B1 with Korg Triode (B1K) Full Kit
At the Burning Amp Festival in 2017 Nelson presented a pre-amp using the Korg Nutube dual triode. The latest revision of the circuit available is now available complete with Fairchild JFETs and all directly supplied by Nelson Pass.
Please check the following links for more information:
There are 4 elements to building a complete preamplifier. Purchase the elements separately, or all together as a "full kit" bundle for $299. To build a complete preamplifier you will need:
What's in the completion kit?
Everything else you need to complete the project other than the Nutube, PCB + JFETs and Chassis. It's an assortment of bits and pieces that joins the Nutube, PCB and Chassis together, turning the whole things into a "full kit", hence the name "completion kit".
The included "wall wart" style power adapter supports an input voltage of 90-264V and has a US style plug. If you don't live in the US you will need to obtain a suitable plug adapter.
Each kit contains high-quality audio-grade parts that have been carefully chosen for their suitability for this project.
At the time of writing (November 2021), we're still in middle of a pandemic-related global-supply-chain traffic jam. These are predicted to extend until 2023. While we'd like to have everything match the build guide visually, quantities of some of the parts you see in the guide might not be available right now. In those cases we have included well considered substitutions. You'll have to use a little imagination when following the guide.
Discussion threads / Links:
- Technical discussion: B1K main thread
- Build Guide: B1K Build Guide
- Pre-order Q&A (old news) in the B1K pre-order Q&A thread
- Prototype feedback (old news): B1K pioneer batch feedback
- Pre-order status (old news): B1K pre-order status page
Bought the Nutube and PCB/JFETs from the DIYA store, and sourced remaining components from Digikey (the Completion Kit was far and way backordered at the time) - Results were spot on at first power-up, even got lucky with zero Nutube noise - Sounds just wonderful as a front end for my DIY Pass A2.
Was very easy to build and sounds very good to me. I installed it inside a diy passive preamp which feeds my diy F6. So now it includes remote volume control and the ability to have it bypassed in case you want to eliminate it to avoid “too much of a good thing” for example, while playing my turntable with it’s tube based phono stage. As it looks, I rarely bypass the Korg because it provides nice sound improvement with all music sources.
This look is not the final, after proving the concept I’ll work on the look
I decided to build this kit because of the possibility to change the sound with the trimpots. My knowledge of electronics is very limited, so I had some hesitations. However the build guide is very good, the number of parts is limited and the forum is very much alive. I took the gamble and bought the full kit. All the parts arrived in bags, grouped by function. That made it easy to comprehend which was which.
Building was not very difficult with the guide.
It is very nice that various Voltage measure points are described, which gives confidence that your build is ok. Everything worked very nice. I was very happy to see the blue lights.
The trimpots are a bit difficult to adjust because a small movement already gives a lot of change in Voltage (T7, T8).
This is my first tube preamp. I did not know what to expect. I was surprised that combined with my Naim 155 XS it separates all musical elements and gives a very steady stereo image. It gives me more high tones than my previous preamp. I had to get used to that.
I experimented with the the trim pots from 9.5V to 14.5V. Big fun to listen to a large part of my cd collection, to decide what the best sound was. At the moment I leave them at 12V, which as I understand gives the least distortion in second harmonics.
I am very happy with the sound my B1K. Many thanks to Nelson Pass, the writers of the build guide and the diyaudio community.
I felt like I'd won the lottery when I was able to buy this kit after a year on the notification list.
And I sure wasn't disappointed.
I've built more than a dozen electronic audio kits, ranging from guitar effects to hi-fi components, from sellers ranging from hobbyists and small manufacturers to big-name kit producers, and this is hands-down the best quality kit I have ever assembled.
It's evident from how it was put together that this is a labor of love, not a highly-profitable commercial venture. Despite my minimal understanding of electronics and mediocre soldering skill, my B1K preamp worked perfectly the first time I powered it up. This experience speaks to the quality of the board, the components, and the assembly instructions.
And....it sounds fantastic! Body, dimension, texture, detail. There's nothing like tubes to add a little 'magic' to your sound.
Highly recommended for anyone who's into serious audio, loves music, and likes to build.
The quality of the parts and the description is very good, the hearing tests started ........
I had been thinking about buying or building a tube amp. Then I discovered the Nutube. This was a fun diy build project resulting in a great sounding pre-amp. I plugged this into my ACA and noticed a new dimension to the music.
When I started this project, the completion kit was not available so I ended up sourcing those components. Another learning experience.
I bought the PCB (w/jfets) and the Nutube only with the intension of building a more compact unit than the whole kit offered here. I was skeptical that I could avoid the "ringing issues” associated with this Korg but using the forum as a guide and realizing/studying what other folks did this buffer/preamp turned out to have a fantastic and hypnotic effect on what came out of my speakers. I love my regular B1 preamp for its clean and precise sound but this B1K just provides a fullness to my soundstage and beautiful presence to the music. I normally listen to (Classical & Jazz) but the Nutube preamp even makes all the early R&R CD recordings tolerable, removing the harshness that plagued the early non-reengineered LP to CD releases. Nelson Pass stuff never disappoints. The 2nd harmonic effects are just amazing.
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