A vaguely organised mess

With some money I had from Christmas, I decided that I wanted to upgrade my audio setup a bit. Somewhere in a previous post I mentioned that I’d bought a pair of Audio Technica ATH-AD700, which are my primary headphones, although I’d really like a pair of Sennheiser HD650s…

The first thing I needed was a DAC, as these headphones don’t really need an amplifier. A DAC is a Digital to Analogue Converter, which takes the digital signals from your music library on your computer, however they’re encoded (I’ve started re-ripping in flac :D). It then converts these into an analogue signal using some technical wizardry to make a nice analogue signal that can then be amplified for your headphones or speakers to play.

I was originally just looking at some high-end ‘audiophile’ (I hate that word…) sound cards, but they were all a bit boring. I wanted an external solution, and the most cost-effective and fun way to do this would be to build my own. This doesn’t mean I was going to read up on digital circuitry to design one, oh no! There are some members of Hi-Fi forums that design these devices in their spare time, and publish the schematics for free on the internet, often selling a circuit board to go with it.

I settled on the Gamma 1 from AMB Audio, a fairly small but well reviewed DAC. I ordered the parts, and a couple of weeks later everything had arrived, including two parcels from America, one of which incurred some interesting customs charges. That, however, is another story.

Building this DAC involved a fair amount of surface mount soldering (SMT) work. This is the first time I’d done it, but it went very well considering the incredibly small size of the chips and that it worked the first time I plugged it in. SMT soldering is where the legs of the device don’t go through the circuit board, they sit on top. This and that the fact that SMDs are generally much smaller than their through hole equivalents makes soldering them with conventional irons quite tricky, but you can still do it. If you interested, Curious Inventor has an excellent video on the subject.

With no further ado, here are some pictures of the assembly in all its gory detail:

The mess that I laughingly call my ‘workspace’. Spot the oboe? Those are the trick to soldering quickly and accurately.

The first IC soldered.

A few more.

Adding some resistors to the mix.

Showing the 3.5mm output, which can handily also drive headphones. I still want to build a proper amplifier though… Also pictured is the illuminated input select switch: it glows red when powered on and switches to green when music is playing. Finally, you can see the ‘audio grade’ output capacitors which came in at a whopping >£1 each.

The IC originally pictured, now surround with capacitors, resistor networks, transformers and all sorts of magic.

This shows the tiny size of some of the parts: the chip in the foreground (in the centre, not off to the left) easily fits on my little finger nail. That’s the tip of a normal biro for some size comparison. I still don’t know how I managed to solder that…

The Gamma 1 in in all its glory. The circuit board is about the size of two credit cards next to each other.

I’m listening to Dire Straits right now, with it sitting on my desk, a USB cable in one end and my headphones in the other. I haven’t heard any other proper Hi-Fi equipment, but I can certainly say that it sounds good. VERY good.

I’ve ordered a case for it to live in: the brilliantly named ‘Box B2-080BK’ which will arrive (hopefully) on Tuesday, so I can case it up properly. I’ll drill the needed holes using the drill press at school.

I really enjoyed building this, and now want MOAR! I have a little list of things I’d like to build:

• An AMB Mini3: a portable, battery powered headphone amplifier
• A CKKIII headphone amplifier: a proper, mains powered beast
• A Sennheiser HD650, reterminated to two XLR plugs for balanced listening. Not exactly a build, but meh.
• A Twisted Pear Opus balanced DAC, which is a step up from my Gamma 1 and also balanced
• An AMB β22: The ultimate headphone amp. This might be a way off… It should be an awesome project though.

So there we are, that should keep me busy for a while amongst my other hobbies.

On Saturday 29th August, 2009, SYO went to Edinburgh to play in the NAYO Festival of British Youth Orchestras. Since I enjoyed it so much, I thought I’d write a blog post on it.

I had been camping with my scout group in Bude for two weeks before, which meant that I couldn’t go to Edinburgh with the rest of the orchestra on a coach, although from what I heard this was probably a good thing, as there was no air conditioning on a sunny morning… Instead, I caught a plane from Exeter, and was up in Edinburgh by about nine in the morning: since I was there several hours before everyone else, I took the opportunity to do what tourists do and buy some computer games. From the Game store there, I bought Deus Ex Complete and the Fallout Collection: both games I’ve wanted for a long time. We met up with the rest of the orchestra for lunch in the canteen of the Edinburgh College of Art, which involved some suitably greasy lasagne.

Following that, we wondered down to the concert hall, for a rehearsal which lasted all afternoon. This was especially important for me, as this concert was my first as Principal Clarinettist, and I was playing solos in Peter and the Wolf and Night on the bare Mountain. The rehearsal went well, and after this we walked back to the canteen for profiteroles and lentil soup. Yes, you read that right. It became more interesting when various profiteroles were inserted into the lentil soup: you can see more of that on Anita’s video.

The concert itself went brilliantly. It was the best that we’ve every played as an orchestra (while I’ve been there, obviously), and recordings were made which will appear on YouTube soon (in theory). The Cat (listen from 3:10 onwards, although this isn’t me playing it…) went really well, and so did the solo in Night on the Bare Mountain, which was amazing. As you can see, the room that we kept our instruments/clothes in had an amazing sign on the door:

After the concert, we returned to the hall of residence in which we were staying, to eat some food and then sleep. Unfortunately, since we were late back from the concert we missed the opportunity to use the room that we originally intended to, so we ended up in one of the lounges, eating sandwhiches and discussing xkcd. We were thrown out of that room at about one in the morning, so wandered the corridors for a couple of hours, annoying people and creating some awful in-jokes which will haunt SYO for years…

The next morning, after eating breakfast we were driven into the centre of Edinburgh, with the original plan being to visit the castle. A select group of players, however, decided not to do that, so headed along Princes Street generally making a nuiscance of their selves (me included). We found an exhibition of silly signs (part of the Fringe), so photos were taken…

We stood in a park-y thing for a few hours, watching the ‘Awesome Singing Dude’ (Group Hug!), and then I was harrassed brutally by various people (ANITALOUISEANNA), and had things done to my face with eye liner which were not suitable for young children.

The journey back (with the rest of SYO this time) was amusing… The highlight of the journey was the rewriting of various songs from Les Miserables to be based around shortbread. One is included for your amusement:

There is a shortbread on a cloud,
I like to eat it in my sleep,
Aren’t any crumbs for me to sweep,
Not from my shortbread on a cloud.

There is a room that’s full of shortbread,
There are a hundred pieces of shortbread,
Nobody eats or chews too loud,
Not from my shortbread on a cloud.

There is a shortbread iced in white,
Hold it and take a gentle bite,
It’s nice to taste and it’s soft to touch,
I say, “Shortbread, I love you very much”.

I know a place where shortbread’s eaten,
I know a place where shortbread’s loved,
Gavin at all is not allowed,
Not in my shortbread on a cloud.