Cary SLI-80 Tube amp suddenly blowing fuses


Very strange problem. Everything works and plays fine, however, the past 2 days I have blown the ac fuse (3 amp slow blow 250v) twice now! The bizarre thing is that it only blows when the Cary is in a resting state ~ for an hour or two. When I am playing music, everything is fine! Strange. Could it be random power line surges? Do you think it is a deeper problem within the 6 month old Cary? Should I swap out the power cord?

Thanks,

Jason
jfiluk
Hedge- Give Cary a call. They're great guys and will talk you through all the ins and outs od biasing, etc.

Have fun!
The manual I received with the amp state that one uses mA to bias with. I have had no trouble biasing the amp. It's actually much easier than adjusting bias on the VTL amps I've owned.
When you bias an amp you are setting the idle current in the output tubes. This is measured in mA. I think the confusion comes fronm the fact that different manufacturers use different methods for measuring this current. The Cary measures this directly with an ammeter. Others will insert a small value resistor (say 10 ohms) in series with the output tube and one determines the idle current by measuring the voltage drop across the resistor. For example, if you measure a voltage of 0.65mV across a 10 ohm resistor, then by Ohm's Law (V=I*R) the current is 65mA.
John, you're definitely more on the ball than I am when it comes to this stuff. I've only owned VTL amps, and the Cary. With the VTL amps, one measures the voltage vs. the amperage. Of course, using your formula, it looks like one is actually indirectly measuring amperage?