Just popped the fuse in my amp.....

[JumpMarine]

I was playing my 18 watter dimed with a MASS and the fuse popped. this is the first issue that I've had with it since building it about 9 months ago. I have to pick up some fuses yet, but how should I go about troubleshooting so as to not damage anything else? I see no visible signs of a blown tube or any fried componants on the board. Now it isn't unusual to have power flutuations in my area, in fact I've been through a few dvd players over the years that have been fried due to the fluctuations...even with surge protectors.

 

[muttonchopsrule]

Re: Just popped the fuse in my amp.....

the only time i've blown a fuse under "normal" operating circumstances are when the power tubes took a crap. do you play the amp a lot dimed? it could be a little bit of a long shot that the power tubes could be bad after 9 months, but that would be the first thing i would check after popping a new fuse in there. when the fuse blows, 9 times out of 10 that's telling you that something isn't working properly in there, but on the other hand 9 times out of 10 a problem in a tube amp is tube related. so the fuse blowing doesn't necessarily mean that anything has been damaged in the amp.

i would just power up and see what happens with a new fuse. if it blows again, or if your sound is way off volume or distortion-wise, change the power tubes.

 

[JumpMarine]

Re: Just popped the fuse in my amp.....

I play it dimed about 50% of the time the rest of the time it's at about 30% volume with the OCD for gain. It wouldn't suprise me at all if the power tubes are shot though. That would suck because the EI's are nearly impossible to get now.

 

[Gearjoneser]

Re: Just popped the fuse in my amp.....

I wouldn't worry about it. The fact is, you're taking a low wattage amp and running it at the top of it's capability, and the fuse did it's job. Just back it down a little in the future, or blow the fuse. It's just like strumming a guitar as hard as you can.....eventually a string will break, but the guitar is still fine.

 

[LesStrat]

Re: Just popped the fuse in my amp.....

Yep. Could be that the fuse was getting "old." Could be the power fluctuations weakened it. Could be many other things that are NOT due to an amp problem.

Replace the fuse. If it keeps blowing them, THEN worry about why.

 

[JumpMarine]

Re: Just popped the fuse in my amp.....

After digging around a bit more in the amp I've determined that 1 of 2 SS Rectifier diodes is bad. They are both in close proximity to a 5 watt Resistor that get very hot and that's what most likely took it out. .20 fix!

Looks like it's going to be an issue again in the future due to the location on the board so I'll pick up a few extras as well. Although I'm wondering if it would be an issue of remoting both diodes away from the resistor.

 

[Scott_F]

Re: Just popped the fuse in my amp.....

You are burning through your tubes when you dime it. It's like speeding in your car. It drinks more gas. Tubes are expendable. That's why they designed them to be changed out so easily.

I'm not sure I'd run my car engine at red-line 50% of the time though. Definitely gets hot I bet. Thiose little cathode resistors can get blazing hot.

 

[JumpMarine]

Re: Just popped the fuse in my amp.....

Scott, is there any possibility of adding noise to the circuit if I remote the two rectifier diodes away from the resistor? The heat that the resistor produces won't be an issue any more as there are no other componants near it.

 

[JumpMarine]

Re: Just popped the fuse in my amp.....

I also discussed this with Aaron(the designer) and he said to just keep the diodes off of the board by simply keeping the pigtails long when I put them back on the board. He was also nice enough to send me a couple of new diodes for free. Great customer service for an amp kit!