2. tech-talk
  3. 1392953041

why do hi-end fuses keep blowing, while std don't?

I've had my McIntosh MC275 for several years running flawlesly. Up until last Nov I was using stock KT88 and rolled small tubes and had a Hi-Fi Tunning fuse without issues.

In Nov-13 I upgraded the KT-88 to Psvane black bottles measuring 60mA plate current. A few power-ons after I rolled the tubes, I turned on the amp to let it warm up, but returned to a blown fuse. I thought a tube might be bad so used a std fuse, but never had a problem again.

Two months ago I bought a new high-end fuse, replaced it, and soon thereafter the same happened: blown fuse. I replaced it with a std fuse again, which is still running.

So I want to upgrade the fuse, but chances are if I use the 2A fuse it will happen again. Yet I don't want to use a higher value fuse. I'm thinking the Psvanes might be drawing significantly more current than the stock KT88 and the Hi-Fi Tunning fuse might have a tighter spec, driving said fuses to fail while the std ones survive. Would you agree?

Suggestions as to how to resolve this?

thanks much!
lewinskih01
lewinskih01 OP
909 posts
 
I asked McIntosh...

"We do not recommend the ‘high –end’ super fuses… it is impossible for them to improve sound and it may be causing your problem.
But any amp that blows fuses should have all the tubes tested."

So I learnt I'm delusional since I hear an improvement in sound with hi-end fuses, and my tubes must be bad even though they are not blowing up standard fuses.

Unfortunately this manufacturer is not helpful.

Any other ideas?
onhwy61's avatar
onhwy61
5,229 posts
 
You need to get rid of the McIntosh and get an amp from a manufacturer who understands and supports aftermarket fuses.
timrhu
2,779 posts
 
Those two sentences from McIntosh seem perfectly reasonable coming from the manufacturer of any amp.
rodman99999
6,159 posts
 
Those two sentences seem to indicate total ignorance, from the manufacturer of any amp. Not surprising, from those with the hubris of McIntrash. Of course; that's just my own personal opinion, based on personal experience with both.
mapman's avatar
mapman
22,309 posts
 
I'm interested to hear what the fuse maker says.
More to discover