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Cary amp fuse blowing 1 advice 2 Bay Area fix?

Hi. Well, starting yesterday, when I turn on my Cary SLI-80, after around one minute, the fuse blows on the left hand side. Tried it twice now.

1. Could this possibly be due to a bad tube? All the tubes appear to light up fine. Is it worth experimenting with swappping tubes, trying to nail down the bad one (I'd hate to put my amp through six more blown fuses while I experiment unless it's likely to find the cause.)

2. I'm always inclined to send a unit back to the manufacturer for repair. That of course takes weeks round trip plus risk of damage or loss. SO, if any of you know someone in the BAY AREA, Northern California, that could fix this, that might be preferable.

Thank you!
Art
artmaltman
12 responses Add your response
polk432
1,142 posts
 
I just got my v12r amp back from Cary for a check up. When I shut the amp off my left 1/2 amp fast blow fuse goes out on the left side. It does not happen when in standby, and works fine after changing the fuse and turning the amp back on. Yesterday I shut the amp off, and before I turned it back on, I took the fuse out and put it back in, then fired up the amp and the fuse did not blow. The bias is around 238 or so on each side. Hope this helps out. polk432
artmaltman OP
769 posts
 
Yes I have had to replace a fuse after tubes blow. The fuses are located in the back of the amp near the a/c cord. You unscrew the black cap. Make sure to use the proper fuse! If I recall correctly, it is specified in the manual.
Art
gethyper
1 posts
 
I think I may have blown the amp fuse. Has anyone here ever replaced that one?
-A
dmsmusiq
2 posts
 
Hello, I've had this happen twice. Once in a SLAM 100 and once in my SLM 200. Both times is was a bad Jensen coulping oil cap that are sometimes prone to fail. I replaced with a higher voltage Mundorf silve & oil cap with a 1200v rating as oppose to the 600v rating of the Jensen and had no further problems. By the way the Mundorf caps brought an already great sounding amp to a level of musicality that was stunning to say the lease. I've had various Cary amps over the last 10yrs and this is the best upgrade I've heard in them. Hope this helps. Dmsmusiq in SACTO.
zimmerma's avatar
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zimmerma
102 posts
 
I too have had fuse-blowing difficulties with Cary amps.

With my CAD V12, Dennis Had himself recommended that I replace the 3 amp slo blo with a four amp.

And with my CAD 2A3 SET, Albert at Space-Tech Labs lowered the voltage (and thus the wattage) to a safer level than the excessively high original Had design.
In fact, I am considering having Albert do the same thing with my V12.

It seems that Dennis Had designs his own amps with a very high voltage level for the purpose at hand... it does jack up the wattage rating, but is very bad for tube life, not to mention the inconvenience of blowing fuses of the manufacturer's own recommended rating!
artmaltman OP
769 posts
 
Tubes it was. I swapped in a set of Svetlana KT-88's and it'a biasing fine now and sounding great.
Thanks all.
Art
artmaltman OP
769 posts
 
I called Gerald at Cary, and he suggested it probably was the power tube. And to be extremely careful with the bias setting.

I checked the manual and there is an AC fuse (which did not blow) and two "tube fuses" (one of which did blow). The tube fuse is correctly half-amp 250 volt quick blow.

Sounds promising.
I'll update this tomorrow.

Thanks,
Art
gundam91
506 posts
 
If all fails, try Nick Gowan in Campbell. His contact info:

408-370-7578
gowan@tsound.com
www.tsound.com

Highly recommended by many of the local audiophiles. Super nice guy and his price is very reasonable as well. But he's just way too busy.....

FrankC
pehare's avatar
pehare
835 posts
 
Been there done that....for me it was shorted (aging)powertube. I put in a new matched quad & fuse & was good to go. call gerald @ cary & have him troubleshoot it for you if you have doubts. be glad it's fused:)
jburidan
803 posts
 
I wouldn't start rolling fuses. Did you check the bias? When doing so, you have to go back-and-forth between the left and right bias pots until both sides are stable at the recommended bias. At the same time, check for power tubes with glowing plates. It might be a bad power tube. Lastly, call Cary. Don't mess with the fuses.
artmaltman OP
769 posts
 
I think I'm using a half amp 250 volt fuse.
I'll check with Cary on this.
(IPA ok?)
Thanks,
Art
markwatkiss
508 posts
 
Interesting,I had exactly the same problem with my Cary V12 and it was the left channel.It was the 3amp slow blow fuse,not a tube.My service tech replaced the 3 with a 4 amp slow blow and that resolved the problem.If it works u owe me a beer.
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