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Standby switch on 5E3

5/18/2000 2:16 AM
Chris Taylor
Standby switch on 5E3
I am working up the plans for a DIY 5E3 with 4 6V6's , I am sure I will be posting more questions as the project proceeds. My first is how do I wire up a standby switch with this? I will be using a Hoffman PT for this. Thanks!!
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5/18/2000 2:55 AM

Just put a toggle switch in the B+ between where it leaves the rectifier and goes to the first 16/450 filter cap on the original Fender 5E3 schematic. Some people place it directly after the first Filter cap and before the 5k resistor. I did mine the first way, with no problem.  
Note: The schematic shows the CT from the OT going to the junction of the first cap andthe 5k, and electronicaly it is, but it is actually wired in the Fender layout so that the red CT wire goes directly to the rectifier. I wired mie so that the actual red ct wire does go to the board at the intersection of Filter cap 1,the 5K resistor, and the B+ wire from the rectifier.
5/18/2000 2:56 AM
Jim S.

Take a look at the schematic for tweed Super, Pro, or Bandmaster and see how the standby switch is wired for these amps. The switch is situated between the rectifier tube and the first filter cap/choke. There is a .05uF/600v cap that's connected between the hot side of the switch and ground.
5/18/2000 3:41 PM

Like Jim, this is how I wired my 5E3 standby. I looked at a tweed bassman schematic.  
The only complaint is the sound of the filter cap discharging (or something!) as you flip to standby after playing. It produces a rather annoying buzzzzzzz that fades out after a few seconds.  
I remedy this by just turning it off after playing, effectively skipping the stby. You only need stby when powering up (as far as I knoww....)  
5/18/2000 4:00 PM

"I remedy this by just turning it off after playing, effectively skipping the stby. You only need stby when powering up (as far as I knoww....)"
I personally believe that standby should be sued for power up and NOT power down, I like to let the filter caps drain on their own. HOWEVER, you SHOULD be able to use standby after the amp is up and runing if you have to leave it fora few minutes etc w/o any annoying noises. I use a lift of the center tap for my 5e3 mutation, and get no noises whatsoever, I also like this because i'm not hitting the 5y3 with high voltage while it's cold as well.. ond tknow what the long term effects are on a rectifier tube, but I do know I really don't want one to short out!! *laugh*
5/18/2000 12:20 PM
Lee M.

On mine, the standby switch lifts the power transformer center tap.
5/18/2000 2:40 PM
Chris Taylor

Thanks guys, stay tuned for future questions!!

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