I see, but my teacher said that the higher the bandwidth, the sound will become more detail like it can amplify such a high frequency then audio frequency range isn't a problem.
Either your teacher doesn't know about audio electronics and human hearing range or you must have misunderstood his lectures
actually, he showed us a 500Khz amplifier he built 😢. I asked him many times, but he always said that a high frequency response will give more detail rather than THD. He gave us an example like a professor (a VHF amplifier) can easily solve (reproduce) a elementary school's problem (audio range).
In serial from C3/C4 to the ground, something like 470R or so for a gain of 20x.
Most of the time it is correct that a higher bandwith gives lower distortion.
In usual amplifiers (Blameless concept) there is two 6dB / oktave rollof in the open loop gain.
The higher the bandwith the higher the open loop gain can be at audio.
And open loop gain / amp gain is near how much the distortion is decreased by the feedback.
In usual amplifiers (Blameless concept) there is two 6dB / oktave rollof in the open loop gain.
The higher the bandwith the higher the open loop gain can be at audio.
And open loop gain / amp gain is near how much the distortion is decreased by the feedback.
seem misunderstood here , What is meaning about 500Khz amplifier ? human ear only hears sound frequency 20Hz-20KHz may be shorter range more for some people. or freq sample for class D amp. ..meaning .
Here is a print screen of a Bode plot from a fast amplifier.Brown is output voltage and green is input voltage to inverting coupled amplifier-
The Bodeplot shows that we have a feedback factor of 115 dB at 10 kHz.
From the fourier transform in the simulator i got input voltage 1,9uv with a distortion of 9,18%. That is equal to a 0,17 uv distortion component of the input signal. 0,17 uv / 1v = 0,17 ppm or 0,000017% distortion. In the real world the amplifier will not measure that good because not identical transistors and problems in the PCB layout. Resistors and capacitors will affect too.
The important thing in this thread is that it is the speed of the amplifier that makes it possible to have such a high feedback factor.
The Bodeplot shows that we have a feedback factor of 115 dB at 10 kHz.
From the fourier transform in the simulator i got input voltage 1,9uv with a distortion of 9,18%. That is equal to a 0,17 uv distortion component of the input signal. 0,17 uv / 1v = 0,17 ppm or 0,000017% distortion. In the real world the amplifier will not measure that good because not identical transistors and problems in the PCB layout. Resistors and capacitors will affect too.
The important thing in this thread is that it is the speed of the amplifier that makes it possible to have such a high feedback factor.
The Hiraga amplifiers (20 W, 30 W and Monster) have a bandwidth reaching into the MHz-region, and the first two are using only bipolar transistors...
200Mhz bandwidth is impossible number for an audio amplifier, even for some composite amplifier which are used high speed op-amps.
Maybe the VHF amplifiers will be what you want.
Maybe the VHF amplifiers will be what you want.
200 MHz might be the GBW product, not the -3dB bandwidth, of a wide band audio amp. It might have the -3dB point at 200-250 KHZ, with it rolled off by feedback (as in, cap across the feedback resistor).
Not to mention the trouble you get into when using such a high bandwidth amp. ‘Oh, some gear in the chain picked up some HF, my amp blew it full power down my speaker and now my tweeters are gone… I heard nothing!’
Normally we have a RFI filter on the input and a Zobel + coil on the output to pretend RF 0scillations.
The fact that an amplifier has a very high bandwith for small signals doesn´t mean that it can load watts in the MHz area.
The fact that an amplifier has a very high bandwith for small signals doesn´t mean that it can load watts in the MHz area.
It could. But it should have it’s closed loop bandwidth and input signal bandwidth limited so that doesn’t happen. If it doesn’t that’s user error. Small amps like this, with a wide band output stage, can put of it full power into the hundreds of kHZ or few MHz.
Power amplifiers have gain-bandwidth products of tens of MHz. This number is somewhat meaningless because the amplifier is not being run at unity gain in closed loop.
A better number to look at is unity loop-gain bandwidth, the frequency at which the loop gain reaches unity. 1MHz is typical.
Ed
Searching on TI site, the BUF634A has -3dB at 200MHz. Look ok for your request. Just parallel many devices to get higher current output.
The task now is only looking for input. Some famous op-amp for audio is not yet to get that number.
The task now is only looking for input. Some famous op-amp for audio is not yet to get that number.
With your choice of source, that is one way to ensure you'll pass all the RF rubbish to your tweeter. High input impedance would be icing on the cake.
Your teacher should assess all aspects of using such a broad-spectrum amp in analog applications. The amp you proposed will oscillate as well... and that is valid if you DO pay attention to power supply, interconnecting and grounding. And if you do not.... hmmm. Talk to your teacher about what I wrote here... see what he has to say. If nothing, quit the subject... that will be better for you in the long run than learning things the wrong way and then having to undo the wrongdoings.
See here... with commentaries from the man himself (also, see post #119... that design should meet all your specific requirements):
Last edited: