Output tubes burn-in

As I have always done, I listen and enjoy the burn in process. Part of the key to enjoying high end systems is to witness first hand the changes that occur as things settle in and form the new sonic envelope and space. The same goes for speakers, cartridges and cables. Hey, you have a great system, play it, enjoy it and listen.

Just listen to the music and stop worrying about it.

Pretty cool that you have and still use a Dual 75. I have a Dual 75a that i bought from a dealer in around 1974 and have maintained it over the years, had it recapped, etc. several years ago, and just ordered a new set of output tubes from ARC. I don't really use the amp anymore, but have kept it for sentimental value. Out of curiosity, what did you use to plug into those quarter inch jacks to bias the tubes? I have a meter, so that's no big deal, but I'm not sure how those jacks are wired.
And, fwiw, different tube equipment would seem to react differently to burn in, in terms of sound. I just retubed my SET Lamm amps, I really could detect no shortcoming in hearing the new tubes, in fact, the amp probably sounded better. In burning in my new phono stage recently, (an Allnic) it took forever, and the sound changed dramatically over time.

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?