DRA KIT - battery powered real multibit 16 bit 192 kHz digital-analogue converter
Plus version – more strictly matched converters, paper based PCB and higher grade parts
The DRA available in several versions as a kit as well as a finished product.
For ordering the finished version with 3 years warranty, tick all options above!
Why does an internationally recognized audio designer develop a premium product based on a chip that had not been produced in the last decades?
The response from the commonplace kind would be that you must listen to it. But to understand it really, we need to be clear with some of the facts. Once we are clear with these facts, we need to take stock and put them onto the scale again.
First of all the further development of the multi-bit technology was put on hold not at all because of practical and theoretical obstacles. Purely economic reasons led manufacturers to quit the production of real multi-bit D/A converter. The promising pulse mode (one or few bits) quantified conversion was quite a rational direction from several aspects, if not at all it was more rational from every aspect. Of course some high-end manufacturers put efforts in reviving the old technology, therefore after some years of silence, the Burr-Brown – owned by TI these days – launched its new, top real multi bit super-chips: the 20 bits PCM1702 and the 24 bits PCM1704. Though these are out of production by now, they are still in the top league based on their objectively measurable parameters, as well as according to subjective test results (not to mention their prices on e-bay).
Based on subjective tests of experimental versions – even with relatively simple implementation – it became more and more obvious that the story of PCM56 has not yet come to an end. That deep and touchable imaging, the natural dynamics and atmosphere that can be reached by these unambitious 16 bits circuits well worth to achieve much more than professionals and market had assumed from it till now.
So why have not been these chips hyped by D.I.Y. communities, or why have not been they implemented by big names at that time?
Although it was not so cheap deal, it was nowise positioned as flagship product. The stable working at 384kHz, it was obvious to implementing in oversampling and digital filtering circuitry, despite it was not so mature at these days.
Due to mono set-up and using less and less current MSB first serial timing protocol instead of industrial standard I2S, perhaps the solicitous, incorrect digital interfacing was the main obstacle to the overwhelming success in the do-it-yourself world.
Not to mention that however 16 bits, it has 15 bit monotonicity, so we need to set very accurately the two half sections above and below crossing zero by external surrounding if we want to make big hit. Extra care is needed on details like avoiding current leakages.
Thus the decision is born: create new quality utilizing all experiences accumulated till now.
The kit contains fitted, soldered, measured, adjusted, working panels without input and output connectors and batteries. Depending on the matching tolerances of the converter chips, PCB material and other parts are available at two different levels: normal and plus levels.
Matched PCM56P-K converters
Paper based PCB board for the converters
2 SPDIF inputs can be RCA or BNC (can be ordered separately)
Lithium iron phosphate (LiFePo4) batteries minimize noise with very low inner impedance (can be ordered separately)
board pin connector for I2S input allow experimenting with USB-I2S modules
fs up to 192 kHz, but 176.4 kHz acccepted at I2S input only
Discrete low jitter interface logic
I/V conversion in passive way, with resistor and voltage gain stage
Output voltage: 1,9V