RETRO-MEASURE: Dynaco A-35 speakers (1972-1976). Technological maturity and audio. Comparison of the qSpin predicted room response vs. in-room measurement.

Audiophilia has a rich history filled with many products and ideas over the decades. Many of the "vintage" products can still be found these days on the used market and many carry with them an interesting story or might have developed "cult followings". I find it interesting examining these older "retro" products to help provide context when we think about the sound quality we have these days.

Some companies like the one we're looking at today - Dynaco - founded by David Hafler and Ed Laurent back in the mid-50's are well known. The company's products were popular through the '60-'70s including a foray into quad-channels. The company eventually got acquired and the brand decommissioned by 1980.

Dynaco was known for their amplifiers and "Dynakit"s they sold in the emerging hi-fi market back in the day to audio enthusiasts. Along the way, by 1969, they got into the speaker market with their "A-Series" line of products including the very popular A-25 (>1M sold worldwide according to Ed Laurent) and the speaker we'll be examining today - the less popular, larger Dynaco A-35 sibling.

Thanks again to linnrd for digging up this pair of old speakers for me to examine from his gear archive. It looks like these have been very well taken care of over almost half a Century. Well, at least there's no need to "break in" these speakers. ;-)

SURVEY: What audio playback system and/or streaming music service are you using in 2023?

Hey there gals and guys. I've been busy over the last while getting some things at work going, so this means it's time for a survey to hear from you ;-).

It's always good to know what audio lovers are doing out there and this could of course help me look at interesting topics to examine in the future. The last time I did this was back in 2019, looking at adoption of streaming services and lossy vs. lossless among the readership - much has changed since then!

I've seen various hobbyist poll results over the last while. A common question being asked these days is "Which digital streaming service is most popular?". This certainly makes sense given the growth of Internet streaming over the years, but much too simplistic! As an audiophile blogger, my interest isn't so much about which commercial service is "winning" since it really doesn't matter too much to most of us I think, and will fluctuate depending on where one lives and what services are available. Instead, audio enthusiasts these days have access to all kinds of ways to listen to music and choices to make including whether we like "spatial audio" as a recent feature.

In Archimago's Musings style ;-), let's go deeper and get a detailed survey going, collecting anonymous data on who you are, what you use mostly, and what kind of systems you enjoy in 2023 - not just what music service...

MEASUREMENTS: Intona 7055-C USB 3.0 SuperSpeed Isolator. And Darko & Lavorgna hear no difference with the Silent Angel ethernet switch. [Importance of open discussions.]

Over the last couple years, I've shown in my PC measurement system the benefit of using USB isolation to break ground loops when test devices are connected to the ADC. There was the ADuM4160 device which was limited to "Full Speed" (12Mbps). Then I posted on the Topping HS01 which operates at a fixed USB 2.0 "High Speed" (480Mbps).

Over the Christmas holidays, I got a hold of the Intona 7055-C USB Isolator which can run at USB 3.0 "SuperSpeed" (5Gbps), basically a pass-through device which provides galvanic isolation of the USB signal and ground lines, with the flexibility of being downward-compatible with 480Mbps (most important for USB audio), 12Mbps, and even Low Speed 1.5Mbps devices.

Although audiophiles have been talking about isolators like this for years used in home set-ups, they're really meant for industrial applications where devices with USB ports might be subjected to high-voltage surges and spikes. This "C" model is designed for protection up to a modest 1kV over 60 seconds. The more expensive 7055-D can handle up to 5kVrms over 60 seconds.