audio concepts PA-3B schematic?

Zen Mod · 8th July 2003, 09:49 PM

anyone?

Zen Mod · 31st July 2003, 02:36 PM

pleeeeeeeaseeeeeeee!
anyone?

djk · 2nd August 2003, 03:55 PM

It's a single ended diff input pair with the tail fed from an active current source.

The VAS, which is cascoded and has an active current source, is driven by a resistive load in the diff pair.

LEDs are used in the current sources.

Very simple.

Musical Concepts even shows the board layout at their site.

Zen Mod · 2nd August 2003, 10:29 PM

I know that-and that's reason why I asked for schmtcs;
I just wanna see values and to do some analysis,not to copy it.
anyway-tnx for reply

Zen Mod · 11th May 2004, 10:03 PM

hehe........still looking for schmtc.........
?

ronzeman · 30th July 2008, 10:59 PM

Has anyone installed this in thier Hafler? What are the results?

Dick West · 3rd August 2008, 07:36 PM

Are you people discussing the Musical Concepts replacement boards or something from Audio Concepts?

I have MC PA3-B boards installed in a Hafler chassis and love their sound. It is my reference amp. More smooth and detailed than the Hafler with clear solid bass (not boomy or muddy).

But, the LC-100 kit of PS caps should also be installed. They do make a difference.

ronzeman · 3rd August 2008, 08:15 PM

I'm new to these forums...have followed your journey w/ Hafler mods through many threads. I have the MC manual for what they call their PA-3C mods. Any comments as to its value and sound improvements. My Hafler 200 was purchased and assembled by me in 1981.. (Paid $279.00 for the kit..I still have the receipt!)

PS:I sent you an email with same questions while you were answering my first post

djk · 3rd August 2008, 10:38 PM

"I just wanna see values and to do some analysis,not to copy it."

The tail current for the diff pair is 3.6mA, 1.8mA per device.

The cascoded CCS is 22mA for the cascoded Vas.

Green LEDs are used at 3.7mA for voltage references for the CCS.

Zen Mod · 3rd August 2008, 10:47 PM

Quote:

Originally posted by djk
"I just wanna see values and to do some analysis,not to copy it."

The tail current for the diff pair is 3.6mA, 1.8mA per device.

The cascoded CCS is 22mA for the cascoded Vas.

Green LEDs are used at 3.7mA for voltage references for the CCS.

tnx .

8th July 2003, 09:49 PM	#1
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	audio concepts PA-3B schematic? anyone? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

31st July 2003, 02:36 PM	#2
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	pleeeeeeeaseeeeeeee! anyone? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

2nd August 2003, 10:29 PM	#4
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	I know that-and that's reason why I asked for schmtcs; I just wanna see values and to do some analysis,not to copy it. anyway-tnx for reply __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

11th May 2004, 10:03 PM	#5
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	hehe........still looking for schmtc......... ? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

30th July 2008, 10:59 PM	#6
ronzeman diyAudio Member Join Date: Jul 2008	Audio Concepts PA-3C Has anyone installed this in thier Hafler? What are the results?


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2nd August 2003, 03:55 PM	#3
djk diyAudio Member Join Date: Feb 2001 Location: USA	It's a single ended diff input pair with the tail fed from an active current source. The VAS, which is cascoded and has an active current source, is driven by a resistive load in the diff pair. LEDs are used in the current sources. Very simple. Musical Concepts even shows the board layout at their site.

3rd August 2008, 07:36 PM	#7
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	Are you people discussing the Musical Concepts replacement boards or something from Audio Concepts? I have MC PA3-B boards installed in a Hafler chassis and love their sound. It is my reference amp. More smooth and detailed than the Hafler with clear solid bass (not boomy or muddy). But, the LC-100 kit of PS caps should also be installed. They do make a difference.

3rd August 2008, 08:15 PM	#8
ronzeman diyAudio Member Join Date: Jul 2008	Yes Musical Concepts Mod PA-3C I'm new to these forums...have followed your journey w/ Hafler mods through many threads. I have the MC manual for what they call their PA-3C mods. Any comments as to its value and sound improvements. My Hafler 200 was purchased and assembled by me in 1981.. (Paid $279.00 for the kit..I still have the receipt!) PS:I sent you an email with same questions while you were answering my first post

3rd August 2008, 10:38 PM	#9
djk diyAudio Member Join Date: Feb 2001 Location: USA	"I just wanna see values and to do some analysis,not to copy it." The tail current for the diff pair is 3.6mA, 1.8mA per device. The cascoded CCS is 22mA for the cascoded Vas. Green LEDs are used at 3.7mA for voltage references for the CCS. __________________ Candidates for the Darwin Award should not read this author.

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