You may end up with a "long feedback loop" stability problem with this circuit, caused by the wide gain-bandwidth product of the TL082 together with the frequency characteristics of your output transistors Q1 - Q4. This could cause a high-frequency peak in the amplifier's frequency response or even oscillation.this is my first post here. i am working on an audio amplifier for an electric guitar.
this is a simple power amplifier i did not include the per-amp stage here.
any suggestions, improvements and corrections are appreciated.
Yes, but - since this is an inverting configuration, there is no low frequency pole to reduce the forward gain to unity at DC. The result is that any offset errors are amplified and appear as DC through the speaker voice coil. Without knowing what the V+, V-, and Vin values are we can't estimate the gain needed for a "full power" output at max input, but the error could be enough to matter.As shown it has a gain of just one which means if you want a ten volt output, you will need a ten volt input. You could increase R9 to give it a little gain.
I worked with those guys too!Yes, but - since this is an inverting configuration, there is no low frequency pole to reduce the forward gain to unity at DC. The result is that any offset errors are amplified and appear as DC through the speaker voice coil. Without knowing what the V+, V-, and Vin values are we can't estimate the gain needed for a "full power" output at max input, but the error could be enough to matter.
Separate from that, there is a school of thought that prefers inverting opamp circuits for audio because the almost zero voltage swing at the input reduces harmonic distortion in the opamp input stage. But - another school of thought strongly prefers that the audio signal phase be preserved through the signal chain. That is, there should be either zero inverting stages throughout the system or an even number of them, so the net phase shift through the system is zero degrees (as opposed to 180 degrees). In theory, with a system like this, a positive pressure on the microphone diaphragm during the original recording propagates through to the speaker cone moving outward, creating positive pressure at the ear drum.
Disclaimer - I'm not a golden-eared loon, but I used to work with some.
ak
That makes the dubious assumption that the phase is conserved through the whole electronics chain from microphone, through the recording medium, the reproductive mechanism, all the amplifiers, and finally to the speaker.In theory, with a system like this, a positive pressure on the microphone diaphragm during the original recording propagates through to the speaker cone moving outward, creating positive pressure at the ear drum.
Actually, it is well over 90% for professional recording studios, cutting/pressing labs, and both pro and consumer stereo gear. The standard is that each piece of equipment is non-inverting from in to out, so no matter how many processing stages / equipment strings / etc., the net phase change is always zero. If the phase of the mic preamp is correct, everything else is fine.That makes the dubious assumption that the phase is conserved through the whole electronics chain from microphone, through the recording medium, the reproductive mechanism, all the amplifiers, and finally to the speaker.
I'd say the chance of that is about 50-50.
In my opinion:the phase is conserved
Probably best. The amplifier may be used with a different amplifier in the same room. (low frequency cancelation)non-inverting
SVI, RSN, STK, no fun. Give me a good fully discrete output stage.I designed and built audio amplifiers 45 years ago. A few years later all my amplifiers used an audio power amplifier IC.
by Aaron Carman
by Duane Benson
by Jake Hertz
by Duane Benson