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Old 15th December 2011, 02:23 PM   #1151
zdr is offline zdr  Belgium
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Ok, thanks! Now I am much less confused
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Old 15th December 2011, 03:04 PM   #1152
AndrewT is offline AndrewT  Scotland
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Roender was brilliantly lucky or brilliantly profligate to get his pairs that closely matched.

I just paid for premium N & P quad matched sets, dearer than N matched pairs and dearer than stock pairs and the supplied items have Vgs that are 120mVgs different. What a waste of my money.

I have still to test them as pairs simultaneously to see whether the N pairs match up and whether the P pairs match up.
I am very doubtful.

If the pair matching is as bad as I suspect I will reveal who sold them.
If the matching even closely approaches Roender's results I will publicly thank the seller for his product and efforts.
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Last edited by AndrewT; 15th December 2011 at 03:07 PM.
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Old 15th December 2011, 03:13 PM   #1153
zdr is offline zdr  Belgium
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You are talking about NJL0281 and NJL0302? Vgs is a typo?
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Old 15th December 2011, 03:22 PM   #1154
AndrewT is offline AndrewT  Scotland
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I am referring to expensive FETs with an enormous on cost for the matching service.
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Old 15th December 2011, 08:14 PM   #1155
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Quote:
Originally Posted by AndrewT View Post
I am referring to expensive FETs with an enormous on cost for the matching service.
As I remember Andrew you bought lots of LSK170 as FETs for this amp?
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Last edited by AndriyOL; 15th December 2011 at 08:25 PM.
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Old 15th December 2011, 09:25 PM   #1156
zdr is offline zdr  Belgium
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Guys, I busted my ba**s setting up Hfe/Vbe measuring jig and got - nothing Results are pretty consistent with DMM values, meaning they only shift for about 20. I tested few NJL0281D that measured Hfe=78 in DMM, and they all turned up as Hfe=98-99, Vbe=616-617, Ib=1mA, Ic=98-99mA on a heatsink at T=23C.

I did not test p ones, but I can probably expect similar results, meaning they will be with a Hfe at least 20 higher than highest npn.

So, back to beginning. I have 20 NJL0281 with Hfe from 66-90, and 20 NJL0302 with Hfe from 120-140 (DMM values). Is this batch usable at all in any combination?
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Old 16th December 2011, 06:08 AM   #1157
roender is offline roender  Romania
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Hi zdr,

May I suggest you to measure the P type in similar manner? ... do not jump to conclusions so fast

Have fun,
Mihai
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Old 16th December 2011, 10:28 AM   #1158
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by AndriyOL View Post
As I remember Andrew you bought lots of LSK170 as FETs for this amp?
Yes, lot's of lsk and now some 2sk and 2sj.
After many long days matching them I made them available to UK Members (easy posting and cheap posting).
But UK Members were hardly interested. My orders came from Europe and the North Americas.
Shame that the vast majority of these carefully matched pairs got wasted in B1 and DCB1, but who am I to argue, the customer is always right.
A few will remember that I tried to dissuade them, some times successfully to not waste their money on matched pairs. B1 and DCB1 only requires selected Idss devices. Matched over a range of Id is a total waste.

For this project matched pairs are very useful.
Let's see if any wake up to the difference between matched pairs and the usual offerings on this Forum that are miss-described as matched pairs when all they are, are selected Idss pairs or quads or whatever.
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Old 16th December 2011, 11:36 AM   #1159
lucylu is offline lucylu  England
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Hi AndrewT Do you have any matched pairs left for this amp (2sk170bl) . regards john


Quote:
Originally Posted by AndrewT View Post
Yes, lot's of lsk and now some 2sk and 2sj.
After many long days matching them I made them available to UK Members (easy posting and cheap posting).
But UK Members were hardly interested. My orders came from Europe and the North Americas.
Shame that the vast majority of these carefully matched pairs got wasted in B1 and DCB1, but who am I to argue, the customer is always right.
A few will remember that I tried to dissuade them, some times successfully to not waste their money on matched pairs. B1 and DCB1 only requires selected Idss devices. Matched over a range of Id is a total waste.

For this project matched pairs are very useful.
Let's see if any wake up to the difference between matched pairs and the usual offerings on this Forum that are miss-described as matched pairs when all they are, are selected Idss pairs or quads or whatever.
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Old 16th December 2011, 12:13 PM   #1160
AndrewT is offline AndrewT  Scotland
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Search andrewt in Swap Meet, before 2010

LSK170, matched pairs in the UK.
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Last edited by AndrewT; 16th December 2011 at 12:16 PM.
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