Look at it there is no problem 🙄
There is in two cases:
-with the cap referenced to ground (internals are to the reference point like this)
-without R7 and R2, Q5's collector connected to Q8's gate
Everytime there is a way and everytime its the simplest 😉
FET linearity is better and they sound better 🙂
They have high input impedance too, and dont need drivers too.
Sorry, but you don't know what you're discussing, and that schemo is absolutely HIDEOUS. As I pointed out in the above post, Douglas Self investigated this linearity question, and decided it in favour of BJTs.
"They have high input impedance too, and dont need drivers too". MOSFETs have high input impedance under static conditions. This is why MOSFETs are preferred for logic gates that need to hold their states: they draw such small currents that a small battery can keep them powered up for years. Even a big capacitor can keep them going for days or even weeks at a time. It's a whole 'nother story when those gates need to change states.
After all, the "MOS" stands for: metal, oxide, semiconductor. What does that give you? A capacitor. If vgs is to keep up with the input signal, then that gate capacitance needs to charge up in a timely manner. The faster you need to charge a capacitor, the heavier the current:
i(t)=C(dV/dt) -- very elementary
Under dynamic conditions, the input impedance can become quite low, and you will be needing a stiff driver.
@Mosfet54
I see you have raised much the same query here http://www.diyaudio.com/forums/solid-state/287458-very-good-mosfet-design-failure.html
You have been given plenty of advice on problems and what to do.
You seem to be more intent on defending your design decisions where most people would reflect on these and study the alternatives suggested.
You should see this as a collegial approach to problem solving rather than a contest between adversaries.
I see you have raised much the same query here http://www.diyaudio.com/forums/solid-state/287458-very-good-mosfet-design-failure.html
You have been given plenty of advice on problems and what to do.
You seem to be more intent on defending your design decisions where most people would reflect on these and study the alternatives suggested.
You should see this as a collegial approach to problem solving rather than a contest between adversaries.
I think they werent't linear but now they are better than BJTs.
And what if use this capacitance for ur good using it as LPF.
With 47n and 100 ohm = 34kHz corner freq.
How a LPF can sink ur signal which is with a very small current ?
I think this is magic because without this resistor it should be sinkable as u said 🙂
On another hand one could parallel drivers like the mosfets 😉
Ofcourse capacitance is not good for a signal unless its used for a filter 🙂
Ofcourse capacitance is not good for a signal unless its used for a filter 🙂
I talked about complementary pair, not quasi..
Look @ the example, I simulated two OPS-es and this monster start clipping @ +-73V delivering up to 442W 😱 😱😱 😱
Im gonna open thread because this is MONSTER
Not a monster at all. 442W from a bridged amp is not special at all. Most can easily get +/- 73V from a single power amp. It's just a case of having output devices with sufficient voltage rating (+ power dissipation) and high enough voltage rails.
One bit of advise. Please listen to others and learn from what other designers have been doing for decades. If you are so sure of your ideas then stop talking and start building some monster amp and almost certainly waste loads of time and money. Suspect you will end up with an oscillating burning mess.
Only in DIYAudio can a troll get so much attention.
Just sayin' , you do what you please, it's your free time. 😉
Just sayin' , you do what you please, it's your free time. 😉
Its monster since outputs double the supply voltage. The screenshot was just example. These most can output +-146v with same ratings and 73v supply voltage. This is good idea..
Im not going to build a monster @ all because i dont have such speakers.
Im going to build small model which outputs +-12v with 12v single supply voltage. I like this topology very very.
Relative to what? For what purpose, and which features are better? That, right there, is a great big "that depends".
Once again, you contradict yourself. This is what you posted earlier: "FET linearity is better and they sound better. They have high input impedance too, and dont need drivers too". The only devices to which this applies are vacuum tubes (and VTs still have internal capacitance that needs charging fast enough to follow the input). That "100 ohms" isn't just the physical resistor on the circuit board. It also includes the Zo of whatever's driving it. If that Zo is significantly higher than 100R, you don't have a 34KHz LPF. If your Ci is 47nF, you definitely need a Lo-Z driver with good current sourcing capability. There's no getting around that.
Same as any other load:
i(t)= vi/( R - (j/wC))
"I think this is magic because without this resistor it should be sinkable as u said 🙂"
We don't do "magic" here.
@mosfet54
Here is a link to some study material https://www.google.co.nz/?gfe_rd=cr...ctical+electronics+handbook+pdf+free+download
Here is a link to some study material https://www.google.co.nz/?gfe_rd=cr...ctical+electronics+handbook+pdf+free+download
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