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mrklas, I concur with @oldhvymec. When I first got the MC-275 it sounded really good...much better than the parasound A23 I had. However, it was a little bright and the bottom end sounded thin...again, still better than the Parasound. I did seek out Brent Jessee, and bought a mix of Tung-Sol and Mullard's...I think (it's been 4 or 5 years), and it changed the sound, a little more well rounded overall, but still wasn't entirely happy.
I ended up settling on used RCA tubes that I got from an estate sale. The best sounding so far.
@noromance , It could be the KT-88's, but the reason I'm leaning more toward the preamp tubes is because the Golden Lion KT-88 I purchased new. I also have a Golden Lion new 12AX7 in the inverter spot. As I mentioned, the 12AX/AT7 were used RCA's from an estate sale. That's why I suspect those over the power tubes. I will say the RCA tubes are just absolutely excellent with my system.
I was emailing back and forth with Ron Cornelius from Mcintosh in 2016 when I first got the MC-275. He mentioned that the tubes should last on average 5000 - 10000 hours unless driven hard for long periods of time (something that can easily be accomplished by myself as a preferred metalhead, hard rock, blues, then jazz fiend in that order). He also mentioned that the Mark VI version has the color changing LED's when a tube goes bad, but it's only for a catastrophic failure. It does not alert you when a tube is getting weak.
My friend and I went in on a tube tester years ago....but I ended up moving only 13 hours away...so checking the tubes is a bit of an endeavor.
Years ago I heard that the Telefunken tubes would be the best if I could find them and afford them (at the time they were running about $300 - 400/tube). I see that they are making new black diamond Telefunken tubes...has anyone tried them before?
If push comes to shove, I'll pick up a batch of RCA tubes. I am just beginning to worry about how much life they have left in them. I just wonder if the Golden Lion KT-88's have been as good as they are, then how about their 12AX7 and 12AT7's are.
@noromance , It could be the KT-88's, but the reason I'm leaning more toward the preamp tubes is because the Golden Lion KT-88 I purchased new. I also have a Golden Lion new 12AX7 in the inverter spot. As I mentioned, the 12AX/AT7 were used RCA's from an estate sale. That's why I suspect those over the power tubes. I will say the RCA tubes are just absolutely excellent with my system.
I was emailing back and forth with Ron Cornelius from Mcintosh in 2016 when I first got the MC-275. He mentioned that the tubes should last on average 5000 - 10000 hours unless driven hard for long periods of time (something that can easily be accomplished by myself as a preferred metalhead, hard rock, blues, then jazz fiend in that order). He also mentioned that the Mark VI version has the color changing LED's when a tube goes bad, but it's only for a catastrophic failure. It does not alert you when a tube is getting weak.
My friend and I went in on a tube tester years ago....but I ended up moving only 13 hours away...so checking the tubes is a bit of an endeavor.
Years ago I heard that the Telefunken tubes would be the best if I could find them and afford them (at the time they were running about $300 - 400/tube). I see that they are making new black diamond Telefunken tubes...has anyone tried them before?
If push comes to shove, I'll pick up a batch of RCA tubes. I am just beginning to worry about how much life they have left in them. I just wonder if the Golden Lion KT-88's have been as good as they are, then how about their 12AX7 and 12AT7's are.