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Old 1st December 2012, 11:23 PM   #321
beetle is offline beetle  Germany
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Found it. Wrong cap. Will fix it tomorrow.
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Old 2nd December 2012, 12:40 AM   #322
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I can read brain waves C:

I fact it is always the same sh.....
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Old 2nd December 2012, 11:59 AM   #323
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Quote:
Originally Posted by Bksabath View Post
I got pupu load of 327 (FEW UNDREDS) with HFE above 540 and few undreds 337 with with HFE around the 500 mark
PM on its way.
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Old 2nd December 2012, 12:40 PM   #324
FdW is offline FdW  Netherlands
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Quote:
Originally Posted by beetle View Post
Found it. Wrong cap. Will fix it tomorrow.
That's easy done!
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Old 2nd December 2012, 01:17 PM   #325
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For some reason the SK170 in my output buffer fails to properly bias - gate stays positive and output offset fluctuates randomly within a hundred or so mV. Have not yet hooked a scope. Apart from that all other dc levels read fine.

Scratching my head...
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Old 2nd December 2012, 02:53 PM   #326
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What DC voltage do you measure between drain and source of the 2SK170 ?
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Old 2nd December 2012, 03:00 PM   #327
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1v in one channel and 2.3v in the other. Vgs is slightly positive in the first channel
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Old 2nd December 2012, 03:06 PM   #328
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Then the J310 cascode Fet does not provide enough voltage over the 2SK170.
When the Vds voltgae over the 2SK170 falls under a certain threshold there is not enough Vgs left to make the 2SK170 conduct negative.
Search for the highest voltage J310 you can find and use them as the cascode transistors over the 2SK170. This is simply bad luck.
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Old 2nd December 2012, 03:08 PM   #329
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Highest voltage?
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Old 2nd December 2012, 03:12 PM   #330
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I also experimented a bit without the servo or the output buffer. Quite serious random DC fluctuations at the transconductance riaa node. The servo manages to calm these down but because of the integration there is still up to a 100mV dc at output at times even with the servo on. Could this possibly be normal?
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