AEM6000 Based 50W Amp

This is a design I've had in use for rather a long time. It started life as a design exercise to see if I could do a more space-efficient board for my original AEM6000 based amps, as I wanted something that would fit on a 50mm high heatsink. Along the way it changed a little from Tilbrook's original in topology, and rather a lot in component choice. It has better performance than my original design, both through a better tighter layout and also through the use of faster transistors.

I've built a bunch of these, using both Renesas and Exicon lateral MOSFETs, and subjected them to all manner of abuse. I had one fail, due to a leaky mica compensation capacitor (see noiseUnit speaker thread), but apart from that they've been rock-solid.

Lots of component substitution is reasonable. I like to use MELF resistors, but that's mostly just bloody-mindedness. An exception is the feedback divider. No, it won't work with vertical MOSFETs.

I have checked just now, and every single component is currently (December 2020) available.

The design is free for use for non-commercial purposes.

In the design folder I have placed:

PDF file of schematic
PDF file of construction notes
Top and bottom layer stuffing diagrams
PDF file of parts list with supplier info
Gerbers and drill file for board manufacture.

Google drive containing design files.

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That's a great amp and a really good power level for domestic use. I used the AEM6005 boards for many years and really liked them.

Wow, I just had a look through the construction notes. You have done a FANTASTIC job documenting this project! I've got a feeling it's going to be quite popular.
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I've updated the construction notes to version 1.1, Fixing some typos and correcting some god-awful mangling of plots and schematics that occurred when I hit the "reduce file size" button in pages. Reminder not to do that!

I've updated the zip file on my google drive with the new construction notes, and checked that it all works for download. The download link stays unchanged.
Many thanks for this one.

Impressive detail in your documentation. You have made it more than easy for a scrub such as myself.

I will chuck some pcbs in my next JLCpcb order and add it to my long list of amps to be built.

I will report back in a few years once this one gets to the front of the queue......
Congrats for the good work, Suzy. Reminds me of the times when I disovered the advantages of latFETs that made me stop using BJT-powerstages any more. In the eighties I designed PowerMOSFET-amps rated 2x500W and 1x5000W. While these provided about 10-fold bandwith to the bipolar designs their robustness due to the lack of 2nd breakdown was impressive. For building a high performance linear audio amp this was the best technogy ever imho. Although I design TPA-325x audio amps nowadays, for lab measurements I built my own latFET-amp with original 2SJ50/2SK135 that I got my hands on some time ago. Nothing can top these!;)
Hopefully Reichelt doesn't ultimately run out of the Renesas parts too soon, because ordering Exicons from Profusion to the EU might take longer than usual with a hard Brexit coming up. I don't know how prepared everyone is behind the scenes, but they sure have enough other stuff to deal with right now. Definitely a big thank you to Suzy for the early Christmas present!

@Jacques: I will send you a PM once I get tracking info. The boards are 3€ a piece, of course also 2oz copper and ENIG. I don't know how long that will delay manufacturing compared to their standard turnaround time of 24h, but it shouldn't be too bad.
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Hi Suzyj,

Have you listened to this amplifier with the CDE mica capacitors vs ceramic C0G caps in the 6 locations? If you have, are the mica’s an improvement? I’m putting together a Mouser BOM and the six CDE caps make up 36% of the total cost.

Thank you ;)