Re: Re: SOS, different day.......
Move it to Texas for all I care. The topic is about overshoot and ringing and blowing up mosfets if you build stuff based on irresponsible advice. Please
don't talk to me about credibility and proving anybody right or wrong. This is a discussion about good design, reliability, and understanding how circuits work..... you know, the whole purpose of the forum when people actually cared about the content. I don't think it is a personality contest or a credibility contest. If disscussing the real merit and liabilities of a circuit belong in Texas while those who make it up as they go along are ignored. as harmless, God help the future of this forum as anything but an audio chat room or an unmoderated newsgroup. Some of us have worked pretty hard to keep that from happening. But if we are
going to be the victums of personal vendettas and behind the scenes scheming for telling someone they are wrong, it is a lost cause to make any effort at all here and the lowest common denominator will have total say . You will have run off anyone who attempts growth or any disscussion that might happen to be over somebodies head and make them feel threatened when they post nonsense and are confronted about it.
Peter Daniel said:
Move it to Texas for all I care. The topic is about overshoot and ringing and blowing up mosfets if you build stuff based on irresponsible advice. Please
don't talk to me about credibility and proving anybody right or wrong. This is a discussion about good design, reliability, and understanding how circuits work..... you know, the whole purpose of the forum when people actually cared about the content. I don't think it is a personality contest or a credibility contest. If disscussing the real merit and liabilities of a circuit belong in Texas while those who make it up as they go along are ignored. as harmless, God help the future of this forum as anything but an audio chat room or an unmoderated newsgroup. Some of us have worked pretty hard to keep that from happening. But if we are
going to be the victums of personal vendettas and behind the scenes scheming for telling someone they are wrong, it is a lost cause to make any effort at all here and the lowest common denominator will have total say . You will have run off anyone who attempts growth or any disscussion that might happen to be over somebodies head and make them feel threatened when they post nonsense and are confronted about it.
This wasn't exactly my intention and your argument has a point, but it simply shouldn't be streched this long and to such an extend in the original "One transistor Clapping" thread, as it prevents other members from discussing the main topic. And this is all I wanted to point out.
We all know that you have substantial knowledge and experience in that area, and that you care about the forum, but what is going on in last few days in this particular thread is not right by any standards.
Maybe instead of moving it all to Texas (which was just a loose suggestion) we could open a new thread about the exact content discussed by you and SE and everybody could be happy (and satisfied). As everybody know already, moderators are not here to disturb, but to help and organize. I hope there is no bad feelings left
We all know that you have substantial knowledge and experience in that area, and that you care about the forum, but what is going on in last few days in this particular thread is not right by any standards.
Maybe instead of moving it all to Texas (which was just a loose suggestion) we could open a new thread about the exact content discussed by you and SE and everybody could be happy (and satisfied). As everybody know already, moderators are not here to disturb, but to help and organize. I hope there is no bad feelings left
Re: Do not resuscitate
No, Fred. The only secondary inductance seen by the source is the secondary leakage inductance, which is a series inductance, not a parallel inductance.
And the source will see that leakage inductance as 1 over the square of the turns ratio. So for a 1:5 step up, the secondary leakage inductance seen by the source will be 1/25th the leakage inductance, not 25 times the leakage inductance.
Do you recall your reminding me that reducing the impedance of a capacitor is the same as increasing the capacitance? Well it works just the opposite for inductance. Reducing the impedance of an inductor is the same as reducing the inductance.
So what the source sees is the shunt primary inductance and the series secondary leakage inductance with the secondary leakage inductance having been reduced by a factor of 25. Not multiplied by a factor of 25.
Sure. But that doesn't change the fact that transformers such as the 13K7-A are very effective RF filters.
And again, your original concern was over signal transients causing overshoot due to the resonance of the high secondary inductance (which apparently you still don't quite understand) and the input capacitance of the MOSFET.
I think I've shown sufficiently that given the small Q resonance of the 13K7-A coupled with the fact that in a source follower your gate-to-source voltage isn't going to be your input voltage, this is never likely to be any sort of a problem.
Again, I'm not saying clamping diodes are a bad idea. I just don't see that the lack of clamping diodes is any reason to go
and go beating people over the head about it like some self-righteous thug. Particularly when you single out just one person to beat over the head while wholly ignoring those who have done the exact same thing.
se
Fred Dieckmann said:
No, Fred. The only secondary inductance seen by the source is the secondary leakage inductance, which is a series inductance, not a parallel inductance.
And the source will see that leakage inductance as 1 over the square of the turns ratio. So for a 1:5 step up, the secondary leakage inductance seen by the source will be 1/25th the leakage inductance, not 25 times the leakage inductance.
Do you recall your reminding me that reducing the impedance of a capacitor is the same as increasing the capacitance? Well it works just the opposite for inductance. Reducing the impedance of an inductor is the same as reducing the inductance.
So what the source sees is the shunt primary inductance and the series secondary leakage inductance with the secondary leakage inductance having been reduced by a factor of 25. Not multiplied by a factor of 25.
Sure. But that doesn't change the fact that transformers such as the 13K7-A are very effective RF filters.
And again, your original concern was over signal transients causing overshoot due to the resonance of the high secondary inductance (which apparently you still don't quite understand) and the input capacitance of the MOSFET.
I think I've shown sufficiently that given the small Q resonance of the 13K7-A coupled with the fact that in a source follower your gate-to-source voltage isn't going to be your input voltage, this is never likely to be any sort of a problem.
Again, I'm not saying clamping diodes are a bad idea. I just don't see that the lack of clamping diodes is any reason to go
and go beating people over the head about it like some self-righteous thug. Particularly when you single out just one person to beat over the head while wholly ignoring those who have done the exact same thing.se
I hate to tell you this, Peter, but I came to this website to escape SE. He has dogged me for years. I knew nothing about Fred, until I came to this website, but this thread has been hijacked, just like you have realized. It is unfortunate, because this website is very 'uptown' compared to many others.
Coming to this website, and its rules of interaction, I have tried to turn over a new leaf, myself, but I seem to get sucked back into the fray. The subject of this thread should be about the different ways to make an 'ideal' single active part, perhaps with supporting active electronics , power amp of modest power. The Vfet idea is better with a common source design, the mosfet follower for a unity gain amp design. The transformer is there to provide extra gain, and could be replaced by a transformer based volume control. This would make sense in many set-ups. Well, enough for now, can we get back to the subject? ;-)
Coming to this website, and its rules of interaction, I have tried to turn over a new leaf, myself, but I seem to get sucked back into the fray. The subject of this thread should be about the different ways to make an 'ideal' single active part, perhaps with supporting active electronics , power amp of modest power. The Vfet idea is better with a common source design, the mosfet follower for a unity gain amp design. The transformer is there to provide extra gain, and could be replaced by a transformer based volume control. This would make sense in many set-ups. Well, enough for now, can we get back to the subject? ;-)
fdegrove said:
S&B had one that you could wire up as 1:1 or 1:2. But I think they stopped making it.
Since preamps typically have about 20dB of voltage gain, and since Fuling only wanted 5-6 watts to begin with, a simple follower would do.
P.S. Steve, there are some more places where you could tack on some diodes.
I know, but I ran out. So I decided to just cover the most important parts. Should have some more in early next week.
se
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