ACA Mini Completion Kit
This kit is for people that purchased the Essentials Kit and perhaps later decided they would prefer the complete kit.
- Everything in the ACA Mini Bill of Materials V1.1 except those parts included with the ACA Mini Essentials Kit
- For a complete Bill of Materials (BoM) please see the Build Guide.
Note - The power supply is compatible with 100VAC to 240VAC mains. The removable mains cord is fitted with a NEMA 1-15P plug. Some DIYers will need to look in their parts bin or source a cord for the PSU.
"My goal was to make a nice little class A amplifier that brings some interesting circuit design elements but at a much lower cost, while still appealing to more sophisticated audiophiles." - Nelson Pass
The ACA Mini has become one of the top recommendations as an answer to the question "What amplifier should I build first?". The entire project can be completed in an afternoon or two. It's perfect for dorm rooms, small spaces, dens, listening rooms, and everything in-between.
And... it sounds pretty fabulous too.
The Complete Build Guide and the full kit with all the parts you need, make this project accessible to almost everyone with a soldering iron and some basic tools. Please refer to the build guide for the current Bill of Materials (BoM).
Pair it with an ACP+ for an absolutely amazing headphone amp, pre-amp, amplifier combination / mini-system.
Learn more and discuss the ACA Mini in the DIY ACA Mini thread at diyAudio.
Key Information
- Power Amplifier Project
- Designed by Nelson Pass
- Beginner Difficulty
- Complete Kit Available
- Comprehensive Build Guide
Highlights
- Class A design
- Based on the incredibly popular Amp Camp Amp
- No chassis required
Links, Discussion & Files
I built two: paralleled the inputs and driving each section of a set of Klipsch RP-8000’s crossover inputs (2 way) with each output section. Biased at .400 with no problem!
I’ll steal a line that you have to make it to the build guide to read:
“This amplifier sounds fantastic, if you have any interest at all, you really should build one. :)”
Highly recommended!
This was my fist experience building anything electronic. The build was pretty easy and the sound is really impressive. I made a little base out of a wood box from the craft store. I am using it with some old KLH Model 33 speakers and it has plenty of power to drive them in a small room. I also got great customer service from the store. Thanks!
This was my first time building an amp. After some research and advice I settled upon the ACA Mini. The build process was straightforward and not difficult. I ended up making a custom case for this, as well and using different power switch and plugs. I think it came out pretty good. But man o man the sound…this little thing sounds incredible. It’s my new go to amp for my sensitive horns and coaxials. Highly recommend
A real class A amp built in an evening, ideal for beginners and a great replacement for class d desktop amps. Big thanks to NP. Nearly finished a b1 pre to go with it and full range speakers after that to complete the picture. Don't wait on, just get a kit and build one :)
Pros: Really surprised at the sound quality out of this lil amp. I built it as a curiosity but it gives an amazing soundstage that easily outclasses my vintage amps. When paired with efficient speakers and keeping the volume below 75db, it might be the best sounding amp I own.
Cons: my kit did not come with all the correct resistors. Luckily my engineer neighbor came to the rescue and got me the parts I needed to finish. Directions are good, but not dummy proof. It is limited though and really doesn’t like to be pushed above 1-2 watts. But lets be real, its punching way above its weight for its cost.
Overall, I would highly recommend this amp to anyone who is DIY amp curious. Fun to build, great to listen, excellent learning experience. Thanks Nelson!
Thanks to Papa's generosity, we can build this amazing amp with his hand-selected and matched essential parts. What a bargain! It has displaced my 50 wpc Millett NuClassD as my new my desktop amp.
Note that the power switch is really a standby switch, so if you have a tube or other preamp you want to power down along with this amp, you will need a way of switching off the ACA Mini's SMPS to prevent a 'thump' in your speakers when the preamp is powered back on.
I elected to do this by adding a power switch to a version of Mark Johnson's SMPS filter design I had as a separate device. The 'off' side of the SPDT power switch also takes the Mini's power caps voltage down to ground via a bleeder resistor in about 5 seconds.
