Discrete Output Section

Discrete Output Section

This discrete output section was another surprise during inspection as these circuit topologies are usually more expensive than just using a chip based output section.  Many DAC users swear by discrete output sections and they are generally preferred in comparison to IC based amplifier solutions.

To those of you new to circuits and terminology, the term Discrete in this context describes a circuit which uses all discrete components such as transistors, resistors and capacitors, no integrated circuits at all for this circuit section.  Discrete output sections are usually seen at much higher price points as it is much easier and cheaper to just throw in a output amplifier chip.

Power Section

An interesting point about the power section in this DAC is the company incorporated two transformers, using one for the analog section and one for the digital section.  This design concept keeps both sections essentially isolated which keeps any interference in one section from bleeding into the other.

Final notes on circuitry: Many DACs at this price point will offer USB input that generally employs lower grade receiver chips that are only capable of 16/44.1 or 16/48 so it is nice to see the company just ignored the USB option to save on cost and adding a receiver that the end user would probably never use. 

Generally S/Pdif seems to be favored by DAC enthusiasts for PC or laptops  as USB is usually changed to S/Pdif prior to the DAC.  We should note that PurePiper also offers a budget USB to S/Pdif converter unit so this may be another reason they left out the USB input option.

Modification options

Disclaimer:  These suggestions are offered for educational purposes only and modification of your DAC could result in damage and would definitely void any type of warranty.  Any of the described modifications require skills with a soldering iron and understanding of the circuit.  Please leave such modifications to people with the required skills as we dont want you to turn your new DAC into an expensive paperweight.

OpampWe could pull the 2604 and replace it with a higher end unit for the filter circuit.  Without testing, it would be hard to guess of the results would be an obvious improvement or not, however it is an option for modifications none the less. A special adapter could be soldered in to offer the end user the ability to change opamps for testing.

Capacitors
Capacitors in their base function are filters and providing the circuit with better filters usually equates to improved filter function and end sound quality.  Higher grade audio capacitors can improve the sound quality provided you change the proper units.