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Based on 1541 reviews
good build

I couldn't have enjoyed building this more than I did. I am a big fan of the SP1 tube just because it is different. I have made several builds using the Korg tube, from preamps and amps to headphone amps and buffers. The first B1 that I got was already built but I wanted to hear what one sounded like with this design. I wasn't disappointed. The best description of the sound for me was that it was musical. I could go on about all of the aspects, but I got what I wanted here and that is plenty for me.
Kit build is very good and easy to do. Me being me, I upgraded the volume control to an EIZZ stepped attenuator, and opted to make my own power supply, using toroidal transformer and beefy circuits as well. Note that the photo of the power supply shows it in rough form, and the box was cleaned up afterward. I keep the B1 power switch on and just use a switch on the power supply in the front.... I used shielded silver plated copper wiring throughout the build. In other words I maxed out the component quality. The result rivals any other build that I have owned. I have been horse racing it with another preamp build of mine, but can't decide which I like best. They both have their merits.
The B1 chassis needs some help in the support of the top and bottom plates, since the SP1 will give no easement in handling any vibration. This is easily solved by using a bead of silicone for the bottom plate around the perimeter on the inside. I also opted to use additional damping in the form of Dynamat in strategic spots. The one piece of advice that I would give to anyone building this kit is to use silicone supports for the SP1 board! These are inexpensive and pop into place. They are used for the reduction of noise for computer fans. To get the board to be properly held, I used small O rings that took up the additional space left by the silicone support.

Amazing amp, lots of fun to build!

This is the third amplifier I have build and I'm really happy with how it turned out. I went to the trouble of integrating a Khadas Tone Board DAC so it could be used as an "all in one" solution for my desk at work. It sounds great with my HD6XX and was a lot of fun to build. You can see more details about my build here.
Thanks Wayne!


A nice upgrade to my ACAs built in 2018. Look more hi-tech. The panels were shipped from Italy and had them in no time, thanks for the direct link. The only challenge is soldering the DPDT connections. Still using them as monos.

Amp Camp Amp
Eelco R.

This is such a surprising good amp. I had build it to have a taste for class A amplification and it really is super.
I have connected it to a pair of diy speakers from Parts Express (Samba MT) but also had it connected to Amiga MT (Paul Carmody design). The latter is really not sensitive enough, so you run out of oempf. But whatever is there is really enjoyable. The Samba is more sensitive and has more treble. That combination rocks but doesn’t reach as deep. But he, you can’t blame the amp for that 🙂

recommended wholeheartedly

This is a very nice headphone amplifier indeed. It sounds terrific. Many thanks to Nelson Pass and the diyaudio community!

I built mine with the recommended components, except for the decoupling capacitor at the entry, which consists of two 4u7 capacitors in parallel. The heatsinks are hovering above the MOSFETs on a piece of alumininiun u-profile The case is made from scrap aluminium sheet welded together with Durafix.
The power source source is from an 2 * 12V Amplimo toroid transformer and a series of 1500uF smoothing capacitors. It's then followed by a super-regulator for which I built my own PCB.

Nice case

This is a “4” rating only because a panel thinner than 10mm isn’t offered. An option like 5mm would make DIY for us without a machine shop a lot easier. The cabinet is excellent otherwise. Photo of preamp/headphone amp project (work in progress) mounted on the bottom of the enclosure

ACA - Wonder Amp?

This is the first DIY amp I’ve built with not needing tubes costing more than the base build!

A small confession – I just couldn't help but build it with some upgraded Mundorf and Sprague Atom caps and for good measure, Duelund cable.

Paired with an Elekit preamp and some Omega stand mounts the sound really does brings a smile to my face. As a bonus, it heats the room quite nicely.

No wild claims about it being better than my bigger (and far more expensive) EL34/KT88 and 300B amps but it more than holds my attention and has kept the office EL34/KT88 Elekit power amp gathering dust the last few weeks.

No way that I could ever own a piece of Nelson’s best in NZ and so I’m very happy to have spent and afternoon with soldering iron in hand.

Out of interest, I've ordered a linear power supply and a matching case. I t will intersting to see wht a change it brings. Guess I may need to put a blue LED into the pre........

BA-3 nanimous

Simple project, magnanimous sound!
Excellent PSU is a must. The PSU for the Bride of Son of Zen is adequate and sounds great at +-28 Vdc, but I opted for a Sigma 22 design at +-30 Vdc.
Board from diyaudio store is excellent! Fast shipping too. Overall, a great experienced on this project. Very satisfied!!

Better than it should be

At the price I didn't expect too much. That is ok, since I had a general curiosity about the SP1 tube, even though I have worked with it in the past. This particular kit is easy, almost self explanatory. That's good, because there are many like myself that will get so far with something, but not all the way, and it is a PaiN to have research the crap out of something just to find a simple yes or no to a question.
So I got the kit assembled, and appreciated the quality parts choice along the way. Once done the result look s very good, and not something that resembles a kit. Finally it is the sound that makes me sigh in relief. It doesn't sound like a kit. It does however, sound like a tube circuit. In fact it sounds more tubey than most anything I have built in the past. For me, that was the goal, or at least one of the key points.
You will realize how positive this review is by the fact, I am building another one. This with a few upgrades... yes, because I can.

First crossover..sounds great.

For me the first active crossover that i have made.
The sound is on my diy open baffles with AER 8inch and 15inch LII drivers.
It was easy to build the kit complete.
Only ambiguity with regard to the diagram was the deviating resistance values ​​supplied with the fets
otherwise highly recommended.

High end headamp!

A friend of mine trigged me into headphone listening. It is wonderful to be able to listen and enjoy music in the evening at real listening level.
I am a great Pass / Colburn fan and falling across the Whammy I of cause had to give it a try.
Recently I borrowed a set of Hifiman HA1000SE – whee this headphone and the Whammy really is capable putting my HD800 to the wall at a level I have not heard for a headphone before.
Very detailed dynamic sound with energy and nerve I love. It really reveals every change done in my set-up.
To bring it to best possible level I additionally used pure silver wiring, pure copper RCA connector, Jantzen Silver/Gold ac coupling capacitor, copper plates/mica underneath the output transistors, copper alloy screws, OP627 op-amp, Wima MKP10, some extra decoupling, silver solder lead and a 20Kohm 24 pole Elma shunt attenuator.
Being proud of having additional Pass Gear and to honor Wayne I used a look alike chassis – gave up using the heat sink sides.
For now it´s running 40mA bias – I have no clue how much extra performance can be gained by higher levels.
My friend with the HA1000SE is in process of building a tube-based headamp and I can´t wait to compare the amps.
Cool to be able to build something like this.
Hi from Denmark and thanks everybody for contributing to this nice project – reading the very long tread was really inspiring.

Very happy

I got two kits they were easy to build with very good online instructions all in all I’m very happy with the finished amps

Outstanding sound quality, relatively easy to build

It was my first DIY project and fortunately it was successful. I haven’t killed myself working with mains and very glad about that =) Some patience and accuracy is rewarded by incredible sound, depth and wide soundstage. Built with AD823ANZ and am more than satisfied with SQ – very precise, detailed but pleasant for log-time listening. I will upgrade it to discrete OpAmp – probably with Sparkos Labs’ Dual Discrete Op Amp SS3602 – very excited about that.
I believe that there was no red 0.1uF film cap (between RCA GND and safety earth) listed on the BOM on the Project’s Thread (or I have missed that), so be aware to order it. I can not see any issues without this cap, but if Wayne suggests to put it – we should… If you are using Hammond enclosure 2,028” (51,51mm) high – DON’T choose filter caps higher than 35,5mm. 40mm is too high and they don’t fit – need to replace mine =(
Many thanks to Wayne and the Community for a grate opportunity to built such a gorgeous headphone amp.

Just awesome. Pre-drilled is a great feature. I used for a single channel Alpha J (mono-block) along with top & bottom rails. Hard to find anything this size at a better value. Thanks DIYstore!

Amp Camp Amp
Eelco R.
Found the sound that I was looking for

I have been building my own speakers since Corona grounded me behind the home office desk. I have build 6 pairs in the meantime. Mostly designs from Paul Carmody. I like the Amiga most because of it's controlled and low base (used premium filter components).

But that became truly audible once I connected it with the ACA Amp that I have build recently. The sound is crisp and clear but dynamic and engaging at the same time. Unfortunately, the Amiga is far from sensitive so it won't go loud. But since I play it in the study, the SPL is sufficient and neighbors and wife/kids are not complaining either.

So very happy with the Amp and VERY happy with the sound. This is as much high-end sound you can get on a shoestring.

So much fun!

I had a blast and learned SO much building these ACA amps. I had never built an amp before and had very limited soldering experience as well, so this was a perfect first project to tackle. The instructions/photos are top notch and super helpful. I would highly recommend to anyone, just take your time and you'll knock it out in no time. The best part however... these amps sound amazing!! The warmth of these class A amps is sooooo nice! Give them a try, you won't be disappointed.

V1.8 Great Sound and Fun to Build!

Thoroughly enjoyed the build process, which as a novice, took me about 1 day for each amp. Chassis is well made, and the amps sound terrific! Been using daily, and I’m hooked on DIY! Great kits!!

GREAT amp!

Super easy to build, and just delicious juicy sound.

Love it!

Worth the effort

As the DIY store was absent of the “completion parts kit” I consulted NP’s list and sourced most of the needed components directly from Digikey. Chassis is bamboo w/plexi top, volume knob is a vintage CPU heat sink. No ringing whatsoever (have not damped the ‘tube in any way), and best of all it sounds great. Thanks to 6L6 for the well done assembly guideline.

Great experience

I wasn't sure I could do it, I know nothing about electronics, never solder anything before, but I succeeded and the amp sounds very well.

Very pleased with the amp.

This is my 3rd Elekit build and the quality of this kit like the others is excellent. Everything went together very smoothly including the upgrades to the volume pot and transformers. Instructions are very clear. On initial power up I did experience some problems with low audio and static/crackling and only mention this because it was 100% tube related, I managed to buy 2 bad 300B tubes (not from DiyAudio). After isolating the issue and replacing the tubes the amp is performing flawlessly. I highly recommend this outstanding kit.

Glen C.
Excellent quality

Great boards. I made a mistake in the assembly. Removal and rework of the part caused absolutly no damage to the board. Many cheap boards would not have fared so well.

Liked the build so much, I got a second

I have some experience with soldering and building things but never an electronics product. The ampcamp amp sounded so good, I put in my main system and got a second for the dual mono lock operation. The online instructions were good but would have preferred one link with the 1.8 version from start to finish rather than switching from 1.6 to 1.8 versions. The materials are excellent quality and the final product is good looking!

Awesome little Preamplifier

I enjoyed building this pre amp, it was not difficult especially with the instructions available at diy forum..... great job guys!
I made the top cover with my cnc laser in acrylic and painted the underside, I left a window to see the Nutube, I then laser etched the writing in mirror image on the bottom so it looks nice at night with the letters glowing with the Nutube lite....
And it sounds really nice, I liked it so much I built another one but this time with a different case and remote control volume and input selector with 3 inputs....


Thank you for sending, the preamp works very well, I'm still working on the power supply, I have a modified salas + 18-18V. Sounds better than DCB1. Powered by F5.