New Update

March 23, 2014 - filed under: Shop

Dear all DIYers and Buyers,

Due to my work, there is further delay of the sales of DAC, F5 kits and other components like 2SK1530/2SJ201 matched pairs/quads in 2014.  I hope I can arrange some stuff before second half of 2014.


Anyway the sales of 2SK170 and 2SJ74 BL grade will continue as before.


Thank you for all your support.

Spencer Cheung

23rd Mar, 2014

Sales Announcement Update

February 15, 2013 - filed under: Shop

Date: Revised on 23rd Mar 2014

Toshiba 2SJ74BL and 2SK170BL match pair for sales: (NEW PRICES from 1st Nov, 2013)

  1. 2sk170BL/J74BL match pair HK$120/pair (Pair = K170 x 1pc  and J74 x 1 pc)  (about US$16). Idss 6.4 to 9mA only.
  2. 2SJ74BL : HK$160/pair (about US$22 – 2 pcs) or HK$320/quad (about US$44 – 4 pcs). Idss 6.4 to 11mA.
  3. 2SK170BL match quad : HK$100 (about US$13 – 4 pcs). Idss 6.4 to 9mA only.
  4. Note that Idss of K170 at 10mA and above is basically not available.  If found, the price is HKD$100 each.
  5. Unmatch will be same price as match above.  Only BL grade of above jfets are available.


Shipping is HK$35 (US$4.5) to worldwide by registered airmail and paypal fee 5.5% (4.5% for purchase amount >= HK$500). All matched within 0.2mA Idss @ 10Vdc.  Maximum match is 4 pcs K170 and 4 pcs J74 with same idss match together in one group.  Note that the temperature at measurement is about 28 to 30 degC in Singapore.

There is further delay for the sales of other kits and parts.  Tentatively it will be by 2nd half of 2014.

Thank you for all the support.

Toshiba 2SJ74BL measurement

January 3, 2013 - filed under: Gallery,Shop

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

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