My dorky bench equipment

Finally had a chance to put the bench test equipment together. Oscilloscope, two DMMs and two power supplies.

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And the DMMs are well calibrated. So it seems.

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Almost ready for the Livestrong Century

On a beautiful Sunday afternoon, got about 35 miles in to prep for the ride in a couple weeks.

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Happy birthday Ryan & Sophia

We’re entering a busy birthday party season so I thought I better stay ahead of the impending onslaught of photos. Today was Ryan and Sophia’s birthday (siblings four years apart with the same birthday.) It was a Mario and Luigi themed party. And how! For the occasion, I grew my very own mustache.

The girls on the way in:
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The decorations:
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Birthday boy:
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Birthday girl:
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My girls:
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Doing crafts:
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Cake:
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One holiday and three birthdays later

Another mega post since I’ve been really bad about keeping up the blog lately. I blame Facebook. But I digress. So, where to begin…

Let’s start randomly.

Headphones: the girls are music fans and are budding audiophiles.
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Headphones

We visited the Tsengs at their new house. They made us work for our food… The kids made their own pizzas!
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Bonnie made a cake for Alan’s birthday.
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We tried off the grid.
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We had the Olthofs stay with us for a little while before their house closed. Tons of fun having four adults, five kids, and a dog in our house.
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Here is a small subset.
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They went to the zoo one day.
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And gilroy gardens another day.
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Another field trip to the Randall Museum with a picnic lunch.
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Amber’s birthday.
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My birthday.
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Some random “day in the life shots” that I’ve not been so good at lately.
Ashley still ende up in our bed at some point in the middle of the night.
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Mom getting Alissa ready for pre-school.
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The beginnings of my latest project. Another Class-A power amp. This one is also from the brain of Nelson Pass but is a high power one that I’ll build as single channel mono-blocks. They’re going to be big.
Aleph x

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Dumplings made with Chinese child labor

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Bonnie’s flat lying down dumplings:
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My awesome standing up dumplings:
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Thank you Easter Bunny! *Bawk* *Bawk*

The Easter Bunny visited this past weekend and left some goodies for the girls:

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I don’t know why Alissa doesn’t look happy in this picture.
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Nelson Pass F5 Class A Stereo Amplifier

F5

Another project in the books. This one is my first class A power amplifier build. The circuit itself is actually relatively simple. And the casework wasn’t bad either truth be told. But I’m getting ahead of myself.

The design is from one of the godfathers of the DIY HIFI community, Nelson Pass. He runs a DIY website as well as a commercial and a sort of hybrid enterprise that sells retail items but also provides schematics and articles so the enterprising DIY’er can “roll his own.” He’s also active on the diyaudio.com site and chimes in from time to time.

The specific design I chose is the F5. It’s a push-pull Class A amplifier, utilizing JFETs and MOSFETs in a very simple two stage complementary circuit. It spits out about 180W (most of it in heat) and is one of the more popular designs from Mr. Pass.

For my build, I sourced the PCB from tech-diy.com and most of the little bits from mouser. The heat sinks were from antek and the rest of the chassis was made up of scraps actually. I had spare 1/4″ aluminum for the bottom, African mahogany for the front panel, plywood for the rear, and plexiglass (from an old document holder) for the top. I did buy some 1/4-20 bolts and some new RCA jacks and speaker posts.

In any case, pictures are where the fun is so here you go.

The trafo, rectifiers, and first pair of caps that make up the separate PSU enclosure. I used a 4-pole Neurtrik Speak-On connector for V+/G/V-/earth ground:
F5
F5

Here’s the enclosure for the PSU. Made from more scraps:
F5 PSU

Here are the amp PCBs coming to together mounted on the heat sinks:
F5 boards and sinks

Here’s the view of the front/bottom with the mahogany and aluminum holding the heat sinks together:
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And of the rear/bottom:
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In mockup mode:
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The beginnings of milling the rear:
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All put together with the plexiglass top:
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Shot of the front with the powdercoated aluminum letters I splurged on:
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Stacked on the PSU:
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It sounds great and doubles as a space heater! I got it biased up to about 580mV and the DC offset is essentially zero on both channels.

Some sketches I made on the plane on the way home from a business trip:
F5 sketches
F5 sketches

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RS 150 DIY Bookshelf Speaker Build

I can’t seem to stay focused these days… building speakers, amps, and a buffer all at the same time. Anywho… here’s a post for the latest item. A pair of CJDs rs150 TM bookshelf speakers. I need a pair of smaller speakers for the bedroom. They’ll probably be driven from a chip amp (that I’ve actually completed already) using my iphone as a source.

I got the tweeters used and the woofers aren’t that much to begin with so I just bought them.

I made the cabinet with simple birch plywood all leftover from other projects with mitered and biscuited corners. The front corners will be about a 3/8″ bevel as a design feature (I’m a sucker for the laminate look for some reason) with a basic hand rubbed tung oil finish to match many of my other builds.

The sides and back glued up:
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Crossovers installed with foam and just waiting for the front baffles:
RS150 MT
RS150 MT

The problem with not having perfectly square cuts and positioned biscuits:
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Testing out the first speaker:
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Their current resting place book-ending my headphone amp and the chipamp.
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So far, I’ve been very happy with them. They need a little breaking in and they don’t sound nearly as good as the full size designs, but they’re very good for what they are.

The next project will be the opposite end of the spectrum… very large with dual woofers, dual mid-ranges, and my first build with a ribbon tweeter. And of course, I still need to finish the other amps and buffer projects!

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A couple family pictures

We celebrated Bonnie’s birthday last week and took a few pictures with cake:
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Over the weekend, we also spent some time cleaning up the backyard and took advantage of the weather to take another few random shots.
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It seems the kids enjoy smiling for the camera on a tripod (I got a Gorilla one from Eric for Xmas, thanks Eric!) more than when I’m taking the picture myself. I think they mostly enjoy watching me run back and forth to trigger the timer.

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Muni, Metreon, Movie, and MOMA

I took a random day off last week so we took a little field trip. I documented using my fish-eye lens since it rarely gets used and I thought it would be a good exercise for what I thought the day would entail.

First, some warm up shots at home while getting ready:
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We decided to expose the kids to their first muni ride, so we made the short walk two blocks to the L-Taraval:
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After our muni ride, we went to the Metreon for lunch before the movie:
A big bread bowl of soup fed us all.
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After watching The Secret Life of Arietty (and a lot of popcorn), we went to the MOMA by way of the Blue Bottle Cafe on the terrace level.
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The girls enjoyed their hot chocolate and we had our fancy coffee:
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After a quick walk through the MOMA (it was free first Tuesday of the month) we got back on Muni and came home:
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Alissa practiced her photography skills on me:
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And on the West Portal station:
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All in all, a successful field trip!

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