32blownhemi 61 Posted November 29, 2017 It was 80 days from the day I bi-amped my Jubscala's with a second Mc275 to the day it quit working. I took it back to the McIntosh dealer that I bought it from to be fixed & he sent it off. Just got a phone message from him today saying there were two problems. An open transformer & it was under warrantee so fixed for free & bad tubes but the warrantee is up. So I own $300 for the tubes. He said the tubes had extreme wear on them. Asked if I leave it on for long periods of time. One time I left the house & it was on for 8 hours but other than that only when I play it. And I don't really listen to it that often. Just 2 channel, no surround sound. Is this possible? Thank You! Bill Quote Share this post Link to post Share on other sites
derrickdj1 8203 Posted November 29, 2017 Sorry to hear of the incidence. Eighty days is a slap in the face. The $300 is for how many power tube? Quote Share this post Link to post Share on other sites
dirtmudd 20030 Posted November 29, 2017 52 minutes ago, 32blownhemi said: It was 80 days from the day I bi-amped my Jubscala's with a second Mc275 to the day it quit working. I took it back to the McIntosh dealer that I bought it from to be fixed & he sent it off. Just got a phone message from him today saying there were two problems. An open transformer & it was under warrantee so fixed for free & bad tubes but the warrantee is up. So I own $300 for the tubes. He said the tubes had extreme wear on them. Asked if I leave it on for long periods of time. One time I left the house & it was on for 8 hours but other than that only when I play it. And I don't really listen to it that often. Just 2 channel, no surround sound. Is this possible? Thank You! Bill time for this... http://vintagetubeservices.com Quote Share this post Link to post Share on other sites
derrickdj1 8203 Posted November 29, 2017 Time to call it a night. See ya tomorrow. Quote Share this post Link to post Share on other sites
32blownhemi 61 Posted November 29, 2017 Thank you! By the time I got the message it was to late to call him back but his message said "unfortunately you needed a new set of tubes". So my guess is a 'set' is all the tubes? I'll find out tomorrow. I read the link on the vintage tubes although to late as the tubes have already been replaced. Or maybe I'll use the amp that's just got fixed for the low's & replace the tubes in my other 275 for the highs? Should they be giving me back my old tubes? Thanks! Bill Quote Share this post Link to post Share on other sites
32blownhemi 61 Posted November 29, 2017 K, goodnight... Quote Share this post Link to post Share on other sites
robert_kc 138 Posted November 29, 2017 Did you buy the MC275 new, or used? If used, the seller might have swapped in some old tubes. If new, 80 days sounds like a ridiculously short life for a set of tubes. With that said, my MC275 MkV's output tubes needed to be replaced when the amp wasn't very old. (I bought the amp used.) I replaced the output tubes with KT88 Genalex Gold Lion - new (Russia), and it has performed flawlessly since. Other tubes I installed at the same time the output tubes were replaced : 12AX7: V1: Genalex Gold Lion 12AX7 / ECC83 / B759 gold pin (Russia) 12AX7: V4, V5: new Tung-Sol gold pin (Russia) 12AT7: Mullard CV4024 NOS I bought all of the replacement tubes from a seller (Jim McShane) who tests each tube. I think that's important. I own more than 2 dozen tube amps ... and I love them ... but I tell myself that I have to accept that fact that they sometimes can be a PITA ... 1 Quote Share this post Link to post Share on other sites
32blownhemi 61 Posted November 29, 2017 Brand new from an approved McIntosh dealer. I'll report back after I talk to him tomorrow.... One time I accidentally left it on for 8 hours. Including those 8 hours II wouldn't be a bit surprised if the amp didn't have any more than 50 hours on it... Thank You! Bill Quote Share this post Link to post Share on other sites
EMRR 26 Posted November 29, 2017 A set of tubes in most power amps should run 24/7 continuous for something like a year. The bad transformer (audio? power?) may be the cause. Some other maladjusted part could also have taken trans and tubes out. Quote Share this post Link to post Share on other sites
derrickdj1 8203 Posted November 29, 2017 I think I read a while back to replace all the tubes with new ones from McIntosh were around $800. Quote Share this post Link to post Share on other sites
32blownhemi 61 Posted November 29, 2017 Thank You EMMR & Derrick, all he said was transformer on the phone message so don't know which one it was. I'll get details when he gets to work. So a bad transformer could have ruined the tubes? Should run 24/7 for a year? So mine ran continuously for 2-3 days. Something isn't right... So it must not be all the tubes for $300, I'll find out... Bill Quote Share this post Link to post Share on other sites
joshnich 462 Posted November 29, 2017 Sounds strange to me. McIntosh is known to be easy on tubes I have owned a few and never had to replace tubes. I would venture to say that he transformer issue caused the tube failure. Of course it is possible that the tube or tubes were defective to begin with. Please let us know what you learn. If its multiple tubes that would be weird. Of all the tube amps that I have owned I have only had one that had a "tube failure". A Cary Rocket 88. The tube failed and caused a resister to explode. Thought that was strange at the time. I was told that a tube failure is different than tubes just wearing out. I guess more of a violent event. So maybe even the transformer issue was caused by a tube failure! So again inquiring minds want to hear more of what the dealer has to say! Quote Share this post Link to post Share on other sites
derrickdj1 8203 Posted November 29, 2017 I wonder if a tube red plated? Quote Share this post Link to post Share on other sites
32blownhemi 61 Posted November 30, 2017 He said they replaced the 4 big tubes. I asked if all 4 were bad & he said he didn't know how many were bad but that they would replace them all not just the bad one/ones. I told him how little I'd used the amp & he said he'd call McIntosh & see if they wouldn't cover it.... So is this right? All 4 not just the bad ones? Thank You! Bill Quote Share this post Link to post Share on other sites
richieb 5211 Posted November 30, 2017 Probably felt it a good idea to install a matched quad instead of a matched pair with two older, questionable tubes. It's what I would have done. 2 Quote Share this post Link to post Share on other sites
USNRET 5227 Posted November 30, 2017 1 minute ago, 32blownhemi said: I asked if all 4 were bad & he said he didn't know how many were bad but that they would replace them all not just the bad one/ones I call a BIG BS. Now if McIntosh wanted to (and should) replace them all due to the other, rare, malfunction fine. You to pay? NO WAY IIRC an forum member that has been absent for a while (Cigarbum) bought 275s and had power tube failures very quickly. Mc overnighted him all new tubes. I visited him during the event. 1 Quote Share this post Link to post Share on other sites
derrickdj1 8203 Posted November 30, 2017 I had a quad set of 6CA7 tube that came with my amp. One tube would red plate every time I cut the amp on and then the glow would go away. After I learned what that red glow indicated, I got rid of all 4. I don't know if they were damaged during shipping. Quote Share this post Link to post Share on other sites
canyonman 154 Posted November 30, 2017 When I install new tubes in any part of my system I leave that gear on for 48 hours minimum to burn in the tubes and have never had a failure or a problem, being doing it for years. My money is on the tranny taken out the tubes. Tube under normal conditions last damn near forever, I mean a pretty long time as in years.... Quote Share this post Link to post Share on other sites
jimjimbo 8514 Posted November 30, 2017 I agree with Canyonman on the transformer taking out the tubes. You really should owe nothing on the repair of this unit. I normally burn in tubes for 8-10 hours, and then normal playing/listening sessions could go 2-8 hours (depending on whether the wife and grandkids are home....). Mcintosh amps are very, very gentle on tubes. One set of good quality tubes could potentially last 20 years or more, easily. Quote Share this post Link to post Share on other sites
mike stehr 690 Posted November 30, 2017 Gee, and I thought vacuum tubes were burned-in at the factory. 1 Quote Share this post Link to post Share on other sites
