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Old 27th November 2017, 07:33 PM   #271
generg is offline generg  Germany
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First Watt F7 review

:-))
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and the First Wtt is......a really First Class PSS Idea
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Old 30th November 2017, 03:14 AM   #272
lhquam is offline lhquam  United States
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Why do threads go dead after I make a posting?
The same thing happened with F4 Beast Builders.

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Old 30th November 2017, 05:50 AM   #273
Zen Mod is offline Zen Mod  Serbia
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if no one else , you know I love ya

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Old 30th November 2017, 06:43 AM   #274
generg is offline generg  Germany
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They are already possibly kind of "dead" before you make the last posting.

It is nothing related to you, your contributions are of highest quality and maybe it is not always possible for us "lower level" users to answer.
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Last edited by generg; 30th November 2017 at 06:47 AM.
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Old 30th November 2017, 07:30 AM   #275
2 picoDumbs is offline 2 picoDumbs  Australia
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Quote:
Originally Posted by lhquam View Post
Why do threads go dead after I make a posting?
The same thing happened with F4 Beast Builders.


People like looking at porn more than journal articles.
Hahaha
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"If you leave this point unattached to some circuitry, an ideal constant current source will emit a small lightning bolt which will travel until it connects to something." Nelson Pass
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Old 30th November 2017, 07:36 AM   #276
Zen Mod is offline Zen Mod  Serbia
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Dodosessss

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Old 30th November 2017, 07:46 AM   #277
2 picoDumbs is offline 2 picoDumbs  Australia
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PS: They are not dead it's just that many of us are working on many different projects. I'm always jumping between different projects.
Tomorrow I'm planning on checking out if the ultra fast soft recovery diodes do indeed bring about measurable improvements.
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Old 30th November 2017, 07:55 AM   #278
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yeah

especially with slow speakers , you're using



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Old 30th November 2017, 08:14 AM   #279
2 picoDumbs is offline 2 picoDumbs  Australia
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Hahaha
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Old 3rd January 2018, 02:35 PM   #280
Antoinel is offline Antoinel  United States
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Default Still experimenting with DEF wired in a common gate configuration

Wishing you all a safe, healthy and prosperous 2018.

The attached schematic is another application of DEF. Please note the salient changes it has compared with an earlier one:

1. DEF is biased [idle current] at 120 mA or Class AB instead of ~1.3A. Will it still sound great? Yes is the short answer; because the "performance" of this DEF defaults and/or is cleaned up by the voltage source amp [Threshold S150].

2. When DEF bias is decreased [-Vgs] of the depletion FET [SJDP120R085] becomes more negative in value, and the [-Vgs] of the enhancement P-MOS [IRFP9140] becomes less negative in value; with both of the new [-Vgs] values relative to their high bias states. Suppose one has an "ideal" DEF or DEFiSIT whereby ideal means that both FETs initially share a unique [-Vgs] at a constant PSU value, and a high bias. If [by example] the voltage control which is common to [-Vgs] is made more negative, the [- Vgs] of SIT or R085 moves towards cut off, and that of P-MOS moves towards more conduction. No damage to the devices happens; but the original output voltage quiescent point will drop towards the negative rail and thus alter the initially ~equal Vds values at high bias.

3. The input impedance doubled to ~0.7 Ohms [relative to ~0.3 Ohm in previous exp.] at the joined sources of DEF. This joint common source has an explicit value for use as Positive Current Feedback [PCF]. It generates a voltage signal which is proportional to the current flowing in the bottom loudspeaker. This PCF signal may then be used to alter the performance of the voltage source amp as already known. A still higher-valued PCF signal is available at the output of DEF driving the upper loudspeaker.

4. In a separate experiment DEF was operated at a 10 mA bias. It still sounded good and judged fully agreeable. But the sound of this bias-starved Class AB system changed for the "subjectively better" at the higher bias levels.

5. Not shown in the schematic is a zener [8.4 V] which is connected between the gate of R085 and the joined FET sources. It protects both FETs with a priority for R085.
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