If there is audio on the output transistors, confirm that that audio is reaching the relay. If it is and the relay has continuity, you should have audio on the positive speaker terminal. If you have audio on the positive speaker terminal, either the speaker/wiring is open or you have a bad ground for the negative speaker terminal.
You can probably find a 1N914 or 1N4148 diode at the local radio shack if you're in the US.
You can probably find a 1N914 or 1N4148 diode at the local radio shack if you're in the US.
I have audio all the way to the terminals.. but hooking up a speaker, it is too "low" to hear anything.
If you drive a sine wave into the amp and measure the voltage with and without a speaker load, does the voltage on the terminals change?
If I hook speakers up to it, I can hear the audio, but it is very low. If I increase the level of the input it reaches a point where like someone flipped a switch, and it starts working as I would expect it to (but, it sounds distorted- possibly because the input is so loud).
Still thinking something in the feedback loop, and open to suggestions!
Thanks.
Still thinking something in the feedback loop, and open to suggestions!
Thanks.
No, amplitude on the scope does not change with load/no load...
But on my test bench the amplifier seems to be working properly now?? I have not done anything to it since I posted on the 17th... I will install it back in the car and see what happens..
But on my test bench the amplifier seems to be working properly now?? I have not done anything to it since I posted on the 17th... I will install it back in the car and see what happens..
Sorry, I was mistaken.. I still hear audio from the speaker (low), until I increase the input to the point of distortion.
But.. I see no change in amplitude when the speaker is connected/disconnected.
But.. I see no change in amplitude when the speaker is connected/disconnected.
Post a photo of the distorted waveform (preferably a sine wave of 60-100Hz). Also post the rail voltages at the time when the distorted waveform photo was taken.
I do not have a signal generator. I have been using a CD player for input.. However, I can see the gain dramatically increase at a specific point as the input increases. There is a specific point where I can adjust the volume on the pre-amp such that the audio flips back and forth between high and low, like a binary switch as the level of the audio changes (drum hits, etc..)
An externally hosted image should be here but it was not working when we last tested it.
Voltage was 68V (I thought it should be closer to 56V??)
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