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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
summercrema
5 posts
 
Hi Fi Tuning fuse purchased from Analogue Seduction in UK ,  the stock fuse in my  integrated  Amp Cayin CS88a is by LittelFuse 3.15A 250VP , I think  it is a 213 series from catalogue , Littelfuse make many version of the 5x20mm 3.15A fuses. The Amp shipped with two extra fuses  and there is a Littelfuse reseller not far (30km) from me I can go there to find series is the I got.  I thought same rating and same dimension of the fuse is good enough apparently not the case. 
georgehifi's avatar
georgehifi
10,312 posts
 
Are the Hi-Fi Tunning fuses counterfeit?
How do you counterfeit BS, ah yes, with more BS.

Cheers George
geoffkait's avatar
geoffkait
23,365 posts
 
Don’t be a hater, Georgie. Be a lover.
summercrema
5 posts
 
Just an update on the fuse problem I had with the amp,  paid another $120 on a isolation transformer with build in InRush soft start circuit  to use it with the Tube Amp,  no more blown fuse for 7 days already, two blown fuses already cost more than $120. the gain in sonic difference well worth it. 
lewinskih01 OP
909 posts
 
Thanks for the update.
So you keep you amp switch in the on position and turn on/off by turning the isolation transformer? Interesting.
My balanced power conditioner trips if I do that, but will keep it in mind.
Which isolation transformer are you using?
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