Re: mercury trannies
Are they the best? That's subjective. Are they really well made? Yes. Do they enhance the resale value of the amp? Yes. Do they have a great warranty? Yes. Are they pricey as heck? Yes. Are they worth it? You be the judge.
Unfortunately, I have yet to build two identical amps with different brand of trannies. I only use US-made ones, from 3 suppliers and MM is one of them. Heyboer is another and the 3rd remains unnamed.
I'm actually thinking that all future Fender-esque builds will carry Mercury inside. I like all the stuff (well, 'cept for the price) that I listed above. They are widely considered the best.
My own personal feelings is that you'd have to have dog ears to figure it out. It's like SoZo mustard caps and Sprague electrolytics. Widely held as the best out there, so I use them. Are they really any better than Mallory 150's? I dunno. Sozo claims they have to break in for 100 hours or more. I've never had an amp that long that had them inside. I just burn them in for 3 days and off they go.
The thing I am going to start liking a lot about Mercury soon is that they offer price breaks that get better the more often you buy them. So, the more I order, the less they cost. Fair enough.
I'm also a subscriber to the "if it ain't broke, don't fix it" theory. So, at this point, my Edana still uses the same Heyboer trannies that I've used from day one. I have no immediate plans to change. Although, someone will force my hand to use MM in there one day and I will. We'll see how they sound. I use the unnamed guys for the EL84 amps I make and the new 'wreck inspired thing that's coming round the corner. On the tweeds, i've been letting guys decide which transformers to use, but that may change as well. Soon.