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Capacitor "House"


 
7/13/2000 6:07 PM
danhei
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Capacitor "House"
I'm building a copy of an ampeg sb-12. I've seen on alot of people's projects they have this little "house" or something in which the capacitors sit. Usually this is on top of the chassis (where the tubes and trannies are also located). What is the point of this little house? Do I need to get one for my amp?  
Dan
 
7/13/2000 7:52 PM
Don Symes
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Its purpose is to prevent fingers contacting high voltages. On Fender designs they're referred to as 'cap pans'. Most of our favorite vendors have a few sizes on hand.
 
7/13/2000 7:52 PM
Jim S.
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A lot of Fender amps place the filter caps inside a separate compartment or "house", as you describe it. It is not necessary to do it this way. I think the main reason for this design is to protect the rest of the circuitry if one or more of the filter caps either leaks or explodes (which is a rare occurrence unless the caps are very old or the amp is misused). This way, the caps' innards won't wind up all over the place.
 
7/13/2000 10:17 PM
danhei
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Thanks for the tips.  
I think I'm not going to use the pan as it doesn't seem 100% necessary and I don't feel like making an order just for that!  
Dan
 
7/13/2000 10:18 PM
Casey4s
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Dan,  
Those are sometimes referred to as "Dog Houses" the reasons as the other two posters have mentioned are to keep you away from hi voltage and to prevent electrolyte from getting all over in case of a "melt down". A lot of amps simply put the filter caps inside the chassis and you don't have to fool with a dog house. I have made them out of Plastic Radio Shack hobby boxes or simply folded a piece of sheet aluminum to fit and pop rivited it together. But Clark Parts and Ampwares among others carry them now. Just make sure it will fit your caps before you order it from anyone.  
 
Casey4s
 
7/14/2000 11:48 PM
Stephen Conner
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There is actually quite an important safety issue here. The metal can on electrolytic caps is connected to the negative terminal. So, if you use two filter caps in series, the can of the top one will be live. In this case it has to go inside the chassis, or in a dog house, where it can't be touched.  
 
Steve C.
 
7/15/2000 1:15 AM
danhei
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Steve,  
I'm planning on putting all of the caps inside the chassis so touching shouldn't be a problem.  
Dan
 
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