David Vorhis' Listening Room

It was a fortuitous summer season visiting and listening to friends' Hi-Fi setups. I've known about Dave since the 1980s, having built his Dyna PAS preamp modification published in The Audio Amateur. Even if we've corresponded via internet for many years and I've referred to his projects in this blog, I never had the pleasure of meeting him until this past summer. 

It was a wonderful afternoon of talking shop and enjoying music with Dave and his son, Michael, also an avid audio DIY enthusiast, who is well versed with horns and drivers by Yoshimura Acoustic Labs as well as in restoring vintage Jensens, amongst others. I went home with a wealth of new audio knowledge + a pair of Fulton FMI 80s.😉 

Thank you for being such gracious hosts! 

Monochrome pictures of Dynaco components are courtesy of the web, the rest + video clips by yours truly. 

And now, I bring you Dave...

AR-XA, Dynaco PAT4, ST-120 and A25 speakers

My audio journey began 55 years ago at age 17 when I had a mostly Dynaco system all purchased with grass-cutting money--- AR-XA with Grado FTR, PAT-4, ST-120, FM-3 and A25 speakers. I was very happy with that system, but my audio world changed two years later when I heard Audio Research Corporation (ARC) tube electronics and Magneplanars for the first time. There was something about tubes that made music more natural, more real, than any transistor amps I had heard. ARC gear was way beyond my student budget, but I quickly discovered the gateway drugs for those curious about tubes—the Dyna PAS and ST-70. They sounded much better than my PAT-4 and ST-120.

Dynaco PAS 3 preamp + ST-70 power amp

Yet as much as I liked the Dyna tube gear, I was curious to see if I could make it sound even better, closer to ARC. I studied the ARC schematics, and before long I was replacing resistors and capacitors in my Dyna gear and adding power supply regulators. The changes that sounded like improvements stayed; any that didn’t were removed.

Vorhis Dyna PAS-mod preamp featured in The Audio Amateur

One thing led to another, and I ended up writing a series of articles on the PAS modifications which were published in a hobbyist magazine called The Audio Amateur. That was over 40 years ago. With hindsight, I would do things quite differently today than I did back then, but that’s often true in life isn't it?

In the years since then, a lot of gear has cycled through my system, some DIY and some commercial. I even spent several years with an all solid state, all commercial system before rediscovering the natural sound of tubes. Along the way, I learned not to trust reviewers. What matters is how something sounds in my system and in my room. We all have different priorities.

Fortunately, I never disposed of my records. I even have the first record I bought as a teenager – "Swiss Movement" by Les McCann and Eddie Harris. Acoustic jazz from the 1940s through 1980s accounts for roughly 70% of my listening, and the rest is mostly classical.

Top shelf: Analog Instruments Siggwan Tonearm
Middle shelf: Cambridge CXC CD Transport and Fisher FM100B tuner
Bottom shelf: A pair of modified Eico HF22 mono blocks utilizing
a 6SN7 floating para-phase inverter circuit  

During the early years of my audio journey, I assembled kits in order to save money. Today, however, my hi-fi is mostly DIY for the simple reason that I enjoy building and tweaking my system to achieve the sound that I want. I get the most satisfaction listening to my favorite music on equipment that I built. More specifically that means high-efficiency horns and low-power tube amps.

DIY Western Electric 124 mono blocks with Acrosound TO-330 output transformers driving Jensen A15PMs, Yoshimura Acoustic Labs (YL) 5500-G drivers in YL MB150 horns and YL D18,000 tweeters

Jensen A15PM in an open back cabinet, YL 5500-G driver + YL MB150 horn + YL D18,000 tweeter
6 dB slope crossover at 350 Hz and 7 kHz fine-tuned by ear!

Yoshimura Acoustic Labs (YL) was a Japanese company that made speakers for theaters and home systems, many of which were based on Western Electric horns and compression drivers. In the US, YL is perhaps best known for some of its engineers who left YL to form their own companies. These include Seya Goto (founder of Goto), Endo San (founder of ALE Acoustics) and Koizumi San (founder of Onken).

DIY Western Electric 124 amp
with vintage iron and some modern parts

Top left: Audio Innovations T2 MC SUT
Top right: DIY single stage 5687 with Audio Note output transformers line stage preamp
Middle left: DIY D3a/5687 phono preamp
Middle right: Audio Note DAC started out as an ANK 2.1 kit upgraded with Black Gate caps in the PS, AN Kaisei caps and a mix of AN non-magnetic and silver tantalum resistors and wired with AN-Vx in the signal path
Bottom: power supplies for phono and line preamps
On the floor: Emotive Audio 12B4A line stage preamp

A closer view of the D3a/5687 phono preamp

Turntable: Galibier Gavia & Tonearm: Fidelity Research FR-64S; 

MC phono cartridges: Mutech Hayate, Koetsu Black or Benz LP

Of course, I am always making changes and planning new projects. Since Joseph’s visit, I replaced the output transformers in my phono preamp with Audio Note units and I added a new turntable drive system just released by Thom Mackris of Galibier.

The project I am working right now is moving the line stage from its proof-of-concept configuration to a new chassis. Next, if all goes according to plan, I will tackle my first veneering project. It’s time to make my speaker cabinets look a little less DIY!