Simple preamp, noise - Page 2

AndrewT · 25th October 2010, 12:04 PM

I prefer the preamp and other sources to be input filtered to approximately 1octave wider at both HF & LF than the Power amp input filters.

Some builders set the HF filter for a pre-amp at >500kHz (RC~0.33us)
and power amp filters anywhere between RC=1.5us upto 0.3us.

Arsimantur · 28th October 2010, 03:29 PM

Quote:

Originally Posted by pacificblue

- R1 should go from pin2 to ground, not from output to ground.

right, thx

Ok, I made it, it works and it doesn't. Connected to tda7375 - no sound, only vibrating low tone loudspeaker. When connected to headphones sound is quiet. It should be louder with it not quieter!

I give up, how can I make my speakers with tda7375 connected to mp3 player play as loud as connected to pc?

Arsimantur · 29th October 2010, 08:05 PM

It was faulty capacitor C3, I put new one and it works now. I also put 100k resistor in place of 1k (R6) to lower HP filter and removed LP filter(C1). I run it from one 9V battery.

25th October 2010, 12:04 PM	#11
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I prefer the preamp and other sources to be input filtered to approximately 1octave wider at both HF & LF than the Power amp input filters. Some builders set the HF filter for a pre-amp at >500kHz (RC~0.33us) and power amp filters anywhere between RC=1.5us upto 0.3us. __________________ regards Andrew T.

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29th October 2010, 08:05 PM	#13
Arsimantur diyAudio Member Join Date: Oct 2010	It was faulty capacitor C3, I put new one and it works now. I also put 100k resistor in place of 1k (R6) to lower HP filter and removed LP filter(C1). I run it from one 9V battery.

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