What fuse type should I use for my Stereo Power Amp?

[Dave Saelman]

I have a Hafler 9270 Power Amplifier. It had recently blown a fuse due to an external short. The manual just says to replace it with a 7amp fuse. The blown fuse says the following: 250V 3/2 (or 312 wasn't clear) 7A. It does not specify time delay or any other type. Which one should I use?

 

[llwhtt]

312 would be Fast Blo.

 

[cademan]

Could you be more specific about what the external short was? I only ask because if it somehow blackened the original fuse, a new one will just blow again indicating an internal short somewhere.

 

[Dave Saelman]

@llwhtt Thank you very much. That would make a lot of sense. If I used slow blow, it could have very well damaged my amp before the fuse would go.

 

[Dave Saelman]

@cademan - Thanks for your inquiry I believe the short was my fault. I have two stereo systems and I moved my Hafler to the 2nd system. The Hafler back is not designed so well in that the RCA inputs are very close to the speaker terminals. I had two Esoteric Audio RCA cables running from my pre-amp to the amp. These cables have a goldplated end that is contiguous with the negative. My audioquest speaker cable terminiates with a prong. I think the prong touched the outter termination of the rca cable. In my other system I have a completely shielded RCA cable and never had a problem.

 

[gadget73]

312 is a Littelfuse series number. Fast blow as @lhwitt says.

 

[Catmanboo]

Simple. Replace with same as original-after ensuring no stray whiskers around speaker wires. If it pops again, you got problems.