quite sure there is a cap in the input....may be to low in value...
If I can't fix it I will scrap it and before I will take it apart take pictures and post them here. I want too to understand.
Hi everybody,
The situation is very new and I must confirm but I think that I should share this with you.
I can't believe my ears but the sound of the amp has improved significantly .
I have replaced C1(470pF styroflex) by a 560pF. I have also ordered some additionnal values 580pF, 600pF, 620pF. I will make some tries and will be back to give details (if you wish). At the moment I do not want to scrap this amp anymore!
The situation is very new and I must confirm but I think that I should share this with you.
I can't believe my ears but the sound of the amp has improved significantly .
I have replaced C1(470pF styroflex) by a 560pF. I have also ordered some additionnal values 580pF, 600pF, 620pF. I will make some tries and will be back to give details (if you wish). At the moment I do not want to scrap this amp anymore!
many might be wondering why this worked, like i did at first. The answer is when you increased the value of C1, it basically grounded the high frequencies, thus making a very very simple tone control circuit. Increase the cap size more and you can reach a point where only bass can be heard.
I also faced such problem with pre-built kit (a transistor cheap kit)
I also faced such problem with pre-built kit (a transistor cheap kit)
Hi again,
I found also this one, ETI480. I stop digging for today.
This amp shows 4u7F followed by 1k5 and 10k to signal return.The imput impedance of this amp looks very high, could this be causing problems for the sorce?
That is 11k5 + 4u7F
What is your definition of high?
I'm sure AndrewT refers to the schematic for the ancient and best forgotten ETI 480.
I don't know that it's always going to be a problem but sure, the OP's design TL071 input is floating and unless direct coupled to a grounded resistive source, needs to be ground referenced somewhere. Assuming a preamp. or source is <10k, that might be ok but most have capacitor outputs with various or no shunt resistance, even feedback loops. I think its unwise to have such a floating input for a universal device like an amplifier.
I don't know that it's always going to be a problem but sure, the OP's design TL071 input is floating and unless direct coupled to a grounded resistive source, needs to be ground referenced somewhere. Assuming a preamp. or source is <10k, that might be ok but most have capacitor outputs with various or no shunt resistance, even feedback loops. I think its unwise to have such a floating input for a universal device like an amplifier.
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