A fully discrete class A amp. The β22 stereo amplifier
This will be a work in progress for quite a while. I’m looking forward to how I’m going to mess this one up.
What to use it as a power amp for speakers? You can do that, but I believe the primary intent is for headphones or as a preamp. There are multiple configurations possible. I’m going with the 3-channel design which has an “active ground.” σ22 will be in the same chassis because I drew my laziness line there.
Following this… been looking at building one myself for the HE6.
I’m ordering stuff now. I would recommend ordering whatever amb sells on the parts list from amb. Most of the parts they sell aren’t readily available from the usual retailers. Even if there’s a mouser or digikey part number, it is easier to order from amb.
Chassis is on order from par-metal and I’ll show that when I get it.
My cart is almost full at mouser.
And I haven’t figured out standoffs and stuff. I’m waiting for the chassis to figure out where things will go before I figure out what I need here.
Total budget for this project is looking to be about $600. $300 for boards and parts at amb, 75-100 for a chassis at par-metal, and nearly $200 at mouser.
Starting. I have realized a project isn’t done right until you have to order something from mouser you forgot the fist time.
An hour here, an hour there. After the mosfets and heat sinks, I have to do wires and drill so complications are about to start.
Voltage rails read +29 and -29.1. More soldering of boards next. I should have thought through this positioning a bit more but this will work.
And fail. Next update in two weeks ish
I’ve been reading the pages on this amp, it sounds very interesting, which configuration are you building?
The default three channel version. It seems 15 years ago having an active ground channel was en Vogue.
Read all the directions. All of them. You don’t have to be good at diy to do diy - I am proof.
You overestimate my capabilities. And underestimate your own!
My capabilities include buying a used amp on Craig’s List and then spray painting the case. I may also be able to transplant the guts into a shiny new case.
“Boutique Audio Vendor” am I. Custom, Kustom, Cusstum for you.
I hear green is en vogue…
This amp recently came across my radar, early stages of learning how to solder and looking at this down the road once I get a better handle of DIY skills.
Have you completed your amp yet?
No life got in the way big time. Parenting with all this going on is hard. I hope to revisit and finish soon
Understandable over the last 19+ months, thanks for getting back to me.
this is not an easy build, i will say that. the leap from the millet nuhybrid to this is big. the default is 3 boards plus a power supply. the boards are difficult to “debug” until you wire them up because electricity. if you’re like me and can be on the anxious side, that can backfire. patience is in order. solder things, jiggle to make sure they are connected, magnifying glass to make sure the solder is good, things like that are key. also, when doing the jfet’s, the directions say “don’t install to match the board.” and don’t skip that direction. 
i would also take the time to plan out whatever connector makes sense so you can connect and disconnect wires from each board.
i have a metal enclosure with a punch for the electricity and have drilled everything else. that will work fine. get a very very good desolder tool.
