Chip amp distortion with high impedance resistive load.

Circlotron · 26th January 2005, 12:38 PM

I'm thinking about using an LM3875 or perhaps an LM3886 in a project; not as a power amplifier but as a high voltage opamp, driving a load somewhere about 500-1000 ohms. Now the datasheet will tell you how much distortion is produced when driving a 4 ohm or 8 ohm load to however many watts, but does anyone know the likely distortion at say 50v peak to peak with 1k resistive load? I would imagine the figure would be better but I am not sure.

I particularly want to use one of these IC's, not a fancy HV opamp.

peranders · 26th January 2005, 12:56 PM

Note that you can't get 50 V peak, only 40 V!

I'll guess it would work alright but what are you planning to use it for really, some weird class A?

Circlotron · 26th January 2005, 01:39 PM

1. That's peak-to-peak.
2.

Upupa Epops · 26th January 2005, 02:02 PM

Practicaly every amps have by this condition lower distortion, 2 - 10 times, then by normal " heavy " load.

26th January 2005, 12:38 PM	#1
Circlotron diyAudio Member Join Date: Jun 2002 Location: Melbourne, Australia	Chip amp distortion with high impedance resistive load. I'm thinking about using an LM3875 or perhaps an LM3886 in a project; not as a power amplifier but as a high voltage opamp, driving a load somewhere about 500-1000 ohms. Now the datasheet will tell you how much distortion is produced when driving a 4 ohm or 8 ohm load to however many watts, but does anyone know the likely distortion at say 50v peak to peak with 1k resistive load? I would imagine the figure would be better but I am not sure. I particularly want to use one of these IC's, not a fancy HV opamp. __________________ Best-ever T/S parameter spreadsheet. http://www.diyaudio.com/forums/multi...tml#post353269

26th January 2005, 12:56 PM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Note that you can't get 50 V peak, only 40 V! I'll guess it would work alright but what are you planning to use it for really, some weird class A? __________________ /Per-Anders (my first name) or P-A as my friends call me

26th January 2005, 01:39 PM	#3
Circlotron diyAudio Member Join Date: Jun 2002 Location: Melbourne, Australia	1. That's peak-to-peak. 2. __________________ Best-ever T/S parameter spreadsheet. http://www.diyaudio.com/forums/multi...tml#post353269

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26th January 2005, 02:02 PM	#4
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Practicaly every amps have by this condition lower distortion, 2 - 10 times, then by normal " heavy " load.

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