This page contains information about the ONTech DAC 5813. The DAC is built on the "keep it simple" principle.
"Keeping it simple" means that all components are of the highest grade and the that the path from input to output is the shortest possible.
The main component in the DAC is an 18Bit parallel converter - the AD1865N-K from Analoge Devices.
This DAC is one of the best sounding DACís available. It contains an 8 times oversampling filter from NPC. The construction uses the famous SM5813 which has been featured in many high end products.
More than 10 years of experience has been gone into to determining these two main components. Many would claim that this is an old construction and that the components are more or less obsolete, and they are right! But I claim that this is still the best sounding combination today.
The analog power supply is built around an C R C filter which lowers the ripple with more than 20dB. This is followed by an integrated regulator which has a ripple reduction of 80dB and is finalized by 5 transistors coupled as an ripple rejector circuit. In theory, this gives a ripple rejection of more than 180dB (Simulated). In practice, this will be a little bit lower. But the power supply has more than enough headroom for the DAC. The use of discrete transistors ensures very low output impedance.
The digital power supply is a straightforward design using a high quality 5V regulator as well as a 3.3V.
All power supplies use huge capacitors for smoothing. The analog supply has more then 40.000 uF and the digital supply more than 10.000 uF. All capacitors used are high grade / long life, such as Elna Cerafine and Dubilier or BHC Slitfoil.
The supplies are based on separate windings on an E-Core transformer which has a very high noise rejection.
It is rated at more then 20 times the used current.
All in all, this might be your last chance to buy an old-fashioned parallel DAC and not the cheap 1 bit (sigma delta) DACís that most vendors use today.