All of these waveforms show gross levels of distortion, 10--30% THD or so perhaps - if you can see distortion this obviously on a graph, its far far above the threshold of audibility for distortion, the ear is a far better frequency analyser than the eye.
That is correct. With the lossy measures such as source resistance, Ud_min > Ugs_max and differential pair as in the Pass F1 circuit, the distortion can be kept below 5% for 1kHz. However, the tendency to demulate the audio signal with increasing frequency will remain. And as you mean, it may not be seen but it will be heard.
I would start with the speakers. It is easier to analyse and modify speakers, because the most is mechanical. For the vast majority of audio freaks, it already fails at the speakers.
This is the basic building block. There are several of them in every NP amplifier. For example, instead of Rd, NP uses current sources that are basically constructed in the same way. Look here, pages 8 and 9: https://firstwatt.com/pdf/prod_f5_man.pdf
If you have an AB amplifier with global negative feedback then I take your word for it... But you could just as successfully try 2SC5200 and 2SA1943.
MOSFET are fast high power devices which allow wide unity gain bandwidth. This means more FB at high frequencies, i.e. low distorsion @20kHz.
But there are fast BJTs to.
But there are fast BJTs to.
CCS makes all the differece. Simulating variants with Rd is misleading.
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The BJT amplifiers are more efficient. The saturation voltage is usually less than 2V. For positive and negative sides it is a total of 4V taken away from the AC output voltage. For linear operation of the MOSFETs, Vd must not be less than Vgs, and the latter is in the range of 4V to 7V. Doubled it is 8V to 14V, which should be taken away from the AC output voltage. Of course you can drive the MOSFETs to full power, but in this case you need a strong global negative feedback to keep THD small.
Even in NP circuit the difference between Vd = +8V and Vgs = +4V is 4V. And +/-4V is just 1 watt on 8 ohms.
Power is overrated (pun not intended). Most of audiophiliac listening requires few watts, rarely up to 10W. Obsessing with clipping behavior and power rating is mostly waste of time.
I disagree.
It is true that average playback levels are lower than many people think, but today recordings have good dynamic range and you frequently find crest factors of 20dBs, so you may be listening at 1W but unclipped peaks will ask for 100W!
Power amps clip and then they are ruled by their open loop characteristics unless they do not used global feedback.
In my humble opinion, this is one of the main reasons of the "transistor sound".
It is true that average playback levels are lower than many people think, but today recordings have good dynamic range and you frequently find crest factors of 20dBs, so you may be listening at 1W but unclipped peaks will ask for 100W!
Power amps clip and then they are ruled by their open loop characteristics unless they do not used global feedback.
In my humble opinion, this is one of the main reasons of the "transistor sound".
The transistor sound was identified in the days of transformer coupled push-pull transistor amplifiers, that's a very different thing perhaps from what we are talking about here.
Headroom against clipping large transients isn't unique to transistors anyhow, and the answer is soft-clipping circuits or pre-processing, or even compression.
Headroom against clipping large transients isn't unique to transistors anyhow, and the answer is soft-clipping circuits or pre-processing, or even compression.
I see a problem somewhere else. Due to the superimposition of the waves, a steep sum signal can occur. As a result, the conventional voltage amplifier cannot ensure the correct thrust for the speaker diaphragm by the current. This makes the sound duller. YouTube offers many videos where guitarists compare transistor and tube amplifiers. You can clearly hear the difference.
I'll try to show it with the simulations. Six sine signals with the same amplitude but with different frequencies (1kHz, 2kHz, 3kHz, 6kHz, 9kHz, 12kHz) are added and amplified. The simulation of the voltage amplifier together with the speaker model:
You can see the deformation of the current signal through the speaker. In my opinion, this is just as bad as the big THD. But tube amplifiers are only partly voltage amplifiers. They partly power the speakers with electricity. I don't do a simulation with the tube amp, but with my current amp to show the effect of driving with the current:
You can see the deformation of the current signal through the speaker. In my opinion, this is just as bad as the big THD. But tube amplifiers are only partly voltage amplifiers. They partly power the speakers with electricity. I don't do a simulation with the tube amp, but with my current amp to show the effect of driving with the current:
LT1010 isn't able to drive your simulated speakers low impedance. Maybe you see the current limiter in action.
BR, Toni
BR, Toni
According to the datasheet, LT1010 can deliver +/- 150 mA continuous. Meanwhile, the maximum current of 52 mA flows through the speaker. In addition, the voltage at the loaded output of LT1010 is measured. I see a nicely curved voltage curve. There are no flat areas. In this case LT1010 does its job perfectly.
Actually, this situation is understandable if you remember the relationship between voltage and current of inductance.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html
At first quickly, but then more and more slowly, the current approaches its nominal value. If the voltage has changed before the current reaches its nominal value, it is then too late to reach that value. A new goal is set... which again is not achieved because the voltage changes again in the meantime etc. This is where the half-finished current flow comes from. This applies to all voltage amplifiers, regardless of whether they are called HiFi or High End.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html
At first quickly, but then more and more slowly, the current approaches its nominal value. If the voltage has changed before the current reaches its nominal value, it is then too late to reach that value. A new goal is set... which again is not achieved because the voltage changes again in the meantime etc. This is where the half-finished current flow comes from. This applies to all voltage amplifiers, regardless of whether they are called HiFi or High End.