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Old 20th February 2004, 02:46 PM   #1
jmar is offline jmar  United States
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Default Op amps on PCM2902 DAC

I have a PCM2902e that is up and running and it's BLOWING ME AWAY.

The cleanest path of audio I've ever heard.

I'm using the USB port and taking the chip's audio out through a couple of 68uf electrolytics right into my Sansui AU717. (Also using EAC to extract my WAV files).

I'm so impressed with what I'm hearing that I find it hard to believe that some op amps on the output are going to make an improvement......regardless of their "flavor".

Am I nuts or will these (burr brown or analog devices) op amps
really make a "contribution"?

THANKS
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Old 20th February 2004, 10:36 PM   #2
weissi is offline weissi  Europe
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Hi!

Yesterday I have replaced the njm4560 in my soundcard with ths4222 - so far as i can now the results are very good.... itīs a rather noisy device compared to the ad8620 that Iīve tested before (but that was a SOIC part - the ths4222 now is a MSOP like the njm4560)
DAC is a WM8770...

itīs a +-5V device but can drive 100mA if proper installed...
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regards / servus
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Old 21st February 2004, 02:47 PM   #3
MWP is offline MWP  Australia
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Default Re: Op amps on PCM2902 DAC

Quote:
Originally posted by jmar

Am I nuts or will these (burr brown or analog devices) op amps
really make a "contribution"?
Your nuts

How can op-amps make a contribution... they can only color the sound, same as any component.

If you mean by using them for a low-pass/output-buffer and loose the big caps, then they possibly could produce an improvment depending on component choice.
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Old 21st February 2004, 03:08 PM   #4
jmar is offline jmar  United States
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Join Date: Jan 2004
Location: Indiana
I'm trying to understand the function of a "low pass filter" on the audio outputs of this device.

I guess by "low pass" they mean a cutoff point above audio freqs? To pass audio and to filter high frequency noise? (I'm old school, when I think of low pass....it means LOW).

(I am getting a digital "ticking" right before I play a song and for a couple of seconds when I stop the song).


OK, I'll breadboard some of these op amps and listen but it sure sounds great.

(I guess I'm so impressed because I've been out of audio for so
long......a simple Sony CD player and some average electronics).

This simple path of USB WAV to my Sansui is bringing definition to music I've never heard before......actually hearing instruments and "riffs" in songs that I didn't know were there.
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Old 4th May 2004, 05:48 AM   #5
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Default Re: Re: Op amps on PCM2902 DAC

Quote:
Originally posted by MWP

Your nuts
How can op-amps make a contribution... they can only color the sound, same as any component.
If you mean by using them for a low-pass/output-buffer and loose the big caps, then they possibly could produce an improvment depending on component choice.
Op amp can make a contribution, this is a know fact (by tweakers), and it is not the same as any other component. It adds distortions, you can read about them here, for example http://headwize2.powerpill.org/proje...=opamp_prj.htm
And here are the measurements and suggestion why op amps sounding is different ... http://members.cox.net/alexhardware/opa.htm
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