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Old 26th February 2013, 05:50 PM   #271
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Even if Nelson gave us the schematics ( the Russian asteroid hitting me was more likely) a number of the semiconductors are made for Pass Labs and others are End of Life so we are all out of luck here, except Wayne and Nelson who deserve some income and intellectual property protection.

So the big question is when is the pool party at Nelson's - assuming his wine cellar has been restocked since Zen Mod was there.........

Last edited by ticknpop; 26th February 2013 at 05:52 PM.
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Old 26th February 2013, 05:52 PM   #272
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Default Cascoded Amplifier

There was talk in past posts about cascoding. I apologize to DIYers for asking late cascode questions which have already been asked and fully answered. The attached image shows a schematic which utilizes the cascoding practice of the transistors in the dual BA3 Front End schematic of post #225. Looks cluttered, may have a typo or several; but is actually simple to follow. Choose your wine. Classic cascode as in the FW article ZV8, or modulated cascode as in ZV9, or CLF [Xs amp literature] or mix and match.
  • The current schematic like its uncascoded parent appears to approach an absolute symmetry of topology. Everywhere one looks, there are identical and complemetary mirror components [ in an ideal world].
  • Some may refer to the negative feedback used in both schematics as Schade Negative Feedback. I prefer to call it Pass Negative Feedback which is specific to solid state devices. BTW, Pass Negative Feedback also appeared in Figures 1 and 2 plus the front page of US 5,376,899.
  • But; this is a second distinct type of Pass Negative Feedback. It emanated from a second mirror [or identical] current source output [opposed drains of Right amp], crossed over and terminated at the summing port of the Left amp. And ditto for the reverse situation. A simultaneous double crossed Pass Negative Feedback.
I hope that the above is food for thought, entertaining, and not hogwash. Also, the above and its attached schematic have no connection at all to the guts and operation of the Pass Labs Xs amps. Thank you for your stimulating contributions in this thread.
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Old 26th February 2013, 05:53 PM   #273
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Got too many transistors in there. I thought Schade was postive.
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Last edited by buzzforb; 26th February 2013 at 05:56 PM.
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Old 26th February 2013, 05:55 PM   #274
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Quote:
Originally Posted by ticknpop View Post
Even if Nelson gave us the schematics ( the Russian asteroid hitting me was more likely) a number of the semiconductors are made for Pass Labs and others are End of Life so we are all out of luck here, except Wayne and Nelson who deserve some income and intellectual property protection.

So the big question is when is the pool party at Nelson's - assuming his wine cellar has been restocked since Zen Mod was there.........
Your not counting big pool in back yard...with whales?
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Old 26th February 2013, 05:59 PM   #275
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Quote:
Originally Posted by buzzforb View Post
Got too many transistors in there. I thought Schade was postive.
Gone all the way with transistors. Others may wish to clarify the polarity of Schade Feedback.
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Old 26th February 2013, 06:04 PM   #276
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[QUOTE=ticknpop;3387219]Even if Nelson gave us the schematics ( the Russian asteroid hitting me was more likely) a number of the semiconductors are made for Pass Labs and others are End of Life so we are all out of luck here, except Wayne and Nelson who deserve some income and intellectual property protection.

QUOTE]
I agree. Copying the excellence of Mr. Pass, and Pass Labs amps will be a foolish exercise, and futile.
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Old 26th February 2013, 06:11 PM   #277
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Quote:
Originally Posted by ticknpop View Post
assuming his wine cellar has been.........
chicken-stock'd more likely.
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Old 26th February 2013, 06:15 PM   #278
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Originally Posted by Antoinel View Post
Copying will be a foolish exercise
For the pounds, not the parts.
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Old 26th February 2013, 06:37 PM   #279
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Quote:
Originally Posted by jacco vermeulen View Post
For the pounds, not the parts.
We, audio DIYers are not the competition, or pose a competitive threat to Pass Labs. Whatever its practices are [stocking EOL parts; not publishing schematics etc..], they are meant to protect itself from the other big Audio players like KRELL etc.. A prudent business foresight.
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Old 26th February 2013, 06:39 PM   #280
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If he felt this way, He would have released the schematics of his amps, like XA, XA.5, M2, J2. He has not done so. There is a reason.
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