From the Vault: The Borbely Preamp

"Designing a preamp is probably the most challenging engineering task in the audio chain, and many designers have invested a lot of time and effort in it," wrote Erno Borbely in this original 1985 article for the Audio Amateur. "My reason for designing this preamp is quite simple: I wanted to have a top-quality preamp without paying megabucks for a Levinson or Accuphase unit. It is up to you to decide whether or not I have succeeded in achieving the same quality." This article was originally published in The Audio Amateur Issue 4, 1985, and is still frequently referenced.

German audio interface specialists RME Audio, announced two new solutions designed to improve the performance of its ADI-2 series of converters in critical applications. The RME DPS-2 is a super low noise linear audio power supply with a unique µfilter and sensor technology that adds a wide range of unique and highly useful features such as offering two differently filtered outputs. The second product is the LNI-2 DC, an active DC filter with galvanic isolation.

Regulator Needed for Stable, Noise- and Ripple-Free DC Relationship. Does your nice circuit get what he needs from the power supply? Jan Didden explores when a regulator is a regulator. ...when it regulates, you’d think. Yet, in many online fora and discussions you see circuits that ‘do something’ but there’s absolutely no regulation taking place.

audioXpress' November 2022 cover highlights this year's Speaker Design Competition, an extensive Market Update on Wireless Audio technology and two articles addressing Digital Signal Processing techniques. Frans de Wit explains the real improvements that can be achieved on power supply design for high-end audio systems, and Chuck Hansen opens up a valuable series on Power Transformers for audio electronics. Finally, Scott Dorsey visits the Lundahl Transformers factory in Sweden, while Richard Honeycutt revisits Voltage Regulator (VR) Tubes used in Audio Amplifiers.

In this second article, Brian Lowe (Belleson LLC) continues his search for the Unicorn of "Measuring Voltage Regulator Ripple Rejection," this time focusing on the test fixtures. Testing a voltage regulator with exceptionally good performance requires an even more exceptional signal source and measurement setup to measure sub-microVolt ripple across a wide frequency range. Complementing the final article, Jan Didden, offers an informative sidebar about super regulators. This article was originally published in audioXpress, June 2019.

In this article Brian Lowe shares a fascinating journey in his search for a "Unicorn" that is measuring voltage regulator ripple rejection - or power supply rejection ratio (PSRR). Lowe is the founder and principle engineer at Belleson, LLC, and he has devoted a lot of time to this fascinating "quest." This article was originally published in audioXpress, May 2019.

In this great article, author Are Waagbø, himself a confessed "a passionate 50-year-old hi-fi amateur, with many years of practice and experience," and admirer of Erno Borberly work and designs, shares his experience in the relentless search for "the ultimate audio voltage regulator." As Waagbø writes, "Testing more shunt models with selected components and numerous listening tests led to one current-source-fed super shunt, developed by Erno. I developed the PSU, which, together with the sophisticated shunt, sets a new standard for audio voltage regulators." This article was originally published in audioXpress, February 2008.

Discrete, logic and analog semiconductor specialist Diodes has introduced a raft of new ICs for consumer electronics and networks, together with new voltage converters and regulators targeting a range of interesting applications for the audio industry. The new AZV5001 headset detection IC is particularly interesting.