A Beautiful "Class A" Amplifier Kit
What do diyAudio forum members think?
Insane amount of detail, deep bass and crystal highs
The hairs on the back of my head nearly lifted me off the floor!
Great power, bass and massive detail
Highly detailed, yet smooth and sweet
I am amazed at the sound quality
Blows away the Yamaha AV receiver I have been using (until today)
It's not just a kit, it's an education - here's why everyone is falling in love with the Amp Camp Amp
Watch TekThing build the ACA
TekThing is an awesome video blog for technology geeks. In this 30 minute video Patrick Norton talks about the history of the Amp Camp Amp, and then builds a channel from start
to finish! If you like the video consider subscribing to the TekThing YouTube channel for regular geekery or become a patron and get perks! Please note that in this video Patrick applies the Keratherm incorrectly - you need to peel off the backing before applying it!
A step-by-step build guide and forum pit crew standing by to help to get to the finish line
We've just launched "diyAudio Guides" (beta), a brand new place to find and share knowledge about audio DIY. The Amp Camp Amp Build Guide is now more accessible than ever. Follow step-by-step on your phone or tablet while you're actually building the amp or printed the guide as a PDF - it's never been easier to complete your Amp Camp Amp in one sitting!
If you need more help, there's hundreds of diyAudio members who consider it their mission to help any ACA builder get their first amplifier build completed. No question is a stupid question in the ACA thread, so join in the discussion and meet other first time and veteran builders in the Amp Camp Amp discussion thread.
1. The Parts Kit
- High quality genuine parts purchased directly from "Tier 1" US distributors such as Mouser and Digikey
- Printed circuit boards (Revision 1.6)
- Transistors including Linear Systems LSK170 JFETs and IRC MOSFETs
- Switches, LEDs, capacitors, resistors, we include everything
- The same parts quality that Nelson Pass uses in his own amplifiers
- Components purchased either from "Tier 1" distributors or do-it-yourself audio favorites like Parts Express
- Keratherm® MOSFET insulators - very efficient and no grease required
- M3 board mounting standoffs, w/ stainless steel bolts and washers
- Stainless steel mounting bolts and washers for MOSFETs
- Gold plated speaker terminals and RCA Jacks
- Power connector jack
- Copper hookup wire in assorted colors
- Cover plate for XLR hole (for advanced users, the XLR hole gives the possibility to create monoblocks with 15 watts per channel)
2. The Power Supply
- From Meanwell, the best known producer of high quality SMPS in the world
- The power supply is universal and operates from 86-264VAC and 47-63HZ
- It comes from a best-of-breed manufacturer, has less noise, more
power and weighs more than twice as much as the previous power supply
- You can read more about it on the Meanwell 24V 5A power supply page
- This new power supply is also a suitable upgrade for all previous Amp Camp Amps, just plug and play (see notes here)
- This power supply is Nelson's lab tested recommendation, but to save
money you can BYO 19V or 24V 5A laptop style power supply. YMMV!
- It has a generic 3 prong IEC 60320/C13 power cord inlet suitable for use with a "kettle cord"
- We ship it with a Linvox 3271V86 6 foot cord that has a US 3 prong
plug. If that plug doesn't work for you, you can use a plug adapter, or
"borrow" an IEC cord from your least favorite piece of equipment.
3. The Chassis
- From the Italian chassis artisans at Hi-Fi 2000
- Custom design for the ACA / ACA parts kit
- Ships direct to you from Italy with FedEx International
- All the work done is for you - just screw it together!
- 10mm aluminum front panels drilled (dual LED holes), anodized and silkscreened with hole for a front power switch
- 3mm aluminum rear panels drilled (power jack, RCA input, speaker
output, power switch and XLR expansion module hole) and anodized
- 40mm aluminum heatsinks pre-drilled and pre-tapped with M3 threads for easy mounting of circuit boards
- Frequency response: 10 - 20 kHz +/- 0.1 dB
- Power (stereo): 8W into 8 Ohms per channel
- Power (monoblock): 15W into 8 Ohms per channel. See ACA operation modes for details on monoblock operation.
- Power Measurement: Measured at clipping with 3% distortion
- Distortion: 0.7% at 1 Watt (primarily second order harmonic which being even-order is described as "sweet, tubey" and being low-order as "benign/inaudible")
- Input impedance: 10 Kohm
- Max Gain: 14dB
- Damping factor: 10
- Output noise: 100 uV
- Power supply input: Universal 86-264VAC 47-63HZ
- Power supply output: 24V 5A
- Heat dissipation: 20 Watts per Channel
The Amp Camp Amp Kit has received coverage in these publications
The reviews speak for themselves
I am using 4 x ACA's kits to drive 8 ohm Selenium D405 midrange and
BMS 4540 high frequency compression drivers in a Digital XO tri-amp set up... I am impressed with the sound quality - highly detailed, yet smooth and sweet.
Amps go together so easily! Really a great initiation!...absolutely
massive, dense, fluid, sharp as a knife sound. Played a few tracks I'm familiar with and the hairs on the back of my head nearly lifted me off the floor!!
Spent 2 nights assembling the kit and volia now it is singing. Source is a old niam cd2 > BA3 FE > ACA > Markaudio Alpair 6 floorstander. I am amazed by the sound quality. Once again, thank you Papa Pass.
Insane amount of detail, deep bass and crystal highs! Tried few old restored amps with 4000M's, ACA's are perfect match so far. So, thanks Mr.Pass for this eye-opening experience...
I have it my office and it blows away the Yamaha AV receiver I have been using (until today). I am very surprised by the difference. Definition and sound stage are so much better. This with low end bookshelf speakers...I am hooked!
The amp sounds great....great power, bass and massive detail...Amazing amp for the build cost. The amp is dead silent between tracks.
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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
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.
Recommended. It went by quick. I'm burning the amp in to the Grateful Dead as I write. Very surprised and pleased the sound quality, loudness, and bass. Build hints: 1) Read 1.6 (board build) and separate 1.8 (wiring only) instructions end-to-end first including helpful comments. 2) Brush up on soldering technique 3) Would be nice to get a chart listing wire count and length but plenty wire supplied. It worked first time. Easy peasy.
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.