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Selling Zhou Fang’s remaining stocks including some very rare Toshiba transistors

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liubincalvin

Member
Joined 2015
Opening up these metal cans of j75 to get j74 is really pain in the a***** [emoji23][emoji23][emoji23] really a waste...
unfortunately, more people (>90%) are interested in j74 rather than j75. One thing I noticed is that the two j74 matching within a j75 (as well as j109) is generally far worse than what I get from manual matching of individual j74. Toshiba had very relaxed spec. It is not feasible to have very stringent spec for mass production of such fets anyway.

e79cb81f81ee2fb7fc353a22ef3616b5.jpg
 
M

MMAdams

Member
Joined 2013
Borbely Class-A 50 Watt

liubincalvin said:
Still working on the hundreds of j74 matching...[emoji30]
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liubincalvin said:
Hi Steve,

Thx for letting me know. It is faster this time:D
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ticknpop said:
For Borbely amp match all the N's to other Ns and the P's to all the other P's. You don.t need to match P to N ( but nice if you can get it) if you can't get good matches use .1 or .22 source resistors.

Which Borbely 50 watt? Easy to convert early Borbely 50 watt to Borbley ribbon 50 watt or even Millenium with a little pc board surgery
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Can you give me a total for 12 each of K1530/J201 with matching of Ns with Ns and Ps with Ps and without matching. Please include all charges.

Please ignore my direct eMail regarding this purchase.

Thanks.:cheers:
 
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liubincalvin

Member
Joined 2015
Report a dishonest buyer

This is to report a dishonest buyer in the forum. Forum ID: LinearJim, register on 28th November 2016. Vendors pls be careful when dealing with him (not even sure whether he would use the same ID to make orders though).

Event timeline for easy read:

  • 1 Dec 2016, he placed an order with me.
  • 7 Dec 2016, Parcel was dispatched to Canada.
  • Jan 2017, several communications about the parcel not arriving and he requested for full refund. Somehow Canada postal service was extremely slow during that period of time.
  • 31 Jan 2017, I sent him the full refund by starting a new paypal transaction, as I was not aware I can just click “refund” at his previous paypal transition history. He later told me that he was charged with paypal fee and was very unhappy about that.
  • 10 Feb 2017, I gave him another refund, so he will not be charged with any paypal fee. I did this even before I got the first refund back from him.
  • 17 Feb 2017, parcel was delivered, per Singpost’s email.
  • Somewhere during Feb 2017, he sent PM to a forumer, making false allegations about my reputation (not refund to him, no tracking of his parcel, etc). I was just informed today by a kind forumer. The truth is full refund was given to him, and I kept him updated with emails from Singpost. Frankly, I don’t understand what his intention is by sending that nasty false allegation…I already did what I could to settle the case…I don’t know what else I could do better.:confused:
  • May 2017, several attempts from me of trying to contact him to get the MOSFETs back or payment. No responses from him until now. I am pretty sure he can read the message from paypal if he did not log in here, as he was rather responsive when I sent paypal message previously.

Basically, this guy’s dishonest behavior is the main reason I changed my shipping policy about the refund for non-insured parcels.

Unless he can come out here to prove me wrong, it appears to me that he took the MOSFETs and disappeared, besides making the false allegation about me. Making false allegation is something I CAN NOT tolerate!. :mad:
 

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M

mt490

Member
Joined 2010
liubincalvin said:
ok, just some following up about B737. I was wondering whether good BTJ are really similar, so I compare the curves from the B737 and a few common BJT in the market. Here are the plots. Luckily, they look quite different :D:D:D Some have different ideality factor, some have different Vbe(on), etc...

Anyone knows other BJT which could have close Ic vs. Vbe to B737? I will be interested to compare them.
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The B737 is somewhat closer to a 'switching driver' device like a 2SB1215 or 2SB1561 than it is to what we might call small signal devices these days.
 
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liubincalvin

Member
Joined 2015
SingPost parcel insurance policy below. Kindly read it if you want to insure for your parcel. Take note by insuring the parcel, you would need to declare the actual value, thus, may be taxed in your country.

Insurance (per Section E, Conv Art PL 138, Universal Postal Union Letter Post Manual)

For extra coverage and higher amounts of compensation in the event of loss, insurance is available to most countries. Insurance coverage is chargeable at S$1.00 per S$100.00 value (minimum insurance premium is S$5.00), i.e. If you want to insure your mail for S$1,000.00, you pay S$10.00.
 
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