Dac Technology Mature?

georgehifi 08-08-2018 6:35pm
4,118 posts

BTW: I remember that maybe Technics invented the first Delta Sigma, and they called it MASH.

Cheers George

I was told that Vimak invented Delta Sigma theory by one of the few high end audio engineers who has serviced the incredibly complex DS-1800Mk2 dac. As I understand it, Vimak Corporation hold the design patents for the technology, or atleast did (as patents expire). The other factor supporting that contention is that Vimak are the only manufacturer to have ever implemented a fully discrete Delta Sigma dac, as opposed to the usual chip-based design. However i’m happy to be proven wrong if anyone has information to the contrary.

I do believe we're both wrong.

From Stereophile: " Philips invented the delta-sigma modulator in the 1960s, and were the first to apply it to CD players in its 1-bit form (switched-capacitor based)."

Cheers George

@georgehifi Interesting. Here is a list of Patents assigned to Vimak Corporation - https://patents.justia.com/assignee/vimak-corporation
That list includes the following patent -

Multiple clock signal generator apparatus Patent number: 5266908 Abstract: A digital-to-analog converter--preamplifier apparatus serving as an interface between a source of digital audio signal data and an amplifier is disclosed. A digital stage receives multiple digital audio signal inputs, a selected one of which is analyzed by a digital audio interface receiver, processed by a digital signal processing device and a delta-sigma modulator prior to passing to the analog stage for conversion from the digital domain into left and right channel analog audio output signals. Volume control is performed on the audio signal in both the digital domain and the analog domain in order to optimize performance and minimize noise. The present invention automatically adjust for input word lengths of greater than 18-bits.

Type: Grant

Filed: January 26, 1993

Date of Patent: November 30, 1993

Assignee: Vimak Corporation

Inventors: Michael A. Koulopoulos, Russell A. Siggelkoe, Thomas R. Hegg

What I am certain of is that Vimak held relevant patents for the only truly discrete implementation of a Delta Sigma dac i’m aware of. And whilst they may not have invented Delta Sigma theory, they developed it to it’s ultimate potential using proprietory technology in the DS-1800Mk2.

This just in! Read em and weep!

The (delta sigma) technique was first presented in the early 1960s by professor Haruhiko Yasuda while he was a student at Waseda University, Tokyo, Japan. The name Delta-Sigma comes directly from the presence of a Delta modulator and an integrator, as firstly introduced by Inose et al (Japan) in their patent application.

The concept is ancient. Calculus comes from mid 17th century. Often it is the implementation or application that is tricky. Da Vinci invented the concept of a helicopter but it wasn’t possible to build one until technology was sufficiently advanced.