lm1875 pcb layout for gainclone.

Arend · 11th January 2010, 10:39 AM

Hallo,

I am a newbie in diy elektronics, but I want to make a lm1875 amplifier. I've found several pcb layouts for the gainclone circuit, but they aren't in black and white, so I can't use them with out modification.

Does anyone has a pcb layout? It would make it a lot easier for me.

ps. I've found this one: http://i239.photobucket.com/albums/f...Layout1875.jpg but it's not as minimalistic as the gainclone circuit. I don't like the elco in the signal pad. (I don't know what the effect will be on the audio quality)

Regards,

Stefan

AndrewT · 11th January 2010, 11:31 AM

make sure you adopt an AC coupled schematic that has RF filter on the input and Zobel load at the output.

ratza · 11th January 2010, 12:45 PM

See if these suit your needs.

91art · 11th January 2010, 02:06 PM

[QUOTE=Arend;2043180]Hallo,

I am a newbie in diy elektronics, but I want to make a lm1875 amplifier. I've found several pcb layouts for the gainclone circuit, but they aren't in black and white, so I can't use them with out modification.

Does anyone has a pcb layout? It would make it a lot easier for me.

ps. I've found this one: http://i239.photobucket.com/albums/f...Layout1875.jpg but it's not as minimalistic as the gainclone circuit. I don't like the elco in the signal pad. (I don't know what the effect will be on the audio quality)

Regards,

It look like this circuit'PCB, Lots of guys do it . It was said very good.
You can also try 2， 3circuit，It was said the third is the best.The second is better than the firist circuit. I use the samplest.

91art · 02:17 PM

look at this Beginner's Gainclone, HiFi LM1875, The Amplifier Board think it's the same,he explain it very claer,Sorry for my poor English,maybe you don't unerstand what i said

.
and the otrer two circuit without pcb.

Arend · 11th January 2010, 05:50 PM

Thank you very much!

No problem with your english 91art, (I'm also not a native speaker myself)

I'm gonna use the pcb from ratza.

AndrewT · 07:31 PM

Ratza's PCB needs the power ground to pass up between the decoupling capacitors. The long Power ground traces that tie in the caps adds too much inductance to let the little 100nF caps do any good.
The signal ground should be separate from the power ground.
Leave a pair of pads to connect the signal ground to the ground terminal by a copper link wire or a 10r resistor and a pair of inverse parallel diodes.

Look at the Power ground and the Signal ground in post4 middle pic for ideas.

ratza · 12th January 2010, 07:39 AM

AndrewT, you're right regarding traces' inductances. Yet the amp is mute. I just wanted a very compact board in THD technology.

mravlca · 12th January 2010, 02:16 PM

Quote:

Originally Posted by ratza

See if these suit your needs.

Ratza could you post schematic for this project?

Regards Aleš

Arend · 12th January 2010, 06:35 PM

mravlca,

The schematic is from the lm1875 datasheet, the one with the symmetric power supply.

11th January 2010, 10:39 AM	#1
Arend diyAudio Member Join Date: Feb 2008	lm1875 pcb layout for gainclone. Hallo, I am a newbie in diy elektronics, but I want to make a lm1875 amplifier. I've found several pcb layouts for the gainclone circuit, but they aren't in black and white, so I can't use them with out modification. Does anyone has a pcb layout? It would make it a lot easier for me. ps. I've found this one: http://i239.photobucket.com/albums/f...Layout1875.jpg but it's not as minimalistic as the gainclone circuit. I don't like the elco in the signal pad. (I don't know what the effect will be on the audio quality) Regards, Stefan

11th January 2010, 07:28 PM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Ratza's PCB needs the power ground to pass up between the decoupling capacitors. The long Power ground traces that tie in the caps adds too much inductance to let the little 100nF caps do any good. The signal ground should be separate from the power ground. Leave a pair of pads to connect the signal ground to the ground terminal by a copper link wire or a 10r resistor and a pair of inverse parallel diodes. Look at the Power ground and the Signal ground in post4 middle pic for ideas. Last edited by AndrewT; 11th January 2010 at 07:31 PM.

12th January 2010, 07:39 AM	#8
ratza diyAudio Member Join Date: Dec 2007 Location: Sibiu, Romania	AndrewT, you're right regarding traces' inductances. Yet the amp is mute. I just wanted a very compact board in THD technology. __________________ Any solution is a compromise.

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11th January 2010, 11:31 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	make sure you adopt an AC coupled schematic that has RF filter on the input and Zobel load at the output.

11th January 2010, 05:50 PM	#6
Arend diyAudio Member Join Date: Feb 2008	Thank you very much! No problem with your english 91art, (I'm also not a native speaker myself) I'm gonna use the pcb from ratza.

12th January 2010, 06:35 PM	#10
Arend diyAudio Member Join Date: Feb 2008	mravlca, The schematic is from the lm1875 datasheet, the one with the symmetric power supply.

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