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This post is aimed at those individuals still using the old 16 bit chipset, which consists of the SAA7220 filter followed by TDA1541 DAC.(It assumes that you can use a soldering iron.)
In the old 16 bit systems, the 7220 is providing the 4x oversampling and muting.
It is possible to simply bypass the filter entirely and so obtain a non-oversampling DAC which is being fed directly from the SAA7210/SAA7310, without any oversampling in between.
The Method:
The TDA1541 DAC has only three (3) connections to the SAA7220 (word, clock and data).Cut all three lines. The SAA7220 is still connected to the preceding chip, a SAA7210or SAA7310 depending on how old your 16 bit CD player is.
Now connect, using miniture coax (RG196)
pin 1 of the SAA7220 to pin 1 of the TDA1541
pin 2 of the SAA7220 to pin 2 of the TDA1541
pin 3 of the SAA7220 to pin 3 of the TDA1541Thats it!
Results:
Lets start with the bad stuff first. Since the muting function (in the 7220) has been bypassed, the cd player will produce pops and crackles when skipping tracks. Also the pause function no longer mutes the music, so pause is effectively useless. If you can live with that, in return you will getMUSIC!
The highs are cleaner, the mids are exceptionally open (almost like a pentode in triode mode in a vlave amp) and bass seems to go deeper. The bass is still dry however, with snaps and fingers sliding on teh strings clearly audible.
The soundstage is much wider and the entire presentation is OPEN. In fact I felt like I had real musicians playing on a stage in from of me.
Instruments are separated in space, but not etched. And there is much more detail. In fact it seems as though the noise floor has dropped. Instruments which seemed too faint to hear previously now are clearly audible, giving a significantly immersive quality to the music.One thing that I have found a bit strange is that there are some CD's that do not really sound different compared to when teh 7220 was in place.
Anyway, it is a great simple tweak and highly recommended. Thanks to Zarko for his incredibly useful communications.
Follow Ups:
> > Since the muting function (in the 7220) has been bypassed, the cd player will produce pops and crackles when skipping tracks. < <Interesting - because some of the BEST cdp's i have heard produced a very distinct 'poping' noise when skipping tracks.
TBone
But...normally the TDA1541 is followed by some opamp filter stage and buffer. The filter stage is setup for the upsampled frequency.
By removing the upsampling filter, is the filter frequency not too high ? (depending wether your amp has NFB).
You might blow up your tweeters due to excess energy in the aliasing images.
true and the aliases might also cause the output stage opamp to oscillate and fry, might modulate the power supply and could leak HF into the rest of your system. But by all means go ahead and try it.
I forgot to mention: I have elimintaed the ouput stage and am using a single resistor per channel for IV conversion. This is not required for the tweak to work however and I know of at least one person using the tweak with the orginal analogue stage in tact.
Welcome to the Non-oversampling world!> The soundstage is much wider and the entire presentation is OPEN. In fact I felt like I had real musicians playing on a stage in from of me.
Ryan, you are spot on in your description about the sonics benefits of throwing out that "damned digital filter(tm)". I gotta thank Steven Rochlin for posting the first review of the Audio Note DAC 1.1, and introducing me to this revolutionary Back to the Future implementation for Redbook CDs..
> One thing that I have found a bit strange is that there are some CD's that do not really sound different compared to when teh 7220 was in place.
Probably due to lotsa digital filtering/EQ/editing done at the mastering stage?
Anyway thanks again for posting this tweek. I hope you'll get lots of others to try it.
They'll love it.
Enjoy your music (that IS the point),
-Steve (not Rochlin)
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