• Registered: 2012-05-19
  • Posts: 22

Topic: DSL 100 - mains transformer hum

Hi, well after long wait I finally got a 2nd hand DSL 100.  Quick question for you users:
Does this amp have a considerable mains hum due to the input mains transformer?
When I power on with stdby off there is a considerable mains hum, much more than my origional
plexi from 1970! I thinough this amp should have been quieter though the non point to point
wiring may add noise?

Appreciate any benchamarks on noise on mains.

THanks

GC

  • DougH
  • DougH
  • BONAMETAL
  • Offline
  • From: Toronto, Canada
  • Registered: 2011-04-01
  • Posts: 1,705

Re: DSL 100 - mains transformer hum

sounds to me that you should have the filter capacitors looked at.
they may not be filtering the a/c properly (maybe dried out)
Was this amp stored without power for a long time?

---------------

(If only I had 1% of Joe's guitar talent)
  • Registered: 2012-05-19
  • Posts: 22

Re: DSL 100 - mains transformer hum

don't know full history, think I need to go in and investigate if any of the filter caps are swollen.
Just really wanted to have a baseline to know if this hum is normal.  There is vibration on the
cabinet it is housed in...
thanks

4 Reply by RickB (edited by RickB 2012-07-16 16:25:35)

  • RickB
  • RickB
  • BONAMEGAMETAL
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  • From: San Diego
  • Registered: 2009-10-30
  • Posts: 12,198

Re: DSL 100 - mains transformer hum

Bad caps don't neccisarily swell. It could be a leaky power supply filter cap, which can soon go off like a grenade if it shorts through! (I've seen this happen) Is the hum really bad as soon as it is switched on and is the chassis vibration associated with the hum? Best have it looked at by a tech asap because it could be something overloading the power transformer and that could be quite a problem.
Rick

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  • Registered: 2012-05-19
  • Posts: 22

Re: DSL 100 - mains transformer hum

Thanks for the replys, 

Before I go buying a new power transformer I would still be interested to know if the stock amp has very little hum when the power switch is on but standby is off?