DIY Regulated Linear Power Supply For Raspberry Pi Under US$20

I tried to be honest. I often laugh reading many feedback in the online forum discussion when they tried to answer a question about: "is it necessary to have a linear power supply for Raspberry Pi?"

Yes, we are talking Raspberry Pi as media player or NAS connected by a HAT to send the digital out to the better performance external DAC. Then will it improve the sound quality by only changing from cheap switching power supply to the linear? I guess you have find this same conversation in many forum as well.

I understand that buying a finished linear power supply product can be costly. Let's say the price of this mostly above US$100 and spending such that money seems totally useless because your opinion already broken from that forum feedback. They are saying that linear power supply for computer is not logical at all to give any benefit. Which in my opinion their feedback has nothing to do with practical experience, but only based on their subjective opinion. Period!

So I put US$20 on the table and made one for you. Let's begin:)

Marantz CD72 MK2 SP Modification To DAC

The old CD player is probably sound better than currently "Hi-Res" audio player. Either you music collection has been shift to the streaming provider, or just like me, converting all my CD's collection to WAV files and stored in one media library for more practical use, then unfortunately this CD player might not be use anymore.

In the most cases, those high quality CD player are already broken. Especially for the optical lens which will wear by ages, then replacing those part might be cost very expensive. There is also an issue that the reliability of replacement part might be not as good as the original. It is frustrating to keep using those old CD player for sure.

I took the example of this Marantz CD72 MK2 SP I owned. I loved the sound quality from this CD player and of course the look. It is copper chassis inside out.

More detail, the DAC IC using in this unit is the best high-performance single bit DAC. It is the TDA1547 along with SAA7350, aka DAC7.

So I think, I will modify this CD player to become a stand alone DAC unit. The goal is having the same sound signature from this old CD player but with better input flexibility like the stand alone DAC unit.