replacing pcm1716 with wm8740 ??

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mekanoplastik

mekanoplastik

Member
Joined 2002
Hi all. :)

I have a cd player that uses the pcm1716 dac and I thought that maybe it could use a better chip to achieve better sound. I found the wolfson wm8717 and wm8740 as a pin by pin replacements, and I would like to know if it is a good idea to replace the pcm1716 with the wm8740.

Here is a link to the wm8740 specs -> http://www.wolfsonmicro.com/product.asp?pid=7

And this links to the pcm1716 .. -> http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=PCM1716


if anyone has a better replacement chip idea… let me know…

thanks
m.
 
S

Smiffy

Member
Joined 2002
Haven't got the bits yet,specs look better than 1716 but i think i may be pushing my luck a bit on the soldering skills.should be able to put them on,its getting the old 1716s off thats worrying me.seems a bit more complicated than swapping the 5532s for AD8620s was.
Smiffy
 
hjelm

hjelm

Member
Joined 2003
There is a WIKI page for SMD soldering and desoldering where it is described how you could do it. Seems like it is not impossible at least. Please report the results i have a PDS507 that sounds like crap and i want to fix it, have replaced opamps and fiddled with the supply with good results but still not really enjoyable.

Does anyone have a feel for if the wolfson DAC's sound good?
 
S

Smiffy

Member
Joined 2002
Does anyone know how high much dc on the output i can get away with.The amp has an input cap,(MF F16)At the mo i am measuring 3-6mv at the input of the final caps.If poss i would like to pull them out as even the best cap in the world isn't as good as no cap at all.
Ta for any help
Smiffy
 
hjelm

hjelm

Member
Joined 2003
Should be fine i think.

Depends a bit on where the input cap on the amp is located. If it is after the input selector you could get a bang when switching source, especially at high volume.

Do remember that you might have offset on the output if you ever change amp later.
 
S

Smiffy

Member
Joined 2002
Hi Hjelm
Ta for assistance
not quite sure about some of these things so better safe than sorry
No input selector as straight power amp(although 2 way selector in me pot in a box so maybe same thing),first thing on input of amp is a 1uf cap which seems a low value.
Smiffy
 
hjelm

hjelm

Member
Joined 2003
(although 2 way selector in me pot in a box so maybe same thing)
Click to expand...

Yes if you switch that one to another source it could make a noise, could be ok but sometimes you forget to lower the volume and get a suprise.

It is not the voltage that decides if a 1uf cap is enough, not too unusual that they are rated some hundred volts so that way it is fine.

If the amp has a too low input impedance though then it might be a problem with bas reproduction but since the manufacturer has placed it there it should be sufficient.
 
Stones

Stones

Member
Joined 2004
Smiffy said:
Haven't got the bits yet,specs look better than 1716 but i think i may be pushing my luck a bit on the soldering skills.should be able to put them on,its getting the old 1716s off thats worrying me.seems a bit more complicated than swapping the 5532s for AD8620s was.
Smiffy
Click to expand...

Smiffy,

Send me a pm and I will try to assist you.
 
Stones

Stones

Member
Joined 2004
Smiffy,

I have replied to your pm and I would be happy to provide some phone support (to lazy to type), or better still if you can get here (south of Doncaster) I would be happy to spare you a beer and a go with various professional smt rework toys.

You may find the following finds useful.

http://www.diyaudio.com/wiki/index.php?page=SurfaceMountDeviceRework

http://www.usbmicro.com/odn/documents/46.html

Or if you are interested in investment (it will be necessary in time) :devilr: search the common online auctions for example “rework”.
 
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