As I mentioned before, it’s been a 20 year dream of mine to build some type of amplifier that I can use at home and listen to music. 20 years ago I was lusting after a tube amplifier, and even started work on building one during the COVID lockdown. But the more I got into that project, the less enthused I was, mostly because I really have no use for a tube amplifier. In my current apartment I mostly hang out in the living room, and if I’m not listening to Spotify (or some other streaming service), I’m watching movies on Plex or Netflix.
So if I was going to build an amplifier, why not build something to replace what I have? The amplifier I currently have is the Denon AVR-1500, so I thought it might be a good baseline to define some goals from. Wouldn’t it be great if at some point I could just rip it out and simply drop in a replacement with my own amplifier?
The Denon amplifier supports Dolby Digital, DTS, and can do about 80 Watts per channel into 8 Ohm speakers. Now of course, I live in an apartment, and I’ve never even come close to maxing out my Denon amplifier. So 80 Watts per channels seems like total overkill to me. And of course, if you double the power, you only get a 3 dB increase in audio volume, so dropping from 80 Watts down to 20 Watts is only a 6 dB reduction. My current speakers are the Dali Oberon 3s, and they are rated at 89 db/Watt of power. So even at 1 Watt they are incredibly loud. When I was designing my tube amplifier, I was going to max out around 5 Watts. So I definitely am not afraid to drop the wattage down.
So in terms of power, a realistic goal is somewhere in the 20-40 Watt/Channel area I thought. When I did my master’s degree, my thesis was on video compression. And back then I saw how challenging navigating the patents were around H.264 and MPEG4, so I knew that getting into something like Dolby or DTS was going to be challenging. Could I ever do it? Maybe it was too hard for a first project?
My Denon amplifier does HDMI switching, but to me that’s not a deal breaker since I mostly always just use the Amazon Firestick. I could just as easily connect the Firestick into my TV directly and call it a day. Worse case, I could just get an external HDMI switch box.
Once of the aspects I always regretted about my engineering degree was that I never really had any real-world experience with the electrical engineering aspects. I wrote my first software program when I was 14 years old, and sold it from a few BBSes. During my university days, I wrote a program to write DVDs over the course of a week, and released it as a short-lived free product called Singe. During the co-operative education program at my university, because of my software experience, nobody wanted to hire me for software since I was much more useful to them writing software.
As such, I never managed to get any experience building hardware. I even made a plea to the head of the VLSI laboratory at UBC, asking if I could volunteer and get some real world hardware experience. He said if I wanted to work for free, he’d be happy to have me and help me gain experience. When he sent me the first item that he wanted help with, guess what it was? Build the lab a new website.
So while I wanted to end up with a great amplifier to use at home, I also wanted at some level to create my own personal engineering course. That is, over the course of six months to learn and acquire the skills to take something like this from conception to full implementation. I knew it wouldn’t be cheap, and I knew it wouldn’t be easy. But I knew it would be rewarding on many levels.
Once I decided to move forward with this, I started investigating the various technologies that I would use to accomplish it. And those are discussed in full in the next section.