On 11/28/2023 11:47 AM, Steve Wahl wrote:
On Tue, Nov 28, 2023 at 08:16:28AM -0500, Tony Miklos wrote:
On 11/27/2023 6:55 PM, Steve Wahl wrote:
Tony: I would love to see your video if you can find it!
--> Steve
Square wave audio amplifier test vs a sine wave.
Ah, I think I get it.
The square wave has all the odd harmonics, so your 300Hz square is like simultaneously putting sine waves at 300, 900, 1500, 2100, 2700, 3300, ... (at decreasing amplitudes) through the amp.
So you're testing the amp over a wide range of frequencies at once, but also seeing if there's interferences / interactions between those frequencies within the amp.
Is that right?
--> Steve
No, the square wave input is a perfect square wave. The problems arise when you see the ringing (up AND down in the circuit/output. This is not to be confused with a single spike which is sometimes normal with the treble turned up to max. Maybe I'll try testing an amp before rebuilding it and get a good picture of a distorted signal. Even a good signal will show different looking output than the input do to the frequency response of the amp. I had later noticed that I had the input at 300hz instead of 1K. While trouble shooting I often turn the frequency down so it doesn't make my tinnitus a lot worse than normal. (I have the tinnitus all the time but a 1K square wave will make it really bad.) I have the speakers on 100 watt L pads to turn the volume either down all the way or just very quiet so I can make the speakers quiet while the volume of the amp is turned way up.
Tony