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Boss power supplies


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11/8/1999 11:49 PM
M Cook
 Boss power supplies
Every time I use non Boss power supplies with my Boss pedals I get really bad hum. Is there something special in the Boss power supplies that needs to be added to get rid of the hum?  
 
  
11/9/1999 7:54 AM
A.S
I think they are very sensitive to what kind of supply you use. I had the same problem with my OD-1 and my DS-1.  
As it turned out, my 9V supply gave 14.5V.  
I solved this by putting a 7809 voltage regulator in to all my boxes and that did the trick. I really got rid of the hum.  
This makes me believe that Boss pedals need very stable voltage so maybe you should try it.  
 
A.S  
  
11/9/1999 8:45 PM
M Cook
I am using a 7809. I have 3-1000uF and 1-470uF caps in the power supply. They cut out the noise when I use 2 or less pedals. When I power all pedals I get a cycling hum. The 7809 also vibrates when all of the pedals are powered up. The transformer and the 7809 both are good to 1A. Should I add more filter caps?
  
11/9/1999 9:32 PM
A.S
I canīt imagine that would help.  
Do you have 7809 wired correctly?  
I donīt know if Iīm right but I think the 7809 should have a .33uF cap before and a .1uF after.  
Do you have the regulator in your supply?  
I have a 78L09 in each pedal.  
Cracy??? I donīt know but it did the trick for me.  
Good luck  
 
A.S
  
11/9/1999 10:06 PM
Doc
That's a pretty good idea, putting individual on-board regulators inside each pedal. You can pretty much forget about voltage & ripple problems from wall warts with this setup. The 78L09 package is like a typical TO-72 epoxy transistor package?
  
11/10/1999 7:51 AM
A.S
The 78L09 is i a TO-92 and itīs good for 100mA.  
I had one problem when I installed them into my pedals and that was to find the space. I didnīt use any kind of board to put the components on. I just made a birdīs nest of everything connecting one point of it to the adapter input and the other end of it to the V+ cord and voíla, no hum.  
 
A.S
  

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