Greetings dmccan13,
Welcome to where a lot of long-time/hands-on PL enthusiasts compare notes & help each other troubleshoot their gear. If vintage Phase Linear was like old Indy cars, then you have just wandered into
Gasoline Alley. If you haven't already pieced it together, "Gepetto" is the engineer who is the subject matter expert behind all the 21st-century upgrades to Bob Carver's '70s-era PL amps.
Personally, I am in a 'barn find' situation -- the irony is the fact that I seeded the barn myself back around the turn of the century. Recently I've restarted the audio hobby, and after much searching about the interwebs for me this forum stood out in terms of signal/noise ratio on PL stuff. (!)
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I'd like to address your concerns about the 'Flame/Blaze Linear' stories which abound...almost to the echo chamber level in some circles.
Using another car analogy, if during the '70s you hung out with the people
running the Baja 1000 you would hear a lot of true stories about suspension failures.
On the other hand, if you hang out at the Bonneville salt flats you don't hear much about suspension failures..
.but valvetrain failures from extended high rpm runs are prevalent.
A similar thing if we were shoulder to shoulder at the local drag strip, we would be admiring the carnage surrounding failed u-joints,
blown differentials, snapped axles, etc.
The point I'm trying to make is that you really need the
supporting context surrounding the story to better appreciate the failure(s) that are being described to you. For me, all my PL equipment provided solid service despite enthusiastic usage...but the key is that I was using it at home, and not for sound reinforcement. (ie: I wasn't loading wooden chutes with dry ice in order for the amps to be able to deliver sonic excess to thousands of fans in the crowd. :0)
And for those who point out the PL failures in a home setting? Well, again context is key. Back in the day lots of PL gear was bought by passionate/thrill seeker/adrenaline junkie types. (guilty) The same kind of people that bought 350hp/327ci Chevy's, Boss 302 Fords, and Mopar Hemis. And without intending to, they would break their toys in their pursuit of happiness. (Meanwhile, the sensible slant 6 owners would report years & years of absolutely trouble-free driving -- which I believed entirely without question.)
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The only thing left is to address (valid) concerns surrounding bringing 40-50+ year old gear into your house in 2022...and wanting to be able to enjoy real music AND peacefully coexist. (ie: You don't want to have to sleep with one eye open & one hand on the fire extinguisher. :0)
The short answer is that of the hundreds of parts inside your PL amps, some will outlast the owner. (ie: transformer) Nearly all of the other components were designed to provide a 15-20 year lifespan. (Which is true of anything built to a price point for the consumer market - engineers describe the birth > useful life > death of equipment using the bathtub curve.) NOTE: This applies especially to vintage electrolytic capacitors in all equipment by all vendors. (!)
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At any rate, a properly implemented White Oak upgrading of your Phase Linear amps gives you the best of both worlds. Essentially, Gepetto has done what Bob Carver would have done to implement his vision
IF he had the ability back then to access today's technology.
Anyway, like the others said, make sure & read around, for there is a
wealth of knowledge to be found herein.
Best of luck with your vintage audio hobby - fun stuff!
Cheers -