It started when I tidied up my storage bin on last weekends, I remember that I had an unused AD1865 DAC complete board from my previous DAC project. This board is okay, I think it performed quite well at that time, but I immediately replaced it with another DAC project because my curiosity is much faster than waiting 100 hours of capacitors break-in.
So here it is, an old AD1865 DAC board with new refinement and better calculation, using all parts I have in my bin. The building cost is nothing because all the new parts are already in my hands.
This AD1865 DAC is oversampling DAC using CS8412 and SM5813APT 8x oversampling, a very common implementation from many CD Player in 90's. In this case I copied the concept from Teac Esoteric CD Player especially at the LPF calculation.
What changes in this build is the regulator power supply for AD1865 analog voltage input which previously using combination between LM317/337 and TL431 shunt regulator, but now it shared with the op-amps power supply using LM317/337 then also to supply to the AD1865 analog voltage using 7805 and 7905 fixed regulators.
Power supply requirements for AD1865 DAC does not need so much current. This DAC is very efficient. A 12 VA transformer is sufficient to power up all the IC's. The difference is in the LM317/337 resistor calculation along with the capacitors filter which I think give the best ripple rejection performance.
The next thing to do is the DAC chassis. We all know that fancy thick aluminum chassis is expensive. I still have an unused brand-new steel chassis, a locally made, thin and not so great. But using this chassis will not harm the sound quality at all.
It looks good as well.
The chassis here does not have any holes for any terminals required. I need to make a few holes for DAC input/output. This is the most time-consuming work since precision is my goal.
With all the boards ready, it is now the time to put them all inside the chassis.
The overall DAC appearance low profile, wide and narrow size chassis. Looks like professional audio equipment because of the racks mounting holes on each side. I am not using any power switch, so this DAC will always be ON. This will be trouble-free since less components are involved, even at the power switch.
The front panel are clean, only having 2 LED. The red LED for power indicator and the green LED for digital signal present coming from pin 28 of CS8412 IC.
As usual, I check again all connection between IC's pin and make sure all voltage are correct before put all ICs to the sockets.
This DAC build is all finished.
I must say that AD1865NK DAC has its sound characteristic, which is very clean and lively music presentation. The vocal characteristic is warm, blending with overall music instruments with precise and balance.
To be honest, the sound performance result is beyond my expectation, far better when it was tested. This DAC will be in my audio system, and I will be proud of it since I built it with the most economical resources and effort.
Cheers.
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Fantastic job.I think than non oversampling is better for this chip. It is a little bit machanical.
ReplyDeleteHave been through both OS and NOS, and they have their own characteristic. For this OS AD1865 built, I love how this full-bandwidth music presentation with great detail on mid-range.
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