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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
pehare's avatar
pehare
639 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:)
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
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
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
zimmerma's avatar
Ag insider logo xs@2x
zimmerma
43 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!
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