Audio Amplifier Projects

simple two-way loudspeaker
In this design of a simple loudspeakerenclosure an attempt hasbeen made to achieve a reasonablygood quality with a minimum ofmaterial. In spite of inexpensive drivers,this aim was met.The cross-over filter has a 6-dBroll-off, which means only one componentper driver: L1 for the wooferand C2 for the tweeter. There is alsoan impedance-correction network,R1-C1, for […]

loudspeaker protector
This circuit automatically disconnectsa mid-range loudspeakeror a tweeter from theoutput of an amplifier when toomuch power is applied. A relaywith a normally closed (n/c)contact is used as the switchingdevice.

ACTIVE POTENTIOMETER
The potentiometer introduced by Panasonica little while ago is of a qualityexceeded only by the likes of the Penny &Giles potentiometer (which cost in excess of£ 100). The Panasonic devices have multilayertracks made from conductive plasticsand carbon, which are linked to the terminalsby silver electrodes. The five-foldwiper is also made of silver and guaranteeshigh […]

Surround speakers
To convert a standardstereo installation intoa surround soundsetup, at least threeadditional speakersare needed, of whichthe centre one mustbe magneticallyshielded. The miniaturespeakers describedin this articlehave been designedsolely for this purposeby the German loudspeakerspecialistVisaton.

active power buffer
Frequently,a directvoltage isrequired ina circuitthat mustbe free ofhum and noise,but not regulated.For instance,the supplyto an audiooutput stage mustbe able to vary with themains voltage and theload. Another exampleis when in the workshopa variable-ratiotransformer (variac) isto produce a well-filtereddirect voltage withgood loading capacityfor general purposes.