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"death cap" in/out on bfvc??


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5/23/2000 12:45 PM
Colin B
"death cap" in/out on bfvc??
Hi all, lurker asks question.....  
 
Just finished putting a three conductor cord on my bfvc, no more shocks!! now I have a question, (probably been asked a thousand times... apologies) Should I leave the "death" cap (right term??) attached or not? I've wired it black to fuse then switch then tranny, white to cap(grounded to chassis) then tranny, grn to chassis ground. Should I leave the cap in and if so what purpose would it serve?  
 
btw how do i keep from getting a subject line showing up when i reply to messages??  
 
Thanks  
 
Colin
 
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5/23/2000 12:55 PM
Stephen Conner

The death cap doesn't serve any useful purpose any more so it can come out.  
 
Steve C.
 
5/23/2000 1:01 PM
Colin B
Thanks Steve..... (e)
e
 
5/23/2000 1:21 PM
Graywater
Re: "death cap" in/out on bfvc??
Colin,  
 
Just for "historical" purposes (possible future restoration to "museum" specs) I clip the "death cap" lead connected to the switch and leave the cap in the chassis unconnected - just seems like the "right" thing to do :>  
 
GW
 
5/23/2000 2:29 PM
Keith

Does it hurt anything or pose any danger if the cap is left in place after changing to a 3 prong power cord?
 
5/23/2000 7:01 PM
Jim S.

I think the best configuration is to have a working AC polarity switch that has three positions, with a center OFF position that disconnects the cap from either side of the AC line. Most silverface Fenders (from Princeton up) have this and a lot of new amps are still made with this feature. The idea is that you normally leave the switch in the center position but in case you are forced to plug the amp into either a miswired outlet or an old two-prong outlet via a "cheater" adapter, then you can get rid of the floating ground hum by setting the switch to one side or the other.  
 
Two-position polarity switches (as found on blackface Fenders) are less than ideal, since the cap (assuming it's still wired in) is always either connected to neutral or hot, even when the chassis is properly grounded. If it's set to the hot position, there could be some current leakage to ground, especially if the cap is going bad. This is usually not dangerous, as long as the connection from chassis to outlet ground is better than the connection from guitar player's skin to ground. Occasionally, a leaky cap will cause a GFI outlet to trip if the polarity switch is set to the hot side. This could present a mystery to a musician who doesn't know much about electrical wiring.  
 
Whether the polarity switch is two or three postion, I generally leave the polarity cap in (or replace it if I suspect it might be going bad.) However, on my 1969 Princeton Reverb that I'm rewiring, I plan to remove the polarity switch and cap and install a standby switch in that hole instead, since standby seems like the more useful feature to have.
 
5/23/2000 7:29 PM
Gil Ayan

quote:
"Two-position polarity switches (as found on blackface Fenders) are less than ideal, since the cap (assuming it's still wired in) is always either connected to neutral or hot, even when the chassis is properly grounded."
 
 
True. What I have done in my little DR is: one position is OFF and the other ties the ground to the neutral lead. So the cap really does nothing at all per se, but it's still sitting there. :)  
 
Gil
 

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