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Old 23rd August 2012, 02:06 AM   #41
RNMarsh is offline RNMarsh  United States
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I didn't think it was possible, but if you're not counting current sources, this one has 8 transistors and 1 current source.
Would I ask the impossible?
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Old 23rd August 2012, 02:12 AM   #42
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You guys are a riot. go back and read what Scott said he was interested in doing. What he proposed, pls.
Post from Scott: "I thought from reading the audio reviews Boulder has superceeded the CTC BT anyway with discrete op-amp modules (Dick Burwen did it first but that's another story) and more than doubled the price point. So I think we should do a group discrete op-amp and give it free to the community." {my bold}
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Old 23rd August 2012, 02:14 AM   #43
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Originally Posted by RNMarsh View Post
Would I ask the impossible?
May I ask why 30 ohms? I think opamps are usually spec'd for 600 ohms.
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Old 23rd August 2012, 02:23 AM   #44
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So the first two transistors are BF862? That just leaves 6 to go... Output stage anyone?
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Old 23rd August 2012, 02:26 AM   #45
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Old 23rd August 2012, 02:26 AM   #46
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That is more then 6, i know.
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Old 23rd August 2012, 02:36 AM   #47
bcarso is offline bcarso  United States
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So the first two transistors are BF862? That just leaves 6 to go... Output stage anyone?
I could tell you, but I'd have to kill you

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Old 23rd August 2012, 02:39 AM   #48
bcarso is offline bcarso  United States
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Originally Posted by Joachim Gerhard View Post
That is more then 6, i know.
Back when transistors cost a lot of money, circa 1970, I had a "supervisor" (a grad student with an instrumentation bent --- I was hired so he would have to focus on his dissertation) who got to the point that he would specify how many of them I could use.

Transistors, most of them, are not that expensive anymore. And most are also very good.
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Old 23rd August 2012, 02:41 AM   #49
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Just for fun how about lateral MOSFET output stage? Charles Hansen swears by them I don't know how available they are though, perhaps CH already cornered the market.
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Old 23rd August 2012, 02:46 AM   #50
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Semelab makes laterals that are similar to Hitachi-Renaisas. They are quite big but can be used in line stages too.
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