Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: accmeint on September 01, 2011, 12:09:37 pm
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Gentlemen,
About 5 years ago I completed building the 5f6a bassman amp from the library of information. My son uses it all the time for guitar, and an electric drum kit. The amp sounds great but every couple of years I have a problem with the power transformer, (I think). What is my evidence for saying this? About 2 years ago my son said that the amp was blowing fuses and wouldn't work. I pulled out the power transformer and replaced it and the amp has been working flawlessly for the past 2 years of every day use. I taped off all of the secondary leads from the PT I removed and plugged it in and it tripped the house breaker. I figured that the problem was a fluke and now solved. From that point on I only used 250V 1A slo-blo fuses thinking that this would provide some added protection.
Well fast forward 2 years..., about a week ago the amp is back to blowing fuses and my gut tells me its the power transformer again.
Obviously, there is a problem lurking somewhere in this amp that is the root cause of this. Any suggestions on where to start looking? I probably need to record some voltage readings once I get the amp working again.
Thank you for reading this.
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Tubes? Rectifier tube in particular. Don't assume stuff.
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A 2 x 6L6 amp running on a 1 amp fuse? Hmmm. That would seem to be right on the hairy edge of that fuse, with nothing necessarily bad going on in the amp. Myself, I think I would try a 2A regular-blow fuse and see how it flies. I don't think you'll flame anything.