Archive for the ‘Shop’ Category

Sales update

Monday, January 22nd, 2018

22 Jan 2018


MOSFET: Toshiba 2SK1530-Y/2sJ201-Y pairs for sales:

NNN-PPP 3 pairs, match NNN and PPP only: HK$600.  AVAILABLE

NNNN-PPPP 4 pairs, match NNNN and PPPP only: HK$800. AVAILABLE

Note that there is no NP match but those order early may have Limited stock!



Toshiba K170BL – only 6.5mA to 9mA (HK$100 for 4 pcs)

Toshiba J74BL – 6.4 to 10mA (HK$110 each pc); >10.5 to 11.2mA (HKD$75 each pc)

Toshiba K170 / J74 pair HK$150 each pair (6.8 to 10mA).  Limited stock!

Note all jfets can be matched to maximum 4 pcs in one group of same channel type.  Example NNNN, PPPP, NNPP, and NNNNPPPP.  All within 0.2mA Idss tolerance.

Thank you for all the support! 

Due to my daytime job and out of country most of my time, I can only ship once a month.  Please email to me for any inquiry.

Toshiba 2SJ74BL measurement

Thursday, January 3rd, 2013

Many diyers have been buying some fake 2SJ74 from China sources or even from US source and thus some of them ask me for the measurement curve of this genuine Toshiba part.  Here is the file which you can enlarge to see the curve and estimated Yfs (gain) of the part.  The jfet selected is at about 10.8mA Idss (top curve).  The setting of Tek 577 is highlighted for easy reference but you can zoom in the pdf to see actual setting of equipment.


Note that the part is laser marked as it is new part production in 2008, probably the last production batch in Japan.  For ink mark, those are very old part that I have sold before – 2SJ74V.


You may notice that I have increased the price from 2013 because there are not too many stock left for sales.

J74 measurement

WM8804 to CS8412 converter board for D1V3 & D1V33 new upgrade

Monday, July 23rd, 2012

I have sold hundreds of D1V3 & D1V33 few years ago but I have not forgot continue support for this classical DAC using the best R2R PCM63 DAC chips and Jfet IV common gate topology.  There is a new life to the old classic DAC if you upgrade the receiver from CS8412, CS8414, or DIR9001 to WM8804 which many diyers as well as hi-end audio professionals are all agreed to its best sound performance.  Now this WM8804 to CS8412 converter board is available for sales for just HK$250 net (about US$32).  It is fully assembled and tested with no extra shipping and paypal fee.  I believe it is the best news for all D1V3 and D1V33 users as well as other DAC users because this converter board can output 4 digital modes and thus it can meet most DAC technical needs.

16-bit Right-Justified Mode
24-bit Left-Justified Mode
24-bit I2S
16-bit I2S

Please take note that there is a chance that this converter may not work perfectly or even not working in other DAC platform as there is no 100% compatibility due to different chips in different time of history.  But as usual, I shall advise my best guess after reviewing the DAC circuit before you buy and provide remote trouble shoot support as usual.  So take your own risk when using this in other DAC and I will not accept any return unless the converter is DOA.

Technical details: WM8804 to CS8412 Converter Board Technical Details 3

8804_8412 circuit diagram

New FDA-1B Full Balance PCM1794A DIY DAC kit

Saturday, July 7th, 2012

See Store page for NEW PRICES.


This FDA-1B PCM1794A DAC is an upgraded version of the obsolete FDA-1 Single Ended DAC.  FDA-1B has been developing for 1.5 years since FDA-1 was selling. More than 7 version PCBs have been tested before launching to DIYers. It has improved all the weaknesses of FDA-1 and added additional features and functions to enhance the sonic performance and flexibility of the design. Thus it is a more complete and mature design with separate Front Panel control board, I2S input via RJ45 socket and optional ASRC function via daughter board plug-in!


Since it is a DIY DAC and thus most of the parts are selected to be through-hole parts except the ICs and some film capacitors.  In fact most of the film capacitors pad are designed with both SMT (Surface Mount Technology) and TH (Through Hole) pads/holes and thus user can make a change in case better parts is available on hand.  In the I/V section, all TH resistors and some filter capacitors are also provided with a SMT pads in case people want to try the SMT parts.  For the digital section TH resistor pads can also be soldered with a 0805 SMT resistor due to its pitch is 2.54mm. Thus this PCB design is really remarkable and flexible for DIYers to experiment with different types of part for sound tuning!


For the Front Panel control board, it is mainly SMT parts with TH for LEDs and sockets.  Thus it provides a good basic training for all DIYers for SMT soldering.  In fact, SMT parts (with size 0603 and above) are easier and faster to hand solder than TH parts after managing the skills.  What you need is just a 5x magnify glass with stand, small head tweezers, 0.4mm to 0.5mm diameter solder wire and your two stable hands.


New update manual Rev 2: FDA-1B DAC Manual_r2a

This file help to locate all difficult to find resistors, capacitors and diodes: 15c-Part_Location

Go to Store page if you want to buy this kit.

Here is some photos of the FDA-1B DAC kit.

Note that ONE type of I2S input daughter board with RJ45 socket will be provided free.  There are 3 type RJ45 pin assignment boards that can be selected during order – Fetaudio, Kingrex and M2Tech.

The pin assignment can be found in attached document:


SSOP28 to DIP28 converter kit

Sunday, March 28th, 2010

This is a converter board SSOP28 to DIP28.  Two pin header is included in the kit and please see the photo.

This is good for IC such as WM8805, PCM1792, PCM1794, PCM1798, SRC4192, AD1896, AD1955, DIR9001, CS8416CZ etc….  Very good and easy to test out a new SMD IC with same packaging.

Shipping is HK$31 to worldwide.

Stock available in Price List.