1A fuse instead of 1/2A fuse: any problem?

Do so @ your own peril. Not a good idea to up fuse raings in electronics.

really bad idea. Have you checked out HiFi Tuning fuses? they have fuses at the rating you need (500ma). MusicDirect.com carries the HiFi Tuning line if you are interested, check em out.

If you need to deviate you want something that will blow sooner rather than later. A 1A fuse won't blow as soon as a 0.5 amp fuse. It will tolerate a higher "spike" that might damage your equipment. Replace fuses as recommended by the OEM or with a lower amp rated fuse if you must deviate.

Actually you have QUADRUPLED the power that can pass since power is proportional to the square of the current.

Fuses DON'T blow at their rating. The rating is the current they will carry forever (almost). As current increases over the rating, the time until the fuse blows decreases. A half amp fuse will, depending on type, blow quite quickly at one amp, whereas the one amp fuse will not blow.

Put a 2a or a piece of wire in there, then you won't have to worry about those wimpy shutdowns.

Oh, and I should have added - keep a fire extingusher handy

You can order those size fuses from most all the big electronic parts stores or maybe even you local electronic parts store or even Radio Shack. If it was a slow blow .5A you can use a 1A fast blow, but it is better to stay within the design. I have tried the HiFi Tuning Line fuses (very expensive for a fuse) and did not notice any change in sound. Might have been one but it is too small to tell for me.

Ezekiel makes a good point about "fast blow" vs "slow blow". I did need to replace a fuse at one point and Radio Shack did have them.

I don't need Radio Shak fuses.The whole point is to try Isoclean fuse which supposedly is the best there is.And yes,it cost 30 bucks too.

Sorry - I lost track of your original issue. HiFi Tuning Fuses from the Cable Company might be an option. They appear to have an 0.5 amp option in 2 different size fuses. I used a Radio Shack fuse temporarily and then switched to one of these for my power amp. I thought I heard an improvement in sound.

See the link below. Click on the order form and scroll way down to see the list of amp ratings & sizes etc.
http://www.fatwyre.com/featuredprods.html