oscarsear Posted March 22, 2005 Share Posted March 22, 2005 Been sticking with a purportedly reputable supplier of NOS tubes for my litte CARY integrated..Upscale Audio... Well I'm gonna try someone else. In less than a year I've had 5 tubes of varying types fail, many on initial run in. This week I had an Amperex 7308 "tweet" out on me. It cost $75.00 and was installed last November. Upscale isn't responding to the e-mails. I going to try out a supplier recommended on the forum, "Vacuum Tube Valley" outside of San Fransisco. I'll have my Phillips 6922's in play by this weekend. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted March 22, 2005 Share Posted March 22, 2005 pre-amp tubes should'nt be smokin' on you ... what is yer heater, and plate voltages ..?? Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 Granted, I know very litle about the operation of tube pre's, but it sounds to me like you're fighting the symptom, not the cause. Can you or anyone close do some checks on the voltages things are running at? Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted March 22, 2005 Share Posted March 22, 2005 ---------------- On 3/22/2005 8:05:54 PM oscarsear wrote: In less than a year I've had 5 tubes of varying types fail, many on initial run in. ---------------- Hummm... I'd be starting to consider the preamp being checked at this point. Might not be the tubes that are faulty. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 22, 2005 Share Posted March 22, 2005 I seen a rectifier tube do baby nebula inside of itself, one go up like a flashbulb, and had output tubes frazzle and pop. But I've yet to have a driver tube die in circuit, even the dead ones. Where the heaters barely glow, runs hot, and hardly puts out gain. IME.... Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 22, 2005 Share Posted March 22, 2005 Might just as well jump on the band wagon. Quit buying new tubes and get the gear checked out. Tubes don't fail like that especially preamp tubes. Upscale is long dollar for sure but he has a reputation for selling top quality hard to find tubes that are well tested. Craig Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted March 23, 2005 Share Posted March 23, 2005 You are getting some REALLY good advice here . . . Quote Link to comment Share on other sites More sharing options...
oscarsear Posted March 23, 2005 Author Share Posted March 23, 2005 O.K., some more help please. The Cary SLI-80 is an integrated amp. How would I check the voltages on these tubes for this unit? I have suspected the hardware with these problems before. I've personally discussed this prospect with Kevin Deal (Upscale), from whom I purchased the device. Kevin assures me that it's NOT the unit but is quirky tubes. I do monitor my bias regularly, especially since having these routine and costly events. Also, let me more clearly define which tubes: One KT-88, One KT-90, One rectifier 5U4, One 7308 (6922), and one fuse. (Sorry 4 tubes not 5) I also employ a power conditioning unit to all of my equipment. The KT-88 dropped out after 1 month of running. The KT-90 fried out on its premier outing, went up like a 220 volt toaster (with the bias set low). The rectifier tube also was bad at its initial outing. According to Kevin the rectifier problem caused the KT-90 to fry , and it also blew a mainline power fuse. The 7308 tube started up with serious noise after 4.5 months. I run my system 10 to 12 hours daily. It's well ventilated and electrically isolated. ????????????????? pleeeze share with me your thoughts and ideas. Thnxx Dave Quote Link to comment Share on other sites More sharing options...
dodger Posted March 23, 2005 Share Posted March 23, 2005 Do you run 10 - 12 hours per day listening or just keeping it on? Quote Link to comment Share on other sites More sharing options...
Colin Posted March 23, 2005 Share Posted March 23, 2005 I ran my pre-amp for aslmost a decade before swapping out for new sets of 12Ax7 (AT?) tubes, they weren't glowing or sounding bad, but I thought it was long enough, no difference in the sound and the old tubes are back in rotation... so, check the amp man Quote Link to comment Share on other sites More sharing options...
oscarsear Posted March 23, 2005 Author Share Posted March 23, 2005 Dodger, I actually have the pleasure of listening to my stereo 10 to 12 hours daily. When we moved into our new home I saw to it that all television went upstairs. The stereo has no downstairs competition....mine-all-mine. It's turned off the balance of the time. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 23, 2005 Share Posted March 23, 2005 ""O.K., some more help please. The Cary SLI-80 is an integrated amp. How would I check the voltages on these tubes for this unit?"" Flip it over, pull the bottom cover, and check voltage/current at the pins of suspected tubes with a multimeter. With the unit powered up of course. (You may not be into that....) The small mini-pin 6922 tubes are just used as a input buffer for the 6SN7, they can't be running that hard for that task. Maybe when you lost a 5U4 it stressed out a part of the driver circuit. Not enough to blow fuses or shut the amp down or whatever, but maybe enough to run the pre-amp buffer tubes hard. I can see maybe getting stuck with a bunk output tube or a rectifier, but losing a 7308 that you just starting using last November? Will the amp still bias up output tubes properly? IMO, I'd try to check the voltage at the plates, cathodes, and the heaters of those driver tubes. Regardless of what Kevin Deal says..... You said you live in North Idaho? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 23, 2005 Share Posted March 23, 2005 Well now that you clarifying things and it's not all the same tubes going out on you. Kevin could be right. But if you have sourced all these tubes from Kevin has he not offered to replace the ones that failed on innitially be placed in use? I run my amps about 16 hours a day with the mostly the same tube compliment for the last year and no signs of any tube failures. In fact with all the gear I mess with tube failure rarely ever happens. In my VRD's I have pulled them out periodically and tested with no signs of weakening. Craig Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted March 23, 2005 Share Posted March 23, 2005 I have purchased NOS tubes from Kevin at Upscale and never had a problem to date with any of those tubes. On the other hand, I've also received some nice tubes from Vacuum Tube Valley, and I highly recommend that vendor. I know its makes one suspicious about the tubes since different types of tubes are going.....but my money is still on the unit. Carl. Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted March 23, 2005 Share Posted March 23, 2005 Have you tried measuring the voltage that's coming out of the wall? Maybe it's too high. Quote Link to comment Share on other sites More sharing options...
oscarsear Posted March 23, 2005 Author Share Posted March 23, 2005 I'll try to answer all the ?s. 1st, yes Kevin replaced all those tubes which failed on initial run-ins. I believe it's possible that the bad rectifier may have soured/toasted other tubes in that ciruitry. It did allow the current to pull high enough to blow a mainline fuse. No power surges from the main line as I employ a Balanced Power conditioner for all components. The unit is holding bias without problems. I contacted Cary and they're not pleased with this tale either. Kevin still asserts that it's a run of bad tubes. I'll keep y'all updated as information blossoms. You have all been very helpful and I really appreciate it. Thnx Dave Quote Link to comment Share on other sites More sharing options...
3dzapper Posted March 23, 2005 Share Posted March 23, 2005 "I believe it's possible that the bad rectifier may have soured/toasted other tubes in that ciruitry" Dave, more likely the other way around, the shorted output tube put a current load on the rectifier that it couldn't survive. Look on the bright side, at least the fuse blew before the power or an output transformer. A "soft start" device may help you in the long run. It will be interesting to see Cary's input. Rick Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted March 23, 2005 Klipsch Employees Share Posted March 23, 2005 Buy a Solid State amp. Solves your problems... Aragon makes some good ones... Quote Link to comment Share on other sites More sharing options...
jdyer Posted March 23, 2005 Share Posted March 23, 2005 Screw Solid State--the man's looking for the best sound he can get, otherwise he wouldn't have bought an expensive piece of tube gear. Your two suppliers, Kevin and VTV are reliable and very expensive. If you had a tester, you wouldn't need to pay those prices. Once you figure out your problem,(which may be bad luck), your tubes will last nearly forever. Cary will treat you well. If Upscale isn't responding to your emails, I'm not surprised--they were really friendly until my check cleared. Best of luck with it. The people on this forum can help, and remember, this is not the way it normally is with tube gear. John (p.s., buy a tester, and, except for output tubes, ignore the curve tracer nonsense, and trust your ears for microphony) Quote Link to comment Share on other sites More sharing options...
jdyer Posted March 23, 2005 Share Posted March 23, 2005 And Trey, You've been really helpful the couple times I have talked to you. I'll bet you break out the old tube stuff when you're sure the bosses aren't going to pop in. Take care. john Quote Link to comment Share on other sites More sharing options...
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