Phono Preamp:  Tube design... (circuit design added 7/06)

Portable Headphone Amplifier:  3V Battery powered High Performance unit (added 9/04)

Portable Microphone PreAmplifier:  High headroom input circuitry. 9V Battery powered. (added 9/04)

Power Amp using a TDA2003:  This is the weakest amp on my site. There are weaker ICs available, but I won't add them until sonmeone actually asks for them. Note that the circuit is quite simple, the IC even seems to be DC biased internally on both inputs. (circuit design added 7/06)

Power Amp using a TDA2005:  This is a stereo IC, so that you can make a stereo amp with a single IC. The amp is internally DC-biased and the amplification is also set internally. Don't even try to set a different amplification, it's no use. There are also schematics of bridged amps with this IC, but I think it's a fraud the distortion grows one decimal order higher. Bridging the amp is only any use when you're limited to a certain power supply voltage (e.g., batteries). At a constant PSU voltage, the bridge-tied version delivers theoretically up to four times the power of the "single-ended" version.... (circuit design added 7/06)

Power Amp using a TDA2007:  This is a stereo IC, so that you can make a stereo amp with a single IC. The amp is internally DC-biased and the amplification is also set internally. Don't even try to set a different amplification, it's no use. There are also schematics of bridged amps with this IC, but I think it's a fraud the distortion grows one decimal order higher (general property of bridged configurations)  (circuit design added 7/06)

Power Amp using a TDA2009:  This is a stereo IC, so that you can make a stereo amp with a single IC. The amp is internally DC-biased and the amplification is also set internally. Don't even try to set a different amplification, it's no use. There are also schematics of bridged amps with this IC, but I think it's a fraud the distortion grows one decimal order higher (general property of bridged configurations). (circuit design added 7/06)

Power Amp using a TDA2030:  For me, this IC is an essential classic. It behaves almost exactly like a regular op-amp, you can have lots of fun experimenting with it. The two clamping diodes on the output protect the output transistors against glitches caused by complex load (speaker sets). The Boucherot's cell on the output is typical for power amps.  Generally speaking, this IC is slow, which means both higher THD and no problems with oscillations.... (circuit design added 7/06)

Power Amplifier Clipping Indicator:  (schematic / circuit design added 9/02)

Power Considerations for the TC4864 Audio Power Amplifier:  Microchip Application Note Published 18-Jul-01   (app note added 2/06)

Power Down for Portables:  06/21/01 EDN Design Ideas  /  (added 12/04)   James Prescott Joule first formulated the relationship between electrical current and dissipated power in the 19th century. Joule's Law states that the power a circuit dissipates is equal to the square of the current times resistance, (P=I 2 R). The SI (International System) unit of work bears Joule's name in honor of this discovery....

Pushpull Class a 2a3 Stereo Amp:  (diagram added 6/03)

Pushpull Class a Amp using Type 5687 Dual Triodes:  (diagram added 6/03)

Qsx Mark Ii the Extreme Phono (RIAA) Amplifier:  (circuit added 7/02)

Quadraphonic Amplifier:  This is a four channel amplifier ideally suited for use with quadraphonic equipment such as a Sound Blaster Live card. (added 4/02)

Reference Design for the Tas5110dad Digital Audio PWM Power Output Stage:  The true digital audio amplifiers (TDAA) system consists of a PCM–PWM modulator device and a PWM power output device. The PCM–PWM processor accepts a serial PCM digital audio stream and converts it to a 3.3-V PWM audio stream. The TDAA output stage provides a large-signal PWM output. The digital PWM signal is then demodulated providing power output for driving loudspeakers. This patented technology provides low cost, high quality, high efficient digital audio applicable to many audio systems developed for the digital age. The TAS5110D6REF reference design demonstrates the integrated circuit TAS5110DAD from Texas Instruments (TI). The board does not contain any PWM processors. (added 3/05)

Riaequalized Stereo Phono Preamp:  (electronic circuit added 7/03)