Bizarre Mini Amplifier + White Noise Generator?

December 12, 2013 by James Hobson 29 Comments

[Jordi] made this awesome looking mini amplifier which has a rather unusual feature. He’s calling it the Bizarre Mini Amplifier because it also has a white noise generator built right into it! Bizarre right?

Now, most people would just find a suitable amplifier and put it into a nice box, but not [Jordi]! He’s designed the amplifier circuit from the ground up! It features four distinct stages like most typical amplifiers:

Impedance Adapt Stage: Two OPAMPS for both the left and right channels — The high input impedance allows for different audio sources to be connected without affecting the output.
Mixer stage: Combines the left, right and noise signals into one, using a third OPAMP. A potentiometer is the output resistor which allows for the volume control.
Filter Stage: A simple filter stage that uses a R-C low-pass filter, another potentiometer controls the tone.
Power Stage: A final power amplifier to boost the output.

After building the circuit, there was a bit of troubleshooting to get it to work properly, so if you’re interested [Jordi] has done a great write-up of this on his blog.

Finally, he decided to add a white noise generator after he discovered it helps him sleep. This is the one part of the project that he didn’t actually go into detail for! But, considering it’s just white noise, we could probably figure out what he did. Stick around after the break to see the device in action!

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Improving Terrible Computer Speakers

December 15, 2011 by Brian Benchoff 33 Comments

[Victor] likes to watch movies on his laptop, but the tiny speakers in his machine don’t do [John Williams] and other perfectly fine soundtracks justice. To pump up the jams a little bit, [Victor] got a pair of Trust Mila 2.0 speakers for Sinterklaas. Unfortunately, these speakers were terrible – noise everywhere, tinny output and a brighter-than-the-sun blue LED. These problems were fixed once [Victor] replaced the amplifier in both speakers.

After shopping around for a new power amp to go in each speaker, [Vic] hit upon the MAX9575 3.2 Watt amplifier. This little guy met all of [Victor]’s requirements. The only problem is that the MAX9575 is only available in a TQFN package.

After a deep breath and much sweat of the brow, both amps found a new home in their respective speakers, deadbug style. It probably would have been easier to etch a PCB, but we’ll give a tip of the hat to [Victor]’s fine motor skills anyway.

Because of the insane soldering skill demonstrated in the title pic, [Vic] now has a really nice pair of speakers. Check out the demo of the improved speakers after the break.

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Solid State Amp (with Style)

August 14, 2007 by Will O'Brien 15 Comments

[Jesse] sent in this beautiful 300 watt amp project. It uses six LM3886 amps to create a pair of 150 watt amps that are bridged to create a single 300 watt amplifier. Usually I don’t mind my lack of multi-language ability, but many of the parts were sourced from this site. It looks like the cases were bought in Hong Kong, anybody know were I could get some in the US?