A New Amplifier Build and Speakers / Listening Room Update

I'm taking a detour and making a 2 channel class AB amp to power my subwoofers. Since I already have the amp boards I designed, made and tested10 years ago, the bulk of the project will be building the chassis / case.
The transformer is a 540VA toroid that puts out 102VAC CT, and that translates to around +/- 73VDC. I may switch this for one with a lower voltage, if I have one that's big enough.

The amplifier circuit design is based on the Luxman M-02 folded cascode. Of course, all of the very excellent transistors that were available when that amp was first designed are now obsolete and long out of production, so I had to find suitable modern replacements for them. But that was 10 years ago and even some of the ones I used that were available then are obsolete today. I'm pretty sure I have enough of the ones I used originally to complete the second board to give me a stereo pair.
I do need to make the power supply, but that is fairly simple.

The chassis will be made entirely from 1/8" thick aluminum and that and the heatsinks shown in the video should provide enough cooling.

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[IBuildIt]

I'm taking a detour and making a 2 channel class AB amp to power my subwoofers. Since I already have the amp boards I designed, made and tested10 years ago, the bulk of the project will be building the chassis / case.
The transformer is a 540VA toroid that puts out 102VAC CT, and that translates to around +/- 73VDC. I may switch this for one with a lower voltage, if I have one that's big enough.

The amplifier circuit design is based on the Luxman M-02 folded cascode. Of course, all of the very excellent transistors that were available when that amp was first designed are now obsolete and long out of production, so I had to find suitable modern replacements for them. But that was 10 years ago and even some of the ones I used that were available then are obsolete today. I'm pretty sure I have enough of the ones I used originally to complete the second board to give me a stereo pair.
I do need to make the power supply, but that is fairly simple.

The chassis will be made entirely from 1/8" thick aluminum and that and the heatsinks shown in the video should provide enough cooling.

[nickkropat]

This looks like a ton of fun to get into. Amps have always been interesting, but I had no idea they were so hobby-accessable. Being able to design your own boards would be next level fun - thanks for posting this!

[daifeichu]

I went to college for electronic engineering technology, a three year course close to 30 years ago. I was never into audio but I did enjoy designing and making my own non-audio circuits. I can't remember a lot of the theory I learned these days but I am very impressed with how much you've taught yourself. You are correct that it's best to learn by making projects, coming up with solutions to any problems, testing, re-designing circuits. I had lots of fun doing that sort of thing, just wish I could remember more of it.

[SMKreitzer]

Thanks for the detour John. Merry Christmas.

[monkeys]

Thank you John for another great video. I understand what you're saying as I learn the same way! Looking forward to seeing the rest of this project!

[sudd]

you are having way too much fun and learn a lot in the process.
now you diy amp also, it is going to be flexible speaker and amp solution in the end, i am sure it all is going to sound great in the end :)

i just bought a multi way plate amp to keep things simple for myself. but i still have my mindsp shd studio as volume control and dsp, i could get some kind of nanodigi product and expand my optine and go with power amps later.
i am struggling with hiss noise at the moment.

[SteveDohertyCA]

Those carpet tiles really tied the room together.

[ZFred]

What an amazing job you are doing with the room and videos.

[soniclab-cnc]

I have that MiniDSP 4x10. I added the digital io board and the volume/selector front panel module. I made a nice enclosure with cnc aluminum and maple. It is very clean and useful for my setup.

[andrederenoncourt]

I like the way you explain your work. And I can relate to your learning methods. That's why it's good to always have people around you you can fully trust. That can see from an outside perspective. Thank you for really taking the time to perfect your craft.

[DyslxicDog]

That response level is impressive. A little processing could nail that flat.

[mndlessdrwer]

If you really want to eliminate floor reflections then carpet really is the best way to go. Ideally you'd use a premium deep-pile carpet with a decently dense carpet pad underneath it, but any carpet will offer some degree of absorption and diffusion compared to a hard surface. Honestly, if I ever have a home where I can build a home cinema with all of the channels then I'll probably end up carpeting the walls and possibly even the ceiling. Drape over some curtains, install some attractive pillars with sconces for lighting, and enjoy, but that's far into the future.

[newmonengineering]

Reading books is the core of the knowledge but the actual practice of building what you read is significantly better experience. I do the same think. I keep books for reference but I love to build and see it work, or fail. And when it fails you often learn something you didn't from the book

[Clobercow]

John,

I would love to get into amp design, and it seems you're a few steps ahead on just understanding all of this. I would be happy to learn along with you and I hope you share the details!

[GregsGarage]

I'm similar with regard to learning. I can put a circuit together and understand 99% of what is happening. If I just sit and read schematics or read about calculations, it doesn't stick... I'm SO ready to build a tube amp (guitar not hifi). I just haven't had time to devote to making it happen (too many projects stacked up). I'm VERY curious to see how your transistor amp turns out. I bet it will rival anything you've had your hands on.

[frasergreig]

Hi John. Splendid efforts as always. Is there potential in the scrap bin or even the home Reno abandoned channel to update us on your basement? I remember (I think) when you originally carved up the basement for utilities and a electronics workshop, but not entirely sure how that migrated to the current listening room. It’s a bit nosey I appreciated that, but would be neat to see the evolution of the space from someone that really dug the home Reno channel, and the stairs in particular! Thanks for all you do.

[Wolfpack-N]

Is there a way for us to get the full details of the amp and how to so we can recreate this product as well? Thanks!

[rompdude]

I recently acquired what looks to be an identical Yamaha amp, compared to my Wharfdale, it really seems to lack on the low end. It's nice amp and has optical in, which the other doesn't.

[KTJO]

I enjoy learning electronics as a hobby as well. There is a lots of interesting electronic learning opportunities in Ham radio which has exposed me to it. There are also a great many synergies with that and audio electronics.

[tchnwzrd]

I've always wanted to get into the nuts and bolts of how amplifiers actually work