My building PowerAmp

audio-gd · 1st November 2004, 02:45 PM

The idea is form Xccuphase A-100. But I had change it.
Sorry for my English.

Rudy · 1st November 2004, 03:12 PM

after a fast look at it

the input for the servo needs to be before the relais output and before the coil, and the servo doesnt work like this, the feedback needs to be the capacitor and not the resistor, swap them

why the 42V ac when you can simply use 12V AC and place them uppon the main power supply

edit : you should also use an other opamp instead off the "audiograde" one, it needs to be a low offset opamp.

Rudy

audio-gd · 1st November 2004, 03:54 PM

The servo feedback in the board is as your say,But I protract it's wrong.

Use the 42V AC I think it can work more well,

"edit : you should also use an other opamp instead off the "audiograde" one, it needs to be a low offset opamp."

Can you give me a advice?

Thanks you again

peranders · 1st November 2004, 04:51 PM

The servo opamp can be any good JFET audio opamp, such as OPA134, AD8610, OPA627 and many many more. Offset voltage is rather unimportant. Input bias currents are more important.

audio-gd · 2nd November 2004, 02:23 PM

I have test this , when use OPA2132 is best.

I design the servo opamp is dual opamps ,because I have more this IC to change.

Sorry for my English again.

audio-gd · 2nd November 2004, 02:36 PM

It's soon to complete!

wigginjs · 2nd November 2004, 02:44 PM

Wow, those are really nice looking.

carlmart · 2nd November 2004, 04:50 PM

Quote:

Originally posted by audio-gd
It's soon to complete!

Is this amp based on the Xccuphase A-100 circuit? What did you change?

Where did you have the pcb made?

Carlos

audio-gd · 3rd November 2004, 11:31 AM

The Xccuphase A-100 has a diamond diff VAS stage,and my amp have use this type.
But I don't need the balance input, and I difficulty to partnership the MOSFET ,so I use the SC5200/SA1943, but in the pcb I have predispose the place of MOSFET .
This pcb is my design,and made in China.

peranders · 3rd November 2004, 11:44 AM

audio-gd, your pcb looks real good.

Do you have any more close-ups?

1st November 2004, 03:54 PM	#3
audio-gd diyAudio Member Join Date: Oct 2004	Thanks Rudy The servo feedback in the board is as your say,But I protract it's wrong. Use the 42V AC I think it can work more well, "edit : you should also use an other opamp instead off the "audiograde" one, it needs to be a low offset opamp." Can you give me a advice? Thanks you again

1st November 2004, 04:51 PM	#4
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	The servo opamp can be any good JFET audio opamp, such as OPA134, AD8610, OPA627 and many many more. Offset voltage is rather unimportant. Input bias currents are more important. __________________ /Per-Anders (my first name) or P-A as my friends call me

2nd November 2004, 02:44 PM	#7
wigginjs diyAudio Member Join Date: Dec 2003 Location: Columbia, SC	Wow, those are really nice looking. __________________ The Four Chairs DIY Home Theater

3rd November 2004, 11:31 AM	#9
audio-gd diyAudio Member Join Date: Oct 2004	To Carlos The Xccuphase A-100 has a diamond diff VAS stage,and my amp have use this type. But I don't need the balance input, and I difficulty to partnership the MOSFET ,so I use the SC5200/SA1943, but in the pcb I have predispose the place of MOSFET . This pcb is my design,and made in China.

3rd November 2004, 11:44 AM	#10
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	audio-gd, your pcb looks real good. Do you have any more close-ups? __________________ /Per-Anders (my first name) or P-A as my friends call me


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1st November 2004, 03:12 PM	#2
Rudy diyAudio Member Join Date: Feb 2003 Location: Belgium	after a fast look at it the input for the servo needs to be before the relais output and before the coil, and the servo doesnt work like this, the feedback needs to be the capacitor and not the resistor, swap them why the 42V ac when you can simply use 12V AC and place them uppon the main power supply edit : you should also use an other opamp instead off the "audiograde" one, it needs to be a low offset opamp. Rudy

2nd November 2004, 02:23 PM	#5
audio-gd diyAudio Member Join Date: Oct 2004	I have test this , when use OPA2132 is best. I design the servo opamp is dual opamps ,because I have more this IC to change. Sorry for my English again.

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