Ambitious Paradisea+ modds

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polaron

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Joined 2013
Hi everybody
This time I would like your help to upgrade a Paradisea+ dac.
I just bought one second hand, to tweek. I'd like to change capacitors, resistors, op amps and may be the transformer. I think it will be nice to install a very good r core transfo.
Here is a picture of a specimen before upgrade.

I found a few nice posts about tweeking these dacs, but I don't know exactly what are the values I should choose for it.
Here a website with nice resistors and obbligato capacitors.

I will post pictures where you can see the caps values and the colors of the resistors, as soon as receive my dac - maybe tomorrow, if not friday.

With some luck, someone who have already done this will answer to me...

Thank you very much!
 
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polaron

Member
Joined 2013
abraxalito said:
If I were you, I'd focus on installing star grounding on signal grounds as it looks as though the whole design relies on a single groundfill.

What's the DAC chip it uses?
Click to expand...

Hi abraxalito
"The DAC uses the legendary 16 bit/44.1KHz NOS Phillips TDA1545A non-oversampling DAC chip, has no digital filters, uses the award winning National Semiconductor LM4562 operational amplifier for active I/V conversion, and features a vacuum tube buffered output stage (a single NOS GE5670). "

(reviewed by Jeff Day)
Text in this review :
mhdt paradisea
 
abraxalito

abraxalito

Member
Joined 2007
polaron said:
Hi abraxalito
"The DAC uses the legendary 16 bit/44.1KHz NOS Phillips TDA1545A non-oversampling DAC chip, has no digital filters, uses the award winning National Semiconductor LM4562 operational amplifier for active I/V conversion, and features a vacuum tube buffered output stage (a single NOS GE5670). "
Click to expand...

Awesome chip but really a waste to put such an RF-sensitive opamp right after it. Sounds like a useful mod would be converting this to passive I/V - with sufficient filtering the LM4562 could be then used as a post-amplifier (though I'd suggest something faster like AD815 myself).

Also worth upgrading the supply to the 1545 with lots of electrolytics across pins 4 & 5 and another to filter the pin7 reference.

Plenty of opportunities for effective modding with that DAC chip.

Does the Amanero board support EIAJ serial format? - that's what the 1545A expects. If not you could go over to the TDA1387 which is I2S.
 
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polaron

Member
Joined 2013
Well, I was thinking about replacing the original opamp by Sonic Imagery Labs opa or Dexa. But may be your idea of "less is more" is a better one, specially in this kind of circuitry, I guess... but I have to study it, because it's hard for a newbie like me to understand the details of what you are saying, even if it is a simple thing, (I got the idea), and I know it is, but for me still is complicated, but if it makes better results, I can give it a try...

 
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