Output tubes burn-in

Whart, Years ago, a friend gave me a Weston milliamperes meter device. Connected to it is a "banana" plug that fits into the balance and bias ports on the Dual 75. I follow the biasing insturctions outlined in the ARC Dual 75 insturction manual. It works great.

I'm "Old School" and have owned this amp since it first came out. I've heard that ARC built only 130 of them.

Tpreaves, That's the problem with listening...once you hear/hit that "magic" sound, you always want it to be there. Isn't that what we audiophiles strive for in our listening?

Whart, The ARC gear I have has been with me since about the early 70s. I have the D 75 and D51 amplifiers and the SP-1C preamplifier which was WZJ's first preamp, I believe. The original face plate it came with said "Electronic Industries." I later got the one I now have which says Audio Research (its a rack mount plate). I'd love to hear some of their new equipment, but now-a-days they are way out of my league.
Did you ever listen to the D75 with the speaker wires reversed from the normal connection? Their literature says the D75 (and the D51) was "an INVERTING amplifier - the output signal is 180 degrees out of phase with the input signal." From that statement I've always listened with the speaker wires reversed (at the amplifier) from the normal amp to speaker connection. The resulting sound is simply seductive. You hear more detail, delicacy, and atmosphere than you would ever hear with a standard connection. I asked ARC about this and they confirmed it saying some people preferred to listen to the amp that way. I wonder how many owners of that amp never really realized this and the potential it produced. I listen to it this way all the time.

Whart, ARC does have a museum for their products. Anyone in the Minnesota area are told to stop in. I had mentioned to them on several occasions that I owned the SP-1C and they asked if I would send them pictures of it for the museum, which I did. It sounded like they were still working on what will be on display there, so no literature or photos of the place are available yet.
Here is another story you might enjoy. WZJ personally delivered the preamp to me and an audio friend in Milwaukee back in the 70s. We all three listened to it through my friends Bose speakers. We treated Bill to a prime rib dinner at my friends home to thank him for making the trip down and bringing the equipment. Those days are long gone!
Also, I remember going to a high-end audio store Chicago back then to hear ARC's Dual 100 amplifier. It was a monster, having two huge chassises and a large number of tubes.
Heard the story about ARC’s evolution experiment in sound over the years.
I've owned a Marantz 10B, (which I stupidly sold), had a pair of KLH Model Nines (which I stupidly sold), run by a Marantz Model 15. That never worked well, and made me a devoted tube man. Later, I owned the A&D mercury uni-pivot tone arm (which I....), and finally a pair of Infinity Servo-Static One speakers. The Infinitys’ were great, but they were made out of "bubble gum and tape." Sounded terrific when they worked. The company’s service at the time was horrible. Arnold Nudell had a great product, but very unreliable. I still have two pairs of them in non-working order stored away.
Try the amplifier/speaker lead reversal if you get your ARC amp running. I'd be curious to hear what you think.

Whart, Hope you don't mind another audio story. Since you mentioned Opus One, here is another.
My friend owned/co-owned the audio store "Opus Two" in Memphis, TN. When I visited him back in the early 70s, they had rack mounted Marantz Model Nines (two), 10B and 7C preamp all arranged in a very attractive wood paneled wall. It was stunning to see.
He also had the KLH Nines.
I was helping out one day in the store and in walked Isaac Hayes. He was very shy and was interested in the new "audio chair" that had just become available. It was the chair which had speakers enclosed within a “cocoon” type of arrangement. Isaac asked the price of the chair was and was told it sold for $700. He reached into his pocket, pulled out a wad of money, rolled off seven one hundred dollar bills, and then asked, "Does it come in red?"

Whart, Memphis. My old audio buddy from Milwaukee lives outside of Memphis. When I visited him and his wife about five years ago, we went to Memphis. You are right about your impression of the place. I didn’t care for the city.

I was floored, however, by the beautiful architecture of the homes there (especially East Memphis), and could not believe how much one got for the money in a house...at that time. The homes were beautiful.

My friend was a MacIntosh guy. He had a Mac C-22 preamplifier and 2105 power amplifier. I use to get jealous that his Mac would drive his KLH Nines while my Marantz 15 would clip and cause fuses to blow in my Nines. He also had a Marantz 10B.

There was a rivalry between MacIntosh and Marantz fans during those heyday years at the beginning of high-end audio. You could see it in the advertising literature of the day. Ads in Audio, Hi Fidelity and Stereo Review magazines showed Mac equipment in the home of some rich guy with a black Herman Miller lounge chair and ottoman. One got the sense of “being rich and owning MacIntosh.” Even the gothic font in their name denoted class!

The Marantz crowd beamed with pride at the beautiful brushed gold look of the equipment, and the quality finish. The 10B was simply “Da bomb” as the kids say now-a-days. And, the Marantz crowd believed that their gear sounded better than MacIntosh. I still have some of those old magazine ads in a scrap book somewhere.

Besides WZJ (who I consider the Steve Jobs of audio), the other guy I’ve been impressed with is Dr. Roger West of Soundlabs. I met him at a CES show in Chicago sometime in the 90s. Listened to his speaker and was quite impressed. He is a very nice person, having taken the time to talk. He apparently worked at Electronics Industries and knew WZJ.