KVR Audio

akisd28 · Post by **akisd28** » Mon Jan 03, 2005 4:55 pm

Hi,

My JCM800 blew a fuse last night. It was a T1A250V. I went to the store and asked for the same type and they gave me an F1AL250V. Is there any difference between them they didn't tell me about? They look identical (apart from the fact the old one is now brown...

) and their value is obviously 1A for each of them, but what's the difference between the "T" and the "F"?

TIA,

Akis

C00kie · Post by **C00kie** » Mon Jan 03, 2005 5:04 pm

Apparently the F is fast-blowing and T is slow-blowing. So yes they are different but luckily you are on the safe side.

WARNING: if the fuse is blown, there normally is a reason why. So if the amp was rather old & beaten but now works fine there is probably nothing to worry about. If however the new fuse blows again rather quickly then concider to have it serviced.

ew · Post by ew » Mon Jan 03, 2005 5:05 pm

I'd check on that-I'm wondering if the T is a slow-blow and the F is a fast-blow.Most amps use slow-blows in the output stages.

EDIT:Ah-C00kie beat me

ew

Sielsynth · Post by **Sielsynth** » Mon Jan 03, 2005 5:08 pm

C00kie is correct with his answer. The "F" is for fast blowing or very fast blowing and the "T" stands for Time-Lag or Time-Delay. These specify how long the fuse takes to open when the rated current is exceeded by X percent. You have a fast blow so you should be safe. It may of course blow more frequently if there are small current surges.

akisd28 · Post by **akisd28** » Mon Jan 03, 2005 5:15 pm

Thanks, guys!

Well, that's what I found out by searching on the net. I'll use that one and I'll look for a T one tomorrow. The ampo is an original 1983 JCM800, rather old and beaten...

COOkie, do you know of any reliable place to have it checked up if something goes wrong? I've been living in Holland only for a couple of months, you know... I had taken it to Feedback (Rotterdam) a couple of months ago for a BIAS adjustment, but AFAIK, they sent it to WestAmp for that. I'd go directly there, but I don't have a car.

Thanks,

Akis

C00kie · Post by **C00kie** » Mon Jan 03, 2005 5:23 pm

Wise decision...

Sorry, dunno. I just take my stuff to the nearest shop with nice guys (you could do worse than Feedback) and trust their contractors. I heard my shop sends it to Amersfoort, supposedly the Koch workshop. Dunno weather thats just rumour or for real...

akisd28 · Post by **akisd28** » Mon Jan 03, 2005 5:45 pm

Thanks.

Well, my amp blew the first fuse right away... When I put the second one, I noticed that the power amp tubes were glowing stronger than my room's light bulbs!

From what I found on the Internet, that particular fuse is there to protect from tube failure. I just can't stop thinking that my amp's BIAS wasn't really adjusted...

ew · Post by ew » Mon Jan 03, 2005 5:50 pm

akisd28 wrote:Thanks.

Well, my amp blew the first fuse right away... When I put the second one, I noticed that the power amp tubes were glowing stronger than my room's light bulbs! From what I found on the Internet, that particular fuse is there to protect from tube failure. I just can't stop thinking that my amp's BIAS wasn't really adjusted...

Your bias wouldn't be the cause of that here-my guess would be that you've got a diode in the power supply that's shot...
ew

akisd28 · Post by **akisd28** » Mon Jan 03, 2005 5:57 pm

It seems it needs a service anyway.

Did I get the right fuse?