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Based on 1920 reviews
FW F6 clone

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!

Pass B1 Korg Triode Nutube (B 1 K) full kit..

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

B1K with Amp Camp bridged mono

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.

Amp Camp Amp
Carlos D.
Fantastic fun project for an audiophile newby...

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

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.

Exellent Preamp

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!

Save some time

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 3 or 4 days max. Thanks!

Well done and easy to assemble

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.

Great amp!

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.

40mm Heatsinks
Joseph W.
2 pair 5U X 300mm

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

Amp Camp Amp
joey c.
Amp Camp Amp

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

love this kit

The build was not very difficult. Just follow instructions and you wil get there.
I build two ACA's to serve as dual mono block. The sound is magnificent.
I use it with and AUDIOPHONICS EVO-SABRE diy DAC, without an additional pre-amplifier. That still gives plenty of volume to listen.

Excellent by all means

amazing quality A++
from a 30 year + experienced audiophile / DIY builder


Arrived in the UK well packaged along with the B1, easy to assemble. Amazing Sound for the cost, thanks Nelson & the DIY team
& community. Made the Ash box with speaker terminals on the rear will house a filter inside.

Amp Camp Amp
Surprisingly good!

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.

Do not hesitate!

If you're reading this, you are curious about this little amplifier. Build one (or many)! You will be amazed. Make sure all transistors are soldered where they should be, take your time to set the bias--and enjoy! The sound is amazing with plenty of bass. Cheers!


Best sounding for the buck. Thanks for the design Papa Nelson.

ACA MINI-BIG Amplifier

Great kit, quality parts, easy to assemble. Most importantly the sound is amazing for the price. Thanks to Papa Nelson for the design. Thanks to the Diy community for the help and support.

ACN for SLOB speakers

I built an ACN for SLOB speakers using two P089ZB filter kits and a pair of RK27 breakout PCB's.

I used the soft start

I used the soft start which seems to be doing the job just right. I am using it on a 75w/ch class A amp running two 500va transformers. It has done the job well. I used a 0.47UF for the snubber in C2.

I may still build the Speaker protector board

Dissipante 2U
Brian D.
Very nice case

This case is very nicely designed. Assembly is pretty straightforward, as mentioned the instructions are pretty limited but I was able to work it out without to much problem. I do wish the rear panel had a bit more support, it flexes a bit when plugging in the power cord. It shouldn't be too hard to brace it though. The finish is extremely good, and the packaging protects it well. Overall I'm thrilled with the end result!

A very sweet little amp for my desktop

Having built a pair of ACA the ACA mini looked just the job for a compact amp to sit on my desk and drive a pair of Deware Tiny Radials I built from $20 plans. I'm feeding the ACA mini from a Dragonfly Cobalt USB DAC with a QED 3.5mm to RCA cable. The Tiny radials are 80db sensitive 57mm full range drivers that get down to 80hz courtesy of integrated passive radiators. The combination is fast and punchy, holographic, slightly sweet and more than loud enough. It's a very addictive listen as everything sounds so good sucking you in and making it hard for me to complete this review!

SMPS DC Filter and NuTube Anti-Vibration Mount

This kit is a fun build. I suppose if you're in a hurry, you can complete it in one day, but I took my time and enjoyed the process. Built it just as provided with all the kit parts. Didn't feel any need to substitute designer parts in, as the standard parts all were of excellent quality. Opted to include an SMPS DC Filter P089ZB Kit and Pete Millett's NuTube anti-vibration mount as part of the build. Note only the blue foam on the anti-vibration mount fit. The B1 is paired with a set of ancient Welbourne Laurel tube mono amps with a Raspberry Pi running Moode Audio Player and a JDS Labs ODAC providing the inputs. I'm loving the sound. There's always a surprise in re-listening to music that I've heard many times before, as this combo is revealing details that I'd missed before. Great clarity and channel separation.

Aleph J
One more Aleph-J finished

Just finished my Aleph J in a 5U case (big and heavy sitting on my bench) and the sound is just beautiful with my Focal Sopra 2 speakers. Those demanding beryllium tweeters just sound sweet as honey with the Aleph J and the low impedance dip in the base region is a piece of cake for this monster.
Only added the excellent Neurochrome speaker protection to be feel more on the safe side.

Before this I made me the F6 that is also one excellent amplifier to keep.

P.S. the service from the DIY -store is world class!

A fantastic deal on the best parts for an ACA Mini

Huge thanks go to Nelson Pass for making this possible. This kit contains the hard to find parts needed to build the mighty little Mini ACA amp. It has matched Toshiba JFETs and also the coveted Harris MOSFETs for the output stage. The included PCB is an added bonus! This is, by far, the best value in the DIYAudio store right now. Get the kit; build the amp. You will be so glad you did. BTW, I built mine a bit different than standard with my own PCBs. But that's how I roll. :-)

Great all round

It’s a Pass design so it sounds great. No need to say more really. But the ‘go naked in the world’ concept is also brilliant. Not only does it keep the cost in the ‘no-brainer of a purchase’ category but, as someone else commented - this thing belongs in the MOMA.

Had some glitches with delivery - first time I’ve ever had any issue with the Store’s brilliant Delivered Duty Paid arrangement for non-US delivery. The Store was very responsive and helpful with putting this right. Thanks Jason.

There were two caps missing but luckily I had near-identical substitutes in the spares bin and, after all, this is DIY so two caps shouldn’t stop the build. Again the Store was prompt with sending the missing caps.

Another superb addition to the Store’s arsenal of great-sounding pieces at what amounts to a steal of a price for what you get.