Output tubes burn-in

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?

Listen while you burn in. It won't make any difference. In most cases the results of burn in is small except for speakers. Enjoy
Alan

Thanks, Kisawyer. Yep, even back in the day, you didn't see those much.
I suspect the really early ARC stuff, including the Pelpoe(?) Industries equipment that WZJ first made, is extremely collectible these days. I owned alot of ARC stuff over the years, had the companion SP 3-a-1 preamp, then eventually went to the SP-10mkii preamp, which I used for a long, long time. Also a succession of amps, including D- 70mk ii, and Classic 60, all of which I used on my Quads. I kept the Dual 75 a for some reason, and used to use it in my home theatre system, which was at one point all tube amps. Kinda got warm watching a movie. :)
The company still makes really good products, and provides amazing support, with that mid-western sincerity that seems so out of place in NY- but I find kind of endearing.
I still have a bunch of older equipment that I eventually need to restore, including a pair of Quad II amps, a pair of vintage Decca ribbons and of course, my original Quad ESLs. Just a question of time, money and priorities.
Thanks for the info, and continue to enjoy your amp. I kinda liked the build style of the Dual 75, with that gap in the cage.

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.

Kisawyer: Man, you are really one of the few! They should reserve a place at the museum for your system. The D-51 was a sweet little amp. I vaguely remember the SP-1, honestly can't say if I ever heard it. You are right, of course, that the products were branded Electronic Industries early on- somehow, I pulled 'Pelpoe' out of my, ahem, ear? I couldn't remember the connection with that name- I did a quick search and they bought him out early on, but I think that was really before ARC. You also know that some of his first amps were basically heavily modded Dynaco St 70's, right?
I doubt i ever inverted the leads- I used the amp with my old Quad ESLs (which weren't quite as old in 1974), and I think i just used the 16 ohm tap. I also vaguely remember something about a floating ground, but I may be misremembering that. It has been a while. I still have all the packing and literature that came with mine (I need to hunt for the screwdriver) so I will dig down when I retube. I need to replace the barrier terminals- they have had their barriers broken off since the 1970's when the amp was in active use- i just never got around to replacing them, and ordered new terminal strips from ARC which arrived yesterday, along with a new set of power tubes.
The company, as you know, went through a variety of 'sounds' over the years. They even introduced a failed solid state product at one point- i think they called it the 'analog module'- they were sealed modules on the circuit board that were 'like' tubes- I don't think that went very far. And of course, they had their 'white period' when the tube stuff sounded drier and less euphonic. I've heard the current Ref stuff and it sounded great on big dynamic speakers.

You should let the company know if they don't already that you are still running these pieces. It would be an interesting PR exercise for them to show an owner who has had their equipment for 40 years and still enjoys it.
That's very cool.