Sorry Dave I asked what is the primary impedance at OPT to see if it can be reduced to more output power.
I will check the bias in a couple weeks and will spend some time with my multi-meter and try to find the primary impedance of the output transformer. However, I am really not inclined to tinker with the transformers. I don't need more power and I believe the transformer quality is already darn good.
I DO believe there is a qualitative difference among transformers, but I THINK the transformers in my SE40SE are at least good. I had a delightful discussion some years ago with Jack Elliano at Electra Print. I don't remember if I telephoned him or if he telephoned me. In any event, after chatting with Jack for about 10 minutes I was convinced there IS a qualitative difference among transformers. Both Quality Control and the interleaved winding technique are significant and I believe Jack winds the good stuff. My belief in this has not changed.
My modified Golden Tube SE40 already sounds extremely good - vastly better than my unmodified Cary 572SE MK2 SET. The Cary amp has very good parts internally and had a super fancy Sterophile Class B rating when introduced. Cary even used what appears to be POI coupling capacitor and a few other better quality capacitors under the hood. The Cary 572 should have good iron. The 572SE MK2 should sound better than my modified Golden tube SE40 or at least closely similar in quality, but the comparison is not close. Also, several years ago I had the chance to listen to a test project on the Golden Tube and a Atma Sphere 60 watt amp at a friends home a few miles from my home. Yes, there were differences, but the modified SE40 Golden Tube was darn close. Perhaps the Bass from the Golden Tube was better and the midrange & highs were slightly better from the Atma Sphere. I convey all of this to convey that my modified Golden Tube isn't a "project dog" needing significant help. The Modified Golden Tube SE40 is a wonderful amplifier and the transformers must be at least "very good" in terms of their quality.
Next, the output transformers in my SE40 are whoppin huge! They are the size of a large grapefruit. This has 2 impacts. First, they barely fit in the chassis. Second, they would surely be very expensive to replace with something from Jack Elliano. If an ST70 PA060 transformer from Triodeelectronics costs $165, a fancy one from Jack should probably cost $220. The "whopper" in my Golden tube would probably cost twice that amount and then... would it actually fit inside the chassis?
I will convey what I find for the primary impedance of the output transformers when I check the amp in a couple weeks. I plan to check the bias on the vacuum tubes to ensure there isn't any wandering.
Oh, I do have a related question... how often should I check the bias on my vacuum tubes - perhaps annually or every 6 months depending on use ?
When I red-plated a couple weeks ago I hadn't checked the bias for perhaps 2-3 years. I am guessing this is probably too long.