F5T Pre-amp + FDA-2A AD1955 DAC in one box

This is a pre-amp plus a FDA-2A in one box.  It was built in year 2012.  I use a old Yamaha DA8X box to house eveythings insides.  See the pdf files at bottom for details. DAC: FDA-2A with USB, Optical and AES digital input.  Push button for digital input selection at the front panel. DAC direct output is available in RCA sockets. F5T Pre-amp: Alps volume control from DAC output and note that there is no other analogy input for the preamp. The pre-amp is based on Nelson Pass F5T power amp design and striped down to only one pair…
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Sale for this month (May 2014)

During last week, I manage to have a short trip back HK for few days.  Thus I have limited time to sort out the kits for sales.  Here is what I can offer at this moment. 1. F5T kit A or B in the list.  Total 4 kit A OR kit B is available.  Note the jfets and mosfet are with updated prices. F5T-BOM-Cost-21Apr2014 Link of kit: http://www.fetaudio.com/archives/1725   2. FDA-2A AD1955-WM8805 DAC kit is only available for 2 sets.  HKD$1550 each. Links: http://www.fetaudio.com/archives/1666   3. Toshiba K1530 / J201 pairs (not match).  This single pairs is good for bulding a mini…
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Sales Announcement Update

Date: Revised on 23rd Mar 2014 Toshiba 2SJ74BL and 2SK170BL match pair for sales: (NEW PRICES from 1st Nov, 2013) 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. 2SJ74BL : HK$160/pair (about US$22 – 2 pcs) or HK$320/quad (about US$44 – 4 pcs). Idss 6.4 to 11mA. 2SK170BL match quad : HK$100 (about US$13 – 4 pcs). Idss 6.4 to 9mA only. Note that Idss of K170 at 10mA and above is basically not available.  If found, the price is HKD$100 each. Unmatch will be same price as match above.  Only BL grade…
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Toshiba 2SJ74BL measurement

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,…
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F5T Turbo Power Amplifier kit for sales

Those who had brought my F4 kits few years ago can purchase this kit or boards for a quick conversion from F4 into F5T because all the holes and mosfet locations will be same as the F4 pcb.  The optional MUR3020W can be obmitted if not use.   If F4 buyer has the original IRF9240/240 power mosfet, it can be re-used. The To-92D transistor are Toshiba 2SC2705Y/2SA1145Y rated at 800mW and thus it is very safe to use at 60 deg C environment for less than 200mW dissipation.  It would survive safely under a maximum supply voltage of +/-32V.  The…
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