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Based on 2073 reviews
Hugely enjoyable amp

The performance of ACA Mini comes as a most pleasant surprise - but then again, not really. Coming from our friend and generous contributor, Nelson Pass, the ACA Mini truly delivers with outstanding performance. Coupled with the also magnificent Korg Nutube B1 preamp, the amplifier projects a solid soundstage of width and depth, creating a realism within the music which belies the diminutive size of the amp footprint and component count. Clearly, Nelson's pursuit of the First Watt principles are demonstrably manifest in the ACA Mini.
Thank you, Nelson.
Thank you also to the DIY Audio Store team who take such good care in completing our purchases.
There is little more to say beyond my strongest recommendation of this amplifier. A straight forward build with a caveat to ensure that Nelson's excellent note is carefully followed on the crucial process for the bias settings. There will be no issue with this process if the designer's clear instructions are respected.

Iron Pre
Christophe G.
Brilliant really

I built an SE version first, as I could get hand on an early kit from another DIYAudio member. The build is really easy to do, even more when using the dedicated case from Hifi2000.
The Iron Pre sounds so natural, and so airy, that I was totally happy when I tested it. So happy that I ordered the balanced kit, which is yet waiting for me to build.
It's probably the best pre-amp I own. No, it is the best pre-amp I own.

Great for my Nutube NEB-2

Just what I needed. It eliminated all hum and hiss from NuTube harmonic generator board so I could use standard wall wart for 12VDC power. Its small size allowed it to be mounted in a wooden cigar box that I mounted the NuTube in.
DIY store was great to work with when the USPS lost it in the mail the first try.

Amp Camp Amp
Daniel H.
Simple, Transparent, Delightful

The build experience was tons of fun. All components that came with the kit were well within spec. After listening to Mr. Pass talk about his stash of parts, I feel like a got few gems. Populating the PCBs and wiring the amps up was a great couple of afternoons (I built a pair). Build instructions are perfectly clear.
As far as what they sound like:
They are crystal clear and massively transparent. They will simply recreate the source material they are provided.
I run them as a set of unbalanced monoblocks in a relatively nearfield environment and enjoy them almost every day.

Amp Camp Amp
Neil J.
Good project. Good documentation. Great amp.

I’ve built several tube amps, but haven’t had success with any solid state builds until I took this kit on.

And what an amp! I listen to it every day with bookshelf speakers. It sounds beautiful. Like my favorite tube amps, this amp demonstrates how much can be done with a simple minimal design.

I keep buying more

it's just like that. When you find something and fall in love with it. DHT is not new to me, so this did not surprise me. But then after the first one, I built another. And another. Simple build, stunning sound. So this is the last one that I built, but not the last one to be built. This is a shot during the build. Used some very cool stuff like the stacked/mechanical volume control.

I enjoyed this project.

Nice quality of components.

During the build without chassis, it took me some time to measure and figure out the hole-pattern for the PCB on the heatsinks. I couldn’t find any values for it in the guide or forum.

Now i can proudly say i have built my own stereo power amp! And i have learnt some new things.

My feet are wet and the water was indeed fine. Dare I go deeper?

Thank you, both creator Pass and supplier DIYAudiostore.


Beautiful sound, beautiful in its simplicity. Mr. Pass has taken all the guesswork out of selecting the jfets. Ridiculously low price, easy build, with stunning results. Dead silent. Rich, natural sound. Will probably end up building one or two more.

What a good DIY kit

Building for the first time a pre amp and it was a great experience! The guide of Jim (very detialed step by step) and also some youtube videos where very helpfull. Thanks so much also Jim for the after sales! Did no upgrades so far, first going to try it on the F6 (still in build phase).
Tip: i used the pass guide for the last adjustments.

Greg P.
Easy Choice

Being designed the way that it is, the Galaxy chassis much better to work with than previous chassis that I have had in the past. My customer is very pleased with the result.

So Great!

I couldn't be happier. The kit is awesome. The support is great. And the sound? Fantastic.

great quality and support

I was impressed with this pre-amp from the get go. Both as a kit and as a component in my sun room. Intriguing visuals, really good sound and "I built it" as a bonus. One of the best quality kits I have done in the recent past, and easy assembly and support.

Great Job to the team for all their work

Inexpensive kit makes great sound

Sound is big on my 95db sensitive speakers.nice sounding.
No complaints.

Manus H.
Great sound from an easy build!

Building and finishing the case was much harder the building the electronics. Easy to build for even a novice like mem using the standard bill of materials. Worked first time with no noise at all, even at full volume. Upgraded the op-amp already, with impressive results. Drives my Audeze LCD-X very well. I am really very happy with my decision to build this and the sound quality of the final result. The case it not too bad either!

Front End 2022

Transparent, detailed gain without sterility. I would call it top notch to enhance without detraction or subtraction from virtues of the amp stage.

Single ended usage @ 36v, used with Pass DIY Sony single ended SK60 VFET, superb.

Epic sound

As bridged monoblocks they have the best sound ive heard to date in my system. instrument detail , stereo image in vinyl has exeeded all my expectations and the overall sound is beautifull, gives you a smile. Totaly recomend it and will buy again to build for friends

Oh happy Day

This is my first complete kit, I've made.
- Full ACA mini kit and binding posts from the store
- diyaudio fire metal solder
- Araldit standard
- Ohmmite Heatsinks (8 x VM1-038-1AE)
- Aluminium plate (dimensions 250 x 190 x 15mm)
- Some small material
The amplifier sounds wonderful and it will be used with 6 x 9inch and 12inch full range speakers (another one is planned:-)). The adjustment for biasing was a little time-consuming but at the end it's a very nice experience.
(see my post #2,255 at the ACA mini thread)

Great DIY Project and Great Sound

One of the really nice things about Pete Millett's Starving Student II amplifier is that you literally get everything you need to build it except the solder. It's an easy build, and when you are done, you have a headphone amp/preamp that sounds great and looks like a commercially made product. It has no issue whatsoever driving the Sennheiser HD650. Highly recommended!

Dalton L.
F5 Turbo V2 - An Alaskan Amp!

A wonderfully designed amplifier! These PCBs are easy to solder, feature clear writing and proper spacing. The circuit is easy to assemble with some patience- follow the guide/watch NocturneVid66's assembly videos, and you're off to a great start!

This build is a dual mono (common star ground) in a 500mm dissipante chassis. Biased to 340mV, it runs at approximately 114 degrees F while never exceeding 10mV of offset across either channel. I highly recommend the available thermal pads from the site as well!! I chose to cassacode as well as put caps on the output boards. Cassacode if your needs demand it, skip the caps unless you have HF osculation. Power caps are 22,000uF x 16 = 352,000uF total at 63v rails; all wire is oversized, and I soldered screw-down wire terminals for connections between boards.


I made mono blocks with the superb pcb you are selling and the fets.
i am astonished by the results. they have only few hours and they start to open up!
Thanks Mister Pass and DIY audio store, what you do is revolutionnary.

Superb sounding amp

I've built it with 32V rail and 0.47ohm source resistors this does produce a lot of heat. Make sure you use big heat sinks with this combo. This amp sounds really good with ACP+ or Wayne's 2018 Linestage, clean, detailed and musical. It has no issue driving a pair of Boland Accoustic BTX180 made by Peter Boland of NZ. These are 4 ohm demanding speakers but the amp drives them effortlessly.

Amp Camp Amp
Steve M.
Fun little amp!!

First and foremost, this is a nice little project! That being said there were a couple of small issues I ran into. First, two of the resistors were the incorrect size. I dug out some correct ones from my stash, not a big deal. Secondly, the instructions were sometimes difficult to follow. For example making the back panel power bus, I soldered it to all three terminals before reading "do not solder to speaker terminals yet". Maybe I was in a hurry, but I had to unsolder and redo that bus like 6 times. Read all the way through each section before soldering anything. I also had to redo the enclosure to heatsink mounting a few times to make sure everything fit without touching. It's entirely possible that my excitement got the best of me, and I got ahead of myself (normal occurrence). After all is said and done, this is a fun little amp. It definitely does not have the power reserves that my Yamaha M-80 has, but it can drive my Cornscala's (6 ohms) to reasonable levels, and sounds pretty good doing it! I will soon be trying the mono mode, when a friend brings his ACA over for a listening session. I have high hopes for that as well. I would definitely build another one, given the chance.

Aleph J
Emmett R.
Aleph J Finished and Impressive

I just completed my build and testing of the Aleph J amplifier. It’s occupying the 4U chassis of the F6 amplifier I built and have been enjoying for the past 18 months. I liked the F6 a bunch, but at times I wished for more authority over my speakers. The Aleph J certainly has that! It sounds great. It’s detailed, has a nice soundstage, and packs a punch. So far I’ve tested it with B&W 686 S2’s and a vintage pair of ADS 1230L’s. The Aleph boards were top notch, and the build guide was very helpful. I’m grateful to the DIY Audio forum for for the great service and products it provides! Keep up the good work:-)

Amazing ACA mini June 2023

Once again the ACA mini as a kit with essential kit components
At all documentation descriptions 5 stars ⭐️ ⭐️⭐️⭐️⭐️

Pesante 2U
George A.
Quality Chassis

The Pesante 2U is a professional looking chassis. Used for three way active crossover. The price to performance is exceptional.