Output Current from PCM56P K?

[Zoran]

@georgehifi
In this tryout setup I didnt adj. the msb via trimm.
So with adjj. the sound will much better...

 

[guytou]

hi all ,
any comment on how to adjust 4 DAC MSB with a single trimpot ?
how about dispersions between chips ?

 

[Bernhard]

Good question.

If the chips are just parallel, all currents add up, all errors add up, the MSB adjust of one chip compensates the total error.

In the Wadia, chips may carry different data at one time, so it may not be valid to use one pot for all chips.

 

[georgehifi]

Zoran,

PCM56 is happy with anything up to 500 ohm per chip.

You will only loose sound quality with 100 ohm and unnecessary preamp.

Heat is not an issue and depends only on supply voltages.
See datasheet.

Bernhard when you said above you will only loose sound quality with 100ohm, is this compared to 500ohm?
I thought the PCM56 in current output would have it's lowest distortion (best sound quality) at the lowest ohms? I'm confused




Cheers George

 

[Bernhard]

Bernhard when you said above you will only loose sound quality with 100ohm, is this compared to 500ohm?
I thought the PCM56 in current output would have it's lowest distortion (best sound quality) at the lowest ohms? I'm confused




Cheers George

I meant the unnecessary preamp...
100 is very slightly better, but if you need a 5x preamp to compensate for the low output, better use 500.

 

[guytou]

hi George , PCM 56 sounds very good even with 1.3k , as bernhardt already pointed ,IMHO it's due to it's ladder architecture ,not the same than PCM 53/63/1541 ,i.e.different wiring of ladder can present the same/not the same impedance with bit switching .

hope this helps

 

[georgehifi]

I meant the unnecessary preamp...
100 is very slightly better, but if you need a 5x preamp to compensate for the low output, better use 500.

Gotcha

Cheers George

 

[Gabdx1]

hi George , PCM 56 sounds very good even with 1.3k , as bernhardt already pointed ,IMHO it's due to it's ladder architecture ,not the same than PCM 53/63/1541 ,i.e.different wiring of ladder can present the same/not the same impedance with bit switching .

hope this helps

I just tried with 750 R and its awful high in distortion: sounds like a broken tube or cheap tube amplifier!!!

I guess that with 375R it will sound right because the distortion is not bad when the music is playing low, but when like the orchestra has bass and treble and high it’s all fuzzy!

 

[georgehifi]

Mine are sounding very very good with this load whatever it is, the designer said the PCM56's are seeing close to zero ohms, can somebody sim it and back him up?
The PCM56's are slightly warm to the touch and seem happy.

Cheers George


http://www.diyaudio.com/forums/attachment.php?s=&postid=1662993&stamp=1227135832

 

[Bernhard]

The PCM56's are slightly warm to the touch and seem happy.

That depends on the supply voltage.

 

[Gabdx1]

Hi guys, Hi Bernhard !

Just to give you news ill try it with around 33nf and 375 ohm still and if it works fine and fix my bass issue/humming on my sensitive speakers, ill buy the 15nf caps