Can you please tell me the toroidal coil details for this circuit? And is it suitable for 8 ohm speakers?
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What if the power is 12v?What makes you think those inductors will be toroidal?
Is this some sort of class-A transistor amplifier?
The size of the inductor will be determined by the amount of power you want it to supply, which you didn't specify.
It will be suitable for 8Ω speakers, if you have the right supply voltage, which will be determined by the amount of power you want it to supply, which you didn't specify.
Thank you.If you really want to drive one or more speakers from an audio signal, there are IC chips and or modules on the market designed for that purpose. This will decrease your parts count and increase you chances of success:
https://www.digikey.com/en/products...IgTCBcDaIIYFcAmBLA9gAjgWwA4BsUAzFAUwCcQBdAXyA
Surely you must know that your SPICE simulations mean nothing, because Baranek's law applies. (I'm sure it applies equally to amplifiers as it does to loudspeakers.)You found a useless audio power amplifier circuit.
The coils cut high audio frequencies.
I changed its transistor and base resistor value for a higher output power.
I simulated it to show that the output power is 1.8W with severe distortion.
The speaker and transistor each heat with 4.5W all the time even when not playing sounds.
The DC in the speaker causes its cone to be pulled over to one side causing more distortion.
The input impedance is less than only 2 ohms.
It’s drawn wrong. The choke should connect to the power transistor collector, and the speaker should connect between that point and ground with 4700uF in series.That circuit is fundamentally flawed because all of the transistor current flows through the speaker voice coil. It does burn out the speaker. That is why that one generation of transistor car radios had an external transformer mounted on the speaker.
That would most cetainly be an improvement.It’s drawn wrong. The choke should connect to the power transistor collector, and the speaker should connect between that point and ground with 4700uF in series.
My simulation shows the severe distortion when a transistor is close to cutoff with poor linearity.Surely you must know that your SPICE simulations mean nothing.
The choke, transistor and speaker are all in series then the sequence makes no difference.It’s drawn wrong. The choke should connect to the power transistor collector.
I would not go so far as to say simulations in SPICE mean nothing. Obviously simulations have their limitations. But Audioguru has some valid points. Even a simple analysis shows the circuit is highly inefficient and has major distortions over an equivalent IC chip or Module designed to be an audio amplifier.Surely you must know that your SPICE simulations mean nothing, because Baranek's law applies. (I'm sure it applies equally to amplifiers as it does to loudspeakers.)
Besides, that inductor is probably wound with silver wire, and that would make the output pure, just like a silver bullet kills a vampire!
SPICE simulations don't mean anything for those people to whom Baranek's law applies!I would not go so far as to say simulations in SPICE mean nothing. Obviously simulations have their limitations. But Audioguru has some valid points. Even a simple analysis shows the circuit is highly inefficient and has major distortions over an equivalent IC chip or Module designed to be an audio amplifier.
What point are you trying to make? This circuit has nothing to do with the original one under discussion? This does look like a fairly nice amplifier but I could do it with an op-amp without so many parts.SPICE simulations don't mean anything for those people to whom Baranek's law applies!
I got my facts wrong - the silver bullet kills a werewolf, not a vampire. View attachment 246461View attachment 246462
Here's what you can do if you add a handful of small signal transistors. (If you insist that a handful means five then the BCV61 is a dual.) MY version of Spice doesn't have the 2SC5200 so I substituted an MJL3281A.
Spice predicts 0.02% for the distortion, mainly 2nd harmonic.
0.3Ω is the DC resistance of the choke. The bias sets about 500mV across the choke resistance to give a standing current of 1.8A.
by Jake Hertz
by Aaron Carman
by Aaron Carman