I have right now 2 cd players at home:
Old Technics SL-P1000 which I just purchased and fixed (without any mods,based on pcm54hp)and modded Rotel 991 (installed second transformer, reference XO,opa627,PCM63p-k).
I make some comparsions between 2 player.Rotel cleraly winner on small level signals -60 and -80 db (I have Denon test cd).On Technics is very strong quantisation noise at such small levels.Basses is also better and more articulated in Rotel.
But overall Technics have more opened and dynamic sound ,more drive.
So,for me is no clear winner.
Strange.
Old Technics SL-P1000 which I just purchased and fixed (without any mods,based on pcm54hp)and modded Rotel 991 (installed second transformer, reference XO,opa627,PCM63p-k).
I make some comparsions between 2 player.Rotel cleraly winner on small level signals -60 and -80 db (I have Denon test cd).On Technics is very strong quantisation noise at such small levels.Basses is also better and more articulated in Rotel.
But overall Technics have more opened and dynamic sound ,more drive.
So,for me is no clear winner.
Strange.
Hey, another maniac 
I have also tested both chips.
PCM54:
11 pieces, regarding distortion all have been bad or mediocre on -60dB, adjusted MSB.
Noise was bad in Denon DCD1420, claims to be real 20bit *lol*
Noise was better in a DCD1500.
PCM63:
7 pieces, better but disappointing. Noise floor good but that makes distortion even worse.
Maybe high oversampling rate is not good for sound
Try PCM56 with MSB adjust, get a DCD1500mkII and a bunch of 25 PCM56, replace standard pots with multiturn and you will see...
I have also tested both chips.
PCM54:
11 pieces, regarding distortion all have been bad or mediocre on -60dB, adjusted MSB.
Noise was bad in Denon DCD1420, claims to be real 20bit *lol*
Noise was better in a DCD1500.
PCM63:
7 pieces, better but disappointing. Noise floor good but that makes distortion even worse.
Maybe high oversampling rate is not good for sound
Try PCM56 with MSB adjust, get a DCD1500mkII and a bunch of 25 PCM56, replace standard pots with multiturn and you will see...
i always liked the PCM58 DACs ...
This discussion brings back fond memories. For some time, I had an Onkyo DX-5700 (aka "old tank") a while ago that I got to sound pretty good. It used a pair of PCM58 DACs. Made some power supply changes (based on scope pictures, considered the changes improvements ) to reduce noise and (of course ) messed around with I/V converters and filters. Was actually pretty happy with it. Was JUST about to put in a low jitter clock, but the laser died and I couldn't get a replacement anymore. 
mlloyd1
This discussion brings back fond memories. For some time, I had an Onkyo DX-5700 (aka "old tank") a while ago that I got to sound pretty good. It used a pair of PCM58 DACs. Made some power supply changes (based on scope pictures, considered the changes improvements
) to reduce noise and (of course ) messed around with I/V converters and filters. Was actually pretty happy with it. Was JUST about to put in a low jitter clock, but the laser died and I couldn't get a replacement anymore. mlloyd1
Hi Anthony & Bernhard ,I am for a long time a PCM 56 aficionado , at this time i am using 4x PCM 56 in non-os with MSB trim inplemented , and a straight wire from the I/V resistor to the RCA jack , and the sound beats all the DACS I have tried , except maybe the 1541 for the treble quality .
For now I have to test various supply voltages , it's a bit hard because I think the MSB adjustment (since the MSB trim is taken from the -V) .
Anthony , I think that yet in 16 bits the LSB weights only about 70 microvolts , and this level could already sink in the supply noise , that could be a reason for 16 bits is already sufficient for our purpose .
For now I have to test various supply voltages , it's a bit hard because I think the MSB adjustment (since the MSB trim is taken from the -V) .
Anthony , I think that yet in 16 bits the LSB weights only about 70 microvolts , and this level could already sink in the supply noise , that could be a reason for 16 bits is already sufficient for our purpose .
guytou said:
Hi,
do you use 4 x per channel or total ?
Which value for I/V ?
I read that PCM61 and also maybe PCM56 can work with high value of I/V resistor without distortion.
If treble quality is not satisfying, try other chips, performance varies a lot !
I also think that 16 bit is enough because higher linearity isn't possible anyway.
It only increases dynamic or in other words lowers noise floor, but then distortion is more noticeable.
Manufacturers claim to have 20 or more bit but my test of PCM63 and PCM1702 show other result.
PCM1702J, differential mode, left and right channel.
PCM56
You can see noise floor of PCM1702 is better because of more bits, but distortion is worse.
You can directly compare pictures with left side y scale.
Noise floor is -60 dB both DACs @ 1 kHz.
For PCM56 it is flat for 1702 noise gets better to 7kHz.
Hi bernhard , i'm using 2 PCM 56 per channel with a common 750 ohms I/V resistor , but when I was with 1 DAC per channel and a resistor of 1k2 (=Zout) , i found the sound OK .
Now with 2 DACS in parallel , it's seems like I lost some accuracy , but maybe I have to try separated I/V resistors, or return to a single DAC and a active discrete I/V stage , but it's clear that the best quality I've obtained is with 1 DAC per channel for the moment.
I confirm it's worth to inplement MSB adjustment , the result is on another level (don't howl , i'm adjusting with my ears !).
Please continue your very interesting search(since I'm little involved in measure , it's useful ) and congratulations for your DAC project , I'd like to do too a 16bits/192 with a PCM 56 and a 8 bits to do a good DAC for DVD-A .
Now with 2 DACS in parallel , it's seems like I lost some accuracy , but maybe I have to try separated I/V resistors, or return to a single DAC and a active discrete I/V stage , but it's clear that the best quality I've obtained is with 1 DAC per channel for the moment.
I confirm it's worth to inplement MSB adjustment , the result is on another level (don't howl , i'm adjusting with my ears !).
Please continue your very interesting search(since I'm little involved in measure , it's useful ) and congratulations for your DAC project , I'd like to do too a 16bits/192 with a PCM 56 and a 8 bits to do a good DAC for DVD-A .
mlloyd1,
So we are in two! I still have that player, and it is the one to beat.. and it's not easy! I have implemented [back in 97] a careful reclocking, and a general cleanup, because the digital section was incredibly noisy. But the Dac/ analog part.. it's a mystery for me, why is it sounding so good. The problem is, that also mine is ailing, the extreme mileage in its spindle motor... so I am using it only very rarely these days.
Ciao, George
So we are in two! I still have that player, and it is the one to beat.. and it's not easy! I have implemented [back in 97] a careful reclocking, and a general cleanup, because the digital section was incredibly noisy. But the Dac/ analog part.. it's a mystery for me, why is it sounding so good. The problem is, that also mine is ailing, the extreme mileage in its spindle motor... so I am using it only very rarely these days.
Ciao, George
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