2. amps-preamps
  3. 1057837334

Amp blowing fuses

I have a BAT VK-200 amp(purchased used 8 mos ago) and a BAT VK-31se(recently purchased new). 2 weeks ago I came home, put on an album-no sound. I pulled the amp and inserted my old b&K ST-140 mono blocks. When I turned them on one was OK but the other had a loud hum through the speakers, I switched interconnects and it went away. I called BAT and talked to Steve and he told me how to check and replace the fuses in the VK-200 amp. I did this and I was up and running in a few minutes. Could it be the bad interconnect that caused the fuses to blow? By the way these are 10 amp fast blow fuses. I just got the VK-31Se new a few weeks. This is my first piece of tubed equipment, is there something that I should be worried about with that unit? I will be calling BAT agian, but I would like to hear some of your thoughts and experiences.
jdodmead
sean
6,231 posts
 
Just because you've got a cap in series with the circuit does not mean that you are guaranteed to be "DC free". Sean
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s23chang
620 posts
 
Sometimes a bad tube can also blow a fuse. I had an amp that was working fine until it blow the fuse one day. I replaced the fuse and I saw the rectifier tube was very unstable and it blow the fuse again. I replaced the retifier tube and problem still exist. I then trace the circuit until I found out that one of the output tubes had a short. You never know...
gpdavis1
50 posts
 
BAT told me that the VK-200 needs an upgrade to the bias circuit, at $500, which might be your problem. I know that S/N 274 and earlier need the upgrade and S/N 371 and later do not. I am not sure where between these two S/Ns BAT made the modification to the bias circuit, but yours may be one of the older models which needs the work.
sean
6,231 posts
 
Hmmm.... BAT tells you that earlier models "need" an upgrade and that it costs $500. That sounds like BAT put out a bunch of under-designed, defective products, realized what they did wrong later and now want to charge people $500 to correct their mistakes. Not good and doesn't say much for BAT. Sean
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gpdavis1
50 posts
 
If BAT is doing the upgrade at no cost for original owners, then I think they have it covered. Do not know that they are, though. If I was an original owner I would certainly be telling them that I expected the fix for nothing.
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