Embarking On A Gainclone 5.1 Channels

Alphas · 8th October 2004, 04:01 PM

What comments welcomed

I am using two LM4781 for total of 3x2 = 6 channels
One will be for the sub and a preamp to drive the vu meters, lm 3915.

thomas997 · 8th October 2004, 10:18 PM

I just "finished" a five channel amp.. It still needs a lot of case work and a proper power switch. Also Ill add another channel to power a sub eventually (5 channels are lm3875, the sub will be 2 lm3886)

Is 35W enough for your sub though?

What size/voltage transformer do you have, and heatsinks?

For mine I have a very low voltage (18.5V DC) so the chips barely need heatsinks at all. Its the transformers that get the warmest, I should add some air holes above it.

Make sure you have a lot of wire around if your doing star ground, mine is a rats nest.

Alphas · 9th October 2004, 07:28 AM

did u seen microjean pcb layout,

look good, I might want to use that.

fireman · 9th October 2004, 12:56 PM

Quote:

Originally posted by Alphas
did u seen microjean pcb layout,

look good, I might want to use that.

Alphas,

Your pictures don't show !

Could you post a link or something ?

Alphas · 10th October 2004, 06:37 AM

Quote:

Originally posted by fireman

Alphas,

Your pictures don't show !

Could you post a link or something ?

I notice that too

Alphas · 29th October 2004, 02:52 AM

Alright I got a bunch of LM4781s, LM3886s, LM3915s, LM1973s and LM1972s. Now I intend to make a 7.1 channels project, the total wattage may exceed 250watts, any comments?

mAJORD · 31st October 2004, 08:57 AM

well if you can't see those layouts now you got eye problems :P

btw, whats all the digital gear down the bottom of the schematic ?

Riku-78 · 31st October 2004, 02:37 PM

Didn't take the time to parse the whole schematic, but it appears you have implemented some sort of digital control. What kind of parameters can you control? I doubt there is an Atmel microcontroller, RS-232, IR remote, LCD display and a front panel push button interface just to assign attenuation.

Alphas · 1st November 2004, 05:13 AM

yeap, there will be digital controls for each channel, the LM 1973 and Lm1972 are the digital volume controls, but I am doing away with the irda remote control, RS232 but adding vumeter, front panel attentuation interface and LCD into the amp.

The circuit is based from microjean 6 channels, but this is for 7.1 channels, = 8 channels. But from where I lived, there is a hard time trying to make a PCB out of the schematic.

microJean · 1st November 2004, 07:34 AM

Hy there!

The board I designed is for my needs. I like programming the microcontrollers and audio makes no difference.

The digital interface is designed for debugging purpuses. The final board (if will ever be final) doesn't need all those chips like 2 memory modules, rs232 interface etc.

The schematic has been changed in the mean time, temperature sensor was added, fan control and some volume interface gagets (work in progress , http://microjean.go.ro ).

Bye...for now!

8th October 2004, 04:01 PM	#1
Alphas diyAudio Member Join Date: Jan 2004 Location: AUDIO	Embarking On A Gainclone 5.1 Channels What comments welcomed I am using two LM4781 for total of 3x2 = 6 channels One will be for the sub and a preamp to drive the vu meters, lm 3915.

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8th October 2004, 10:18 PM	#2
thomas997 diyAudio Member Join Date: Feb 2004 Location: Vancouver	I just "finished" a five channel amp.. It still needs a lot of case work and a proper power switch. Also Ill add another channel to power a sub eventually (5 channels are lm3875, the sub will be 2 lm3886) Is 35W enough for your sub though? What size/voltage transformer do you have, and heatsinks? For mine I have a very low voltage (18.5V DC) so the chips barely need heatsinks at all. Its the transformers that get the warmest, I should add some air holes above it. Make sure you have a lot of wire around if your doing star ground, mine is a rats nest.

9th October 2004, 07:28 AM	#3
Alphas diyAudio Member Join Date: Jan 2004 Location: AUDIO	did u seen microjean pcb layout, look good, I might want to use that.

29th October 2004, 02:52 AM	#6
Alphas diyAudio Member Join Date: Jan 2004 Location: AUDIO	Alright I got a bunch of LM4781s, LM3886s, LM3915s, LM1973s and LM1972s. Now I intend to make a 7.1 channels project, the total wattage may exceed 250watts, any comments?

31st October 2004, 08:57 AM	#7
mAJORD diyAudio Member Join Date: Apr 2004 Location: Brisbane Australia	well if you can't see those layouts now you got eye problems :P btw, whats all the digital gear down the bottom of the schematic ?

31st October 2004, 02:37 PM	#8
Riku-78 diyAudio Member Join Date: Oct 2004	Didn't take the time to parse the whole schematic, but it appears you have implemented some sort of digital control. What kind of parameters can you control? I doubt there is an Atmel microcontroller, RS-232, IR remote, LCD display and a front panel push button interface just to assign attenuation.

1st November 2004, 05:13 AM	#9
Alphas diyAudio Member Join Date: Jan 2004 Location: AUDIO	yeap, there will be digital controls for each channel, the LM 1973 and Lm1972 are the digital volume controls, but I am doing away with the irda remote control, RS232 but adding vumeter, front panel attentuation interface and LCD into the amp. The circuit is based from microjean 6 channels, but this is for 7.1 channels, = 8 channels. But from where I lived, there is a hard time trying to make a PCB out of the schematic.

1st November 2004, 07:34 AM	#10
microJean diyAudio Member Join Date: Dec 2003 Location: Romania	Hy there! The board I designed is for my needs. I like programming the microcontrollers and audio makes no difference. The digital interface is designed for debugging purpuses. The final board (if will ever be final) doesn't need all those chips like 2 memory modules, rs232 interface etc. The schematic has been changed in the mean time, temperature sensor was added, fan control and some volume interface gagets (work in progress , http://microjean.go.ro ). Bye...for now!