Korg Nutube B1 Preamplifier PCB + Fairchild JFETs
At Burning Amp Festival 2017 Nelson presented a version of a pre-amp using the Korg Nutube dual triode. We now have the latest version of this circuit available in the store complete with Fairchild JFETs and all directly supplied by Nelson Pass.
Please check the following links for more information:
- PCB (5.5" x 3.25", mounting holes 5.0" x 2.75")
- 8 Fairchild JFETs and tweaking resistors (all direct from Nelson) for just $25
What's not included:
- The Nutube. You will need to supply your own Nutube, and they are available from the diyAudio Store separately for $49.99.
- All other parts required to make the project
- The board is compatible with both DGS and DSG JFET pin orientation. Use the correct holes for the JFETs you are using as directed in the article "JQ1,Q2 is used for the Fairchild J113's and the KQ1,Q2 fits the 2SK170, 2SK370, and LSK170 Jfets."
This is a great preamp kit designed by Nelson Pass, comes with exceptional quality parts, and easy to build. The Korg Nutube 6P1 tube is not just a very cool device to look at, but also a very low power consumption vacuum tube which made it a perfect solution to convert it as a battery-powered preamp. Unlike a regular vacuum tube preamp, the Nutube 6P1 is not interchangeable. Although tube rolling is not possible to this preamp, Nelson adds a feature to adjust audio harmonics by a pair of trimmer pots each controlling the left and right separately. I can experience a different sound stage and 3D space by adjusting the value of the trimmer while the amp is powered on, how wonderful!
The kit already comes with audio grade electronic parts. Chassis is simple but elegant and solid, high-quality parts from Italy. I completed the kit with original parts which sounds very good already, later changed a few electrolytic caps with some polypropylene from the signal path suggested by the group member, this further improved the sound quality.
This little preamp kit is easy to build with lots of fun to discover. Worth every penny!
She’s so magazine with First-Watt F4 more than Ba-3 Preamp.
Although her voltage gain is small, she doesn't sound like it.
What a great preamp!
Easy to built and what a sound! I am really amazed about its soundscape: deep, large and full of details...
I recommande it absolutely ! Sincerely yours, Thierry Malarmey-Dorel
I have built two nutube pre amps now...one balanced one in a Galaxy 1U chassis, and one single-ended one built into an ACA chassis to make a Pass DIY integrated. Both of them sound really good and construction was straightforward with no problems except the third time I fitted a Nutube to its circuit board the little legs just didnt want to go into the little holes on the board. I used 3mm Sorbothane sheet to stick the nutube to the board and I have not noticed any microphonic effects. Good job, Nelson and DIYaudio ( thanks to 6L6 for the build guide also )
The pcb is of very good quality. The diyAudioshop sent it very fast. Included JFETs are matched very well.
How does it sound? - Beautiful! Absolutely no hum or noise. Open wide soundstage. Interesting possibility
to adjust positive and negative 2nd harmonic. Together with my BA-3 poweramp great.
This little soundmachine is a giant!
Dirk / cubicincher
This preamp looks so tiny - but the sound is giant!
The pcb is of excellent quality, as well the matched JFETs. I would say it is not difficult to build.
Delivery time from diyAudiostore was very fast. Well packed.
How does it sound? - Fantastic! The possibilty to adjust the harmonic profile is a very cool gimmick.
Build it - Test it - Enjoy beautiful music with it!
Plays wonderful with my BA-3 poweramp and others.
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