I think you missed the point.
All Mountain Lions are Cougars, but not all Cougars are Mountain Lions.
The difference is just a set of epigenetics triggered somehow. Again, not sure what causes it. It's similar to the difference between a domestic pig and a wild pig. The only difference between those two pigs is that one is wild and one is domesticated; they have the same DNA, and could potentially have the same mother or grandmother. Something triggers the difference. (I suspect it's the non-industrialized water, but that's another subject)
So I'm not saying your story isn't true. I'm saying you should call it a Cougar because until it is an adult you won't know if it'll hit that epigenetic shift that turns it into a Mountain Lion.
Where I grew up there are a lot of Cougars, and some Mountain Lions. The state out lawed hunting with dogs, which had a pretty severe rubber band effect. Basically they over populated IN A HURRY. There were a lot of news stories about Cougars wandering through playgrounds of schools, in people's yards, eatings dogs, etc. Some old lady even walked backward for a mile as one was hunched down to attack as soon as she turned around and exposed her back without her cain/walker.
There was even one in my neighborhood in town, and the police would drive up and down the streets shining lights into alleyways and trees for weeks. Then they hired an out of town "expert hunter" that instead shot someones prized horse, so he left town... The Sheriff whom was a family friend, last I know, had personally shot 8 of them that had take residence in people's covered porches and such (often by removing the dog).
But as common as they were, an actual Mountain Lion was a rare thing. They had territory and the Cougars were the ones that got pushed into town etc. Not everyone gets to see them. Old mountain men in the area don't speak about them as if they are same species, because by site it's like seeing a wolf vs a coyote.
My father was lucky enough to see one cross the road in front of him, while riding his Harley over a mountain pass. It barely even took notice, with a small glance, then casually walked across the road like a boss. My father described him as being golden brown colored that looked like he used shampoo and conditioner, the body alone being at a minimum of 6ft long, and the muscles rippled as walked, showing through the fur, as if it lifted weights. But the attitude really stuck with him, where his rumbling Harley was nothing more than a fart in the wind to this badass Mountain Lion.
My former step father also has seen one. He described it in a similar way. But, because he's crazy as ****, he decided to kill it with his .44 Magnum. He missed on the first shot, and the Mountain Lion started running. He fired again, missed, then the Mountain Lion was approaching a group of trees in a shallow U like shape. He said he shot 3 more times as it ran sideways, from tree to tree , that had a decent gap between them (10, 15ft?) that allowed the cat to basically be at a full sprint. He was so blown away by the intense speed and power that let it run sideways between trees, dodging bullets, that he didn't even fire the last shot because he thought it deserved to live - too majestic to kill - even though the Mountain Lion lined up a shot as it was getting away.
Last edited:
What zero crossing?!
SE amp delivers 5W. No zero crossing!
Zero crossing is pristine clean, like in any other SE amp! Jan, please stop fantasising! Calculate. If load resistance is 8 Ohm, shorting of 2 Ohm in series causes 1.25 of gain. I.e. 1.25 times higher, why 50 or 100?! And it happens exponentially, not abruptly like relay contacts!
I used even 1 Ohm resistor, that means 1/8 of load resistance, i.e. 1.125 of gain change. In class AB amp change in gm is 2 times, when it goes from 2 transistors in parallel to 1, and the region is near zero, and depends on temperature!
Your magazine authors definitely discussed something different, very far from my design, if loop gain was ABRUPTLY changing 50 to 100 times! ;-)
Last edited:
I am referring to the Swinik amp, you have an Q2-Q4 NPN-PNP output stage biased by a resistor, right? The NPN and PNP takes turns in conducting, no? So there is a xover when the NPN just turned off, and the PNP not yet turned on, and vice versa, no?
Or are we talking about different schematics?
Jan
Or are we talking about different schematics?
Jan
They are not biased by resistor. And they are not relays, they are transistors.
Class A delivers up to 0.6V/1 Ohm current to the 8 Ohm load before Q2 or Q4 start assisting. I.e. 0.6V * 8 Ohm = 4.8V in load. It is a SE class A region. When the voltage on the load reaches 4.8V transistors start ASSISting in PARALLEL, adding current exponentially, so at the 50V close to the rail the resistor delivers still 0.8/1 Ohm current, i.e. 0.8A, while Q2 and Q4 ADD to this current 50/8, i.e. 6.25A. Loop gain due to this transistors starting from 4.8V output to 50V output exponentially increases 1.125 times only.
I.e. I have to correct only 12.5% of distortions on full power, not 500 - 1,000 % as you claim.
What happens in class AB amp that corrects 50% of distortions (gm doubling) NEAR MOST CRITICAL LISTENING REGION? Worse thing happens! 4 times worse! And the same transistors with exponential characteristics are used!
Jan, you definitely do not read to understand, you read to argue.
They are not biased by resistor. And they are not relays, they are transistors.
Class A delivers up to 0.6V/1 Ohm current to the 8 Ohm load before Q2 or Q4 start assisting. I.e. 0.6V * 8 Ohm = 4.8V in load. It is a SE class A region. When the voltage on the load reaches 4.8V transistors start ASSISting in PARALLEL, adding current exponentially, so at the 50V close to the rail the resistor delivers still 0.8/1 Ohm current, i.e. 0.8A, while Q2 and Q4 ADD to this current 50/8, i.e. 6.25A. Loop gain due to this transistors starting from 4.8V output to 50V output exponentially increases 1.125 times only.
I.e. I have to correct only 12.5% of distortions on full power, not 500 - 1,000 % as you claim.
What happens in class AB amp that corrects 50% of distortions (gm doubling) NEAR MOST CRITICAL LISTENING REGION? Worse thing happens! 4 times worse! And the same transistors with exponential characteristics are used!
Jan, you definitely do not read to understand, you read to argue.
Well, maybe I am wrong, but is it not true that at one point the NPN is off and the PNP is not yet on and vice versa?
By definition if the NPN is on (+Vbe across 1 ohms), definitely the PNP is off because its B-E is reverse biased. And vice versa. So the NPN and PNP cannot be on together, it is either-or. So there is a hand-over point when the current through the 1 ohms reverses and conduction moves from the NPN to the PNP and vice versa.
BTW My factor 50 to 100 came from the transistor gain. Your calculation of the 12.5% would be correct with a diode across the 1 ohms. But there is a B-E across it, so at the point where the Vbe reaches about 0.65V, Ice starts to flow which means the gain rises massively. (I assume 50 - 100 Hfe).
Jan
No! Massively increases their ability to assist class A amplifier. They do not work by themselves, they are in parallel with 1 Ohm resistor. That's the whole point that you are still missing!
They are both off in most critical region, up to approximately 5W. SE amp delivers pristine clean sound with distortions fading out faster than decay of sounds and reverberation.
On forte-fortissimo when SE amp has no guts they start assisting increasing current addition exponentially creating full joy of listening.
Last edited:
They are both off in most critical region, up to approximately 5W. SE amp delivers pristine clean sound with distortions fading out faster than decay of sounds and reverberation.
On forte-fortissimo when SE amp has no guts they start assisting increasing current addition exponentially creating full joy of listening.
OK. Thanks. I thought we had a technical discussion. My mistake.
Jan
Yes, I was trying. But instead of thinking and calculating you keep repeating what does not matter. For example, you think of class AB amp where output transistors are driven by VAS stage with HUGE output resistance driving their base currents. And of course their Beta impacts dramatically! In the most critical listening region! Here beta does not matter, because in my amp output transistors are driven by class A amp with nested feedback and low output resistance! Do you see the difference now? No? Sorry...
Well since you don't address my concern about the handover between your NPN and PNP, which causes xover distortion, plus the large gain increase when all of a sudden 50 or 100 times the current is turned on, I can only conclude that you do not want to discuss that, but rather go on about how great your amp is and my refusal to think.
And have no doubt that your amp is great, but that's not what I wanted to discuss. And single-sided discussions are rather pointless.
So I will bow out here.
Jan
I can not address your concerns unrelated to my amp. You refuse to follow my explanations. Time to SIM?
Try to simulate 2 cases: class AB output stage driven by a current, and a pair of emitter followers with 1 Ohm resistor between bases and emitters, driven by voltage.
And see for yourself how beta in 1'St case, and it's change with current matters, and how it does not matter in the 2'Nd case.
Try to simulate 2 cases: class AB output stage driven by a current, and a pair of emitter followers with 1 Ohm resistor between bases and emitters, driven by voltage.
And see for yourself how beta in 1'St case, and it's change with current matters, and how it does not matter in the 2'Nd case.
Last edited:
I agree that in this case beta matters much less, but change of beta with current of all 3 EFs are multiplied, and phase shifts added! And resulting gm is even higher, so the problem with voltage biasing of temperature dependent huge transconductance devices higher in power of 3!
I prefer my cats to be skinned by my own methods; as you know I prefer SE on low power levels. Well, in my last experiment I got 45W from SE 2 - stage pentode amp with nested feedbacks, but I pay huge electric bills for such sound quality!
Here, in the amp being discussed, I got a compromise; only 40W of constant class A dissipation for 100W of max output power.
Last edited:
John,
Opamps are usually 4~8mA bias, and hfe of audio power BJTs 100~150.
So the output stage would have ~700mA bias.
And difficult to change (e.g. to 100mA for a headphone amp.)
But why not use MOSFETs and a resistor to bias ?
That way you can choose the bias as you want, instead of what you can get.
Attached schematics is meant for headphone.
Patrick
Attachments
Add to this "bias" technological currents that don't follow output currents, adding dirt to it, and get the whole picture...
Of course, with that simple topology of a single IC and 2 complementary power output devices, you can use power fets instead. It is slightly more complex and not as obviously current limiting, but it could be a good design. You can also increase the voltage swing by adding a couple of Zener diodes between the IC and the output devices.
However, the simplest form of this design actually sounds pretty darn good, so long as you let it run Class A, 250-500ma typically. That is how I ran it for years.
It would be interesting to SIM this design, and also Wavebourn's design, looking for higher order distortion, etc.
However, the simplest form of this design actually sounds pretty darn good, so long as you let it run Class A, 250-500ma typically. That is how I ran it for years.
It would be interesting to SIM this design, and also Wavebourn's design, looking for higher order distortion, etc.
Attachments
Last edited:
- Status
- Not open for further replies.