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'whine' from 210/65

AuthorMessage
 

salvocaster
Posted on Monday, December 15, 2003 - 09:32 am:   

I've got a 1975 210/65 (original owner), and it's just developed what can best be described as a soft 'whining' sound on the high power setting. It goes away on the low power setting....
any ideas?
Langley
Posted on Tuesday, December 16, 2003 - 12:42 pm:   

Tubes and/or Caps is my guess.
Steve Kennedy
Posted on Wednesday, January 14, 2004 - 04:55 pm:   

It sounds as though you may have some gentle "arcing" when set for high power. A cracked resistor or an extreme amount of deposited dust or dirt around the output tube circuits can cause this.

Also, dirty or cracked tube sockets or pins can cause this. Does gentley wiggling the output tubes have any effect on this? If not, you may have to carefully gently probe and pressure components (with a wooden chop stick, NOT a pencil or mettalic object!)and connections internally to find the culprit.

Warning: The high voltages present in these amps CAN kill you. Leave this for a qualified technician if you are not completely comfortable in this environment!

You can also observe the inside and outside of the amp chassis (while on and whining) in a pitch-dark room and look for any glowing or sparking where it shouldn't be.