K, a couple of updates:
1-Talked to Craig, the visit w/ Jack was something of a disaster. The point was to see if he could make something to match the Tango ITs but it seems Jack didn't make anything according to Craig's specs for our amp project and decided to make stuff for a new IMD cancelling 3-stage speaker amp using extra resistors and caps in the signal path. Not at all what Craig had planned on. All he wanted was for JAck to make a copy of the old ITs he used for the 304TL amp but Jack's attention is just on another planet atm w/ his new project. An analogy is that Craig was going up to work on a new Intake system for the 911 turbo flat-6, then Jack shows up w/ parts for a Bentley Continental. Anyway, Craig is backward engineering the IT and if necessary will have someone else make it.
2-The whole IMD claim on the Tangos is actually quite a bit of BS as neither of us heard any IMD and that's much more offensive than THD. Jack's theory is that the Tango windings should produce a bright and shrill IMD sound for things such as horns and such that can go too bright. The Levi did nothing like that, so he's talking a bit out of his ass there. He also believes coupling caps don't affect sound signatures. More BS. Point is, I think it's best to leave the amp design process to Craig, and Jack stick to making transformers rather than impacting our overall design. Note, Jack doesn't have any of the Tangos in question, hasn't measured or heard them and is only hypothesizing based on what he believes their winding technique to be. Also Jack is always speaking in terms of speaker listening, not more rigorous headphone listening and he's using Pentodes, not Triodes. Remember to always take people's comments in context.
3-My Japan contact is transitioning to a new job and moving so he's been preoccupied but I hope to get some figures back from him soon. He might be making a trip back to my place for a visit in which case I'd like to at least get a sample set for testing and confirmation.
4-So the plan is Craig will offer the 2A3x4 w/ Jacks ITs and OPTs, those of us going w/ Tangos can do that as well. I still have yet to hear from a few folks as to which way they wanted to go on the build so I'll hit them w/ PMs.
5-At this point, we are still stuck waiting for Jack to make a proper IT and sourcing the Tangos at a reasonable non-ripoff price.
