Audio Crafters Guild Introduction

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Norman Tracy

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    • Audio Crafters Guild
Audio Crafters Guild Introduction
« on: 10 Jun 2019, 06:18 pm »
Recently I was gently reminded by the administrators of Audio Circle that I am remiss as a circler classified as Industry Member in that I lack an introduction posted to Industry Introductions. Time to fix my oversight. As the following will illustrate “what a long strange trip it’s been” for 30 years now on and off.

I operate a company named Audio Crafters Guild that produces Hi-Fi electronics, loudspeakers, and offers engineering services and custom builds. One could (and I do) ask if ACG is a company or a construct by which Norman services his at times manic compulsion to create and endless fascinations with the intersections of art, craft, technology, and taste we find in Hi-Fi components. I also dabble in high end audio journalism and enjoy being active in Lone Star Audio Fest. I have been an audiophile for 50 years (yes, I’m in my 60’s) watching and participating in the second golden age of Hi-Fi through the 1970s and ‘80s when everyone aspired to and most of us eventually obtained stereo Hi-Fi rigs. While closing in on retirement I continue to work a day job as an Electronics Design Engineer designing electronics for the pipeline industry. My professional résumé includes time in IT (Windows and UNIX), seismic recorder instrumentation design, and the retail side of Hi-Fi/Home Theater/Home Automation. Married to a wonderful woman, we have three sons, three grandkids, and two dogs. My hobbies include sports cars and photography.

ACG was started in 1987 and the first product was the X-DAC 3.0 DAC. It was available as a blank PCB + manual kit, built PCB, or fully built DAC in aluminum case work. This was when audio engineers were learning how much effect jitter has on sound quality and the X-DAC 3.0 used the then new Analog Devices’ AD1891 to asynchronously isolate the DAC clock from CD source. The local clock was based on emitter-coupled logic (ECL). Pardon the low-res photos from early days of digital photography.

By 2005 a trend started at ACG that continues to this day, specifically working with both electronics and speakers. The oneZ single driver full range was ACG’s first released speaker product. Based on the iconic Fostex FE103 driver in a mini-monitor configuration. The 2005 Great Plains Audio Fest (precursor to Lone Star Audio Fest) served as the venue for oneZ’s introduction. The larger speaker I have my hand on in the photo below is a custom commission based on the Fostex FW207 and FT96, very alive and punchy like the better golden age JBLs. Three of these makeup the L/C/R array in a dedicated Home Theater I was commissioned to design and install. Recently returned to that HT for a 4k video and audio electronics upgrade and a dozen years on the speakers are still fun, detailed, and exciting without being aggressive.

ACG displayed at Rocky Mountain Audio Fest 2006 partnering with Facet Audio Labs. The ACG 1000 series of amplifiers were introduced. Available in stereo, mono, and integrated models along with the 1000 Energy Pack upgrade option.

After the 1000 series were introduced while developing incremental improvements to the ICEpower platform an opportunity arose to provide engineering and design work on a project aiming to use music therapy to treat individuals suffering from dementia and other neurological disorders. Deliverables on that project I can share with the NDA no longer in effect included a 100 kHz bandwidth power amplifier and speakers called the N-KEs mk I and N-KEs mk II. The medical research upon which the project was based called for amplification and transducer bandwidths beyond 20k Hz a characteristic that continues to influence ACG designs.

The N-KEs mk I is a special favorite of mine because the director of the project wanted to use a woofer from Hartley Loudspeakers ( a brand that goes back to the very beginnings of Hi-Fi. Hartley Loudspeakers keeps such a low profile I was surprised (and pleased) to learn they remain in business. Project budget allowed for an extravagant implementation in a large sealed enclosure with maple tone wood baffle, ribbon tweeter, and Murata’s piezo super tweeter. The resulting sound made a strong case for the big-box big-woofer architecture for Hi-Fi speakers that ruled the 1960s and 1970s.

The N-KEs mk II is a powered high output monitor using Volt woofer, RAAL tweeter, and DSP for crossover.

At Lone Star Audio Fest 2010 the 1000 series amplifiers were again featured in a tri-amplified system that included DEQX crossover/DAC. Speakers another ACG design with compact monitors and stereo push-pull dual driver subwoofers.

After life outside Hi-Fi required some time off after which ACG returned to Lone Star Audio Fest 2016. Layered Baltic birch plywood is a favored material featured in both the monitor and equipment rack. This monitor uses the Fostex F120A alnico magnet full range driver with AMT super tweeter.

The design of the tube + J-FET hybrid line amp that became 700 NT-JFET preamp started in 2016 and was ready for introduction at 2017 LSAF.

The ‘NT’ acronym conveniently is both the designer’s initials and Nu Tube the name Korg gave their lovely 6P1 direct heated triode around which the circuit is based. The triode juice and tonal density the 6P1 brought to the party inspired the ACG 700 series. For LSAF 2017 an analog electronic crossover was added to the 700 NT-JFET preamp allowing the SEAS based monitors to be bi-amplified.

In 2017 I discovered a special non-typical woofer that meshes perfectly with my design aesthetic. Paper cone, 7” diameter, useable in a sealed enclosure, and a formed silk surround. This led to the Audio Crafters Guild NT10 a mid-sized monitor inspired by and paying respectful homage to Akira Nakamura’s iconic Yamaha NS10. As a young audiophile in the 1970s and ‘80s we had access to many great sealed enclosure loudspeakers, led of course by the legendary AR and Advent models. I really enjoy the tight defined bass produced by hi-fi speakers that successfully use sealed enclosures. I also find they interface especially well with subwoofers. Thus I consider the NT10 ACG’s offering to allow the choice of sealed box bass for the 21st century music lover. Other aspects of my design aesthetic used in the NT10 include a tweeter with response to 30k Hz, Baltic birch plywood construction, and a simple-as-possible 4-element crossover. The NL10 was introduced to the public at LSAF 2018 driven by the 700 NTJ-FET Analog Signal Processor preamplifier and 1000 series amplifiers.

By 2018 with two years of development to the original NT-JFET preamp circuit it was time to incorporate those lessons into a new revision.

The revision B circuit keeps the basic architecture NuTube 6P1 +J-FETs with upgrades including lower noise J-FETs, on-board latest generation low noise voltage regulators and an output buffer capable of effortlessly driving following power amplifiers or headphones. My favorite change is the improved mounting system for the 6P1 that is more rugged, has better suppression of microphonics, and displays the interesting and unique device through the front panel.

As has become my habit LSAF 2019 was the public introduction of the new revision of the 700 NTJ-FET Analog Signal Processor preamplifier. At the other end of the system a hot-rodded version of the NT10 I call the NT10 OCD extended the basic NT10 design adding tone wood braced carbon fiber enclosure and external crossover featuring copper foil inductors and Mundorf capacitors.

And there we have the ‘introduction’ 1987 through 2019. Audio Crafters Guild takes it name from the intersection of art, craft, and technology we find brought to bear on the fascinating endeavor we call high end Hi-Fi. I appreciate your consideration of my efforts towards advancing the state of our art.