High Quality Audio Preamp.

[Nigel Goodwin]

Circuit Diagram has been changed accordingly..

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But in my view,(need ur guidence)
Soundcard output impedence is low and our preamplifier input impedence is enough high. This impedence mismatching will cause the noise.. Am i right!!!.

No, it's how it should be - you don't want impedance matching, it's a BAD thing! (exept for certain specific purposes).

 

[Ayne]

What u say! it's all right and ready for PCB???

 

[Ayne]

Finally PCb has been completed.
Put Suggestions and comments about my PCB and components layout.

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Thanks.

 

[audioguru]

It looks good and it should operate good.

 

[palesha]

Finally let us know what frequency response u got?
How u find the quality?
What software used 4 making nice pcb.

 

[Ayne]

Finally let us know what frequency response u got?
How u find the quality?
What software used 4 making nice pcb.

I am using **broken link removed** for making PCB's. Many members of this web use Eagle(I think), But i like PCB123 becuse it is free and no restrictions.

 

[audioguru]

The frequency response of a modern opamp like the TL072 with a voltage gain of only 7 is about 320kHz at low levels and 100kHz at high levels. An old 741 opamp has trouble above only 9kHz. An old LM358 or LM324 has trouble above only 6kHz.

The distortion is about only 0.003% up to 2kHz and less than 0.02% up to 20kHz. The old LM358 and LM324 have 3% crossover distortion with a gain of 1 and higher distortion at higher gain.