Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: fossilshark on March 02, 2017, 03:17:19 pm

Title: Fuse blowing randomly
Post by: fossilshark on March 02, 2017, 03:17:19 pm

Sometimes the fuse blows on startup but i put a new fuse in and then it starts up perfectly, could the filter cap be too big for something to handle the startup current draw? The amp is 50 watts and im running it through a custom 4x12 so i dont have to turn it up very loud but when i turn it past 4 (with the gain on 9) the fuse blows after a few minutes of playing. I suspect its the output tubes im using, i salvaged them off something and im using them until i buy some el34s. What is the first thing i should check to make sure the amp isnt getting hurt?

Title: Re: Fuse blowing randomly
Post by: PRR on March 02, 2017, 03:33:02 pm

Is there a number on that fuse? They are not all the same.

Title: Re: Fuse blowing randomly
Post by: HotBluePlates on March 02, 2017, 03:36:35 pm

Make sure the output tubes fit snugly in their sockets.  Loose sockets (or the occasional JJ tube with skinny pins) could lead to the tube losing contact with pin 5 & bias.

Title: Re: Fuse blowing randomly
Post by: fossilshark on March 02, 2017, 05:20:03 pm

Theyre 2 amp fuses. It could be the sockets

Title: Re: Fuse blowing randomly
Post by: sluckey on March 02, 2017, 05:22:39 pm

Quote from: fossilshark on March 02, 2017, 05:20:03 pm

Theyre 2 amp fuses. It could be the sockets

Does the amp require a slow or fast fuse?

Title: Re: Fuse blowing randomly
Post by: fossilshark on March 02, 2017, 06:13:57 pm

Slow blow i beleive and thats what im using