What problems can happen at high gain?

cpemma · 25th August 2004, 10:29 PM

I've a need to boost the voltage gain of a pair of TDA1514A chip amps to cope with the very low output from a portable CD player source.

Datasheet says top limit for the chip is 46dB, which I think is a voltage gain of 200; I reckon I need a voltage gain of about 90 (39dB) instead of the 30 it's currently set to with 20k & 680R.

Are there likely to be any undesired effects just increasing the gain? Should I be adding a pre-amp instead?

Quality hi-fi is not of the essence, the system is in a trailer, driving mid-fi outdoor speakers and running from a generator a few feet away

Mr Evil · 26th August 2004, 01:58 PM

Increased gain will give you the following undesirable effects:

Increased noise
Increased DC offset
Increased THD
Reduced bandwidth
Other things I've forgotten

I doubt you'll have any problems. 39dB is still quite small.

25th August 2004, 10:29 PM	#1
cpemma diyAudio Member Join Date: Jul 2003 Location: S Yorkshire OK	What problems can happen at high gain? I've a need to boost the voltage gain of a pair of TDA1514A chip amps to cope with the very low output from a portable CD player source. Datasheet says top limit for the chip is 46dB, which I think is a voltage gain of 200; I reckon I need a voltage gain of about 90 (39dB) instead of the 30 it's currently set to with 20k & 680R. Are there likely to be any undesired effects just increasing the gain? Should I be adding a pre-amp instead? Quality hi-fi is not of the essence, the system is in a trailer, driving mid-fi outdoor speakers and running from a generator a few feet away

26th August 2004, 01:58 PM	#2
Mr Evil diyAudio Member Join Date: Aug 2004 Location: Behind you	Increased gain will give you the following undesirable effects: Increased noise Increased DC offset Increased THD Reduced bandwidth Other things I've forgotten I doubt you'll have any problems. 39dB is still quite small. __________________ http://mrevil.pwp.blueyonder.co.uk/

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