CD Mod- Avoid opamps after TDA1543?

[bezobraznia]

Hello,
I have Philips CD614 cd-player with TDA1543 dac... Unfortunately signals that came to it are already oversampled, but this is not my goal... So question: is it posible avoid output opamp stage with help of Doede Douma idea for increasing power.
Doede Douma TDA1543 DAC part

Thank You in advance!

Attachment: shematic of the same part on my CD-614

edit: My idea is using only one TDA1543, not eight.

[00940]

You'd have to change the 270R resistors for something like 2.2K.

But this sounds better to me :Single rail, active I/V for TDA1543, TDA1545A

[bezobraznia]

Thank You for reply, but I don't want replace opamp with discrete part in output. I just want that sheme:
cdm4 -> decoder -> dac tda1543 -> amplifier

Reggards!

[00940]

If I wasn't clear...

Yes, you can use a simple resistor for the I/V as done by Doede.

Just remove from the cdp the two LM833, the caps 2660 and 2661, the resistors 3660 and 3661.

You thus have access to the tda1543 output pins (pin 2 of the opamps). From pin 2 to gnd, add a 2.2K (or 2.7K) resistor, in parallel with a 1500pf cap (on each channel obviously). Then add a 0.47uf cap in between pin2 and the output to block DC offset. You're done.

[bezobraznia]

Thank You very much Ben, You was so comprehensive!
Now modding process is understood to me!

Best reggards!
Niki

[00940]

I'm sorry, I forgot that your TDA1543 wouldn't have a 9V supply as Doede's. The value I gave for the I/V resistors are too high.

See : http://www.diyaudio.com/forums/showt...483#post173483

http://www.pinkfishmedia.net/forum/s...12&postcount=5

[bezobraznia]

I was thinking about independant power ... i have small 12VDC transformer and plenty of space inside CD player
I will make it regulated and it would be no problem sending it to pin.5 VA+ , i suppose that will have to break connection of pin.5 with CD-Player then?

Niki

[Scorpio(DDMF)!]

If you're considering moding the CD-614, my suggestion would be to optimize decoupling first (especially one of the M50432 decoder/filter).

Layout is a mess on this unit

I think you'll be pleasantly surprised by the results

Cheers!

[bezobraznia]

Thank You for reply, I'll do that, but what You mean "especially one of the M50432 decoder"? Be more specific please? Talk to me in "pins and farrads" if it's posible
Thank You in advance!

Best reggards!
Niki

[bezobraznia]

I was made changes with standart 5V from CD player and 3 x 1Kohm like 00940 propose. Output capacitors - Wima MKP 0.47uF
There is much improvements in the sound, especially in mids.
Thank You!
Reggards!