Mini Audio Amplifier circuit by BC559-BC549

This is very small audio amplifier circuit which can be handled just with 1.5V DC battery. This circuit just need very small power to work.
The maximum output current is IP=VP/RL=62,5mA. If the transistor beta is B=150 then the maximum base current is about 400µA. This is quite much for an amplifier input so a preceding stage is very useful. IC designers normally would even build a 3 or 4 stage amplifier (and e.g. a 20 transistor bias circuit), but our PA should be as simple as possible. For maximum power gain in a direct coupled (best for low component count) amplifier the common emitter configuration is best suited, and a CB or CC stage is much worse. At low voltages a CC also has the disadvantage that the output voltage smaller than the input voltage by VBE. If you want to drive a CE stage from a CC stage you need an input voltage of 2·VBE»1,4V, which is nearly impossible form a single cell supply. Two CE stages are much easier to connect, but this makes feedback more difficult because the total amplifier will be noninverting. A solution will be a differential pair which has nearly the same characteristics like a single CE stage but features an inverting and a noninerting input. A further advantage is that the inherent temparature compensation makes the biasing more stable.

Source: http://www.weberconnect.de/nfpa2.htm

Digital Volume Control circuit with DS1669

This is digital volume control circuit which uses DS1669 as the main volume control. This is stereo volume control, you can use stereo push button switch for to control both channel by together.

source: http://audio-circuits.blogspot.com/2009/10/digital-volume-control-circuit-with.html

Laptop Speakers - USB, Portable, Compact, Travel Speaker for PC and Mac - B-Flex 2 Hi-Fi Stereo USB Speaker (Black)

BUY Laptop Speakers - USB, Portable, Compact, Travel Speaker for PC and Mac - B-Flex 2 Hi-Fi Stereo USB Speaker (Black)

Portable, powerful sound from any USB port

Need better sound from your laptop? The stylish new B-Flex is a compact stereo speaker on a USB flex cable for laptops and desktops. Plug and play for PC and Mac with no batteries or wires. Easy to use, great for travel, mp3 players, DVDs, presentations, and gaming. Features dual 1 watt digital amps and 2 full range paper cone micro drivers for crystal clear sound. The B-Flex digital circuitry even works on computers without sound cards.

The patented flex design allows you to position the speaker for optimum listening enjoyment. The only product of its kind, the B-Flex has been featured in the New York Times, on ABC News, on Gizmodo, and on virtually every gadget site in the world. WIRED magazine says the B-Flex "puts laptop speakers to shame."