[Mass. Wine Guy]

I recently bought an Arte Forma I-150 amp, which is very fine. The other day I was doing something with the speaker connections (with the power off). When I tried to restart the amp, it blew a fuse. I replaced it and it's been operating well. It takes an 8A slow blow fuse, but all I could find was a regular 7A fuse.

Today, I noticed that it shut itself off. I turned it on again, it acted normally while doing so, then about 20 minutes later or so I again saw that it was off.

To my knowledge, this is the first time I've seen this happen in the week or two that I've had the amp.

What could be causing this?

Thanks very much.

[eclein]

I no zip about electrical stuff but you have a different fuse than what supposed to be in it correct? The amp is shutting itself off to protect itself for some reason...I'm guessing fuse.

[srb]

Eclein is right.  While I perhaps wouldn't expect shutdown with the slightly smaller fuse in normal operation, you need to put in the factory specified 8A fuse to make sure there isn't a fault within the amplifier.
 
I assume your 7A replacement fuse was also a slow-blow type?.  They really shouldn't be that hard to locate, even Radio Shack carries them:
http://www.radioshack.com/product/index.jsp?productId=2103761
 
Find the exact replacement and see if that eliminates the problem.  If not, then perhaps something did happen to the amplifier.  Murphy's law states that a transistor will blow first to try and protect the fuse that is protecting it.  Or something to that effect.
 
Good Luck.
 
Steve

[Mass. Wine Guy]

I played a CD just to put a signal through to the amp and the issue seems to have vanished, as the amp stayed on afterward even without a source signal. I can see not putting in a higher amp fuse than called for, but one that's 1 amp less I didn't think would be a problem. Of course, I also know zip about these things.

Radio Shack does not carry the smaller 8A fuses, which the amp takes. I have some on their way to me that I bought by mail. I'll put one in the moment they arrive.

[srb]

I can see not putting in a higher amp fuse than called for, but one that's 1 amp less I didn't think would be a problem.

I am a little surprised myself.  You would expect that if an amp was slightly under fused that it might blow either when driven continuously at high levels or maybe when turned on, as a high inrush of current charges up the power supply capacitors, but not when sitting idle.
 
Hopefully once you replace with the proper fuse you won't see this problem recur.
 
Steve

[JLM]

Any resolution here MWG?

[Mass. Wine Guy]

Yes. I haven't seen the odd behavior after that one day. I got the proper fuses, so I hope it was a one-time thing.