio channels.

Because of its susceptibility to atmospheric and electrical interference, AM broadcasting now attracts mainly talk radio and news programming, while music radio and public radio mostly shifted to FM broadcasting in the late 1970s.  This system was not very practical, as it required the listener to use two separate radios. Synchronization was problematic, often resulting in "ping-pong" effects between the two channels. Reception was also likely to be different between the two stations, and many listeners used mismatching models of receivers.

Guitar vocal adaptor amp

What’s more, unpredictable feedback may cause damage to the speakers and is very unpleasant on the ear. This cheap little  easy-to-build project can help solve these technical  problems.

How many amateur music groups sing  through an amp borrowed from a guitarist or bass player? These days, music is a major hobby for the young and not-so-young. Lots of people  enjoy  making  music,  and  more  and  more dream of showing off their talents on stage. But one of the major problems often encountered is the cost of musical equipment. A guitar (or bass guitar) amplifier is designed first and foremost to reproduce the sound of the guitar or bass as faithfully as  possible.  This is where the technical problems arise not in terms of the .25” (6.3 mm)  jack, but in terms of the sound quality (the words  are barely understandable) and volume (the amp  seems to produce fewer decibels than for a guitar).  That’s  just what this circuit attempts to do. The frequency response of the amp doesn’t need to be as wide or as flat as in hi-fi (particularly at the high end), and so this sort of amplifier won’t permit faithful reproduction of the voice. If you build an adaptor to compensate for the amp’s limited frequency response by amplifying in advance the frequencies that are  then attenuated by the amp, it’s possible to  improve the quality of the vocal sound.

Guitar vocal adaptor amp

Guitar Amp Circuit

Bass guitar super bridge amplifier 200 watt.  If you want to circuits amplifiers for bass guitar, or for using in every situation such as both listen to in the house, outside the house or outdoors. this. Guitar amp tone effects placement, Information about distortion voicing, effects placement, and cranked-tube-amp tone at any volume.. Amp parts | guitar center, Enjoy the lowest prices and best selection of amp parts at guitar center. most orders are eligible for free shipping!

100W Guitar Amplifier

Guitar amplifiers are always an interesting challenge. The tone controls, gain and overload characteristics are very individual, and the ideal combination varies from one guitarist to the next, and from one guitar to the next. There is no amp that satisfies everyone's requirements, and this offering is not expected to be an exception. The preamp is now at Revision-A, and although the complete schematic of the new version is not shown below, the fundamental characteristics are not changed - it still has the same tone control "stack" and other controls, but now has a second opamp to reduce output impedance and improve gain characteristics.

One major difference from any "store bought" amplifier is that if you build it yourself, you can modify things to suit your own needs. The ability to experiment is the key to this circuit, which is although presented in complete form, there is every expectation that builders will make modifications to suit themselves. The amp is rated at 100W into a 4 Ohms load, as this is typical of a "combo" type amp with two 8 Ohm speakers in parallel. Alternatively, you can run the amp into a "quad" box (4 x 8 Ohm speakers in series parallel - see Figure 5 in Project 27b, the original article) and will get about 60 Watts. For the really adventurous, 2 quad boxes and the amp head will provide 100W, but will be much louder than the twin. This is a common combination for guitarists, but it does make it hard for the sound guy to bring everything else up to the same level. more info on here

Guitar Amplifier Circuit

This is a medium power guitar amplifier is recommended especially for portable amplifier. The amplifier is a combination between a simple integrated audio driver, LM391-80 and a stage of output power designed contratemps with bipolar transistors.

Thermistor NTC, which is in temperature contact with output power transistors, allows to separate AO LM391 power stage when it heats too much.

The start of the thermal protection is at a NTC flow current NTC of approximately 200uA. Electrolytic condenser asure a “smooth start” to remove clicks that may occur when connecting the amplifier. It can happen that the protection can be too sensitive, in that case certain adjustments are admitted in the value of R4 or thermistor.

The standby current can be adjusted with P1. This potentiometer is initially 0 and then is adjusted to achieve a current of 50mA. Current can be increased up to 400mA if you want low distortions.

The power transistors are placed on the same side of printed circuit board, so that it can be mounted on a heatsink jointly with the thermistor. The heatsink must be large enough and have the thermal resistance of maximum 10K / W.

L1 has 20 turns with 0.8mm emailed copper, coiled over R21. C9 is a ceramic capacitor.

Guitar Amplifier Circuit

Guitar Amplifier Circuit

Guitar pre-amplifier

A preamplifier circuit suitable for high impedance type electric guitar pickups is given here.The circuit is based on a uA 741 op-amp (IC1).The IC1 is wired as a non-inverting amplifier.The POT R1 can be used as a volume controller.The POT R6 can be used as tone controller.The switch S1 is used to produce “brilliant” or “soft” tonal effects.

• Assemble the circuit on a good quality PCB or common board.
• The amplifier can be powered from a 12V battery  or 12V DC power supply.
• Up to 24 V DC can be used to power the circuit.i recommend 12 V DC.
• The IC 1 should be mounted on an IC base 

Circuit Diagram:

Guitar pre-amplifier

Mini Portable Guitar Ampls

This small amplifier was intended to be used in conjunction with an electric guitar to do some low power monitoring, mainly for practice, either via an incorporated small loudspeaker or headphones.

The complete circuit, loudspeaker, batteries, input and output jacks can be encased in a small box having the dimensions of a packet of cigarettes, or it could be fitted also into a real packet of cigarettes like some ready-made units available on the market.

This design can be used in three different ways:

Mini Portable Guitar Amplifier

Max output power: 1.5W @ 9V supply - 8 Ohm load; 60mW @ 3V supply - 8 Ohm load

Frequency response: Flat from 20Hz to 20kHz

Total harmonic distortion @ 100mW output: 0.2%

Max input voltage @ 3V supply: 8mV RMS

Minimum input voltage for Fuzz-box operation: 18mV RMS @ 3V supply

Current consumption @ 400mW and 9V supply: 200mA

Current consumption @ 250mW and 9V supply: 150mA

Current consumption @ 60mW and 3V supply: 80mA

Quiescent current consumption: 6mA @ 9V, 4mA @ 3V supply

Fuzz-box current consumption: 3mA @ 3V supply