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Hoffman Amps Forum image Author Topic: Building a relay switching circuit  (Read 7563 times)

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Offline JustMike

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Building a relay switching circuit
« on: May 18, 2011, 07:56:35 am »
 I want to put a simple "solo boost" ckt in my Home built JCM-800. I robbed a circuit from a Silver Jubilee for the heater rectification. It works, but I think I need to reference ground somewhere in the circuit because there is hum and when I touch the footswitch with my bare hand, the hum goes away.



I built the little daughterboard on the right side of the diagram and I'm using a Rat Shack solid state relay. Like I said, it works, but there's no reference to ground. The neg. side of the caps ties to htr B+, so that's not it.
I'm learning...

Offline Geezer

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Re: Building a relay switching circuit
« Reply #1 on: May 18, 2011, 11:46:25 am »
Is your footswitch jack isolated from ground/chassis?
If yes, then try (temp using clip leads) a 47R or 100R resistor (whatever close you have) from the "sleeve" terminal to the chassis....does that help?

G
   Cunfuze-us say: "He who say "It can't be done" should stay out of way of him who doing it!"

Offline JustMike

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Re: Building a relay switching circuit
« Reply #2 on: May 18, 2011, 07:01:45 pm »
OK, I got it working. Of course, it was a wiring problem. Now, the issue is that with no switch plugged into the jack, the LED is on. And I believe that's just the way this simple circuit is. Of course, with the LED on,the boost ckt. is activated. But I want it by default to be off.


  Wait a minute, it's a Cliff jack. So I can wire the jack to be shorted when nothing is plugged in, right? That would do it. (I think).

 (edit) No, I don't think so. OK, now I'm confused...help.
« Last Edit: May 18, 2011, 07:16:32 pm by JustMike »
I'm learning...

Offline TIMBO

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Re: Building a relay switching circuit
« Reply #3 on: May 18, 2011, 10:56:15 pm »
Thanks to Geezer this is how the Silver Jubilee relay circuit ended up, because i got caught out with the LED being on when the switch is off and relay off. This way every thing is ON when turned ON

Offline Willabe

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Re: Building a relay switching circuit
« Reply #4 on: May 19, 2011, 01:07:22 am »
OK, I got it working.

Yes, but how. What did you do/change?


          Brad           :icon_biggrin:

Offline TIMBO

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Re: Building a relay switching circuit
« Reply #5 on: May 19, 2011, 02:21:23 am »
This is the original

Offline JustMike

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Re: Building a relay switching circuit
« Reply #6 on: May 21, 2011, 11:57:43 am »
Thanks all. I got it working.
I'm learning...

 


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