Class A matched SE J-FET stereo buffer kit revised and improved PCB layout!

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Note on 15th Apr 2015 : We will now ship the kit with Aerovox 1.5uF film cap. on the coupling path instead of Siemens capacitors. We tested on LCR meter and verified that the Aerovox has same ESR performance as Siemens and with 1.5uF value the low frequency limit is extended further.


Note on 5th May 2013 : Due to the scarcity of the buffer J-FETs, Toshiba's 2SK170, we have to raise the price of the kit inevitably. Even the price is raised, the supply is limited and we may stop the kit at any time. So don't miss the chance when supply is still here !!

Note on 22 Sept 2013. This kit is back to stock now. We now ship the kit with the new version of PCB. Improved signal routing, improved grounding, better performance !!

This is a kit of a pure class A buffer amplifier, with reference to the B1 audio buffer.


The design takes minimalist approach, single-ended configuration for warm and clean sound with the output loaded by current source for optimal performance.

The kit contains all the on board components EXCEPT the power supply filtering capacitors. Components included in the kit are :

1. Matched( matched to 100uA or less !), low noise rare Toshiba J-FETs 2SK170BL 2 pairs;

2. non-polar low loss Acrontronics MKP 10uF capacitors and Aerovox 1.5uF film capacitors for coupling purpose.

3. Dale metal film resistors;

4. 10K dual gang volume pot ;

5. 2mm thick and 75um copper thick PCB ;

6. LED and diode, terminal blocks for easy connection .

The board requires dc supply input of +18V, 200mA to operate.

PCB dimension : 170mm x 74mm.


PCB thickness : 2mm.


Copper thickness : 75um !!( 4 times normal thickness)