USB powered NOS USB DAC with built-in headphone amp

dsavitsk · 30th July 2006, 01:14 AM

Schematic at: http://www.ecp.cc/images/HPDAC_0.1b_sch.GIF

Larger pic at: http://www.ecp.cc/images/HPDAC_IN_L.jpg
-d

kec · 31st July 2006, 05:29 PM

dsavitsk, or anyone else,

Question: How is a OS DAC (PCM2706) changed into an NOS one? Please forgive me, I'm new to this DAC stuff. Just trying to learn.

-Ken

dsavitsk · 31st July 2006, 05:42 PM

Quote:

Originally posted by kec
dsavitsk, or anyone else,

Question: How is a OS DAC (PCM2706) changed into an NOS one? Please forgive me, I'm new to this DAC stuff. Just trying to learn.

In this case, the PCM2707 is only used to convert USB to I2S. This I2S signal (which is NOS) is sent to a TDA1543 chip to do the actual conversion from digital to analog. If the 2707 is used as a dac, then it probably oversamples or something, but I don't use it that way.

-d

kec · 31st July 2006, 05:50 PM

That's what I kinda figured looking at the schematic, but just wanted to make sure.

Thanks,
Ken

renfrow · 2nd August 2006, 06:17 AM

Pardon my newbness, but, is this something you would shove (appropriately :-) a wav file out a usb port to listen to music?

Tom.

kec · 2nd August 2006, 04:03 PM

Quote:

is this something you would shove (appropriately :-) a wav file out a usb port to listen to music

In a word, yes. But not only wav, any audio - although you would really only want uncompressed wav or lossless compression like flac, ape, etc. The reason is to get error free data without any correction to it.

-Ken

dsavitsk · 8th August 2006, 08:04 PM

Some updates at http://www.ecp.cc/HPDAC.html

Akira386 · 8th August 2006, 11:57 PM

Shouldn't PSEL be connected to GND? (LOW)

dsavitsk · 9th August 2006, 04:08 AM

Quote:

Originally posted by Akira386
Shouldn't PSEL be connected to GND? (LOW)

When used with an external PS then PSEL is low, but here it is USB Bus powered which means it needs to be high. PSEL high sets the HOST pin to be determinitive of max power draw from the bus, which here is set to 500mA.

-d

Akira386 · 9th August 2006, 05:11 AM

Making PSEL HIGH, the internal regulators are activated. Which makes the REG101 redundant.

Am I wrong?
If I am, then how PCM "knows" when to activate or deactivate the internal regs?

30th July 2006, 01:14 AM	#1
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	USB powered NOS USB DAC with built-in headphone amp Schematic at: http://www.ecp.cc/images/HPDAC_0.1b_sch.GIF Larger pic at: http://www.ecp.cc/images/HPDAC_IN_L.jpg -d

2nd August 2006, 06:17 AM	#5
renfrow diyAudio Member Join Date: May 2005 Location: Salt Lake City, Utah, USA	Pardon my newbness, but, is this something you would shove (appropriately :-) a wav file out a usb port to listen to music? Tom. __________________ Now, we can do this the hard way, or... well, actually there's just the hard way. -- Buffy Summers (Buffy the Vampire Slayer)

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31st July 2006, 05:29 PM	#2
kec diyAudio Member Join Date: Mar 2001 Location: California	dsavitsk, or anyone else, Question: How is a OS DAC (PCM2706) changed into an NOS one? Please forgive me, I'm new to this DAC stuff. Just trying to learn. -Ken

31st July 2006, 05:50 PM	#4
kec diyAudio Member Join Date: Mar 2001 Location: California	That's what I kinda figured looking at the schematic, but just wanted to make sure. Thanks, Ken

8th August 2006, 08:04 PM	#7
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	Some updates at http://www.ecp.cc/HPDAC.html

8th August 2006, 11:57 PM	#8
Akira386 diyAudio Member Join Date: May 2005 Location: Sao Paulo	Shouldn't PSEL be connected to GND? (LOW)

9th August 2006, 05:11 AM	#10
Akira386 diyAudio Member Join Date: May 2005 Location: Sao Paulo	Making PSEL HIGH, the internal regulators are activated. Which makes the REG101 redundant. Am I wrong? If I am, then how PCM "knows" when to activate or deactivate the internal regs?

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