In this post, I will making an external power supply for this Nakamichi DAC-101.
My goal in this modification is to have better linearity from the better power supply components. This new power supply will intended to use at home audio connect to the mains AC outlet.
From my previous post about this DAC unit, the internal 12 volt switching power supply in this unit was broken. I think this could become the common problem for every Nakamichi DAC-101 because of the poor switching power supply design. By using proper size transformer to supply to all DAC components inside this unit, it will improve the overall performance and reliability for sure.
The photo above is tell everything about what this power supply will be made. At the end, there will be a Nakamichi DAC-101 unit and the power supply unit. The separate box between them will keep the aesthetic looking of the Nakamichi still in original state yet the noise from the power supply will be isolated to the DAC unit.
The Power supply the old Bando transformer dismantled from vintage hi-end CD player. This transformer secondary output are dual AC 15 volt in center tap configuration. The transformer total power output is about 90 VA and this is a lot power to supply for the DAC unit.
Actually nothing special in this power supply design. It is a common dual rail power supply with the DC output about +17 volt and -17 volt.
The only great things is the components using here mostly high grade components, such as fast recovery Motorola diodes for full wave rectifier, big 4,700uF capacitor from Nichicon FW and big 220nF Vishay MKP capacitor. The reason I am using those components is because they perform best in the linear power supply circuit.
Those power supply components will be put inside an aluminum casing.
Working with this universal aluminum case require lots of work, especially if I did it manually by using hand drill and grinding.
In the normal situation, I mean without Covid-19 pandemic like this, I better go to specialty workshop and ask them to make desired holes for input and output terminals sockets. The result will be lot better.
Well, this project should be done anyway, so here is the result.
Really okay in my opinion.
The output from this power supply are DC +17 volt and -17 volt with center tap as a ground. This cables will be connect directly to the power input at the Nakamichi DAC-101 using 3 strands of 18 AWG cables.
For the next post, the internal DAC unit need to modify to accept this kind of new voltages configuration.
Stay tune:)
Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.
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