diyAudio Store

Great amp! So happy to have it - sounds just beautiful! Build is very straight-forward, even for newbies like me (have previously built only WHAMMY preamp). Patience and double checking is the key. Only thing which confused me is no marking for positive LED side on the PCB's silk-screen. Firstly, I have soldered it as LED's minus to the GND on both channels, but it appeared that left channel is driven from the negative rail (guys from forum responded within an hour-two!), so LED should be soldered in opposite (+ to the GND). 300VA audio grade shielded transformer from TOROIDY works very well - no hum. 600 mV offset in Deluxe 4u chassis gives just a bit less temperature than suggested maximum. It runs hot, but stable within months. F6 works with Troels Gravesen's Discovery 861 DIY speakers (92 dB efficient) which were built together with the amp. They work incredibly well together. Bass is deep, detailed and extremely controlled. Mids are full of body and details. Highs - just blew my mind! So airy, clear and detailed. But no fatigue whatsoever - can listen for hours and hours! It was a long way, but result totally worth it!
Kit is awesome, many thanks to the DIY Store, DIY community and our hero - Mr. Nelson!

Yes, The preamp works and sounds Great, I'm very happy , Thanks for standing by the Nutube warranty, with the shipping problem..

I'm new to this world, having only built two of the ACA 1.8 amps before this mini. Bought the completion kit from the store to go with it. I loved this project. Very affordable, cool to look at, and amazing sound. I keep coming up with ways to case it, but like the naked look so much I never start the case. I like how it sounds and keep carrying it back and forth between work and home, then between different set-ups at home! May buy another one to build with one of the grandkids....

Built two ACAs, (running them in bridge mode mono), then built the B1K as the pre-amp into the ACAs. Takes 30 to 45 minutes of play to warm up and then sounds super. B1K adds some warmth to the music. Both are great kits to build, it is surprising how good the combination sounds. Adjust voltages carefully on both for best sound - per designer recommendations.

This is an awesome kit. I tested its 5 watts per channel on Fostex ESR-206 with 98 db/1W meter and it is beautiful. The pairing with the acp-amp-camp-pre-amp (also available here, thank you!) makes it excellent. A beautiful, totally awesome combo.

One caveat: adjusting bias may be a bit of a challenge for the neophyte, but it is totally doable.

I started this project being amazed by all the comments and fantastic feedback posted everywhere. I thought this is definitely something, well, I am a natural maker with very little electronics knowledge and an audiophile newby, so it could be an inexpensive way to begin this journey and it catches me deeply.

The sound signature is delicious, the only drawback is its small power, but found out thanks to James from TungstenAudio and his genius and generosity, that it is possible to hack the ACA and take it to a better level, I followed up his recommendations and wow, more power and even better sound, it reminds me the sound stage of a tube amp, very, very nice.

You can find the suggested upgrade here https://www.diyaudio.com/community/threads/aca-amp-with-premium-parts.328357/post-5569767

I am running a pair of Elac's Debut 6.2 (87 dB sensitivity) and they sound great.

My next step is to try a 48V linear power supply and see how it performs, if it does't give more power I will purchase another one to build a mono block set.

Thank you to Nelson Pass for his creativity and generosity and to DIY audio to make it so easy and also thanks to James from Tungsten audio for the tweeks, he really took this mini amp to another level.

I am using these JFET's in a set of Folded Cascode CEN IV boards. They have worked perfectly.

I tested them on a couple of testers I have and each quad set match exactly. Haven't had time to complete the first project yet, but soon.

Since one week I'm listening with the ACP to my favorite playlists of music and I am really fascinated of the musical flow of this Amp. I've build it with a Wolfson DAC together in one enclosure and a separate linear unregulated power supply 2x18V/50VA with main power filter, DC-Blocker and several smoothing capacitors in series. It's the best Preamp I've ever listen to, so thanks to Mr.
Pass and the DIY-store!

The terminal PCB for the ALPS 271 (blue velvet) really saved me a couple of hours work. Really great service! Was able to get the part over the weekend by USPS...like 3 or 4 days max. Thanks!

I used two of these combo to build two Honey Badger power amps in mono configuration. PCB quality is really good and it does the job really well. Good documentation also.

I used two of them to build two Honey Badger power amps in mono configuration. It works really well and the the documentation is clear and detailled. I have no complaints whatsoever.

I've built two mono amplifiers with this kit and after a few months of operation I can write my opinion. The sound is really fantastic. I like it from every point of view. With the right power supply it can deliver a lot of power and pleasure! The building guide i sclear and well done. In addition there are a lot of informations in the general discussion thread. I only have one point of criticism, regarding the footprint used for many passive components. They are often a little small, so if you use different components (for istance dale resistors, ) you have to mount them vertically. Even the drill size should be increased for many components.

Showed up neatly packaged and arrived quick considering shipment from Italy. Very pleased with the purchase.

I have purchased two of these boxes, and the quality was very good in both. Everything aligns well, and they are easy to assemble. The heat sinks are nicely made and are very flat on the inside surfaces, which made mounting amplifier modules easy and helped keep them cool during operation. The custom machining work on the back panel for installation of Neutrik XLR connectors and an AC input socket was first rate.