Conclusion

This was the final project born in my workshop in our house in Norfolk, completed just as our house sale went through. This means that I wasn't able to audition the amplifier through my reference system which had been in storage for quite some time previously, so I was relying on the modest system in the workshop when making the initial design choices.

It spend some months in the office at work, allowing me the opportunity to finalise the firmware during the lunch-hours. And in the evenings, my poor Audax mini-monitors were somewhat over-driven! I was rather impressed with the overall system performance, especially given the size of the room (approximately 25 foot square).

Now that we've finally moved in, I'm still getting used to the new listening room, and also having difficulty making time to listen to music because there is simply so much that needs doing elsewhere. But initial impressions via the ATCs are very good indeed. The eventual acid-test will be to compare this amplifier to my optimised prototype LM3875 gainclones, which perhaps ought to sound better because they are dual-mono?

Despite the project being largely finished, there's plenty of scope for experiments and improvements. It's still a "work in progress", and one day I might get around to producing PCBs once I've set myself up for DIY production. But for the time being I'm pretty pleased with how it turned out, and I can't wait for another excuse to do another metalwork project on that scale again!