BE-100 issue - red plating and hum

  • Thread starter Thread starter SuperMoos
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SuperMoos

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Hi All,

Having a bit of a problem with my BE-100. I just finished band rehearsal and had to turn off my BE mid-set. After a song I noticed abnormal hum coming through the speakers. Amp still sounds normal apart from the hum. Looked at the tubes and saw 2 power tubes glowing very red. It was the left pair; the pair on the right looked normal. Turned off the amp after that.

Not sure where to go next. Could it just be as simple as failing power tubes? Not sure what would cause sudden red plating. Could it suggest a resistor or something has gone bad? What do you guys think?

Best regards,
Robert
 
I will check the bias. But can it drift as much that it causes sudden red plating? Tubes have been in there for about 6 months.. never any issues.
 
Mine were completely out of range... I believe that power tubes after few months have to be rebiased
 
If you play altmost 2 to 3 times a week is importan to check bias every 3 months and change power tubes every 6 months.
 
SuperMoos":r6vido4m said:
I will check the bias. But can it drift as much that it causes sudden red plating? Tubes have been in there for about 6 months.. never any issues.
Click to expand...
Sure, anything can happen
 
Alright - seems like the general consensus is that this problem is tube-related. That would be a great relief - I was afraid that I might need to take my amp to a tech or something.

Will replace the tubes tonight and report back!
 
SuperMoos":33diwmyn said:
Alright - seems like the general consensus is that this problem is tube-related. That would be a great relief - I was afraid that I might need to take my amp to a tech or something.

Will replace the tubes tonight and report back!
Click to expand...
Check the bias with the tubes that are currently in it to find out what the problem is. Your tubes might still be fine.
 
Yes set of tubes for sure. Please make sure you bias the amp for around 32ma per tube. Thanks
 
Alright, I put in a new set of tubes, adjusted bias to approx 30 mA per tube. She's good as new! Issue solved - thank you guys for the input!

Best regards,
Robert
 
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