John Curl's Blowtorch preamplifier part II

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What I found most interesting is the model in figure 1. The addition of 2 resistors can change a marginal circuit to something more acceptable.
The whole 'current dumping' concept has not become as popular as its potential to reduce distortion would seem to make it, because the ACTUAL circuitry is compromised just to keep the distortion within a specified limit.
Yet, it is a 'something for nothing' approach, and is interesting to understand why.
 
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The last work I’ve seen on current dumping is by our Dimitri diyAudio - View Profile: dimitri from 1995.

Theory, analysis, new approach, practical circuit. :up:

George
 

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I don't think anyone knows that more than 25 years ago Tom Colangelo came up from Connecticut uninvited to interview and HR had no one else but me interested in audio enough to talk to him. He was very nice and energetic and he showed me all the Levinson designs he had done (I think it was the 23 that he was most proud of). In the end IIRC making the transition from discrete to IC's would have set him back too far into learning mode. I remember being very sorry, he was such a great guy but I had to do do what was best for the company.
 
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Resistors have two kinds of noise: First is the noise related to the resistors value.
The second is primarily activated by DC voltage across the resistor. Passive crossovers usually suffer mostly from the first noise called: Nyquist noise. Since most passive crossovers operate at line level, the problem is minimized.
 
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