Just finished my two mono blocks and was totally amazed that a single ACA would easily drive a pair of large advents (~86db sensitivity) in our small music room. Absolute jaw dropper and dynamic wide sound stage. I only drive one pair of Advents, while the Sansui drives the other pair and paradigm speakers.

Genuinely, thank you all for your experiential knowledge and support...

Easy to build with a clear head and no distractions... Yes!

I bought this as a fun holiday project, and with appropriate reverence for the talents of Mr Pass, but with none for myself as I'd never soldered before. I kitted-up with a basic soldering iron and a decent multimeter and took a deep breath. Rest-assured, if you're a reasonably methodical person capable of following basic instructions, you'll be fine. Faults were easy to track down using the diagnostics supplied and first principles. Mistakes were easily remedied. Once I'd biased the channels (simple but finicky process) and checked for DC offset (almost negligible at about 3mV), I hooked the amp up to my usual Sugden IA4 running as a preamp. This being a low power amp, I was happy to be feeding it to very sensitive Klipsch Forte IIIs. I expected it to sound decent. It's way better than that, it blew me away. While it lacked the muscularity of a higher-powered amp, it had no problem driving the speakers to ear-splitting levels with real class. The midrange clarity and soundstage are lovely, really suiting quieter acoustic music. The biggest issue I noticed, is that during particularly busy sections, the amp couldn't deliver the clean and tight bass that the Sugden can - the ACA bottom-end reaches plenty-deep, but its presentation is more disorganised and smeared. Another thing to note: this amp runs hot. Very hot. It has that classic slightly warm class-A sound and the heat that comes with it. This is probably not an amp to leave on all the time.

So, is the Amp Camp Amp any good? Well, there is joy and pride to be found in building the amp yourself, but that only goes so far if it sounds bad or even just disapoointingly fine. Fear not, it's much better than that. I'm so impressed that I'm building a new desktop system around it for my workspace. I've selected Omega speakers for their ease with flea-watts... and I see those Zen Triode kits... However, ACA? I freaking love it!

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 finally purchased this DIY, my first one to build as a complete kit. I up the stakes by replacing all the caps with AudioNote (blackgate version) Caps and Mundorf for the coupling cap. i also used silver solder and silver wire for all. All I can say it is all the hype I've read. I paired it Klipsh Rp600M and sometimes switch it to my Maggie LRS just to listen how it sounds
well, compared to my reference system, it is holding up its claim to fame. i am amazed that this simple design, using upgrade caps and driven by a Tube amp, can sound that good. i suggest use better caps as you can

I had modest expectations for this little amp. I have had this kit sitting all summer waiting for a rainy day. Well, we got snowed in for 4 days so I took the opportunity to build this unit. I took my time. It’s been a while since my early Hafler kits in the mid ‘80’s.
The build guide is very helpful. Thanks 6L6 !
First tried the amp with an iPod and my spare ProAc Tablette’s. Not enough gain for daily use but promising enough…
Today, on a whim, I connected it to my Acoustat 1+1 electrostatics (Meridian G02 preamp with plenty of available gain)
I’m impressed! This shouldn’t be enough power but it works AND sounds quite good. Vocals are lovely.
Depth and soundstage : check. (pretty close to my Meridian G57 power amp, until it runs out of gas, of course.
Very tempted to build another to hear monoblocks. I may have to bring out my Klipsch Heresy III’s to see what happens on a high efficiency speaker.
Very rewarding to build this and discover it is better than expected! Well done, folks.

I ordered two ACA kits to make as mono blocks, ordered with black face plates. Received one of each. Not the end of the world, fun to build, and they still sound great!

Ran out of “free” time after the first one, and it sounded so amazing that I lost my sense of urgency for the second. But last night the wife went to bed too early. So I headed to my happy place and finished the second ACA. After setting the DC offset and running a couple of songs through it, I couldn’t resist sneaking quietly upstairs and removing the first one and bringing it downstairs. After hooking them up in monoblock configuration, I turned on some tunes to try them. They sounded amazing, and in my excitement managed to wake up the wife. It’s a good thing she has the patience of a saint. I can’t wait to try them together with my B1 nutube preamp. I’ll wait until she goes to work to put them through a proper workout. You guys are great, keep doing what you are doing, and I’ll keep enjoying my relatively new hobby.

What a great kit. Very doable for a first timer. Actually did 2 kits right away to have the mono blocks. Lots of fun and they sound amazing.