Level indicator with 10 LED - Schematic + PBC layout __ Jan Kolar
Level meter for home theatre systems - Having trouble adjusting the levels in your home theatre system? This simple project makes the job easy. __ SiliconChip
Magnetic Longwire Balun (MLB) also usable for dipoles and homemade RF choke - Ham RadioBALUN, TUNERSSchematic __ Designed by Guy Roels ON6MU
Magnetic longwire balun and VHF-splitter - Ham RadioBALUN, TUNERSSchematic __ Designed by Guy Roels ON6MU
Mono Hi-Fi Tone Control - This is the mono tone control circuit. The circuit will give you high fidelity (hi-fi) output. Built the 2 similar circuit to make it stereo. Use high quality electronic parts for better audio output quality.
Musical Instrument (Expandable) Graphic Equaliser - This equaliser is designed as a preamp suitable for musical instrumentsguitar, bass and keyboard in particular. Unlike most conventional graphic equalisers, each slider ranges from fully off to fully on, and not the more conventional +/-12dB or so that is normally available. __ Designed by Rod Elliott ESP
Mute for Big Briar Etherwave® Theremin - This circuit permits the addition of a "mute" switch to the Etherwave® Theremin, useful for placing the theremin in a silent mode without having to turn it off completely. There is no "pop" during the mute-unmute transition. A MUTE STATUS light-emitting diode doubles as a convenient power indicator. The circuit was constructed on a small circuit board installed inside the theremin. The MUTE CONTROL switch __ Designed by Arthur Harrison
Notch Filter Autotunes for Audio Applications - 24-Jun-10 EDN-Design Ideas Tracking notch filters find use in harmonic-distortion analyzers; they also can remove heterodyne noise from ham-radio systems. A conventional tracking switched-capacitor notch filter relies on a bandpass filter, a voltage-to-frequency converter, and a notch filter to track the incoming signal and remove undesired tones. The bandpass filter in these circuits sometimes adjusts to the wrong frequency, meaning that the undesired tone would have no attenuation__ Circuit Design by John R Ambrose, Mixed Signal Integration, San Jose, CA
Parametric & Graphic Eq's Plus Peaks & Notches - If you're into playing with tone controls and notch filters to see how they change the sound out of your effects, you will undoubtedly have built several glops of R's, C's and pots, maybe some L's to make up the tone networks. While this is fun, it's not very flexible. Sooner or later you might wonder if there is a more general solution to messing with tone controls. __ Designed by © 1999 R.G. Keen
Passive filters fill the bill at audio frequencies 02/01/01 EDN-Design Ideas Low-frequency filters, particularly at audio frequencies, usually take the form of active filters. These filters eliminate expensive inductors with windings of many turns. Both analog and digital active filters are most compatible with large-scale integration at the subsystem and system levels. __ Circuit Design by Richard Kurzrok, Queens Village, NY
PC Speaker Volume Control - This simple circuit can be used to control the volume of PC speaker. The volume can be adjusted to any value between total silence and full volume. __ Designed by Tomi Engdahl
Peak reading audio level meter - indicates peak audio response on an analogue meter, similar to a tape recorder recording level meter __ Designed by Andy Collison
Pre-amp with tone control - This a 2 in 1 circuit where 2 modules joined in one circuit. With this circuit, you no longer use tone control circuit before your amplifier, but you can add an equalizer between this circuit and your amplifier circuit. In this circuit, P1 is used to control the volume level, P2 to control Bass level and P3 controls Treble level.
QRP Longwire balun - Ham RadioBALUN, TUNERSSchematic __ Designed by Guy Roels ON6MU
Remote Volume Control & Preamplifier Module - This up-to-date control module works with any universal infrared remote and features a blue LED readout and an optional rotary encoder. Its ability to both attenuate and amplify means that it can operate as a simple volume control or as a high-performance stereo preamplifier! __ SiliconChip
Remote Volume Control for Stereo Amplifiers - You can add a remote motorised volume control to just about any stereo amplifier. Here's how to do __ SiliconChip
Remote Volume Control for the Ultra-LD Amplifier - Revised preamp board lets you add our remote Volume Control unit to the Ultra-LD Stereo Amplifier __ SiliconChip
Remote Volume Control Part 2 - Second article completes the construction & gives the set-up procedure __ SiliconChip
Resistor-Switch Networks for Audio Volume Control - The traditional potentiometer is implemented with an electrical contact that slides over a resistive layer. An example of a well-known audio-grade potmeter is the Alps Blue. I still use this one myself. A high-end (good and costly) alternative is the rotary switch. This device consists of a series of discrete resistors and switches, of which always one switch is actually closed. Resistor-switch networks can offer advantages over the potentiometer such as: * Improved quality of the electrical contact, in comparison with the slider. * Improved consistency between separate audio channels (stereo or multi-channel) * Less sensitive to dust and wear.
Reverse RIAA Equaliser - Test phono preamps for correct equalisation, or convert unused phono inputs. __ Designed by Rod Elliott ESP