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An interview with hifi legend Nelson Pass

By | February 21st, 2018|Categories: Part-Time Audiofile|Tags: , , , , , , , , , |


The man, the myth, the legend: Nelson Pass

Part-Time Audiophile talks to Nelson Pass

Nelson Pass formed his first audio company with a friend while studying physics at the University of California-Davis in the early 1970s. He went on to co-found Threshold Electronics and design the well-regarded Adcom GFA-555 amplifier. In 1991, he started Pass Labs to further explore his ideas about amplifiers and other electronics.

In his four-decade career, to paraphrase a line from “Lethal Weapon,” Pass likely has forgot more about building amplifiers than most engineers will ever know.… Read the full article

KIH #52 – Nutube

By | December 4th, 2017|Categories: DAR|Tags: , , |

Had I heard a preamp with a Korg Nutube in it? That was np aka Nelson Pass. I had not. But with Google being everyone’s favourite uncle, I had shortly afterwards at least read up on it. Now I knew that a Korg Nutube, not a keyboard, looks like a larger 17-legged opamp but is actually a device with an anode grid filament that operates like a triode and exhibits actual twin- triode curves. Yet it is built by applying vacuum fluorescent display aka VFD tech from Noritake Itron Corp.… Read the full article

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Burning Amp Festival November 12th in San Francisco

By | October 18th, 2017|Categories: Part-Time Audiofile|Tags: , , , , |

San Francisco, CA November 12, 12017 — Burning Amp Festival 2017 is coming to the Fort Mason Center in San Francisco on Sunday, November 12th from 8:30 a.m. to 8:00 PM. New This Year: BAF’s hours have been extended due to the increased interest and popularity of DIY audio amongst music-loving enthusiasts of all ages.

Held in the fall since 2007, BAF has grown into a premier international event for do-it-yourself audio enthusiasts and professionals.  DIY audio is the original maker movement dating back to the 1940’s and 1950’s when Hi-Fi was in its infancy, and a lot of great-sounding equipment was assembled at home by enthusiastic amateurs.… Read the full article

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Introducing The Occasional Magazine

By | October 5th, 2017|Categories: Part-Time Audiofile|Tags: , , , , , , , , , |

Welcome to the evolution.

Occasiona-Magazine-cover-NEWThe Occasional Part-Time Audiophile is a new thing. Another experiment. And while it may be new to us, it’s not exactly new. The history of our hobby is as much a story of the writers, and the magazines that wrote for as it is of the companies, and designers that have also come, and gone. I want to respect that history because it’s worth celebrating. Even if I’m no one special. One paragon of the industry, not so long ago, said that my efforts were interesting, but “Seriously, Scot.Read the full article

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Pass Labs New More Affordable XA Series Class A Power Amplifier

By | April 17th, 2017|Categories: Positive Feedback|Tags: , , , , , , |


[Note:  All components in BOLD are loaned; all components in standard face are owned by me.]


The GamuT Audio Zodiac Reference Loudspeakers and Balanced Audio Technology VK-255 SE stereo amplifier.

GamuT Audio Zodiac with SACD rack_web

The GamuT Audio Zodiac Reference Loudspeaker next to one of our racks of SACDs.


The Evolution Acoustics MM2 Loudspeakers with a pair of Audionet MAX monoblock amplifiers and the PRE G2 preamp on the Walker Audio Prologue Rack.


GamuT Audio Zodiac Reference Loudspeakers; Evolution Acoustics MM2 loudspeakers with Wave Kinetics isolation feet; Nova Rendition II loudspeakers outfitted with Walker Audio Reference HDLs on the upper and lower bi-wires, and Townshend Audio Super Tweeters, all contacts treated with Walker Audio Extreme SST Contact Enhancer.… Read the full article

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Pass Labs launch new XA Series Class-A power amplifier

By | April 17th, 2017|Categories: Part-Time Audiofile|Tags: , , , , , , , , , , , |


XA25 stereo power amplifier.

Pass Labs will be showing off their brand-new XA25 Power Amplifier at AXPONA this week, and announced today that the company has started shipping the Class-A amps which have an MSRP of $4,900 USD ($6,500 CAN).

According to Nelson Pass, the brand new design embodies everything that traditional, and current designs feature, but with lower-power requirements, a more simple single-ended circuit with fewer parts, and gain stages in the signal path. This translates into lower voltages allowing for higher-bias current in gain devices to run more deeply into Class-A.… Read the full article

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First Watt F7 Amplifier

By | March 28th, 2017|Categories: Positive Feedback|Tags: , , , , , , |

The First Watt series of amplifiers started as an exploration of uncommon circuit designs in a low wattage format, and has been an ongoing endeavor for two decades now. From Nelson Pass we have seen many an iconic audio product, such as the Threshold electronics, the Stasis circuit that Nakamichi commissioned, and of course the Pass Labs products. You must wonder how a designer can stay so creative over the years, and where does this diverse collection of circuits come from?… Read the full article

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The First Watt F7 Power Amplifier – Simply Sublime

By | January 29th, 2017|Categories: Positive Feedback|Tags: , , , , |

First Watt F7 Power Amplifier

When I first requested an opportunity to write about the next new First Watt amplifier, I was candid with Nelson Pass that it was possible my Von Schweikert Audio VR-35 Deluxe loudspeakers and passive Bent Audio AVC-1 linestage might not be a good match for any First Watt amplifier. Several months later, I received a note from Nelson informing me that a First Watt F7 was cruising its way from his Sea Ranch, CA. digs to the Tune Saloon in Southern Indiana.… Read the full article

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Impressions: Robinson's Brutus Awards for 2016, Part The Second

By | December 10th, 2016|Categories: Positive Feedback|Tags: , , , , , , , , , , , , , , , , , , , , |

Gather around, audiosports fans! It’s that time of year again…Positive Feedback‘s Brutus Awards season. Here is ‘Part The Second’ of Robinson’s Brutus Awards 2016. Part 1 can be found HERE.

Electronics, Part 1

Gryphon Audio Kalliope Quad and Qcto (256fs and 512fs) DSD DAC

Robinson's Brutus Awards for 2016

The Gryphon Audio Kalliope DSD DAC upon arrival… (photograph and processing by Robinson; Freehand style pipe by the Czech Pipemaster Michal Novak. Two works of art!)

Here was one of the true audio surprises for me in 2016.… Read the full article

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