lm1875

siemensc65 · 20th May 2006, 06:23 AM

my lm1875

Circlotron · 20th May 2006, 08:24 AM

I see the loudspeaker current-sense resistor signal gets sent into the feedback network and inverting input. You amplifier will have an output impedance higher than normal. This is not always a good thing because the speaker output will rise a lot at it's resonant frequency.

preiter · 23rd May 2006, 12:11 AM

In a vain attempt to educate myself, I wonder if you wouldn't mind answering a couple of questions about the design.

I don't understand the resistor network on the output of the device. You have a resistor between the speaker output and ground, another in parallel with the speaker and the 10k resistor. What are those for?

Also the two caps on the input, what do those do?

I understand the basics of chipamp circuits, but when they start to get fancy I'm totally lost.

Leolabs · 23rd May 2006, 02:23 AM

"dian liu hui shu",not bad.How does it sound???

siemensc65 · 23rd May 2006, 03:28 AM

the pcb on this sch

20th May 2006, 08:24 AM	#2
Circlotron diyAudio Member Join Date: Jun 2002 Location: Melbourne, Australia	high output impedance I see the loudspeaker current-sense resistor signal gets sent into the feedback network and inverting input. You amplifier will have an output impedance higher than normal. This is not always a good thing because the speaker output will rise a lot at it's resonant frequency. __________________ Best-ever T/S parameter spreadsheet. http://www.diyaudio.com/forums/multi...tml#post353269

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23rd May 2006, 12:11 AM	#3
preiter diyAudio Member Join Date: May 2006	In a vain attempt to educate myself, I wonder if you wouldn't mind answering a couple of questions about the design. I don't understand the resistor network on the output of the device. You have a resistor between the speaker output and ground, another in parallel with the speaker and the 10k resistor. What are those for? Also the two caps on the input, what do those do? I understand the basics of chipamp circuits, but when they start to get fancy I'm totally lost.

23rd May 2006, 02:23 AM	#4
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	"dian liu hui shu",not bad.How does it sound???

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