Years ago when getting started into DIY audio, I picked up three different chip amps from my local electronics shop. They were cheap and easy enough to build according to the data sheets, so I had a go at them. To my dismay, they sounded HORRIBLE! I couldn't figure out what went wrong until I really started digging into the data sheets.

While I didn't build the LM3886, I'm going to pick on it since it is a very common chip amp:
National Semiconductor LM3886 (from national.com, bought out by ti.com)
Claims 68watts into 4ohm speakers with 0.1% THD+N from 20-20kHz

National did pretty good with most of their claims, but I'll focus on something that stands out: The Distortion Vs. Power graphs. (As a comparison, I discovered that one of my other chip amps did their power testing at 10% distortion... which is pitiful. Every chip amp data sheet I've looked at has some kind of failing with this graph.)

...

I was fortunate to stumble across this place on a trip to Yokohama earlier this week.

https://g.co/maps/nzebr

I was walking around the area near Sakuragicho Stn. after dinner, and, through the windows I could make out a back wall filled with LPs, two turntables built into the bar countertop, and a pair of giant multi-way speakers. The sign out front said "Modern Jazz and Coffee". So, naturally, I went in.

First, the history of the place as it was explained to me:

First opened in 1933. Destroyed by American bombs during the war, 6000 SP records gone, re-opened, and was in business until the owners death in 1994, then taken over and run by the owners younger sister until 2007, when, at the age of 77 (!) she gave it up. Volunteers somehow managed to preserve the records and furnishings, including the sound system, and, some 5 years later, decided to relocate and reopen at a nearby location just, if I've got this right, a...

Cut my boards today and screwed up the first one. Used a ruler as a guide and it moved during the cut. Not happy!
The only thing that worked was my router and the template for the driver cutouts. Drivers sit recessed and flush.
Tomorrow I'll have to make the boards match.
You live and you learn I guess...

I just remembered I hadn't announced it here on the blog. Time to change that.

I'm holding a little contest, to encourage people to get into circuit board design, and to showcase the talent on tap here at diyaudio.

The idea is pretty simple. I hand out a circuit schematic, you design a circuit board based on the schematic. It's all done in Eagle CAD software, which is free to download and available on Mac/Windows/Linux platforms.

The circuit is a headphone amplifier of my design, and fairly simple. It's easy enough to come up with a workable layout, the trick is to come up with a really good one, that is small, convenient, clear, logical, good looking and that follows sound electrical design practice.

Winner will get a pair of boards, complete with all components, built by me. Runners up get sent pairs of the winning board design.

Deadline is the end of the month, so get on it!

All the info is here....

Finally!
After a century ride in January (
https://www.shadowtour.com/Century_Rides/Stagecoach.htm
)
A trip to Finland in February for training
And numerous other distractions...
I've finally drawn the first lines for my speaker panels. Once it stops raining I can start cutting...!

Cortex-M0+ Processor - ARM

Just 11uW/MHz at 90nm so under 1mA current draw when running at 100MHz Freescale says they'll be first to show working silicon but I bet NXP will end up shipping the real volumes.

Introduction

I am a steady user of the SIMetrix/SIMPLIS Intro Spice simulator and many peoples ask me how to use it. Because the same questions come back all the times and the answers often need to be quite elaborate and are time consuming, I decided to open a new Blog for this subject.

Since I am a member of this forum, I noticed there was thousands of threads and they often get loss very far from the first page after few days, where almost nobody can see them.

This is not the case with the blogs because there is not many yet on this site, also, it is possible to edit a blog anytime and not a post in a thread after 30 minutes ... This make corrections easy and I am not perfect, I often make some little or big mistakes.

I will not accept other members comments until the blog is almost terminated. Anybody having a request or a comment for me about this blog can send me private message, I will be glad to answer it and update my blog if...

Of late I've been enjoying snacking on this book EDAgraffiti which is a romp through various aspects of the economics of semiconductors. Recommended for those who are interested not just in the technical side of the digital revolution but also the commercial perspective too.

One comment from the book jumped out at me, which was a prediction made by Clayton Christensen a few years ago about the end of Moore's Law. He's reported as saying the following at an engineering conference organised by Cadence. Moore's Law will come to an end when the semiconductor industry tries to deliver more capability than the mainstream requires at a price which is higher than the mainstream wants to pay. 450mm wafer processing technology and EUV lithography pretty much do seem to fit the bill here.

This article on The Inquirer is saying pretty much the same thing - gaming and video transcoding have kept the push for faster PCs alive but even in those applications demand is now...

The B-board line buffer is back from the fab and running on the bench.

Cute little board. Diamond buffer with BD-135/136 transistors and a built in Z-reg. Designed to buffer the output of op amp circuits to help drive cables and otherwise isolate the op amp feedback loop from the big bad outside world. It can also be used as a unity gain preamplifier, or, with by changing a couple of resistors and adding small heatsinks, to drive headphones.

Development thread here.

UPDATE: Also finished a second set of boards, configured as a headphone driver (5x bias current, heatsinks).

I'm confuse what to take up in college, I'm really interested in audio systems what college degree should i take?